
                              Gerald L. HURST's
            Chemistry and Explosives - UseNet  Articles Collection            
                            File 1 of 2: CHEMISTRY


  All of his articles to rec.pyrotechnics and alt.engr.explosives since 1995
 This file is available at: http://www.geocities.com/CollegePark/Library/4196
                  and at: http://members.xoom.com/explosive

******************************************************************************

Gerald L. Hurst, AKA Jerry (Ico), is a Cambridge Ph.D. chemist with experience
in  explosives  and  fire-related matters,  having been Chief Scientist of the 
Atlas Powder Company, the then largest explosives manufacturer in the U.S.: he
developed the trade secret formulas for Liquid Paper (Gillette),  patented the 
so-called  "Mylar"  balloons  (the metallized helium balloons  found in super-
markets),  Astrolite A-1-5  (coinventor)  and  the best-known  Kinepak  binary 
explosive.  He has  an extensive  forensic  experience in  arson/murder  cases
dating back 30 years:  much of his present work involves the analysis of fires
and explosions to determine the cause and origin.

All of his  amazing  posts since  early 1995 have been collected in two single 
files to spare the reader a lot of on-line time, since the original Deja News'
files exceed 10 MB.  Each  article  is  a  trustworthy source  of  the  finest 
informations  on its own subject  freely  available  on the Internet:  Jerry's 
brilliant,  accurate and  helpful style  really  stretches one's thinking on a
wide variety of  matters,  most notably chemistry and explosives,  making both
the budding and the skilled chemist learn and smile at the same time. 

******************************************************************************

   1. 1995/03/29 DOC0001  Re: Activities vs. Concentrations: Opinions Sough
   2. 1995/03/29 DOC0002  Re: Ohmic Heating
   3. 1995/03/29 DOC0003  Re: Ohmic Heating
   4. 1995/03/29 DOC0004  Re: Oxygen solubility Deuterium oxide?
   5. 1995/04/01 DOC0005  Re: glass reaction
   6. 1995/04/07 DOC0006  Re: Nitro Cellulose
   7. 1995/04/08 DOC0007  Re: N2O
   8. 1995/04/08 DOC0008  Re: fingerprints:how?...
   9. 1995/04/09 DOC0009  Re: help getting co2 from air
  10. 1995/04/11 DOC0010  Re: Common Ion Effect qesution
  11. 1995/04/11 DOC0011  Re: Question on dessicant
  12. 1995/04/11 DOC0012  Re: Quick question on water
  13. 1995/04/11 DOC0013  Re: Quick question on water
  14. 1995/04/11 DOC0014  Re: Renaming SCI.CHEM;   or   "Are chemists 
  15. 1995/04/11 DOC0015  Re: Searchable Online Journal Databases?
  16. 1995/04/11 DOC0016  Re: Solubility Of Gases
  17. 1995/04/11 DOC0017  Re: cyanide reagent
  18. 1995/04/14 DOC0018  Re: Sarin
  19. 1995/04/15 DOC0019  Re: Picrates
  20. 1995/04/15 DOC0020  Re: Toothpaste & OJ
  21. 1995/04/15 DOC0021  Re: help: What is definition of Binding Energy?
  22. 1995/04/16 DOC0022  Re: CAN ANYONE IDENTIFY THIS CHEMICAL: C_3 H_8 (N
  23. 1995/04/16 DOC0023  Re: CHEMICAL ENGINEERING
  24. 1995/04/16 DOC0024  Re: Question on dessicant
  25. 1995/04/16 DOC0025  Re: Question on dessicant
  26. 1995/04/18 DOC0026  Re: Vinegar and Acetic Acid
  27. 1995/04/18 DOC0027  Re: help with g92 calculations.
  28. 1995/04/18 DOC0028  Re: nalgene tubing rupture
  29. 1995/04/20 DOC0029  Re: Mercurous Perchlorate
  30. 1995/04/25 DOC0030  Re: Cyanogenbromide (BrCN)
  31. 1995/04/26 DOC0031  Re: oxidation-reduction reactions
  32. 1995/05/08 DOC0032  Re: 1Ammoniun Nitrate
  33. 1995/05/08 DOC0033  Re: 1Ammoniun Nitrate
  34. 1995/05/08 DOC0034  Re: Geometry Q in sci.chem?
  35. 1995/05/08 DOC0035  Re: h202 as oxidising agent
  36. 1995/05/09 DOC0036  Re: 1Ammoniun Nitrate
  37. 1995/05/09 DOC0037  Re: Please help: Brownian Motion
  38. 1995/05/09 DOC0038  Re: diesel fuel/kerosene
  39. 1995/05/09 DOC0039  Re: keeping CO2 liquid ?
  40. 1995/05/17 DOC0040  Re: A: How to glue polyethylene or polypropylene
  41. 1995/05/17 DOC0041  Re: ANSWER TO NOT SO HARD CHEMISTRY A-LEVEL QUEST
  42. 1995/05/17 DOC0042  Re: ANSWER TO NOT SO HARD CHEMISTRY A-LEVEL QUEST
  43. 1995/05/17 DOC0043  Re: ANSWER TO NOT SO HARD CHEMISTRY A-LEVEL QUEST
  44. 1995/05/17 DOC0044  Re: ANSWER TO NOT SO HARD CHEMISTRY A-LEVEL QUEST
  45. 1995/05/17 DOC0045  Re: MISSING USGS RECORDS OF 04/19/95
  46. 1995/05/17 DOC0046  Re: Rust? stains on concrete
  47. 1995/05/17 DOC0047  Re: Tagging ammonium nitrate (or something like t
  48. 1995/05/17 DOC0048  Re: sodium azide
  49. 1995/05/18 DOC0049  Re: Lawsuit against fertilizer mfr (Okl city bomb
  50. 1995/05/18 DOC0050  Re: me on TV in Boston WCVB
  51. 1995/05/19 DOC0051  Re: Gallium Oxide
  52. 1995/05/19 DOC0052  Re: Lawsuit against fertilizer mfr (Okl city bomb
  53. 1995/05/19 DOC0053  Re: Lawsuit against fertilizer mfr (Okl city bomb
  54. 1995/05/20 DOC0054  Re: Speed of combustion of gasoline
  55. 1995/05/20 DOC0055  Re: Speed of combustion of gasoline
  56. 1995/05/21 DOC0056  Re: ANSWER TO NOT SO HARD CHEMISTRY A-LEVEL QUEST
  57. 1995/05/21 DOC0057  Re: Glass
  58. 1995/05/21 DOC0058  Re: Use of Perchloric acid in non-perchloric acid
  59. 1995/05/21 DOC0059  Re: salt & ice.  Cool beer question
  60. 1995/05/22 DOC0060  Re: Results - Was "Sugar and Diet Coke"
  61. 1995/05/23 DOC0061  Re: salt & ice.  Cool beer question
  62. 1995/05/24 DOC0062  Re: salt & ice.  Cool beer question
  63. 1995/05/24 DOC0063  Re: salt & ice. Cool beer question
  64. 1995/05/25 DOC0064  Re: Flash Point (Was: toxicity)
  65. 1995/05/25 DOC0065  Re: salt & ice.  Cool beer question
  66. 1995/05/25 DOC0066  Re: salt & ice. Cool beer question
  67. 1995/05/26 DOC0067  Re: salt & ice.  Cool beer question
  68. 1995/05/30 DOC0068  Re: Cleaning Silver in the Home?
  69. 1995/05/30 DOC0069  Re: crystals
  70. 1995/06/05 DOC0070  Re: Flash Point (Was: toxicity)
  71. 1995/06/19 DOC0071  Re: Fluorine gas
  72. 1995/06/19 DOC0072  Re: Your view:fundamental question in ENTROPY
  73. 1995/06/20 DOC0073  Re: Exlosives 2nd try
  74. 1995/06/20 DOC0074  Re: Your view:fundamental question in ENTROPY
  75. 1995/06/26 DOC0075  Gas expansion and plate velocities
  76. 1995/06/26 DOC0076  Re: Gas expansion and plate velocities
  77. 1995/06/26 DOC0077  Re: H2S instead of H2O
  78. 1995/07/03 DOC0078  Re: What are HCI and NaOH????
  79. 1995/07/09 DOC0079  Re: help!  where can i buy iron sulfide?!  (or ma
  80. 1995/07/26 DOC0080  Re: Need info on cryogenics
  81. 1995/08/03 DOC0081  Re: Need help finding C-N compounds
  82. 1995/08/06 DOC0082  Re: Twink - What's in it?
  83. 1995/08/07 DOC0083  Re: Ammonia gas removal from air.
  84. 1995/08/07 DOC0084  Re: Ceramic-filled Paint
  85. 1995/08/07 DOC0085  Re: The quick & easy "lava lamp"
  86. 1995/08/07 DOC0086  Re: Twink - What's in it?
  87. 1995/08/08 DOC0087  Re: Potassium Permanganate - What is it?
  88. 1995/08/08 DOC0088  Re: RECIPE FOR NITROGEN TRI IODIDE WANTED
  89. 1995/08/08 DOC0089  Re: Titration of Nitric Acid with Sodium Hydroxid
  90. 1995/08/08 DOC0090  Re: Twink - What's in it?
  91. 1995/08/08 DOC0091  Re: imperial units to si units conversion
  92. 1995/08/08 DOC0092  Re: sucrose density
  93. 1995/08/16 DOC0093  Re: Twink - What's in it?
  94. 1995/08/16 DOC0094  Re: sucrose density
  95. 1995/08/18 DOC0095  Re: sucrose density
  96. 1995/08/27 DOC0096  Re: colloidal potassium
  97. 1995/08/27 DOC0097  Re: sucrose density
  98. 1995/08/27 DOC0098  Re: sucrose density
  99. 1995/08/28 DOC0099  Re: ethanol(spell check!!!)
 100. 1995/08/29 DOC0100  Re: A specific general chem question
 101. 1995/08/29 DOC0101  Re: A specific general chem question
 102. 1995/08/29 DOC0102  Re: Why thinking hurts - was Re: sucrose density
 103. 1995/08/29 DOC0103  Re: colloidal potassium
 104. 1995/08/30 DOC0104  Re: PH Question
 105. 1995/08/30 DOC0105  Re: PH Question
 106. 1995/08/30 DOC0106  Re: PH Question
 107. 1995/08/31 DOC0107  Re: PH Question
 108. 1995/09/01 DOC0108  Re: chemistry
 109. 1995/09/01 DOC0109  Re: dumb question : water or ice - which denser?
 110. 1995/09/01 DOC0110  Re: dumb question : water or ice - which denser?
 111. 1995/09/02 DOC0111  Re: dumb question : water or ice - which denser?
 112. 1995/09/02 DOC0112  Re: sucrose density
 113. 1995/09/03 DOC0113  Re: FREON 12 Substitutes - Whadda ya know?
 114. 1995/09/04 DOC0114  Re: Help needed: Why is hydrogen floride toxic ?
 115. 1995/09/06 DOC0115  Re: temp decrease in soda cans
 116. 1995/09/12 DOC0116  Re: question re: freezing point depression
 117. 1995/09/13 DOC0117  Re: [Q] cold trap
 118. 1995/09/15 DOC0118  Re: Aluminum plate to clean tarnish off silver wo
 119. 1995/09/15 DOC0119  Re: Beginner's question
 120. 1995/09/17 DOC0120  Re: Beginner's question
 121. 1995/09/24 DOC0121  Re: MIT engineers; how they spend their time and 
 122. 1995/09/24 DOC0122  Re: nitrite to nitric oxide
 123. 1995/09/25 DOC0123  Re: Archimedes (was Re: Horst teaches . . .)
 124. 1995/09/25 DOC0124  Re: WHO is MIT engineer Decobert's boss there at 
 125. 1995/09/28 DOC0125  Re: Minimum Coulomb Interactions for plutonium
 126. 1995/09/28 DOC0126  Re: Minimum Coulomb Interactions for plutonium
 127. 1995/09/30 DOC0127  Re: ALUMINUM BOMB
 128. 1995/09/30 DOC0128  Re: question!!!!!
 129. 1995/10/03 DOC0129  Re: Impact of chemistry on philosophy?
 130. 1995/10/03 DOC0130  Re: what is flash point?
 131. 1995/10/07 DOC0131  Re: what is flash point?
 132. 1995/10/08 DOC0132  Re: definition of isodesmic???
 133. 1995/10/08 DOC0133  Re: what is flash point?
 134. 1995/10/10 DOC0134  Re: what is flash point?
 135. 1995/10/10 DOC0135  Re: what is flash point?
 136. 1995/10/12 DOC0136  Re: what is flash point?
 137. 1995/10/13 DOC0137  Re: Nitrogen Triiodide
 138. 1995/10/16 DOC0138  Re: H2O Bridges
 139. 1995/10/25 DOC0139  Re: Hints on building a freeze dryer
 140. 1995/10/25 DOC0140  Re: Where did the MOLE come from?
 141. 1995/10/26 DOC0141  Re: Weighing metals (Jason)
 142. 1995/10/28 DOC0142  Re: Chemistry Problem..(Please help!)
 143. 1995/10/29 DOC0143  Re: Hot Water
 144. 1995/10/29 DOC0144  Re: Hot Water
 145. 1995/10/29 DOC0145  Re: QUESTION: (bio)chemistry of popcorn
 146. 1995/10/29 DOC0146  Re: Where did the MOLE come from?
 147. 1995/10/29 DOC0147  Re: thermochemistry question
 148. 1995/10/30 DOC0148  Re: thermochemistry question
 149. 1995/10/30 DOC0149  Re:solubility of gasses in liquids:QUESTION
 150. 1995/11/03 DOC0150  Re: *so* sorry and glad
 151. 1995/11/03 DOC0151  Re: Copper + Silver nitrate-----> *Please Help
 152. 1995/11/04 DOC0152  Re: Additive to make paint glow
 153. 1995/11/04 DOC0153  Re: exothermic reactions
 154. 1995/11/05 DOC0154  Re: Endothermic Reaction
 155. 1995/11/06 DOC0155  Re: thermochemistry question
 156. 1995/11/07 DOC0156  Re: Dancing mothballs?
 157. 1995/11/09 DOC0157  Re: sodium hypochlorite (bleach) and organic impu
 158. 1995/11/13 DOC0158  Re: Caloric Value
 159. 1995/11/13 DOC0159  Re: Coulombic forces
 160. 1995/11/13 DOC0160  Re: delta H question
 161. 1995/11/13 DOC0161  Re: delta H question
 162. 1995/11/14 DOC0162  Re: odor of acetamide?
 163. 1995/11/16 DOC0163  Re: Quiz question - please help
 164. 1995/11/16 DOC0164  Re: Quiz question - please help
 165. 1995/11/20 DOC0165  Re: Liquid Paper Solvent
 166. 1995/11/20 DOC0166  Re: Question...
 167. 1995/11/21 DOC0167  Re: U-In8: First Commercial Cold Fusion Cell?
 168. 1995/11/22 DOC0168  Re: Swallow Me
 169. 1995/11/24 DOC0169  Re: Swallow Me
 170. 1995/11/24 DOC0170  Re: Swallow Me
 171. 1995/11/29 DOC0171  Re: Air Fuel Mixture Ionization
 172. 1995/12/02 DOC0172  Re: Bubbling in soda.
 173. 1995/12/05 DOC0173  Re: Bubbling in soda.
 174. 1995/12/17 DOC0174  Re: Chemie und deutsch
 175. 1995/12/19 DOC0175  Re: SEMTEX - what is it?
 176. 1995/12/20 DOC0176  Re: Freezing hot water
 177. 1995/12/20 DOC0177  Re: Freezing hot water
 178. 1995/12/21 DOC0178  Re: SEMTEX - what is it?
 179. 1995/12/21 DOC0179  Re: SEMTEX - what is it?
 180. 1995/12/21 DOC0180  Re: SEMTEX - what is it?
 181. 1995/12/21 DOC0181  Re: SEMTEX - what is it?
 182. 1995/12/21 DOC0182  Re: calcium carbonate in iron pipes question
 183. 1995/12/23 DOC0183  Re: Thermal decomp of Ammon Phosphate ?
 184. 1995/12/27 DOC0184  Re: Elevation of boiling point?
 185. 1995/12/28 DOC0185  Re: Elevation of boiling point?
 186. 1995/12/29 DOC0186  Re: PRAYER, Tue 26 Dec 1995 Overdose sermon
 187. 1995/12/29 DOC0187  Re: blue sky & ozone
 188. 1995/12/30 DOC0188  Re: Decomposition of Ammonium Nitrate
 189. 1995/12/31 DOC0189  Re: blue sky & ozone
 190. 1995/12/31 DOC0190  Re: blue sky & ozone
 191. 1996/01/01 DOC0191  Re: blue sky & ozone
 192. 1996/01/04 DOC0192  Re: Nitroglycerine (medicine), storage & hand
 193. 1996/01/04 DOC0193  Re: PRAYER, Sun 31 Dec 1995 Carbon in us, Carbon 
 194. 1996/01/04 DOC0194  Re: Vapour Pressure - Mixtures
 195. 1996/01/06 DOC0195  Re: 'Lavalamp'- which fluids are used ?
 196. 1996/01/06 DOC0196  Re: New definition or concept: Half-life of One s
 197. 1996/01/06 DOC0197  Re: New definition or concept: Half-life of One s
 198. 1996/01/07 DOC0198  Re: Fresh water from sea water - new economical p
 199. 1996/01/07 DOC0199  Re: Magnesium
 200. 1996/01/08 DOC0200  Re: Fresh water from sea water - new economical p
 201. 1996/01/08 DOC0201  Re: Fresh water from sea water - new economical p
 202. 1996/01/08 DOC0202  Re: Ozone layer/Dobson Units
 203. 1996/01/09 DOC0203  Re: Fresh water from sea water - new economical p
 204. 1996/01/09 DOC0204  Re: Red Mercury
 205. 1996/01/10 DOC0205  Re: Fresh water from sea water - new economical p
 206. 1996/01/10 DOC0206  Re: Fresh water from sea water - new economical p
 207. 1996/01/11 DOC0207  Re: Fresh water from sea
 208. 1996/01/11 DOC0208  Re: Fresh water from sea
 209. 1996/01/11 DOC0209  Re: Fresh water from sea water - new economical p
 210. 1996/01/11 DOC0210  Re: Fresh water from sea water - new economical p
 211. 1996/01/11 DOC0211  Re: What is the difference between KEROSINE oil a
 212. 1996/01/13 DOC0212  Re: 12 Yr Old Son Science Exp. - Need Help!
 213. 1996/01/13 DOC0213  Re: Endothermic Reactions
 214. 1996/01/13 DOC0214  Re: Fresh water from sea water - new economical p
 215. 1996/01/13 DOC0215  Re: What is the difference between KEROSINE oil a
 216. 1996/01/13 DOC0216  Re: oklahoma explosive
 217. 1996/01/14 DOC0217  Re: normality
 218. 1996/01/14 DOC0218  Re: normality
 219. 1996/01/15 DOC0219  Re: Oxygen & hydrogen combine??? What exactly
 220. 1996/01/15 DOC0220  Re: Water injection into
 221. 1996/01/15 DOC0221  Re: oklahoma explosive
 222. 1996/01/15 DOC0222  Re: resistance of solution
 223. 1996/01/16 DOC0223  Re: ammonia powder
 224. 1996/01/17 DOC0224  Re: 35% of h2o2 means how many volumes ?????
 225. 1996/01/17 DOC0225  Re: Cyanide ingestion
 226. 1996/01/18 DOC0226  Re: Picric acid safety
 227. 1996/01/19 DOC0227  Re: Amonnium Nitrate (& other people's proble
 228. 1996/01/19 DOC0228  Re: Amonnium Nitrate (& other people's proble
 229. 1996/01/20 DOC0229  Re: CaHCl
 230. 1996/01/22 DOC0230  Re: Fresh water from sea water - new economical p
 231. 1996/01/22 DOC0231  Re: low temp flames?
 232. 1996/01/23 DOC0232  Re: Solubility of NO2 in water
 233. 1996/01/24 DOC0233  Re: Blending Talcolm Powder
 234. 1996/01/24 DOC0234  Re: Blending Talcolm Powder
 235. 1996/01/24 DOC0235  Re: Fresh water from sea water - new economical p
 236. 1996/01/24 DOC0236  Re: Melting rate of ice cubes
 237. 1996/01/24 DOC0237  Re: Melting rate of ice cubes
 238. 1996/01/26 DOC0238  Re: Archival Plastics
 239. 1996/01/26 DOC0239  Re: Endothermic Reactions
 240. 1996/01/26 DOC0240  Re: HELP!!!  superfluidity/liquid helium
 241. 1996/01/26 DOC0241  Re: HELP!!!  superfluidity/liquid helium
 242. 1996/01/26 DOC0242  Re: Molar masses does't work.
 243. 1996/01/26 DOC0243  Re: Vapor Pressure Determination
 244. 1996/01/27 DOC0244  Re: Why is this pH 13+?
 245. 1996/01/28 DOC0245  Re: Who to complain to about Plutonium.
 246. 1996/01/28 DOC0246  Re: Who to complain to about Plutonium.
 247. 1996/01/29 DOC0247  Re: Pressure of liquid N2 at room temprature.
 248. 1996/01/29 DOC0248  Re: What is the freezing point of water???
 249. 1996/01/29 DOC0249  Re: Why is this pH 13+?
 250. 1996/02/17 DOC0250  Re: Volcano
 251. 1996/02/18 DOC0251  Re: Analog of Capillary condensation
 252. 1996/02/18 DOC0252  Re: HELP PLEASE!!!
 253. 1996/02/18 DOC0253  Re: Science Fair Cold Pack Salts
 254. 1996/02/19 DOC0254  Re: CO2 in coke
 255. 1996/02/19 DOC0255  Re: Science Fair Cold Pack Salts
 256. 1996/02/21 DOC0256  Re: Explosives -- academic research and career ch
 257. 1996/02/22 DOC0257  Re: [Q] Best way to keep fizz in drinks
 258. 1996/02/23 DOC0258  Re: Does Heat Speed Up or Slow Down a Chem
 259. 1996/02/23 DOC0259  Re: Minority Postdoctoral Fellowship Opportunity
 260. 1996/02/23 DOC0260  Re: Minority Postdoctoral Fellowship Opportunity
 261. 1996/02/24 DOC0261  Re: Copper/Cupric Oxide Question
 262. 1996/02/24 DOC0262  Re: Copper/Cupric Oxide Question
 263. 1996/02/24 DOC0263  Re: Does Heat Speed Up or Slow Down a Chem
 264. 1996/02/24 DOC0264  Re: [Q] Boiling water at low pressure
 265. 1996/02/24 DOC0265  Re: [Q] Boiling water at low pressure
 266. 1996/02/24 DOC0266  Re: [Q] Boiling water at low pressure
 267. 1996/02/25 DOC0267  Re: Does Heat Speed Up or Slow Down a Chem
 268. 1996/02/25 DOC0268  Re: [Q] Boiling water at low pressure
 269. 1996/02/26 DOC0269  Re: Does Heat Speed Up or Slow Down a Chem
 270. 1996/02/26 DOC0270  Re: Does Heat Speed Up or Slow Down a Chem
 271. 1996/02/27 DOC0271  Re: Does Heat Speed Up or Slow Down a Chem
 272. 1996/02/28 DOC0272  Re: Does Heat Speed Up or Slow Down a Chem
 273. 1996/02/28 DOC0273  Re: How to melt magnesium ?
 274. 1996/02/29 DOC0274  Re: What is the temprature at which paper burns?
 275. 1996/02/29 DOC0275  Re: liquid heavier than water?
 276. 1996/03/01 DOC0276  Re: non exothermic
 277. 1996/03/02 DOC0277  Re: How to melt magnesium ?
 278. 1996/03/02 DOC0278  Re: [Q] Boiling water at low pressure
 279. 1996/03/03 DOC0279  Re: What is Baume?
 280. 1996/03/07 DOC0280  Re: [Q] Energy of atoms in molecules
 281. 1996/03/09 DOC0281  Re: How did he die?
 282. 1996/03/09 DOC0282  Re: Mineral Spirits of Kerosene
 283. 1996/03/11 DOC0283  Re: supersaturation problems -- help us!!
 284. 1996/03/13 DOC0284  Re: Help with solubilities / mixed salts
 285. 1996/03/13 DOC0285  Re: Help with solubilities / mixed salts
 286. 1996/03/13 DOC0286  Re: [Q] Energy of atoms in molecules
 287. 1996/03/14 DOC0287  Re: Dehumidifier efficiency
 288. 1996/03/14 DOC0288  Re: Dehumidifier efficiency
 289. 1996/03/14 DOC0289  Re: Help with solubilities / mixed salts
 290. 1996/03/14 DOC0290  Re: Is CaCl2 a good humidity absorber to protect 
 291. 1996/03/14 DOC0291  Re: Making pure ammonium nitrate from fertilizer
 292. 1996/03/14 DOC0292  Re: Mineral Spirits of Kerosene
 293. 1996/03/14 DOC0293  Re: Nitrogen Dioxide Question
 294. 1996/03/14 DOC0294  Re: Solvent: Mineral spirit ?
 295. 1996/03/14 DOC0295  Re: [Q] Energy of atoms in molecules
 296. 1996/03/14 DOC0296  Re: [Q] Energy of atoms in molecules
 297. 1996/03/15 DOC0297  Re: Dehumidifier efficiency
 298. 1996/03/15 DOC0298  Re: Is CaCl2 a good humidity absorber to protect 
 299. 1996/03/15 DOC0299  Re: [Q] Energy of atoms in molecules
 300. 1996/03/15 DOC0300  Re: [Q] Energy of atoms in molecules
 301. 1996/03/15 DOC0301  Re: liquid/solid thermometer..is it possible??
 302. 1996/03/16 DOC0302  Re: Phase Changes: water
 303. 1996/03/16 DOC0303  Re: [Q] Energy of atoms in molecules
 304. 1996/03/17 DOC0304  Re: Immobilization of carbon dioxide
 305. 1996/03/17 DOC0305  Re: [Q] Energy of atoms in molecules
 306. 1996/03/17 DOC0306  Re: [Q] Energy of atoms in molecules
 307. 1996/03/17 DOC0307  Re: [Q] Energy of atoms in molecules
 308. 1996/03/18 DOC0308  Re: Immobilization of carbon dioxide
 309. 1996/03/19 DOC0309  Re: Immobilization of carbon dioxide
 310. 1996/03/19 DOC0310  Re: Phase Changes: water
 311. 1996/03/19 DOC0311  Re: Phase Changes: water
 312. 1996/03/19 DOC0312  Re: [Q] Energy of atoms in molecules
 313. 1996/03/19 DOC0313  Re: [Q] Energy of atoms in molecules
 314. 1996/03/19 DOC0314  Re: [Q] Energy of atoms in molecules
 315. 1996/03/19 DOC0315  Re: [Q] Energy of atoms in molecules
 316. 1996/03/20 DOC0316  Re: A question about carbondioxide
 317. 1996/03/20 DOC0317  Re: Blowing Bubbles
 318. 1996/03/20 DOC0318  Re: Immobilization of carbon dioxide
 319. 1996/03/20 DOC0319  Re: Immobilization of carbon dioxide
 320. 1996/03/20 DOC0320  Re: Phase Changes: water
 321. 1996/03/20 DOC0321  Re: [Q] Energy of atoms in molecules
 322. 1996/03/20 DOC0322  Re: patron saint
 323. 1996/03/21 DOC0323  Re: Immobilization of carbon dioxide
 324. 1996/03/21 DOC0324  Re: Immobilization of carbon dioxide
 325. 1996/03/22 DOC0325  Re: CO2 Reaction Question
 326. 1996/03/24 DOC0326  Re: CO2 Reaction Question
 327. 1996/03/26 DOC0327  Re: CO2 Reaction Question
 328. 1996/03/26 DOC0328  Re: CopperChloride
 329. 1996/03/26 DOC0329  Re: Know your limits ! (reply)
 330. 1996/03/28 DOC0330  Re: looking for info...
 331. 1996/04/01 DOC0331  Re: Immobilization of carbon dioxide
 332. 1996/04/04 DOC0332  Re: Help with salt water density
 333. 1996/04/06 DOC0333  Re: What food holds the most heat? Potato?
 334. 1996/04/07 DOC0334  Re: high temp reactions
 335. 1996/04/08 DOC0335  Re: Help with salt water density
 336. 1996/04/08 DOC0336  Re: Semi skimmed milk
 337. 1996/04/10 DOC0337  Re: throwing boiling water into freezing air
 338. 1996/04/12 DOC0338  Singed Hair
 339. 1996/04/21 DOC0339  SONIA DIDN'T DO IT.
 340. 1996/04/26 DOC0340  Re: SONIA DIDN'T DO IT.
 341. 1996/04/26 DOC0341  Re: SONIA DIDN'T DO IT.
 342. 1996/04/26 DOC0342  Re: SONIA DIDN'T DO IT.
 343. 1996/04/29 DOC0343  Re: SONIA DIDN'T DO IT.
 344. 1996/04/29 DOC0344  Re: SONIA DIDN'T DO IT.
 345. 1996/04/30 DOC0345  Re: SONIA DIDN'T DO IT.
 346. 1996/05/02 DOC0346  Re: SONIA DIDN'T DO IT.
 347. 1996/05/10 DOC0347  Re: Unka Al groupies
 348. 1996/05/21 DOC0348  Re: Dangerous/Illegal Demonstrations
 349. 1996/05/22 DOC0349  Re: Dangerous/Illegal Demonstrations
 350. 1996/05/22 DOC0350  Re: Lifting capacity of helium
 351. 1996/06/09 DOC0351  SONIA DIDN'T DO IT
 352. 1996/11/03 DOC0352  Coal tar solvent naphtha compositions
 353. 1997/02/14 DOC0353  Re: Lye/Aluminum reactor?











DOC0001

Subject:      Re: Activities vs. Concentrations: Opinions Sought!
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/03/29
Message-ID:   <3lcg9o$75p@Sierra.onr.com>
Newsgroups:   sci.chem



, I was told (and have read) that the simpler molar-concentration
>: approach is (or can be) considerably less accurate in predicting the
>: equilibrium composition of aqueous solutions, as opposed to using
>: activity coefficients
>
>It was my understanding that it doesn't really matter if you use
>activity coefficients if you are looking for equilibrium constant data
>because the Keq's are all measured from experiment anyway
>Jeffrey N. Woodford

The problem is that Keq is measured at some concentration, usually dilute,
and is not accurate at higher (read "other") levels unless you know how
the activities vary with concentration. How much error to expect also
depends on concentration and can be very large, else we'd find pH's of -1
in concentrated acids or > 14 in bases.
Jerry
<

















DOC0002

Subject:      Re: Ohmic Heating
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/03/29
Message-ID:   &lt;3lchef$75p@Sierra.onr.com&gt;
Newsgroups:   sci.chem



 and there's also electrolysis to worry about -- you don't
&gt;want the rice cooker to blow up from a hydrogen-oxygen reaction!

Alternating current should take  care of this problem, The products would
recombine at the electrodes. An induction coil can be used to limit
current if you like your rice THAT salty (actually, I guess this is done
electronically these days, but I'm an old dog).
Jerry




DOC0003

Subject:      Re: Ohmic Heating
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/03/29
Message-ID:   &lt;3lce4r$5ti@Sierra.onr.com&gt;
Newsgroups:   sci.chem


Organization: Onramp Access, Inc.
X-Newsreader: WinVN 0.91.6


&gt;
&gt;&gt;Not to mention cooking rice ;-).
&gt;
&gt;You might put some salt in the water the rice is in.  Of
&gt;course, ohmic heating might take a little more time that way ];)

When I was a kid I made a hot dog cooker from two nails, a board and a
line cord. The apparatus worked fine for dogs, but did nothing to a
raw chicken leg. You've heard that they put too much salt in prepared
food. Now if we raised the voltage....
Jerry




















DOC0004

Subject:      Re: Oxygen solubility Deuterium oxide?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/03/29
Message-ID:   <3lcbvs$5ti@Sierra.onr.com>
Newsgroups:   sci.chem



In article <schlyer.49.00099B50@um.cc.umich.edu>, schlyer@um.cc.umich.edu 
(B. Schlyer) says:
>
>Does anyone know the solubility of oxygen in deuterium oxide at room 
>temperature?  Would one expect it to be signifigantly different from the 
air 
I have no data, but I would certainly think the solubilities would be 
about the same.  If D2O had different mutual solubility coefficients with
other substances, it wouldn't be so darned difficut so separate the two
isomers.
Jerry

DOC0005

Subject:      Re: glass reaction
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/01
Message-ID:   <3liir9$n75@Sierra.onr.com>
Newsgroups:   sci.chem



>
>Does anyone know of a any chemicals that react with glass other than HF?

Alkali hydroxides such as caustic soda (sodium hydroxide, lye, NaOH) react
with glass, particularly when they are concentrated and hot.  Fused
alkalis will dissolve glass to give a material known as water glass, which
used to be widely used in such applications as storing eggs (in WG 
solution), fire-proofing wood and making so-called "crystal gardens).
Jerry



DOC0006

Subject:      Re: Nitro Cellulose
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/07
Message-ID:   <3m4c8h$dt@Sierra.onr.com>
Newsgroups:   sci.chem



>In article <3m43p3$ta@nntpserver.colpal.com>, Kevin_Flowers@ColPal.Com 
(Kevin Flowers) writes:
>> 
>> Dose anyone have instructions for producing Nitro Cellulose (Flash 
Paper

>It's much safer to purchase it from a magic or novelty store.  
Nitrocellulose is a high explosive.  If you insist, the basic method is 
that same as that used to produce nitroglycerin except you use cellulose 
instead of glycerin.

I don't advise making your own nitrocellulose and can't offer any 
instructions for obvious reasons. However, I do have experience in this 
area based on covert warfare techniques we worked on during the Viet Nam 
altercation and in the commercial manufacture of dynamite, etc. If you do 
make the stuff, the important thing is to get all the residual acid out. 
This means very very long washing with mild base - I mean several days,

Nitrocellulose is not really a high explosive, but it can still be 
frightfully dangerous, especially under confinement.  The material is
also very sensitive to ignition by the tiniest spark because of its high 
surface area.
Jerry











DOC0007

Subject:      Re: N2O
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/08
Message-ID:   <3m5eu5$6bb@Sierra.onr.com>
Newsgroups:   sci.chem



In article <efresco-0704951649500001@mfresco.seanet.com>, efresco@Bush.edu 
(E.Fresco) says:
>
So my question is, does ammonium nitrate
>decompose acording to NH4NO3-->N2O+2(H20) or according to
>NH4NO3-->NH3+HNO3 or some other equasion?
>                                             -Zack

The decomposition is complex, yielding mixture of nitrogen and nitrogen 
oxides including NO and NO2 which you most definitely do not want to 
inhale unless you're tired of breathing.
Jerry






















DOC0008

Subject:      Re: fingerprints:how?...
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/08
Message-ID:   <3m6q9b$ss4@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3m5s50$3n@sct1.sct.fr>, bazoche@world-net.sct.fr (Stephane 
Bazoche) says:
>
>Do somebody could telll me how to reveal or detect fingerprints,
>on a letter for example......???

Blow a little iodine vapor on the paper; the prints will appear as brown 
marks within a few seconds.  Some detectives carry a small glass drying 
tube with a few iodine crystals held in by glass wool plugs. In cooler 
weather it helps to warm the tube slightly.
Jerry
<
DOC0009

Subject:      Re: help getting co2 from air
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/09
Message-ID:   <3m7pua$krg@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3m1hgb$pva@newsbf02.news.aol.com>, odea56@aol.com (Odea56) 
says:
>
>Need to find a way to remove CO2 from a dry air stream.  

Could you use lime, perhaps to remove both H20 and CO2 from the air 
stream?  Sodium hydroxide pellets might be used to remove the CO2 in 
conjunction with a cartridge to remove residual traces of water.
Jerry



DOC0010

Subject:      Re: Common Ion Effect qesution
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/11
Message-ID:   <3md09t$4ap@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3mbogi$i15@wn.aksi.net>, morpheus@aksi.net (Jeremy Dobrick) 
says:
>
>I'm a bit confused about the common ion effect. If I had some lead 
>chloride in a solution and then added lead sulfate what happens assuming 
>I have an excess of lead ions? I thought at first since lead chloride is 
>more soluable it would stay in solution and the lead sulfate would 
>precipitate out. On the other hand the sulfate has a solubility constant 
>that woould seem to dictate that the lead chloride would precipitate out 
>to allow enough of the sulfate to enter solution. Basically I am 
>confused, please help.
>
>Regards- Jeremy

Look at it this way:  Lead sulfate in not very soluble and it is less 
soluble in a saturated solution of lead chloride because the latter 
produces a lot of the common ion, lead. If the lead chloride is truly at 
the saturation point, throwing solid PbSO4 into the mix will cause only a 
very tiny amount of PbCL2 to precipitate because only a tiny amount of 
additional Pb++ can be contributed by the relatively insoluble sulfate. 
The solubility constant of PbSO4 may look "big" but that is a number with 
a negative exponent, which means it is very small and therefore incapable 
of having much common ion effect on compounds which have larger solubility 
constants, such as lead chloride.  

For any chemists reading this explanation I apologize for not introducing 
ideality and for directly comparing the magnitude of the ionization 
constants without allowing for the number of ions per mole of salt.
Jerry





DOC0011

Subject:      Re: Question on dessicant
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/11
Message-ID:   <3merj8$4cm@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3mee5e$ghl@omnifest.uwm.edu>, mlehman@omnifest.uwm.edu (Mark 
W. Lehman) says:
> I am wondering if there is a diffreent substance or mixture that is
>safe and easy to access that I could use as a dessicant instead of
>the silica gel crystals I am currently using. 

Calcium chloride such as is used on the roads in some snowy areas is dirt 
cheap and is an excellent and voracious dessicant.  Plaster of paris works 
fine but has a relatively small appetite for water.  Both of these 
materials are recyclable in the oven.  If POP is too expensive in the 
drugstore, just use some gypsum from gypsum dry-wall board after heating 
in an oven at 300 deg F or so.  Magnesium sulfate (oven-dried epsom salts)
will absorb a lot of water if you don't need extreme dryness.
Jerry




















DOC0012

Subject:      Re: Quick question on water
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/11
Message-ID:   <3mevr7$4cm@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <0098EBAC.1F8E747F@netins.net>, rheldt@netins.net (Ryan Heldt - 
Legend Software) says:
>
>Hi,
>I am a high-school chemistry stundent that is doing
>a small project.
>
>How much energy (in joules or KJ) is required to
>decompose 1 liter water into H gas and O gas:
>      
>2H O ---->  2H  + O
>  2           2    2
>
It takes about 58 (57.8) kcal to dissociate a mole of gaseous water at 0 
deg C. We old timey chemists talk in calories and kilocalories. A calorie 
(thermochemical) is 4.184 Joules.
Jerry

















DOC0013

Subject:      Re: Quick question on water
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/11
Message-ID:   <3mf14r$4cm@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3mevr7$4cm@geraldo.cc.utexas.edu>, glhurst@onr.com (Gerald L. 
Hurst) says:

>>
>It takes about 58 (57.8) kcal to dissociate a mole of gaseous water at 0 
>deg C. We old timey chemists talk in calories and kilocalories. A calorie 
>(thermochemical) is 4.184 Joules.
>Jerry
>
The original question was directed to a liter of water. If this means a 
liter of liquid water you need to add the molar heat of vaporization of 
water to give a total heat of dissociation of 68.3 kcal/mole, then 
multiply this figure by the number of moles in a liter (1000/18.02) and 
finally convert to kjoules by multiplying by 4.184kjoules/kcal.

I should have said all this the first time.

Jerry
















DOC0014

Subject:      Re: Renaming SCI.CHEM;   or   "Are chemists snobs?"
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/11
Message-ID:   <3mesgm$4cm@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



>I have three daughters and I would like them to consider the net as a 
>resource, a source of information, alongside all the other sources of 
>information available.  

I can't speak for others, but I try to answer as many questions as 
possible, except for the "How do I make ..." questions related to 
explosives, poisons etc.  The scientists I have known who were experienced 
and competent usually were very good about answering questions from 
youngsters or or older laymen.  I suspect that high-nosed dismissal 
attitude is more prevelant among wannabes.

Anyway, tell your daughters to ask away and I'll answer as well as I can.
I have three boys, and one of them asked so many dumb questions that they 
finally gave him a Ph.D. in chemistry.

Jerry
<

















DOC0015

Subject:      Re: Searchable Online Journal Databases?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/11
Message-ID:   <3md64j$9c1@Sierra.onr.com>
Newsgroups:   sci.chem




>
>CAS offers an online service called STN International 

Please send me information on STN.



Thanks

























DOC0016

Subject:      Re: Solubility Of Gases
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/11
Message-ID:   <3meu0m$4cm@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3mdbab$2k7f@news-s01.ny.us.ibm.net>, darryl2@ibm.net says:
>
>Why are gases generally more soluble in cold liquids?  This seems counter
>intuitive considering solid and liquid solutes are more soluble in 
>warm solvents.
>
>Is there a mathamatical relationship relating the fugacity of a 
>particular gas in a solvent to the temperature of that solvent?

Try this qualitative viewpoint:

When a solution is heated you would expect randomness to increase with 
increased molecular motion and it does increase through dissolution.  Thus 
most solids are more soluble at higher temperatures.  The same might be 
said of gases, but here vapor pressure and related fugacity effects are 
dominant.

Picture dissolved gases a being liquids dissolved in other liquids and 
typically both the solute and the solvent liquids have a vapor pressure 
which will roughly double for every 10 degrees of increased temperature 
and thus the liquified gas will readily vaporize out.  Since fugacity is 
roughly proportional to pressure, it is obvious that the fugacity of the 
dissolved material rises much more rapidly than that of the gas-phase 
material.

Jerry


Jerry





DOC0017

Subject:      Re: cyanide reagent
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/11
Message-ID:   <3meiip$sul@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3mclau$l5k@news.umbc.edu>, jbloom@zeus.towson.edu (Joshua 
Bloomberg) says:
>
>What is the simplist QUALITATIVE test for the cyanide ion?
>This test must discriminate between cyanate and formate
>ions.
>
>                                -- jbloom@zeus.towson.edu
>
No joke. If you acidify the material, dangle a cigarett from your lips and 
breath very carefully, you'll get a strong metallic taste in your mouth.
Careful though, a good whiff of HCN can knock you unconscious before you 
hit the ground. 
Jerry




















DOC0018

Subject:      Re: Sarin
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/14
Message-ID:   <3mme9s$323@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SGI.3.91.950414013058.11882P-100000@wong>, Ian Russell 
Ollmann <iano@scripps.edu> says:
> That incidents like the one that happened in
>Japan haven't happened more often is evidence of the fact that current
>measures to prevent such occurences are, in general, working. THESE
>CONTROLS ARE NOT ON THE KNOWLEDGE SIDE OF THE PROBLEM OF PRODUCING
>DANGEROUS/ILLEGAL MATERIALS,

> For $5.00 in change you could photocopy entire articles about
>the production of Sarin. Instead of restricting knowledge, the government
>controls the supply of chemical precursors and equipment necessary to 
make
>these agents. Without the precursors, these chemicals are either
>impossible or much harder to produce. Without equipment, it cannot be 
done
>safely. Safety is a must with gaseous toxins such as Sarin, otherwise the
>chemist dies. Don't abuse the newbies.
>
>                                Ian Ollmann
>
Thank you very much for posting the composition of that very effective
nerve toxin.  Would you be kind enough to post a convenient method of 
synthesizing the material, preferably one which requires a minimum of 
sophisticated lab equipment.  Maybe it's time we all dropped our stuffy 
attitudes toward poisons and destructive devices.  I happen to be an 
expert on covert warfare, and am very knowledge in the area of home-made 
bombs, incendiaries, firearms, grenade launchers, etc. I have always
refrained from posting answers to the numerous requests from "students" in
alt.engr.explosives for instructions and formulations.  Actually, most of
this information is available to the public if they just take enough time
to find it. Now that I see the light you have shed on the freedom of
information concept, I feel I may have been guilty of intellectual 
snobbism in not encouraging young people in their pursuit knowledge.  

I suppose I could remedy the situation by changing my policy, and 
answering any question which has an answer that can be found by a
literature search.  On second thought maybe I better wait to see what 
other chemists' opinions might be on this general subject.

Incidently, Safety is seldom foremost in the minds of my young knowledge
seekers  

Jerry













DOC0019

Subject:      Re: Picrates
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/15
Message-ID:   <3mp478$r73@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3mo8ip$4pm@usenet.ucs.indiana.edu>, jverburg@ucs.indiana.edu 
(john verburg) says:
>
>EdKChem (edkchem@aol.com) wrote:
>: >Is there danger to using a saturated solution of picric acid as a 
method
>: of
>: >preparing derivatives of primary and secondary amine compounds. How
>: stable
>: >is the picric acid with respect to these types of reactions?
>
>: >Howell Cobb
>: >cobb@cpsc.ucalgary.ca
>
>: Are you mad?  There are safer reagents in any decent Organic text.  As 
for
>: stablity:  IT ISN'T!  Picric acid is inherently unstable and can 
explode
>: on heating or by percussion.  See Merck Index.
>
>  I used to work for the safty office at The University of Illinois 
>(Chicago, Il). We used to pick up picric acid all the time. Of course it 
>was NEVER dry. Picric acid is unpredictable though. I heard some "old 
>boys" stories about it's disposal, way back when. They used to just shoot 
>it in a field with a high power rifle. Sometimes, it wouldn't explode. 
>Then they had picric acid spilled all over the place. Picric acid in 
water 
>is somewhat stable, but like I said unpredictable. If I had a choice, I 
>would look for another alternative. 
>JVERBURG

As explosives go, picric acid is relatively benign.  It is a bit more 
sensitive to impact initiation than TNT, which means it's relatively 
insensitive.  A 30-06 rifle bullet will not cause it to explode in the 
unconfined state. It is not overly sensitive to heat, and has, in fact, 
been used as a cast bomb filler (Japan, WWII).  The stuff was around for 
over a hundred years before the French realized it could be used in war.

Heavy metal salts of the acid are another thing entirely and should be 
avoided. Even the ammonium salt (explosive D) has a red form which is 
dangerous.

I would not try shooting the material with a blasting cap as a means of 
disposal, but initiation with a primer would be O.K.

Most explosives can be disposed of easily by burning them in moderatley 
thin layers on a pilr of loose straw or newspaper (from a distance, of 
course).

Picric acid can be destroyed by dissolving it in 25X its weight of a 
solution made from 1 part NaOH and 21 parts of Na2S.9H2O.  The reaction 
evolves some H2S and NH3.

I have no data, but I would be careful in working with concentrated 
solutions of picric acid (e.g. in warm acetone).  I suspect that such 
liquids may be susceptible to the LVD phenomenon in glassware or other 
materials with high sound conduction velocities, e.g. hard materials.

Jerry



















DOC0020

Subject:      Re: Toothpaste & OJ
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/15
Message-ID:   <3mpcqu$r73@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SUN.3.91.950415003052.24533A-100000@planetx.bloomu.edu>, 
"Eric J. Smith" <ejs@planetx.bloomu.edu> says:
>
>Tonight over dinner, a friend asked me if I knew why orange juice tastes 
>so bad when you drink it right after brushing your teeth...  I started 
>thinking and came up with the theory that the fluoride from the 
toothpaste
>(either from NaF or that phosphate compound that I can't recall at the 
>moment) was pulling a proton from one of the acids in the juice resulting 
>in a small but bitter concentration of HF in your mouth.  
>
>Does anyone know the real reason that this happens?
>
I'll take a bash at this question: As you know, taste is primarily a 
matter of smell. You can smell things from either the outside or from 
inside via the mouth and there is, a difference.  That's why coffee never 
tastes as good as it smells.  Now some of the neurons in the nose are sort 
of general purpose and some of them are specific to certain compounds. 
There is a body of theory which suggests that the selective ones react to 
specific vibration rates of the odor molecules so that chemically 
different things may have similar smells if the "vibes" are the same.  
Anyway, when the sensors are exposed to strong odors a temporary sensory 
fatigue sets in and, depending on the source of the odor, some but not all 
of the sensors temporarily deaden.  Under these circumstances other aromas 
and tastes will be changed if they are complex in nature and contain 
species similar to the ones that stultified the sensors.  I suggest that 
the aroma of strongly flavored tooth paste from inside the mouth does, in 
fact, anaesthetize some of the sensory nodes.

Jerry




DOC0021

Subject:      Re: help: What is definition of Binding Energy?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/15
Message-ID:   <3mp6hf$r73@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <jensen-1404951237390001@blv-pm3-ip26.halcyon.com>, 
jensen@halcyon.com (MattJensen) says:
>
>(I don't know if this group helps out with homework questions; 
>please direct me elsewhere if you don't. Thanks!)
>
>My friend's Chem 101 homework has a problem as follows:
>  "If the average binding energy per nucleon of two reactants is 
>greater than that of the product, then energy will be  (a) released, 
>or (b) absorbed ?"
>
>It seems a little confusing because a thing has negative-balue 
>Binding Energy if it is stable, right? So does "greater" mean a 
>larger negative number or a number closer to positive (i.e., -3 
>compared to -10?). What is the conventional meaning here, if there 
>is one?
>
>I know very little about Chemistry, and we hope to get a clear
>understanding of this before her first test. Thanks a lot!!!
>
>- Matt

Matt, the term "greater" means more positive.  This can be really 
confusing because many of us chemists say things like "aluminum 
chloride has a very high heat of formation," which means chlorine 
and and aluminum mixtures lose a lot of heat when they react and 
that the energy (actually enthalpy) of formation is very negative 
and that the product thus has less energy and is relatively stable.

In your friends nuclear binding case, the question is formally 
written and she has every right to interpret it literally, especially 
in light of the fact that by your teacher's convention more negative 
means more stable.  Anyway -3 is definitely greater than -10 and any
nuclear reaction going from -3 to -10 (you fill in the units) is going
to yield energy and presumably give more stable products. 

In the case of chemical, rather than nuclear bonding some tables list 
what is known as "dissociation energies," which are the reverse of 
bond energies and are thus positive numbers.

With regard to whether this forum is appropriate for homework 
inquiries, let's just say that opinions differ .  You're more likely 
to get e-mail replies  rather than an open posting in most cases.

Jerry











DOC0022

Subject:      Re: CAN ANYONE IDENTIFY THIS CHEMICAL: C_3 H_8 (NO_3)_3
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/16
Message-ID:   <3mqfio$qmc@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3mpv7s$6pf@desiree.teleport.com>, bobg@teleport.com (Robert 
Greer) says:

>Refrigeration greatly reduces nitroglycerine's sensitivity to shock.  
>*Much* safer when cold.
>
That's true up to a point.  Freezing the stuff (glycerol trinitrate) is 
very dangerous.  Even worse is thawing the stuff back out - as in thawing 
frozen dynamite. Powder companies (read "explosives companies) generally 
used a mixture of NG and EGDN (ethyleneglycol dinitrate), to lower the 
freezing point of dynamites and blasting gelatins in case of use in cold 
climates.

BTW, the original message in this thread is obviously a put-on.  The 
poster got the formula wrong - it's a bit long on hydrogens.  

Jerry

















DOC0023

Subject:      Re: CHEMICAL ENGINEERING
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/16
Message-ID:   <3mqg9c$qmc@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3mpsbs$imp@classic.iinet.com.au>, madams@iinet.net.au 
(maryvonne adams) says:
>
>      HAS ANYONE DONE OR IS DOING THE CHEMICAL ENGINEERING OR WHO CAN 
>      OFFER SOME GOOD ADVICE TO A HIGH SCHOOL STUDENT WHO WANTS TO TAKE
>      THIS COURSE AT UNIVERSITY AND WANTS ADVICE ON SUBJECTS TO DO IN 
>       YRS 11 AND 12 OR SOME SOUND ADVICE ON ANY ASPECT OF IT.
>      IT WILL BE VERY APPRIECIATED. THANKYOU
>      A.A.
>
When you say "high school" are you referring to an Oberreal Schule or 
Gymnasium or an American type high school?  I guess in any case you want 
to be shure to study all the math (calculus and differential equations), 
chemistry and physics possible.  If you're planning to attend an American 
University try to learn to use the English language well, even if it is 
your native tongue.  Bad grammar causes  a lot of grief here even for 
graduate students.

Jerry
<














DOC0024

Subject:      Re: Question on dessicant
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/16
Message-ID:   <3mqgn9$qmc@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3mp36l$1mu@buffnet2.buffnet.net>, krieder@buffnet.net (Kurt 
Rieder) says:
>

>You won't find a much better dessicant than quick lime (calcium 
hydroxide),
>but it's messey and not worth regenerating... so throw it away.  The same
>is true of many of the hygroscopic salts... messey.  Really does depend
>on what you are doing.
> 
I think you mean calcium oxide.  What do you mean "messy"? are you 
referring to the fact that it is usually in powder form? Neither the oxide 
nor the hydroxide is hygroscopic and the latter is not a dessicant.

Jerry



















DOC0025

Subject:      Re: Question on dessicant
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/16
Message-ID:   <3ms7lq$r3k@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <pbedwort-160495134618@131.215.4.119>, 
pbedwort@juliet.caltech.edu (Pete Bedworth) says:
>

>JERRY,
>If calcium oxide isn't hygroscopic what, pray tell, is your definition of
>hygroscopic?
>
>I think you may have meant deliquescent.
>
>PVB

You're quite right. I was thinking about the "messy" part and meant
"deliquescent."  I was pointing out that CaO (but not Ca(OH)2) is a drying 
agent, and, of course it has to be hygroscopic.

There are hard-fired varieties of CaO which are not hygroscopic, but that 
is incidental to my mistake. Sorry about that.

I think Nigel Seeley was right when he suggested that the original 
post was intended to say "calcium chloride."

We once built a plant which ground and packaged ammonium nitrate 
formulations.  Initially we had no humidity control, so decisions to run 
or not to run were based on the appearance of spilled AN powder.  If there 
were pools of liquid, we knew RH was above about 60% and it was no-go.

A friend in a similar business located himself in the Reno area and could 
make crisp product all year round. 

Jerry



DOC0026

Subject:      Re: Vinegar and Acetic Acid
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/18
Message-ID:   <3n11di$53b@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3n0t5u$3l2@geraldo.cc.utexas.edu>, JoshuaL25@mail.utexas.edu 
(Joshua L. Konkle) says:
>
>Ok....vinegar that is 5% acetic acid by weight.  What, without knowing 
the density of the solution would the
>molar value be.  I don't think you can get it.  Anyway, what is the 
standard molar concentration for a vinegar solution.
>I am presuming it to be 1.0M.  ???
>
>                                   Sincerely,
>Hook 'em Horns!                \________/----\________/   
>Joshua L. Konkle                                    U\    /U          
>                                                         U  U     \  /   
TTTTT     
>Chemical Engineering                   U  U    (__)        T       
>University of Texas at Austin        UU                     T      

The specific gravity of 5% acetic acid @ 20 deg C is 1.007.  The 6% acid
is 1.0 normal.  Commercial acetic acid runs from 4 to 9%, so if your into 
pickling, it's good to comparison shop for maximum $/eq :)

Jerry












DOC0027

Subject:      Re: help with g92 calculations.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/18
Message-ID:   <3n14u9$53b@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3muc0e$drc@hermes.louisville.edu>, 
d0gao001@homer.louisville.edu (Daquan Gao) says:
>
>Hello everyone:
>
>I need to know how to do calculations for the following problem.
>Given the reaction: H2O + NH4(+)---> NH4(+).H2O
>How can I calculate the change of enthalpy from the change(or variation ) 
of 
>the total energy?
>
>Can anyone mail me the input file for this?
>I am rather new in using g92. This is for a presentation.
>
>Thank you in advance.
>
I don't know what g92 is, but if your talking about a reaction going on in 
aqueous solution, it seems to me that the enthalpy and energy changes 
would be the same since there isn't likely to be much of a volume change. 
If this is a case of a salt dissolving, I suppose there'd be a tiny PV 
change (negative), but that's calculable more or less if you have an anion 
you can ignore.  Maybe I'm missing the big picture. If so, will somebody 
please straighten me out?

Jerry







>D. Gao
>
>gao01@xray3.chem.louisville.edu 
>




















DOC0028

Subject:      Re: nalgene tubing rupture
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/18
Message-ID:   <3n14fd$53b@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.chem.labware



In article <63785.bmoulton@shark.stmarys.ca>, "Brian Moulton" 
<bmoulton@shark.stmarys.ca> says.
>


>
>...My stills are all connected in series by 5/16" ID Nalgene Premium 
Tubing (autoclavable, non-toxic, LAB/FDA/USP VI grade) - standard Nalgene 
>tubing. The water is filtered first through a Cuno cold water filter to 
>remove any dirt/rust. All of the tubes are secured to the condensers with 
>'O' clamps.
>
>... The split was 2-3" long along the length of the tubing about half way 
>between the tap and the still (2' from both).  I replaced all of the 
>tubing on the system with new tubing and replaced the filter.
>
>... This past weekend the same problem occurred.... Again, there was a 
>cut along the length of the tubing measuring almost 3", half way between 
>the filter tap and the first condenser.
>
From your description it appears that you are running a number of 
condenser jackets in series and that you have had two ruptures upstream 
before the first unit.  I would suggest that you have a big pressure drop 
across this extended system and it is rupturing in the section with the 
highest continuous pressure - perhaps 40 psi or more. Using stronger 
(reinforced) tubing or copper tubing upstream might help. It would be 
interesting to put a pressure gauge on a T in the inlet line for a peek at 
the pressure.

Jerry




DOC0029

Subject:      Re: Mercurous Perchlorate
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/20
Message-ID:   <3n4q61$gvq@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article 
<Pine.SGI.3.91.950419124740.1287A-100000@Mn.Chem.LSA.UMich.Edu>, Brent 
Hamstra <hamstrab@Chem.LSA.UMich.Edu> says:
>
>On Wed, 19 Apr 1995, Jerry Patrick Gordon wrote:
>
>> Does anyone out there have a MSDS sheet on mercurous perchlorate?  
Apparently 
 
>
>Metal perchlorates in general are potentially unstable chemicals. 
>Unfortunately this instability is highly unpredictable. 

I don't know about mercurous perchlorate, but there have been at least two 
reports of supposedly pure aqueous silver perchlorate exploding while 
being stirred.  No proposed mechanism or equation was suggested to explain 
the occurences in the apparent absence of fuel materials.  If the silver 
salt is truly dangerous, I wouldn't trust the Hg2 salt.

Jerry














DOC0030

Subject:      Re: Cyanogenbromide (BrCN)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/25
Message-ID:   <3ni73j$6pq@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3ngsk4$9fn@auntie.bbcnc.org.uk>, tilbrook@chem.surrey.ac.uk 
(David A. Tilbrook) says:
>
>In article <3n8bbb$1lf@doboj.cca.vu.nl>, vinkers@gallium.chem.vu.nl 
>says...
>>
>>How dangerous is this compound ?
>>Sounds quite toxic IMO!
>>
> Depends very much on jusy how much you are using of it. The most 
>dangerous part of it's use that I encounter is actually weighing it out. 
>(We use it for cyanation to produce cyanate ester materials.)
>
>The vapour pressure is quite low so inhalation is not much of a risk. you 
>should still observe full cyanide safety procedures though _ double 
>gloving, basic bath available for immediate neutralisation of 
contaminated 
>materials, first aider and backup in attendance with cyanide antidote and 
>breathing apparatus etc. etc......Oh yes and avoid acids!!! It's the 
>possiblity of HCN generation that's really dodgy.
>
>Have fun!
>
>David Tilbrook
>
**************************************************************
>David Tilbrook                      |tilbrook@chem.surrey.ac.uk
>Polymer Group, Chemistry Dept.      |Tel: 1 44 1483 300 800 x 9591
>University of Surrey, Guildford,    |Tel: 1 44 1483 259 951 (direct)
>Surrey, GU2 5XH, UK.                |Fax: 1 44 1483 259 514
>************************************************************************
>
HANG ON! I believe you're writing about a cyanide salt, not cyanogen 
bromide. The latter IS volatile, and a whiff of the stuff can knock you 
off your feet - no acid needed. I'm sure you know better, but were 
thinking about the usual precautions we chemists take when working with 
KCN, etc.  BTW, I once got a whiff of a cyanogen halide that blacked me 
out on my feet.

Jerry
















DOC0031

Subject:      Re: oxidation-reduction reactions
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/04/26
Message-ID:   <3nm0do$hb8@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <all.16.0017E80F@stpauls.dungeon.com>, all@stpauls.dungeon.com 
(Andrew Byfield) says:
 If H2SO did exist then sulfur would have an oxidation state of 6 so as 
>to give the necessary -2 "charge" to balance the two hydrogens which are 
in 
>the +1 oxidation state.
>*************************************************************************
***
>Andrew Byfield, student and international explorer.
>"Life is a tale told by an idiot, full of sound and fury,
>signifying nothing."  (W. Shakespeare)
>*************************************************************************
***

IF H2SO did exist, it might be looked at as an analogue of H2O2, in which 
case we would assign an oxidation state of -1 to the sulfur.  I'm sure you 
knew this and meant to refer to H2SO4 as having sulfur in the + 6 
oxidation state.

Jerry














DOC0032

Subject:      Re: 1Ammoniun Nitrate
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/08
Message-ID:   <3ok4ug$5qv@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



>

In article <shnst+-0605952115230001@lil-spiffy.chem.pitt.edu>,
shnst+@pitt.edu (Captain Entropy) says in re ammonium nitrate:
>
>I believe it is bagged & shipped as wax-coated pellets; this is the type
>of material which caused the 1947 Texas City, TX, disaster.
>
AN is not coated with wax unless it is classified as a nitro-carbo-nitrate
(blasting agent). The prills are usually porous and would happily soak up
molten wax to create a form of ANFO.  Unfortunately for the blasting
industry, such mixtures exhibit very little water resistance.  The
material in the Texas City disaster is believed to have been contaminated
by some extraneous oil.  It may come as a surprise to some, but anfo does
not support combustion well in moderate quantities.

Jerry

















DOC0033

Subject:      Re: 1Ammoniun Nitrate
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/08
Message-ID:   <3ok4fe$5qv@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <shnst+-0605952127270001@lil-spiffy.chem.pitt.edu>,
shnst+@pitt.edu (Captain Entropy) says:
>
>
>> >> Both were huge bulk stores which were ignited by other sources
(fires,
>> >> I mean). If I remember rightly, the Gulf Coast one was in a ship.
>
>I believe this ignited from compression, just as pressure in large coal &
>slate heaps leads to a rise in temperature and occasional ignition.

I don't understand how static pressure (as opposed to adiabatic 
compression) can cause heat.  It seems to me that a large coal heap might 
undergo spontaneous heating from slow oxidation, but I doubt that AN/oil 
mix would react under similar conditions unless the oil was unsaturated.

Jerry

















DOC0034

Subject:      Re: Geometry Q in sci.chem?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/08
Message-ID:   <3ok58u$5qv@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.math



In article <3oeeti$ic1@senator-bedfellow.MIT.EDU>, tjs@slipknot.mit.edu 
(Toby J. Sommer) says:
>
>I need to drill a hole as close as possible to dead center in a 12"
>pie plate. Anybody know how to construct a true diameter or otherwise
>find dead center of a circular disk?  Since this is a real lab/shop
>problem, drawing tangents and using points out at infinity won't be
>too practical; on the other hand, I can use more than straightedge and
>compass.


Balance the plate on a nail point and tap it with a rubber hammer to leave
an indentation (unless it's a glass plate).

Jerry



















DOC0035

Subject:      Re: h202 as oxidising agent
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/08
Message-ID:   <3ollrv$rga@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3oilg0$7uv@news.annex.com>, alchmist@annex.com (John Milligan) 
says:
>>
>This is valid for your reaction since the ammonium ion creates a basic 
>medium.

Actually, the ammonium ion is slightly acidic, i.e. it wields a proton 
rather than accepting one.

Jerry


DOC0036

Subject:      Re: 1Ammoniun Nitrate
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/09
Message-ID:   <3onuu0$bif@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <emilsson.799973832@aries>, emilsson@aries.scs.uiuc.edu 
(Tryggvi Emilsson) says:
>
>glhurst@onr.com (Gerald L. Hurst) writes:
>
>
>>In article <shnst+-0605952127270001@lil-spiffy.chem.pitt.edu>,
>>shnst+@pitt.edu (Captain Entropy) says:
>>>
>>>
>>>> >> Both were huge bulk stores which were ignited by other sources
>>(fires,
>>>> >> I mean). If I remember rightly, the Gulf Coast one was in a ship.
>>>I believe this ignited from compression, just as pressure in large coal 
&
>>>slate heaps leads to a rise in temperature and occasional ignition.
>
>  I once saw a TV program on the Texas City disaster,and if my 
recolection is
>right, this is what happened:
[TV show description omitted]
>  There is,therefore,no need to speculate on the cause of the explosion.
>
>T.Emilsson
>U.of Illinois
>
The fact that the "answer" to this question was presented on TV will 
hardly satisfy the experts who have looked into this matter and reached 
other uncertain conclusions.  Many of us do not really consider the tube 
as an authority on much of anything.  

There were numerous facts brought out in the litigation which followed the 
explosion that lead to other conclusions regarding the mechanism of the 
explosive initiation, including the fact that the prills were wax-coated 
with almost precisely the right amount of paraffin to reach maximum 
sensitivity.  Also, the material was probably shipped hot and in bag 
material which is also known to react exothermically with AN at the 
shipping temperature. Furthermore, there had been a couple of fires in the 
rail cars which carried the product to the ship.  There have, of course, 
been other AN explosions which are known to have been caused by fire.  The 
last one I remember originated from a fire in an AN manufacturing plant in 
Oklahoma. The material is said to have exploded in the fire after contact 
with melted rubber belting.

Jerry
<










DOC0037

Subject:      Re: Please help: Brownian Motion
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/09
Message-ID:   <3omi65$ggl@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3oj7si$oai@umbc8.umbc.edu>, mark@umbc.edu (Mark Meytin) says:
>
>Hi,
>I am looking for a way to prove Brownian motion - the chaotic
>movement of colloidal particles.  What I need to do is to put something
>under a microscope so that you could see particles moving.  
>
If you want to see Brownian motion in action, use a dark-field microscope 
and observe the smaller bright points of debris in whatever kind of not 
very pure water.  An interesting subject would be a droplet of your own 
blood.  At oil-immersion magnifications, you will be able to see the 
infamous somatids of Dr. Naessens as little bright stars doing the 
Brownian Jig. We Jury-rigged a conventional medical 'scope for dark-field 
and it worked fine.

Jerry


















DOC0038

Subject:      Re: diesel fuel/kerosene
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/09
Message-ID:   <3omqhb$o6v@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <D89yJ3.HD3@ecf.toronto.edu>, fusina@ecf.toronto.edu (FUSINA  
GIOVANNI) says:
>
>  hello!
>
>does anybody know what the chemical composition (molecular formula) of
>diesel fuel is? Do you know where I could find thermochemical data for 
it?
>What about kerosene?
>
>Thank you in advance for your replies....
>
>--Giovanni
>
You can always get an argument on this subject, but both kerosene and the 
most common #2 diesel fuel are mixtures of mostly aliphatic hydrocarbons 
having a flashpoint above 120 deg F. The compositions would comprise 
mainly hydrocarbons in the C-10 to C-16 range.  Depending on where you 
look you may find the minimum flaspoint of kerosene listed at 100 or 150 
deg, more often the former.  If you actually purchased and tested kerosene 
you'd probably get a flashpoint of 125-140. If you want thermochemical 
data you'll have to pick a particular brand and batch because the only 
consistent property you will be able to find is an approximate equivalence 
in the temperatures at which 10% increments distill. Then run a GC - mass 
spec to identify the many components and calculate with your fingers 
crossed and not too many decimal places.  If all you want is heat of 
reaction in some kind of oxidation reaction, you can skip the analysis and 
just consider it as a midrange hydrocarbon like dodecane.  Kerosene is 
cleaner than diesel, usually having far less sulfur and being water clear. 
They even make odorless kerosene for use in, for instance, special ANFO 
for blasting minerals intended as supplements in cattle food.  Kerosene or 
fuel oil for ANFO must have a flashpoint of 140 deg f or greater.  If it 
is intended for kerosene heaters, it is given a "1-K" rating to guarantee 
low sulfur. Fuel oil formulations are changed for periods of cold weather. 


Jerry



















DOC0039

Subject:      Re: keeping CO2 liquid ?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/09
Message-ID:   <3omhae$ggl@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.bio,sci.misc,sci.physics,sci.polymers,sci.research



In article <1995May8.144604.8846@njitgw.njit.edu>, bxa3446@hertz.njit.edu 
(bart adams me stnt) says:
>
>
>Are there any substances that lower the solidification point of CO2 ?
>(in the same way that salt does the trick with water)
>If you know of any, or know some literature where I could find some clue, 
>please let me know,
>
>My e-mail : bxa3446@hertz.njit.edu
>
>Thanks a lot.
>
>Bart Adams.
>
>
>Many things are soluble in CO2 and would consequently lower the freezing 
point.  My old Audrieth and Kleinberg "Non-Aqueous Solvents" doesn't 
mention the subject, but there's been a lot of non-aqueous fluid under the 
bridge since it was written.  There's been a lot more work done in this 
area in recent decades since they found that caffeine could be extracted 
and emulsions could be made with the stuff.  If you're not up to a Chem 
Abstracts search, I'd simply look for a newer book with a similar title in 
the chem library or section.  CO2 will behave like water in the sense that 
it will have a molal freezing point depression constant.

Jerry







DOC0040

Subject:      Re: A: How to glue polyethylene or polypropylene
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/17
Message-ID:   <3pdui2$g8n@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3pdnb0$dhp@saba.info.ucla.edu>, Flint Smith 
<flint@uclaue.mbi.ucla.edu> says:
>
>Bernard Morey <bmorey@melbourne.DIALix.oz.au> wrote:
>>On Mon, 8 May 1995, William R. Penrose wrote:
>>
>>> In article <1995May6.031747.19253@sequent.com> stuartf@sequent.com 
(Stuart Friedberg) writes:
>>> 
>>> >Q: How can you glue polyethylene or polyproplyene?
>>> 
>>> ... hot-melt glue ...
>
>>I'm sure you can't have been trying to join PE or polyprop.  A glue gun 
>>just won't work -- I've tried it.  It may _sort of_ work if there is no 
>>stress on the join, but the slightest movement and ... boing!
>
>Being a destructive guy by nature, I have pulled the colored cups from 
the
>bottoms of 2-liter PE(?) soda bottles.  It takes a fair amount of effort, 
and
>"boing" doesn't describe it.  The glue appears to be (color, texture,
>softness, threads between glue-points) hot melt glue and is very 
effective.
>Maybe your quality control wasn't up to snuff.  Maybe a different glue 
>formula or temperature would account for the difference.
>
>Flint Smith  flint@uclaue.mbi.ucla.edu
>
Soda pop bottles are a PVC laminate having, I've read, about 5 layers.  
PVC, of course can be readily glued with PVC dissolved in a solvent or by 
solvent alone.  Nylon and polyester are difficult to glue, but hot-melt 
works OK.  

Polyolefins can be glued with hot-melt too, perhaps because the chemical 
similarity of the plastic  and the glue (polyethylene + EVA) lead to 
melting point depression of the former from blending at the interface. 
That's a guess, folks.

Jerry
















DOC0041

Subject:      Re: ANSWER TO NOT SO HARD CHEMISTRY A-LEVEL QUESTION.HELP!!!!
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/17
Message-ID:   <3pdoe0$bch@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SGI.3.91.950517130223.6290B-100000@cv4.chem.purdue.edu>, 
Lev Gorenstein <lev@chem.purdue.edu> says:

>
>No, not necessarily!  The RDS may include intermediates, that do not 
>enter in the overal reaction equation and do not enter the kinetic rate 
>law.  Those intermediates concentrations are derived from the other 
>mechanistical equations as functions of other konstants and reactants 
>concentrations.   They then are plugged in the RDS kinetic equation 
>and produce the overall rate law.  That's where you sum up the powers 
>and get the order.  If you sum up the coefficients in the RDS, more 
>likely than not you will get different result (and it'll be wrong).
>
Please refer to my query posted in response to similar material by Joseph 
S. Merola.

Jerry

















DOC0042

Subject:      Re: ANSWER TO NOT SO HARD CHEMISTRY A-LEVEL QUESTION.HELP!!!!
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/17
Message-ID:   <3pdn74$bch@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <jmerola.1151122555C@news.vt.edu>, jmerola@vt.edu (Joseph S. 
Merola) says:
>

>Well, there is still only one rate determining step:  it is the slow
>step in the reaction which determines the overall kinetics of the
>system.  I think this still has a lot to do with the original
>question.  For example, you may have a reaction in which
>A  +    B    --->   C, but the rate determining step in the
>reaction may involve  intermediates X, Y, and Z.   An overall rate
>law is written in terms of the species in the balanced equation, not
>based on the intermediates in the rate determining step.  
>
>
Sure, that's how the overall rate law is written, but if you want to write 
a meaningful RDS you have to do it in terms of X, Y and Z.  I fail to 
understand how one set of reactions in, say, a series of second order 
reactions of similar rate could be chosen as the RDS when such a reaction 
would in no way "determine" the overall rate, but would simply exert 
slightly more influence thereon than the others do.  All of my postings on 
this matter really amount to the simple proposition that if you tell me 
that the rate law for a given reaction is no more complicated than the 
product of a few concentrations individually raised to some powers, then I 
can probably deduce the coefficients in the corresponding reaction.  I 
certainly understand that you can show a rate law equation of some other 
form, which will not permit such an inference.

I make no claims to be particularly knowledgeable in the area of kinetics 
and I am willing to learn from wiser heads.  If you can give me an example 
contrary to my proposition, I'll happily assimilate it into my old gray 
noggin.

Of course, I've often seen relatively slow reactions in a longer sequence 
referred to as the "rate determining step," but I always assumed this was 
a more or less colloquial use of a phrase more aptly applied to cases 
where really large differences were present in the rates.  

Jerry


>
>-------------------------------------------------------------------------
-----
> Joseph S. Merola
> Director of Graduate Education
> Department of Chemistry                Internet: JMEROLA@VT.EDU
> Virginia Tech                          Voice   : (703) 231-4510        
> Blacksburg VA 24061-0212               FAX     : (703) 231-3255        
>                            
>-------------------------------------------------------------------------
-----





DOC0043

Subject:      Re: ANSWER TO NOT SO HARD CHEMISTRY A-LEVEL QUESTION.HELP!!!!
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/17
Message-ID:   <3pdd16$5ss@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <jmerola.1151100075B@news.vt.edu>, jmerola@vt.edu (Joseph S. 
Merola) says:
>
>In Article <3pbvgc$bge@geraldo.cc.utexas.edu>, glhurst@onr.com (Gerald L.
>Hurst) wrote:
>>In article 
<Pine.SGI.3.91.950516153315.4979K-100000@cv4.chem.purdue.edu>, 
>>Lev Gorenstein <lev@chem.purdue.edu> says:
>
>
>
>>>Not exactly correct.  The order of the reaction is the sum of powers, 
in 
>>>which the concentrations of reactants enter in the RATE LAW equation 
for 
>>>the reaction.  It is not the sum of coefficients in the RDS equation.  
>>>When you have the rate law:
>
>
>                   x    y    z
>>>        rate = k*[A] *[B] *[C]*....,
>
>
>>>You can then say:  Order = x+y+z.
>>>
>>>But doesn't the rate law equation derive from the corresponding RDS 
>>equation which would be:
>>
>>        x[A] + y[B] + z[C] ...
>>
>>in which the sum of the coefficients is equal to the sum of the 
exponents 
>>in said rate law equation.
>
>
>No, because the rate law can be a composite of all steps that lead 
>up to the rate determining step.  There may be several equilibra that
>precede the rate determining step and will contribute terms to the
>overall rate law.
>
OK, but if there are several rate determining steps in a reaction, can you 
then write the rate law equation as the simple product of the 
concentrations raised to the respective coefficients as was done in the 
SPECIFIC example above which I used for my derivation?  If the supposed 
RDS is not slow enough to establish the overall rate of reaction then 
there is simply no RDS for that sequence.  You are certainly right that a 
reaction sequence may have numerous steps which influence the overall
rate, but that fact has little to do with the original subject of this 
discussion in my often flawed opinion.

Jerry





DOC0044

Subject:      Re: ANSWER TO NOT SO HARD CHEMISTRY A-LEVEL QUESTION.HELP!!!!
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/17
Message-ID:   <3pbvgc$bge@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SGI.3.91.950516153315.4979K-100000@cv4.chem.purdue.edu>, 
Lev Gorenstein <lev@chem.purdue.edu> says:
>

>Not exactly correct.  The order of the reaction is the sum of powers, in 
>which the concentrations of reactants enter in the RATE LAW equation for 
>the reaction.  It is not the sum of coefficients in the RDS equation.  
>When you have the rate law:
>
>                    x    y    z
>        rate = k*[A] *[B] *[C]*....,
>
>You can then say:  Order = x+y+z.
>
>But doesn't the rate law equation derive from the corresponding RDS 
equation which would be:

	x[A] + y[B] + z[C] ...

in which the sum of the coefficients is equal to the sum of the exponents 
in said rate law equation.

We don't know how many angels can dance on the head of a pin, but the 
number is probably the same no matter how you calculate it.

Jerry








DOC0045

Subject:      Re: MISSING USGS RECORDS OF 04/19/95
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/17
Message-ID:   <3pdve4$g8n@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3pdlof$r6r@mack.rt66.com>, diamond@rt66.com (Russell Stewart) 
says:
>

>
>Furthermore, as a friend pointed out to me, there were cars in the
>parking lot that had the gas in their tanks set off by the explosion.
>This would easily account for reports of multiple explosions.
>
Only in the movies. Although gasoline-air detonations are possible under 
suitable circumstances, they are unlikely to occur in real life car fires, 
except for little bangs under the hood or in more or less empty tanks.

Explosions caused by confined gasoline-air, as inside a room are much more 
common, but hardly likely to give much of a seismic pulse as compared to a 
couple of tons of condensed explosive.  In real life explosions of such 
things as ANFO, C-4 and dynamite, etc., there is very littl flash and 
smoke.  Hollywood adds petroleum products to their explosions so they will 
burn in great fireballs and generate clouds of carbon smoke.

Jerry













DOC0046

Subject:      Re: Rust? stains on concrete
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/17
Message-ID:   <3pbt1j$bge@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3pb192$9vq@luggage.rednet.co.uk>, Bryan Murphy 
<bristlcathsc@online.rednet.co.uk> says:
>
>Pardon my arrogance, but aren't alkalis caustic

Acids, bases and comments can be caustic, each in its own way.  The term 
"caustic" is sometimes used to denote strong bases as in "caustic soda" or 
"caustic potash," but it is also used in the broader sense of "corrosive."

Jerry


DOC0047

Subject:      Re: Tagging ammonium nitrate (or something like that)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/17
Message-ID:   <3pbucu$bge@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3paiuh$f0@gap.cco.caltech.edu>, et@liquefy.ugcs.caltech.edu 
(Ernest S. Tomlinson) says:
>
>On the way to school this morning I caught the last half of a story
>on NPR, about a proposal (by who, I didn't catch--probably some Senator
>Foghorn duckspeaker hit upon the idea) to tag all ammonium nitrate
>produced in the U.S. so that, if it were used in a bomb, it could be
>traced.
>
>The word (not a word, a revolting neologism) "taggant" was tossed
>around in the news-story.  Now I doubt that the word "taggant" exists,
>and if it does, it shouldn't; but it seemed to refer to some special,
>unusual sort of marker that isn't manufactured in the U.S.  NH4NO3
>would be, I guess, adulterated with these "taggants".
>
>My first reaction to this was "Jesus Christ!  Are they gonna 'tag'
>fuel oil as well??"  But I'm reserving judgement until I hear more
>than half a news-story.  Anyone have any info on this?
>
The move to force manufacturers to tag explosives and precursor chemicals 
is decades old. The chief proponents include the BATF and FBI.  Explosive 
packaging is presently labeled with enough code to identify the source, 
date and shift of manufacture, but of course such markers are destroyed 
when the materials are shot.  Various binary code schemes have been 
proposed, but the frontrunner system is apparently one using tiny 
particles made of laminates of colored layers representing bits or bytes 
of information.  The problem, of course, is that the addition of such 
materials may sensitize or otherwise contaminate materials and create a 
potential bookkeeping nightmare.  Also, there is the problem of 
in-plant cross-contamination which would require the otherwise unnecessary 
step of thoroughly cleaning manufacturing machinery between batches.  If 
the little particles are stable enough, we should wind up up to our necks 
in them after a few decades and they will be using "cross-contamination" 
as an argument in more trials than Judge Ito ever dreamed of.

Jerry




















DOC0048

Subject:      Re: sodium azide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/17
Message-ID:   <3pdpde$bch@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3pdl4d$shg@news.acns.nwu.edu>, cathryn@merle.acns.nwu.edu 
(Cathryn M. Majkowski) says:
>
>
>
>Hi,
>
>I was wondering if anyone has any information or knows where I could find 
>information about toxicity levels and sodium azide.  I have some data on 
oral lethal
>doses in men and women, but I can't seem to find any info on non-lethal 
doses.  

According to the Merck Index, "Some azides cause fall in blood pressure 
and inhibit cytochrome oxidase and other enzymes." You'll find this 
information under "lead azide." Only the hypertensive properties are 
mentioned under the sodium salt entry, probably by oversight rather than 
any specificity to the lead compound.

Jerry














DOC0049

Subject:      Re: Lawsuit against fertilizer mfr (Okl city bombing)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/18
Message-ID:   <3pgb6v$rnp@geraldo.cc.utexas.edu>
Newsgroups:   misc.legal,sci.chem



In article <3pg6m0$rmm@moe.cc.emory.edu>, lparker@larry.cc.emory.edu 
(Lloyd R. Parker) says:
>: Consequently, if the 
>: fertilizer can easily be changed to lose it's bombing qualities while 
>: retaining all of it's fertilizing qualities AND the company reasonably 
>: foresaw the killings then there could be an argument for liability.  
>: 
>: ---
>
>Actually, a judge in California has allowed a gunshot victim to sue the 
>gun maker, the argument being that the gun maker should have reasonably 
>foreseen that the product was dangerous.

Judges are likely to let people sue over most anything and let the trial 
sort out the mess; that is why we have the push in congress to limit 
frivolous lawsuits.

I had a case once (consulting) in which a young man found some of those 
little firework torpedos with the non-PC in the parking lot of a 
bowling alley and stuffed them in his pocket.  According to his complaint, 
he tossed the ball down the alley and at that moment his left pocket 
erupted causing him to dance around furiously and yank down his pants and 
receive burns to a portion of his anatomy where no man should suffer.

So ... whom did he sue?  The (Asian) company which had manufactured the 
butane cigaret lighter he happened to have in his pocket.  The theory was 
that the bowling motion caused the flint wheel to turn, creating a spark 
which ignited a fuse on one of the fireworks.  His attorney brought in a 
shave-tail engineer who testified in his deposition that the standard 
pocket lighter is unreasonably dangerous because there is no safety clutch 
or brake on the flint wheel and that the manufacturer should have foreseen 
that this omission constituted an unnecessary hazard.

This case never went to trial, but settled for a ridiculously high amount 
to avoid the otherwise higher cost of defending the suit in court as is 
frequently the case with frivolous suits.

I am currently aware of a pending case in which a woman shot herself in 
the leg with her major name brand (semi-)automatic pistol.  Of course, the 
allegation is that the gun malfunctioned, despite the fact that it had 
been modified and repaired in jury-rig fashion.  This is another case 
looking for a nuisance settlement.

Or how about a case in which an explosion occured in a very small room 
containing 120 lbs of smokeless powder and thousands of primers.  The 
explosion pushed a couple of walls a few inches only, but sent a fire ball 
through the house resulting in two burned and orphaned children.  The 
family sued guess who?  he manufacturer of the computer printer which was 
also in the room. Theory?  The printer shorted, got very hot as a result 
and released an explosive aerosol as the plastic decomposed. The aerosol 
concentration increased until the lower explosive limit was reached and 
then boom!

Absurd you say? Idiotic? Nope, both the plaintiff and defendant attorneys 
checked with local gunshops and national powder manufacturers and became 
convinced that "Gunpowder does not explode unless it is confined." It took 
the defendant's expert (me) a couple of years to convince the truly 
exceptionally intelligent team of defense lawyers and other experts that 
the propellant was the culprit, and this was first accomplished the night 
before the trial when I visited another expert in his apartment and put on 
a demonstration of the explosion of "unconfined powder," We videotaped the 
demo the second time around in such a way as to demonstrate both the 
pressure and fireball effects. The Jury (and our own lawyers), because of 
the press of time, saw the video tape in detail for the first time in the 
courtroom.  We won the case, but it cost at least half a million to 
prepare and try it.

Oops, shut him down - he's telling old war stories again --

Jerry








DOC0050

Subject:      Re: me on TV in Boston WCVB
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/18
Message-ID:   <3pe5gm$g8n@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3pe1lq$3pn@dartvax.dartmouth.edu>, 
Archimedes.Plutonium@dartmouth.edu (Archimedes Plutonium) says:

> the totality is a single atom. A single atom with many atoms
>inside it. The space of atoms is the space of electrons. Our night sky
>is merely the space of the 93rd and 94th electrons. The mass of
>everything we see is just the mass of the 93rd and 94th electron. The
>missing mass of the universe is the nucleus, but we will never see it
>for it is in a atom node. 

Well, sure, everyone knows that the universe is an atom, but where do you 
get this 93rd and 94th electron business.  The universe is clearly not 
merely any old atom, it is a technetium atom and therefore has only 43 
electrons.  This structure accounts for the instability and chaos in our 
world and the bad TV reception.  Certainly, the scientific community is 
obtuse, as is obvious from their reluctance to accept a number of my 
theories.  Maybe I should try TV.

Jerry















DOC0051

Subject:      Re: Gallium Oxide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/19
Message-ID:   <3ph3eh$e6t@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <wpenrose.26.001A07BB@interaccess.com>, 
wpenrose@interaccess.com (William R. Penrose) says:
>
>In article <3p88sm$mri@msunews.cl.msu.edu> root@localhost.com (Phil 
Storm) writes:
>
>
>>        I've posted this a few times....but I was wondering if it is 
possible
>>   to seperate Ga(2)O(3) (gallium oxide) into Ga and O by electrolysis? 
Like
>>   by using Gallium oxide as the anode of electrolysis in an NaCl 
solution? 
>
>Using aluminum oxide (same Group) as an analogy, my guess is that you 
won't 
>do it in aqueous solution.  Al is made by high-temperature electrolysis 
of 
>aluminum oxide in a flux of molten cryolite, a mineral of some kind.
>
Seems to me that chlorine would be more likely at the anode than oxygen.

Jerry











DOC0052

Subject:      Re: Lawsuit against fertilizer mfr (Okl city bombing)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/19
Message-ID:   <3piss8$bh9@geraldo.cc.utexas.edu>
Newsgroups:   misc.legal,sci.chem



  Article Segment 1 of 2
  
In article <cvxdrk-1905951254560001@165.249.8.33>, cvxdrk@arco.com (David 
R. Kinney) says:
>
>In article <tWtuvsnzZJIS083yn@nyx.cs.du.edu>, rcanders@nyx.cs.du.edu (Mr.
>Nice Guy) wrote:
>

>There IS a process (patented some 20 years ago) for the addition of
>ammonium phosphate to ammonium nitrate fertilizer that renders the
>fertilizer ineffective as an explosive.  Additional cost is minimal, but
>ANY additional cost was deemed to be too much by the manufacturers.  See
>the Philadelphia Inquirer (5/19/95?) for a good profile of the patent
>holders and their story.
>
The following is a copy of relevant material I posted in 
alt.engr.explosives and misc.legal: 

>>In article <3ph10u$lo@stratus.skypoint.net>, jlogajan@skypoint.com (John
>>Logajan) says:
>>
>They just had on Jeraldo CNBC show an inventor of a 1962 patent process
>>Apparently his process is to mix diammonium phosphate with the ammonium 
>>nitrate.
>
>>The question is, is it hard to extract the diammonium phosphate from
>>the ammonium nitrate by some means, such as a differential soluability
>>or other fairly simple chemical "cleansing"?
>
I believe the inventor you're referring to was an engineer named Samuel
Porter and the patent was issued in 1968. Mr. Colbert was an engineer who
later joined Mr. Porter and helped him pitch his idea of diluting AN with
DAP, an already well-known fire retardent and fertilizer.  It appears that
similar mixtures were already in use, mainly overseas, where they use more
DAP fertilizer than we do, perhaps because of our calcium phosphate
technology based on work by the TVA with the calcium salts.  Aqueous
mixtures of AN/DAP are often found in home-gardener liqid fertilizers
along with a potassium salt and some green dye.  Presumably, this "prior
art" interfered with broad coverage of the system in the Porter patent
because the claim language vaguely alludes to the necessity of intimately
mixing the materials by co-crystallization and/or what-have-you.

Most of the tests of the mixtures were with fire, and the DAP did what it
had long done for paper, etc - it retarded the fire.  It might be pointed
out that trying to burn ANFO isn't that easy anyway.  In practice, when
you light a bunch of paper under the stuff, it goes out nearly as soon as
the paper has burned away.

The explosive tests were conducted in two series: the first with #8
blasting caps, and the second with the same plus a two feet of 50 grain
detonating cord cut into 2-inch pieces and taped around the cap. These
initiators were used  to set off about three-pound charges in half-gallon
cylindrical ice-cream containers about 4" in diameter and 10" long.

Rather than using witness plates, the Dautriche method or electronic
instrumentation they relied on a "tell-tale" consisting of a fifteen foot
length of detonating cord with one end contacting a piece of steel and the
other terminating in a crimped #6 fuse cap. The fuse cap was inserted in
the distal end of the charge with respect to the #8 detonator.

From a series of shots using the above arrangement they obtained results
which they classified as H.O. (high order), L.O. (low order) and N.D. (no
detonation).  The treated material was reported to show no results greater
than L.O. and mostly N.D., while the "regular" ANFO gave H.O. results
every time.

It should be mentioned that the ANFO and the treated ANFO used in these
experiments was not actually in the form of prills but rather a powder
with about 30% passing through a 35 mesh screen.

One might also note that the ammonium phosphate may actually have been the
monobasic material because of the thermal loss of one ammonia group during
hot processing steps.

Please do not interpret my description of this work as either praise or
criticism.  I am supposed to be an expert in this field and that means
that I must study the subject objectively and carefully before I form any
firm opinions.  I would, however, welcome any comments from those who do
have thoughts on the matter




















DOC0053

Subject:      Re: Lawsuit against fertilizer mfr (Okl city bombing)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/19
Message-ID:   <3piss8$bh9@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
  
  
As to the question of whether or not one could readily separate the AN
from the mixture, the answer is "Yes."  It is a personal quirk of mine to
hesitate in giving instructions that might lead a youngster to try
something he shouldn't.  Probably any young chemist reading this forum
will instantly realize how very easy the separation would be, but it'll
make me squint to see it in print.

Jerry



DOC0054

Subject:      Re: Speed of combustion of gasoline
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/20
Message-ID:   <3pjs5h$1d4@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <9505192144591.The_Win-D.loyl@delphi.com>, loyl@delphi.com (Loy 
Lawhon) says:
>
>I have been asked a question that I have no idea how to calculate:
>
>If a line of gasoline could be laid out for a mile without evaporating, 
and
>you lit one end, how long would it take for the flame to travel the mile 
to
>the other end? Can anyone help me, please? 

If the gasoline is unconfined and unassisted by external air currents, it 
will burn along at the pokey linear rate of a bit over one ft/sec.  
However, if it is in a reasonably large pipe and well mixed with a roughly 
stoichiometric amount of air, expect the combustion wave to transform into 
a detonation before it has travelled more than a few feet.  The reaction 
should then cover the rest of the mile in under one second.  I guess you 
could say the answer is more than an hour or less than a second.

Jerry














DOC0055

Subject:      Re: Speed of combustion of gasoline
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/20
Message-ID:   <3pjrk5$1d4@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <9505192144591.The_Win-D.loyl@delphi.com>, loyl@delphi.com (Loy 
Lawhon) says:
>
>I have been asked a question that I have no idea how to calculate:
>
>If a line of gasoline could be laid out for a mile without evaporating, 
and
>you lit one end, how long would it take for the flame to travel the mile 
to
>the other end? Can anyone help me, please? 
>
>Gasoline vapor burns at a rate of a bit over one ft/sec unless you burn 
it in a pipe. In the confinement of a a pipe of sufficient diameter, you 
can expect a well-mixed gas-air mix near stoichiometry to shift into 
detonation mode after burning a few feet and the reaction can travel one 
mile in about one second.  o


















DOC0056

Subject:      Re: ANSWER TO NOT SO HARD CHEMISTRY A-LEVEL QUESTION.HELP!!!!
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/21
Message-ID:   <3pme7f$cim@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3pl895$nc4@oban.cc.ic.ac.uk>, s.hogg@ic.ac.uk (Simon Hogg) 
says:
>
>
>>OK, but if there are several rate determining steps in a reaction, can 
>you 
>>then write the rate law equation as the simple product of the 
>>concentrations raised to the respective coefficients as was done in the 
>>SPECIFIC example above which I used for my derivation?  If the supposed 
>>RDS is not slow enough to establish the overall rate of reaction then 
>>there is simply no RDS for that sequence.  You are certainly right that 
>a 
>>reaction sequence may have numerous steps which influence the overall
>>rate, but that fact has little to do with the original subject of this 
>>discussion in my often flawed opinion.
>>
>>Jerry
>>
>
>Surely ther is only one rate determinig step for a reaction?!?!?!?
>
>Simon
>
That was one of the poorly stated points I was trying to make.  It seems 
to me that that if one has a reaction sequence with several steps that 
influence the overall rate to similar degrees, then there is no such thing 
as "THE RDS."  Apparently this idea is either wrong or too semantically 
uncertain to be understood, or so I'm told. Sigh.

Jerry




DOC0057

Subject:      Re: Glass
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/21
Message-ID:   <3po5nf$7b5@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



>
>Most glass is just silicon dioxide.  Whether it is crystalline or 
>amorphous glass.  Some glass includes lead (e.g. lead crystal) and some 
>includes boron (e.g. borosilicate glass used in chemistry lab glassware 
>and Pyrex(tm) also, I  think).  You say you want chemical reactions.  
>Reactions involving what?  The production of glass?  
>
>        Si + O2 --> SiO2   
>
>The other reactions (for borosilicate and lead crystal) may be found by 
>doing a little library work.

Hey, you're going to confuse the student with an answer like that.  
Although SiO2 has a "glassy" or vitreous form it certainly is not true 
that "Most glass is just silicon dioxide."  Typically, glass is made by 
dissolving metal oxides in SiO2, most commonly Na2O and CaO to produce 
common soda lime glass.  Lead may be added to give a higher index of 
refraction and make "crystal" or boric oxide may be used to yield 
heat-resistant glass such as "Pyrex."  Sometimes the composition of these 
mixtures is simply written in the form SiO2.xNa2O.yCaO..., but a teacher 
might well want you to show the product in terms of the silicates that are 
actually formed such as Na2SiO3, etc.

Glass is not always made directly from oxides, but may start with other 
compounds such as silicates or borates or materials which form oxides on 
heating. It is believed that the first glass was produced by accident when 
primitive fires melted sand (SiO2) and ashes (carbonates) together, 
driving off CO2 to leave a mixture of oxides (silicates) in the embers.

Of course, modern glass making is much more complicated than my simple 
explanation. Any encyclopedia will furnish a wealth of very interesting 
details.

Jerry






















DOC0058

Subject:      Re: Use of Perchloric acid in non-perchloric acid hood
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/21
Message-ID:   <3pmfan$cim@geraldo.cc.utexas.edu>
Newsgroups:   sci.engr.chem,sci.chem



In article <wpenrose.28.0013B03A@interaccess.com>, 
wpenrose@interaccess.com (William R. Penrose) says:

>The problem comes when the perchloric acid condenses on the oils and 
other 
>organic crud that accumulates in hood ducts.  The organic perchlorates 
will 
>detonate.

Back in the good old days I ran a remote lab or three in which we worked 
with a lot of ammonium and sodium perchlorate as well as various nitrates 
on unfinished wooden benches.  Ocassionally, to protect our hydes, we'd 
remove a table top and destroy it by burning.  The nitrate impregnated 
tops burned with considerable vigor, but those containing a good dose of 
perchlorate salts were downright spectacular.

We also had occasion to deliberately dope blocks of wood with certain 
inorganic chlorates in the name of covert warfare studies.  These little 
items would explode on impact when tossed in the air or struck with a .22 
rimfire bullet.

Not all of us survived those days.  Those of us who did are probably a lot 
more conservative today.

Jerry









DOC0059

Subject:      Re: salt & ice.  Cool beer question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/21
Message-ID:   <3pob32$7b5@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3po6hr$at2@doc.jmu.edu>, connc@sunrise.cs.jmu.edu (charles 
conn       ) says:
>
>A friend of mine told me that we should add rock salt to our
>cooler filled with ice and beer bottles.  He mentioned that this
>would allow the beer to get colder, even to the point of ice
>forming inside of the bottle sometimes.  I was wondering why
>this occurs?  What chemically occurs to allow this to take place?
>Does the salt raise the melting temperature?
>
The salt lowers the melting temperature.  Beware, the mix can easily get 
cold enough to freeze the beer solid and break the bottles by expansion. 
Calcium chloride works even better, because it is more soluble.  If you 
try really hard you could reach 0 deg F.  A fellow named Fahrenheit did it 
once :)

Jerry

















DOC0060

Subject:      Re: Results - Was "Sugar and Diet Coke"
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/22
Message-ID:   <3pp7ch$qrt@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,k12.ed.science



In article <Pine.SUN.3.90.950521191356.3242A-100000@poppy.cs.odu.edu>, 
WILSON BROWN DODSON <wbd@cs.odu.edu> says:
>
>Based on prior help this newsgroup, we conducted our 4th grade science
>fair project on the effect of sugar on 5 different sodas at 3 different
>temperatures (room temperature, set in the hot sun and refrigerated).  We
>recorded the number of ounces left in each can of soda after adding a
>teaspoon of sugar to the can.  We also tried each temperature under 3
>different conditions (a regular can, a shaken can and a can that had been
>left open for 5 hrs). 
>
>At room temperature, the biggest eruption occurred when we opened cans of 
>soda without shaking or leaving them open.  A little less came out of the 
>cans when they had been shaken, and a lot less came out when they had 
>been left open for 5 hours.
>
>When set in hot sun, the results were relatively the same as at room 
>temperature.  However, when left open in the sun for 5 hours, all the 
>carbonation was gone and there was no eruption at all.
>
>When refrigerated, the results were completely opposite from either room
>temperature or being set in the hot sun.  The biggest eruptions were when
>the cans were left open in the refrigerator for 5 hours!???  We haven't
>been able to figure this out.  There was still a lot of carbonation left
>in the refrigerated cans after 5 hours. 
>
>The data appears at the end of this message.
> 
>Apparently, the carbonation has something to do with the eruption effect
>of the sugar.  When a can has been left open for 5 hours, the carbonation
>is gone and the sodas don't erupt at all.  Shaking the can before opening
>it releases some of the carbonation before the sugar is added.  So the
>sugar did not cause as much of an eruption.   We just can't figure out 
>the effect of the refrigeration.  Any help??
>
Can I take a guess, huh, can I (raises hand)?

My guess is that the sugar crystals act like little boiling chips, that is 
they provide tiny nucleation sites for the formation of CO2 bubbles from 
the super saturated solution.  At higher temperatures, the crystals 
dissolve quickly and the nucleation sights are lost before all the excess 
CO2 is purged.  You might test this theory by seeing if you can find a 
preferably porous, particulate material that does not dissolve and watch 
the bubble action on soda pop in a glass or by watching the effect of 
single grains of sugar dropped in a clear container of soda.  Seven up or 
club soda might clarify things (ouch).

Jerry








DOC0061

Subject:      Re: salt & ice.  Cool beer question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/23
Message-ID:   <3ps9rq$s4i@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <efresco-2205951831370001@mfresco.seanet.com>, efresco@Bush.edu 
(E.Fresco) says:
>
>In article <3pob32$7b5@geraldo.cc.utexas.edu>, glhurst@onr.com (Gerald L.
>Hurst) wrote:
>

>> The salt lowers the melting temperature.  Beware, the mix can easily 
>>get cold enough to freeze the beer solid and break the bottles by 
>>expansion. 

>> Calcium chloride works even better, because it is more soluble.  If you 
>> try really hard you could reach 0 deg F.  A fellow named Fahrenheit did 
>>it once :)
>> 
>> Jerry

>First of all Jerry is wrong. 

[Balance of illiterate babbling omitted]

Sorry, Sonny, but Jerry is quite right and, although you are correct
in your statement that CaCl3 (ideally) yields 3 ions per formula unit 
versus only two for NaCl, you have to realize that when a chemist talks 
about "solubility" as a colligative property, he or she automatically 
refers to the relative number of particles in solution, because he knows 
that every other chemist will know enough to factor in ionization or known 
dissociation.

Drop that convoluted explanation of the freezing point depression and
learn something about the molal freezing point depression constant and the 
concept of activity.

Calcium chloride "works better" because it is more soluble in both gram 
formula weights and number of particles in solution at 0 deg C and so your 
ice bath gets to sub-zero quicker. The ultimate low temperature you can 
reach with table salt is slightly below 0 deg F, possibly lower than with 
CaCl2 because of the relatively high temperature coefficient of solubility 
of the latter.  If you think you can figure out definitely which can get 
colder, don't forget to take into account super cooling effects which may 
give transitory lows.















DOC0062

Subject:      Re: salt & ice.  Cool beer question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/24
Message-ID:   <3pulg2$bqo@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <oakes-2305951732300001@toadlike.cchem.berkeley.edu>, 
oakes@lbl.gov (Charlie Oakes) says:
>
[Lots of good stuff omitted]

I got lots of feedback on this subject.  I thank Mr.(Dr.) Oaks for kindly 
reminding me that there is a difference between kinetics and 
thermodynamics and that the molal freezing point depression constant isn't 
really constant.  One can't depend on anything these days, not even 
constants.


That -49.x deg C freezing point depression for calcium chloride brine 
really caught my attention.  Does anybody have a cite for that 
information?  I had no idea it was that great. Is the equilibrium solid 
the hexahydrate at that temperature?  No fair invoking multiple solid 
phases unless they are thermodynamically stable at that temperature.

Jerry















DOC0063

Subject:      Re: salt & ice. Cool beer question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/24
Message-ID:   <3pujgi$bqo@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SGI.3.91.950523201350.15268C-100000@cv4.chem.purdue.edu>, 
Lev Gorenstein <lev@chem.purdue.edu> says:
>
>..................
> in your statement that CaCl3 (ideally) yields 3 ions per formula unit.
>
>Well, Gerald,........... But of course it was a typo of yours.  I'm just 
>using it to show you how bad you looked.
>      
Thanks for the benefit of the doubt about "CaCl3" being a typo. That's 
mighty decent of you.

That was certainly a heartfelt set of flames that followed.  I can only 
say that I humbly apologize to your protege, Zack and that I never would 
have been so unthinking if I had realized my unkind prose would bring such 
swift and barbed retribution. I admire the way you are able to dash off 
your chastizing criticism without a lot of academic fussing over grammar 
and syntax.  This literary ability is rare even for those whose native 
language is English.

By the way, although I understand that you feel that people should not 
talk of solubility in terms of individual ions, I have a technical 
question which I can most easily phrase in such a normally unacceptable  
fashion.  

Given that any cations are acceptable, what set of ionic nitrates in 
about what amounts would produce the highest stable amount of dissolved 
nitrate ion at about 0 deg C. A good place to start might be with Ca(NO3)2 
and NH4NO3?  The question is not merely academic. 

Zack, if you have a bash at this one, I promise to be nice.

Jerry

DOC0064

Subject:      Re: Flash Point (Was: toxicity)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/25
Message-ID:   <3q34tf$dke@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <ctho461.56.000F2FA1@ecy.wa.gov>, ctho461@ecy.wa.gov (Craig 
Thompson) says:
>
>Def 1
>>>The minimum temperature that will enable combustion (or explosion) to 
take 
>>>place.
>
>Def 2 
>>Flash Point
>>- the lowest temperature at which the sample will produce sufficient
>>  vapours that can be ignited by the application of a flame. 
>
>There's a difference?

Well, there's a bit of difference. One might tend to confuse the fire 
point with the flash point.  The former is somewhat higher than the latter 
(someone said a few degrees, but a few tens of degrees might be more 
typical) and corresponds to the temperature at which the (thick) condensed 
source of the vapor will continue to burn if the vapor is ignited. If a 
sample of gasoline has a F.P. of -40 deg (F or C, take your choice) the 
vapor above a (sufficiently deep) pool of the liquid may blow a building 
down, but it will not ignite the pool.  A more rare embrous burning 
material such as charcoal can combust at temperatures way below its flash 
point.

Chemical handbooks are less likely to carry flash point and fire point 
data than they used to be.  Somebody should tell the publishers that the 
ever increasing proportion of high-tech data at the expense of some of the 
old nuts and bolts physical properties of poorly defined materials doesn't 
help us poor dirty-hands chemists who try to analyze the cause and origin 
of fires and explosions.

MSDS sheets are about the best source of flash point data these days. Has 
anybody seen a recent reasonably exhaustive compilation of values or even 
a good old one?

Jerry


















DOC0065

Subject:      Re: salt & ice.  Cool beer question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/25
Message-ID:   <3q189p$7q6@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <oakes-2405951305110001@toadlike.cchem.berkeley.edu>, 
oakes@lbl.gov (Charlie Oakes) says:
>
>it is indeed Dr. Oakes
>
>the -49.x C fpd for CaCl2 is something that i've personally measured.
>the reference to my paper is:
>
>Geochimica et Cosmochimica Acta v. 54 p 603-610 1990
>
>unfortunately i wrote that paper when i was less enlightened than i am
>now and the units are in terms of wt% and my fit is not particularly 
>based on good statistics or for that matter good scientific thought. but
>the data should be of good quality (and least some folks think so).
>
>references to prior fpd measurements in this system are in the paper.
>
>the hexahydrate is supposed to be the stable phase at the eutectic. i
>just took other people's word for that and didnt actually identify it
>myself. in the NaCl-CaCl2-H2O ternary. the dihydrate of NaCl is the
>other stable hydrated salt phase. another possible pt of interest since
>you do allude to metastability is that nucleation of the hydrated CaCl2
>salt and ice for that matter can be particularly tricky in this system
>but that depends on a lot of other factors. my interest at the time
>was with regard to fluid inclusions (a geological thing) and i've found
>that at high CaCl2 mole fractions, nucleation of any solid can be damned
>near impossible in fluid inclusions. going the other way (in temperature)
>the NaCl dihydrate can persist metastably into the NaCl stable field by
>as much as 10-20 C.

Thank you very much for the highly informative reply.  I've had a sort of 
fascination for CaCl2 solutions ever since I did a little work with the 
Michigan brines (35 years ago), reacting them with fired dolomitic 
limestone to precipitate Mg(OH)2, which I subsequently fired into 
Periclase in a zirconia furnace and evaluated for use in steel furnace 
linings.

Is the propensity of the very concentrated solutions to remain 
supersaturated related to the relatively high viscosity?

I have developed and helped to develop some products which rely on what 
I'd call kinetic stabilization to maintain both supersaturated solutions 
and supercooled liquids through transportation, storage and handling, but 
I am far from being an expert in the field.

Jerry










DOC0066

Subject:      Re: salt & ice. Cool beer question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/25
Message-ID:   <3q19ov$7q6@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SGI.3.91.950524022019.16000A-100000@cv4.chem.purdue.edu>, 
Lev Gorenstein <lev@chem.purdue.edu> says:
>
>I hope I wrote my thoughts clearly enough.  In fact I do concern about
>this question (my English, not solubility) very much. 
>
>Lev.
>
Lev,
Your English is more than adequate to carry on any conversion you wish to. 
Most of us wish we could say the same about ourselves with respect to any 
number of languages and probably especially Russian.

Since I don't know Russian, I can't say for sure, but I would guess that 
we take more liberties with our spoken and informally written language 
than you or, say, a typical European would be apt to do in their native 
languages.  In particular, we have a very prevelant habit of developing 
specialized words and phrases peculiar to particular disciplines in 
industry, where we may communicate a lot, but publish little or nothing.

The language used in formal publications is another thing entirely. There 
we show more decorum, and try to write a reasonable facsimile of the 
Queen's English.

In looking at a non-stoichiometric redox reaction, for instance, I might 
say "It's was an 80 O.B. (oxygen balance) mixture."  This phrase would not 
really be understood outside a limited industry where it implies that 
there was enough fuel in the mixture to react with 80 percent of the 
oxidizer present.  Other such jargon may be common over a large number of 
industrial laboratories, but seldom heard in the halls of academe. Of 
course, we all try to remain conversant with the more formal language in 
case one of wins a Nobel prize and has to give a speech :)

Jerry






















DOC0067

Subject:      Re: salt & ice.  Cool beer question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/26
Message-ID:   <3q3upt$qoh@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3ptba1$qh9@ucunix.san.uc.edu>, roberts@ucunix.san.uc.edu 
(Michael Alan Roberts) says:
>

>Calcium chloride is about as soluble as sodium chloride in water, for
>the purposes of THIS discussion. However, you cannot lower the freezing
>point of water to zero degrees Fahrenheit by this method, or even close
>to that figure.

That's a very well thought-out article you composed. You may get some 
flack Lev Gorenstein, who doesn't like to see his young friend criticized 
for lack of coherence (babbling).  The above paragraph, though, has me 
completely baffled. Are you saying that one can't lower the freezing point 
of water with either NaCl or CaCl2 to below 0 deg F ? My understanding is 
that you can go below that temperature with the sodium salt and Dr. Oakes 
tells me that you can get down to below -49 deg C with CaCl2.  
Furthermore, Dr Oakes informs me that CaCl2 forms such a stable 
supercooled liquid at very low temperatures that one cannot induce it to 
precipitate at all.  Sounds to me like reaching 0 deg F would be childs 
play for Dr. Oaks.  I haven't had an opportunity to read the paper he 
published on this subject, but I'm looking forward to it.

Jerry











DOC0068

Subject:      Re: Cleaning Silver in the Home?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/30
Message-ID:   <3qfgj4$14n@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3qafns$aoi@news2.deltanet.com>, Rob Kelle says:
>
>Wow!
>
>This forum is way out of my league.  I searched it out for a reason, 
however.  I recall 
>learing in highschool chemistry a way to clean silver utensils etc. using 
hot water, salt 
>and something else found in most every home.  Could someone please remind 
me of 
>what to use and in what ratios?
>
One method is to place the silver in an aluminum pan under a solution of 
sodium bicarbonate or or you can use glassware and aluminum foil as long 
as the silver is touching the foil. Be sure to wash any oil or grease off 
the silver before treating as this method relies on the electrolytic 
reduction of silver sulfide tarnish.

Copper is often cleaned by scrubbing with vinegar-dampened salt. I use 
this method all the time for my copper-bottom pans. I assume that either 
the chloride or the acetate helps solubilize the copper in the oxide 
tarnish, but I'm sure one or more of the other chemists in this forum will 
tell us exactly what occurs.

Jerry









DOC0069

Subject:      Re: crystals
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/05/30
Message-ID:   <3qffr1$14n@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3qfd0o$gjo@news.ysu.edu>, bg634@yfn.ysu.edu (Itala Sorice) 
says:
>
>
>in an attempt to illustrate the formation of crystals we performed 
>an experiment using various cham. substances(baking soda,epsom
>sl salt, sodium ferrocyanide, ammonium ferric sulfate, pottasium sulf
>sulfate, sugar) A brief sketch of set up--6 test tuv tubes filled
>1/2 with water and 6 subs. added until no more could be dissolved
>A one hole stopper placed in tube e with a string inside and a co
>copper ring on the end.  It sat for 3 days and only the baking 
>soda formed a cystal.  We conclude that the reason why the other
>sol'n didn't form crystatls was because we didn't allow enough 
>solute to dissolve.  Could there be any other explantions?/
>I thank you in advance for any help--please respond to me either
>through gopher or to my E-mail (canf_207)
>itala Sorice

Did you heat the solutions to assure saturation? If you dissolve material 
at room temperature, the solution will only reach saturation after a very 
long time and usually only if you have an excess of the solid. I would 
prepare the solutions at a higher temperature and filter them while still 
warm. If they do not crystallize within a day or so, add a tiny seed 
crystal of the same material to overcome super saturation.  You really 
have to warm sugar solution for a while with stirring because sugar is 
very soluble. The sugar solution is quite viscous and so you must be very 
patient in waiting for the crystals to grow into "rock candy."

Jerry





DOC0070

Subject:      Re: Flash Point (Was: toxicity)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/06/05
Message-ID:   <3qvhje$o7k@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3qv0n4$oqe@seralph9.essex.ac.uk>, whean@solb1.essex.ac.uk 
(Wheatley N) says:
>
>In article <ctho461.56.000F2FA1@ecy.wa.gov> ctho461@ecy.wa.gov (Craig 
Thompson) writes:
>>Def 1
>>>>The minimum temperature that will enable combustion (or explosion) to 
take 
>>>>place.
>>
>>Def 2 
>>>Flash Point
>>>- the lowest temperature at which the sample will produce sufficient
>>>  vapours that can be ignited by the application of a flame. 
>>
>>There's a difference?
>
>Yes, the latter is lower than the former!  If a substance is above its
>flash point, its fumes are flammable - they can be ignited, but not 
unless
>the local temperature exceeds the ignition point (Def 1)
>
>Nigel

Actually, there are cases where the ignition temperature is lower than
the flash point. Embrous combustion, as in the case of charcoal, 
may occur well below the flash point.

Jerry





DOC0071

Subject:      Re: Fluorine gas
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/06/19
Message-ID:   <3s49ng$pie@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3s41tp$5qb@liberator.et.tudelft.nl>, 
dejong@cpt6.stm.tudelft.nl (Maarten D. de Jong) says:
>
>How is fluorine gas handled in laboratory equipment? I've heard somewhere
>that it _can_ be handled in glass, provided it's dryer than the Atacama-
>desert, and the glass is replaced often. While I'm at it, are there any
>uses for pure F2 instead of HF or something similar?
>
Fluorine is usually handled in stainless steel, monel or copper
apparatus. In theory dry glass is OK, but in practice one always
tends to find SiF4 in most reaction products.

Because of it's potent oxidizing power you can make all sorts
of compounds one could not derive from HF. Chlorine pentafluoride
from ClF3, for example, or the ring -CF2N=NCF2- via AgF2 from AgCl
and F2 or the exotic "FEFO" explosive 
F(NO2)2C-CH2-O-CH2-O-CH2-C(NO2)2F
by aqueous fluoination or xenon tetrafluoride or the nitrogen 
fluorides, NF3, N2F4 and N2F2.

When Moses and I were young we used to generate fluorine as we used
it in the lab. Later, when I rebuilt an AEC electrolytic cell I
had the pleasure of collecting tons of the material over a period 
of months in a large home-made SS dewar from which it was moved 
around by cryogenic methods and reacted at about 400 deg F and 
2400 psi in monel bombs with SS bellows valves. For lower pressures
we used Hoke diaphragm valves with home-made copper seats.  We had
a lot of fires and explosions, and got poor milage from our very,
very expensive valves.

In the laboratory, working with metal vacuum systems is a royal
pain compared with glass vac lines. You can pump and flame 
forever after your first reaction, but the degassing of the 
surfaces is never complete.

Jerry




















DOC0072

Subject:      Re: Your view:fundamental question in ENTROPY
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/06/19
Message-ID:   <3s4edm$pie@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <E11541.24.2FE58CC7@CHEMICAL.watstar.uwaterloo.ca>, 
E11541@CHEMICAL.watstar.uwaterloo.ca (Waterloo Team) says:
>
>In article <3s3sk9$1go@news.ecn.bgu.edu> cudap@uxa.ecn.bgu.edu (Donald 
Probst) writes:
>>From: cudap@uxa.ecn.bgu.edu (Donald Probst)
>>Subject: Re: Your view:fundamental question in ENTROPY
>>Date: 19 Jun 1995 13:04:09 GMT
>
>>Jasper Li (ab391@torfree.net) wrote:
>>: De Pauw Edwin (depauw@gw.unipc.ulg.ac.be) wrote:
>>: : In article (Dans l'article) <3qnl2h$13ul@ns3-1.CC.Lehigh.EDU>,
>>: : aas3@Lehigh.EDU wrote (crivait):
>
>
>>: >   Suppose that a chamber is divided into two equal compartments.  
Compartment
>>: >   A contains N atoms (exactly the same) at pressure P and 
temperature T.
>>: >   Compartment B has the same number of atoms at pressure P and T.  
The atoms
>>: >   in A and B are exactly alike physically and chemically except that 
those
>>: >   in A are red and those in B are green.  If thses atoms are allowed 
to mix,
>>: >   does the entropy of the system remain constant or increase ? If 
there is
>>: >   an increase, in what way is there less energy available to do work 
?
>>: >   Does the entropy change, if any, have units of energy/degree 
absolute ?
>>: >   This is a fundamental problem.
>>: : >
>
>>Well, I suppose one way to look at entropy is to examine what would have 
>>to occur to bring it back to its starting state.  For instance, if you 
>>put a ball at the top of the hill, it will roll down by itself,
>>but it won't go back up the hill unless some kind of effort is put 
forth, 
>>either energy or work.  Since for all practical purposes, the green and 
>>red atoms will not by themselves return to their respective 
compartments, 
>>I'd say it constitutes an increase in entropy.
>

>
>The answer to your question depends the final conditions.
>Is the final T and P the same as that of each gas initially?
>Assume that this is so. Then the final total volume is double that 
>of the  each gas initially.  Entropy is increased because the 
>individual gases have been expanded to twice their initial volumes.
>Because of the expansion the gases have lost capacity to do work.
>The total entropy increase is 2Rln2.

OK, then suppose I have a box partitioned into two identical chambers.
Both chambers are filled with air at the same T and P. I call the
left chamber molecules "lefties" and the right chamber molecules
"righties." Now I remove the partition and let the contents mix to
a homogeneous blend of lefties and righties. Does the entropy 
increase?  Of course it does, because the contents of each chamber
have expanded to twice the initial volume. OOPS, that's some kind
of nonsense, isn't it?

Then why do we believe that it might be  different for molecules
which differ only in color? I suggest that the difference lies in
the direction blindness of the Maxwell Demon. If this little guy
had a sense of left and right he could open his frictionless door
only when a molecule (or a hot molecule) was approaching from the 
right and wind up with either all the gas or at least all the hot 
gas in the left compartment, ready to do some work. Since this
phenomenon never seems to occur, we have to conclude that the 
second law is true merely because of the Demon's dyslexia. It 
appears that the demon's weakness applies only to directions, 
not to identifiable physical characteristics. Demons are like 
perceptive semi-permeable membranes; they can select what they
let through. Substitute a non-color blind demon for the 
partitioning piston membrane in the classic experiment which 
illustrates that the mixing of dissimilar gases can produce work
and, voila! you can get work from red molecules moving freely
through the door the the tiny fellow shuts at the approach of 
the blue ones, regardless of the direction of approach.

I propose that the mixing of any two gases results in an increase
in entropy providing only that the two types of molecule differ
in some physical attribute other than the direction of motion.

Jerry













DOC0073

Subject:      Re: Exlosives 2nd try
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/06/20
Message-ID:   <3s7h9f$4u9@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3s6uio$mfm@draco.unm.edu>, bcls@unm.edu says:
>
>        No, I don't want to make explosives and any one who asks me
>can expect a nasty flame.
>        Does anyone know how much (in dollars please) large amounts
>of RDX would be? Say 100 metric tons? This is related to a thread in
>sci.space.tech about the use of explosives as a propellant in space
>engines (please don't post about how strong the material that the
>engine is made out has to be, that isn't relevant for this type of
>engine). RDX is also known as T4; Hexogen; Cyclonite; Cyclotrimethyl
>-trinitramine; 1,3,5-trinitro-1,3,5-triazo cyclohexane; hexahydro
>-1,3,5-trinitro-s-triazine. It is used in many plastic explosives
>so prices there might be enough.
>        The best mix is Compound A-3 which expands at 8837m/s which
>gives a theoretical specific impulse of about 900s (for those of
>you who are interested).

>
It's been a long time since I've purchased any surplus RDX, but
the last material I remember was about one dollar per pound.

Composition A-3 is 9% wax and RDX is already fuel rich so I
would think one could do better with another mix replacing
the wax with an energetic additive having a high oxygen 
balance.

Jerry







DOC0074

Subject:      Re: Your view:fundamental question in ENTROPY
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/06/20
Message-ID:   <3s6v9d$ikk@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3s4llo$7uv@seymour.sfu.ca>, gay@sfu.ca (Ian Gay) says:
>
>In article <3s4edm$pie@geraldo.cc.utexas.edu>,
>   glhurst@onr.com (Gerald L. Hurst) wrote:
>
>[stuff]
>>OK, then suppose I have a box partitioned into two identical chambers.
>>Both chambers are filled with air at the same T and P. I call the
>>left chamber molecules "lefties" and the right chamber molecules
>>"righties." Now I remove the partition and let the contents mix to
>>a homogeneous blend of lefties and righties. Does the entropy 
>>increase?  Of course it does, because the contents of each chamber
>>have expanded to twice the initial volume. OOPS, that's some kind
>>of nonsense, isn't it?
>
>Not really:
>This one has been around for a long time, and is known as the Gibbs 
>paradox (That there is an entropy change when the gasses are different, 
>but not when they are the same - not sure if Gibbs is really the 
>originator.)
>
>The resolution, I think, is that indistinguishability (sp?) is for real, 
>and you have to allow for it when counting microstates. (The infamous N! 
>in the statistical mechanics chapter.) Quantum mechanics rules! (for 
>now)

I am pleased to learn that the illustrious Dr. Gibbs and I have 
something in common. The question of what constitutes distinguishable
characteristics among molecules is precisely what I was attempting
to address.  The Maxwell demon (metaphor for semipermeable membrane)
cannot distinguish between left and right and he cannot distinguish
molecules by their history of residing in compartment A or B.

When we pose a question relating entropy to the "color" of molecules, 
the real question is "what do we mean by color." The implied meaning
is that the color has no real effect, i.e that there is no real method
that could be used to separate the species. If this is so then the
entropy of a mixture of reds and blues is only higher than that of
the pure colors because I say it is, that is because the same demon
who can segregate by color could just as well know left from right
or lefties from righties (by tracking their histories) and could
give us perpetual motion.

Entropy as a philosophical concept of the measure of randomness may
well concern itself with colored molecules, but thermodynamics as
a science concerned with energy might consider mixtures of reds
and blues no more entropic than lefties and righties despite the
fact that we are able to express the exact delta S in terms of
(unavailable) energy and temperature.

Jerry 





Jerry





















DOC0075

Subject:      Gas expansion and plate velocities
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/06/26
Message-ID:   <3slbd2$e7a@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In an article posted in sci.chem,<3s6uio$mfm@draco.unm.edu>, bcls@unm.edu
expressed the opinion that RDX or more specifically the wax impregnated
version, A3, might make a good propellant. He apparently based his opinion
on the erroneous assumption that the detonation velocity could be used as
a basis for calculating specific impulse"

       	 " The best mix is Compound A-3 which expands at 8837m/s which
         gives a theoretical specific impulse of about 900s (for those of
         you who are interested). "

Arno Hahma (In sci.chem article <DALGEs.6pF@utu.fi>, arno@utu.fi)
pointed out that the expansion velocity of the gases was at most about 
3,000 m/s and that this lower figure would yield a much lower Isp:

	"No it doesn't. The shockwave does propagate about 8800 m/s,
	but not the material itself. The propagation velocity of the
	particles (i.e. the gases) is about 3000 m/s at best.

	RDX has an Isp of 2561 Ns/kg from an expansion ratio of 100:1.
	That translates to about 260 s."

I don't want to put words in Mr. Arno's mouth, but I assume that he is 
talking about the "free surface velocity" of the particles, not the 
"particle velocity,"that is, that he is referring to the faster of the 
two phenomena.

Bill Nelson (in sci.chem article <3sg6o8$qja@odo.PEAK.ORG>,
billn@PEAK.ORG) agreed with Mr. Hahma:

	"Wrong. The propogation rate of the shock wave is about 8800 m/s
	(at a high enough density). The rate of material expansion is
	about a third of that.

	Reduce the velocity to 3000 m/sec, and the Isp becomes about 300s,
	which  is not exceptional at all."

It is a well known fact that lined cavity shaped charges using materials
like RDX can accelerate metal jets to velocities in excess of 7,000 m/s 
by collapsing a cone and, for lack of a better analogy, squirting a stream
of particles out like fast grapefruit juice drops propelled by a slow 
spoon. In other words, the hot gasses can propel part of the metal lining 
at velocities much higher than those of the of the gas molecules 
themselves.

Metal projectiles can also be accelerated to hypervelocities by focusing
the detonation wave in a block of explosive into a "reentrant" 
configuration using a solid cone of steel or glass implanted in the 
charge.

But what about the case of a plane explosive wave striking a flat metal 
plate? (That's "plane," i.e. "flat." not "plain.")

The very capable explosives group at duPont, many years ago published
a couple of patents on the use of plane wave driven steel plates to 
generate extreme pressures on impact for phase change reactions (i.e.
carbon to diamond) and for sintering refractory materials (i.e.diamond
dust).

The charges used were  60/40 composition B or the like (close enough
to composition A3 in performance for our purposes) initiated by a plane
wave generator.  The detonation heads of the rather large charges (20 lbs
or so) were used to propel steel plates of about 1.3 mm thickness (in the
case of sintering ) to about 5  mm  (for phase changes) over a distance of
about 4 cm.  The reported terminal velocities of  the heavier projectiles
were about 3,500 m/sec - a bit more than the gas expansion velocities
mentioned by Mr. Arno and Mr. Nelson. However, the lighter plates, as I
recall, were reported to have been accelerated to about 5,000 m/s, a value
slow by comparison to shaped charge jets, but fast compared with reported 
gas cloud expansion velocities.

Now comes the tricky part: How to explain why duPont's plates are
reported to move faster than Mr. Arno's and Mr. Nelson's gas molecules?

One possibility, of course, is that I have had another memory lapse
concerning duPont's data :)

Jerry

DOC0076

Subject:      Re: Gas expansion and plate velocities
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/06/26
Message-ID:   <3slcip$e7a@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



Pardon me for posting the subject article "Gas expansion 
and plate velocity" in this forum. I was excerpting 
material relevant to alt.engr,explosives and accidentally 
sent the edited document to sci.chem in the "synopsis and 
comment" form designed for the other group.

Jerry





DOC0077

Subject:      Re: H2S instead of H2O
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/06/26
Message-ID:   <3sl1ft$e7a@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3skb3v$cf4_006@netcom.com>, eleusis@netcom.com (Eleusis) says:
>>
>> Since I'm always curious about possible
>>alternatives to life as we know it, I'm wondering whether H2S
>>might have properties similar to H2O that would also let it
>>serve as a suitable solvent. I'm not assuming that the same
>>biomolecules would be involved.
>
>
>Good question. The answer is: They both will kill you if you breath them.
>
>Really, H2S is an extremely poisonous gas with the odor of rotten eggs. 
Of 
>course, breathing water will drown you, but that is where the similarity 
>ends ;-).
>
Poisonous to us Humans, yes, but there are creatures in the sea
( e.g. tube worms, I believe) that are nourished by H2S escaping 
from volcanic vents. I remember once marveling at bacterial 
growth on the surface of a sodium thiosulfate solution in a chem 
lab bottle.  I guess one species' poison is another species' 
meat and potatoes. Who knows whether there is some critter in 
the universe that swims in a hydrogen sulfide sea? Personally, 
I tend to favor ammonia as the alternate to water, but that may 
be simple prejudice on my part.

Jerry







DOC0078

Subject:      Re: What are HCI and NaOH????
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/07/03
Message-ID:   <3t82da$dm@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3t6rk8$ej1@oban.cc.ic.ac.uk>, s.hogg@ic.ac.uk (Simon Hogg) 
says:
>
>
>>
>>In article <101323Z30061995@anon.penet.fi> an297554@anon.penet.fi 
writes:
>>>From: an297554@anon.penet.fi
>>>Date: Fri, 30 Jun 1995 10:12:27 UTC
>>>Subject: What are HCI and NaOH????
>>
>>
>>>What is HCI and what is NaOH?
>>>Please follow the h2o = water / n2o = nitrous oxide format.

>>HCl = hydrochloric acid / NaOH = sodium hydroxide
>
>Why did the original post come via an anonymous server????
>
If you spelled HCl with a capital "I" you'd want to remain
anonymous too.













DOC0079

Subject:      Re: help!  where can i buy iron sulfide?!  (or make my own!)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/07/09
Message-ID:   <3tnoj4$i28@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3tkgbp$1l2@chem1.chem>, jejanes@mtu.edu (Jeff E. Janes) says:
>
>JMacd (jmacdon1@fox.nstn.ns.ca) wrote:
>: i tried to make it myself by placing powdered sulfur and iron fillings 
in a
>: test tube and heating it, but all that gave me was a hard yellow lump 
with
>: iron specks in it, not iron sulfide as it was attracted to a magnet.  
it
>
>Did you try crushing the hard yellow lump and look through remains for
>more iron?  If there seemed to be less iron specks than what you started
>with, it had to go someplace, maybe into iron sulfide.  Sulfide with
>bits of iron embedded in it would be attracted to a magnet.
>
Try adding some water to the Fe/S mixture. The mixture will furnish
its own heat after a bit and boil the water while making FeS.

Jerry















DOC0080

Subject:      Re: Need info on cryogenics
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/07/26
Message-ID:   <3v4n09$se3@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SGI.3.91.950725192256.27288A-100000@cv4.chem.purdue.edu>, 
Lev Gorenstein <lev@chem.purdue.edu> says:
>
>On 23 Jul 1995, Roy Newton wrote:
>
>> I have been required to do a speech for a class.  The topic that 
>> I have chosen is cryogenics;  specifically, people who have terminal 
diseases
>> and are being frozen in hopes that we will find a cure and a method for
>> dethawing somewhere in the furure.
>> Information on this topic has been difficult to find.
>> Any info will be greatly appreciated.
>> 
>> Please respond via email:  rynewton@infi.net
>
>Was there any real person who went for this?  The idea itself was long 
>ago discussed in SciFi and media, but in real life was it ever done?  
>Just curious.
>
>Lev.
>
Yes, it's been done many times. For a vivid description see a 
book titled something like "The Great Mambo Chicken...." I've 
got a copy around here somewhere, and, if I find it, I'll post 
the exact Title or send email. There are or were no less than 
two companies in the business.  They use liquid N2 to freeze 
and maintain bodies in large Dewars for a price. Or you can get 
the economy process in which they merely sever and freeze your 
head.  The heads apparently tend to split open, but I guess 
they figure future generations will be able to handle that 
little problem.

Personally, I prefer the California economy burial ($200) in 
which they put you in a spike-shaped coffin and hammer you into 
the ground. 

Jerry



















DOC0081

Subject:      Re: Need help finding C-N compounds
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/03
Message-ID:   <3vpre0$lkg@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3vpaf7$dt3@solaris.cc.vt.edu>, teter@vtaix.cc.vt.edu (David M. 
Teter) says:
>
>
>I am trying to obtain some  C-N compounds for my research.
>
>All I have been able to get so far is tetracyanoethylene (C6N4).  
>
>I would appreciate if anyone could give me a source for:
>
>        tetracyanomethane (C5N4)
>        dicyanoacetylene  (C4N2)
>        cyanuric triazide (C3N12)
>
>If anyone knows of any other C-N compounds, and a source for
>obtaining them, please let me know.
>
How about my personal favorite, cyanogen, (CN)2? I made and 
fluorinated this nifty little molecule to make the explosive 
four membered ring -CF2-N=N-CF2- way back when chemistry
was still a respectable profession.

Jerry











DOC0082

Subject:      Re: Twink - What's in it?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/06
Message-ID:   <401qj2$g87@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3vv4j3$l86@tpsun.taranaki.ac.nz>, Stephen Watkins 
<swatkins@taranaki.ac.nz> says:
>
>Hi -
>
>Could anyone tell me exactly (well, more or less) what chemicals go
>into correction fluid? Also, what was the purpose of the 1,1,1 
>trichloroethane that was added to the fluid a couple of years ago?
>
Specifically, I better not say, but generically the ingredients are:

Solvent
Resin
Plasticizer
Dispersing agent
Pigment
Toner

1,1,1-trichloroethane was not "added" a couple of years ago in the 
USA or Europe. It was in widespread use in those areas in the  
1970's. In those days ozone holes were not a problem and the compound 
was THEN considered the safest of the chlorocarbons. Today one might
choose a CHF compound for such an application requiring low 
falmmability and high evaporation rate.

There are, of course, also water-based fluids which are sometimes used
for photocopy correction. These formulations dry more slowly.

Jerry





DOC0083

Subject:      Re: Ammonia gas removal from air.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/07
Message-ID:   <404g83$3jn@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <404dfp$7ja@news.sas.ab.ca>, rdh@fn1.freenet.edmonton.ab.ca () 
says:
>

>
>I don't believe there is any dry chemical to scrub ammonia from the air. 
 
>Ammonia scrubbers require wet conditions, low pH, and a packing tower (or 
>the like).  The only "dry" chemical that would come close to removing 
>gaseous ammonia is calcium hypochlorite dust.  This would oxidize ammonia 
>but wouldn't be effective and may produce a dust far worse than the 
>ammonia ever could be.
>
I don't see why solid ammonia absorbants wouldn't exist. We use
numerous salts to remove water from air by forming hydrates. There 
are many instances where an ammoniate is more stable than the 
analogous hydrate and it follows that the corresponding substrate 
salts should also be capable of absorbing gaseous ammonia 
preferentially.

Jerry













DOC0084

Subject:      Re: Ceramic-filled Paint
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/07
Message-ID:   <4048j4$3jn@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <1995Aug6.053305.16579@lafn.org>, ab425@lafn.org (Walter 
Blackman) says:
>
>
>Does anyone in cyberspace know about the effectiveness of Ceramic-filled 
>paint and whether its properties warrant its application as a house 
paint?
>
>Would appreciate any information on this type of application and whether 
>its hype as used on space tiles makes it a good choice for a water based 
>paint on my house in ~Los Angeles?
>

Sounds like mousemilk to me. The normal titanium dioxide pigment used
in ordinary white paint is more than adequate in its role. A ceramic
powder would likely not have the high refractive index of TiO2 and
would provide less hiding power. Nobody really cares about hiding power 
for reentry vehicle tiles and we certainly don't need to protect houses
from reentry environments.

Jerry













DOC0085

Subject:      Re: The quick & easy "lava lamp"
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/07
Message-ID:   <405u74$boi@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <405gs5$cmv@sunsystem5.informatik.tu-muenchen.de>, 
fenk@Informatik.TU-Muenchen.DE (Connor) says:
>
>Jim Webb (jnw4347@email.unc.edu) wrote:
>: After a great deal of experimenting, I've recently found a simple and 
cheap 
>: recipe for making these chemistry demos, which does not involve 
hard-to-get 
>: (and pricey) benzyl alcohol. It's so easy, my mind reels with the 
>: possibilities: lava lamp street lights? lava lamp votives? lava lamp 
hood 
>: ornaments? lava lamps with lampshades?
>
>: Enjoy.
>: Jim
>
>Great. Thank you very much. 
>
>I have searched nearly 2 months for a solution of this problem. But
>there was nobody who can give me a answer. Postings in german
>newsgroups, asking in shops where they have such lamps, the men from
>the Technischen Museum Muenchen even don't knew it and have bought the
>liquids, WEB and library search - all negativ. 
>
>I have tryed to use wax and water (glycol, later alcohol), because
>some told me. With alcohol it works a little, but the wax wasn't
>liquid.
>
>The last solution seems to be, buying a replacement glass cylinder
>filled with these mysterious liquids, but it is expensive ...
>

May I suggest that you try a mixture of heavy mineral oil and a
dense (>1.0), water insoluble organic liquid or solid? A starting 
point might be a blend of the oil with a phthalate ester adjusted 
to yield a specific gravity slightly higher than water. Obviously,
one of the chlorowaxes might also serve as denser component.

I'll bet others in this forum can come up with a hundred other
candidates.

One problem you may have to look out for is the possibility that
some organic phases will tend to emulsify at the interface. but
you can check this with a simple test tube experiment.












DOC0086

Subject:      Re: Twink - What's in it?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/07
Message-ID:   <4049fr$3jn@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <B.Hamilton.540.3024EE64@irl.cri.nz>, B.Hamilton@irl.cri.nz 
(Bruce Hamilton) says:
>
>In article <3vv4j3$l86@tpsun.taranaki.ac.nz> 
>Stephen Watkins <swatkins@taranaki.ac.nz> writes:
>
>>Could anyone tell me exactly (well, more or less) what chemicals go
>>into correction fluid? 
>
>My guess would be a white pigment with good blocking power,
>perhaps titanium dioxide, along with some binders and thinners. 
>You might like to contact Mitchell and Dean Limited of Auckland, as they
>produced it.
>
>>Also, what was the purpose of the 1,1,1 
>>trichloroethane that was added to the fluid a couple of years ago?
>
>It was the volatile, non-flammable thinner that enables Twink to dry 
rapidly. 
>The higher density of organochlorine solvents allowed them to disperse
>the pigments and binders for longer - but they still required agitation,
>just like paint. 1,1,1-TCE was replaced because it is due to be phased 
out
>under the ( ozone layer protecting ) Montreal Protocol.
>
TiO2 is correct, but the choice of 1,1,1-TCE had nothing to do with
the relatively high density of the chlorinated materials. Viscosity
and thyxotropy control are much more important factors because of the
large difference between the density of TiO2 and any common solvent,
chlorinated or not. I wish I were free to discuss the technical
aspects of type correction fluid formulation in greater detail. There
is a great deal more art and science associated with these mixtures 
than one might suppose.

Jerry





















DOC0087

Subject:      Re: Potassium Permanganate - What is it?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/08
Message-ID:   <406t6f$26k@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <martind.1.001105FC@lincoln.ac.nz>, martind@lincoln.ac.nz (Dean 
Redfearn Martin) says:
>
>Hello all. I have just found a bottle in my shed labelled Potassium 
>Permanganate. I was wondering if anyone could tell me the typical uses 
for 
>this. Is it likely to be useful to me, or should I just throw it out? If 
the 
>latter, how should it be disposed?
>
Dilute solutions of the material used to be used to kill athletes
foot fungus. It is a strong oxidizer, so you don't want it in 
contact with organic materials. Acids are also a no-no because
they exacerbate the oxidation problem. It's nice to see someone
trying to get rid of the stuff for a change. The kids on the net
are always looking for the stuff for pyro purposes. Permanganate
is used by bluejeans manufacturers to bleach (streak) denim
to make it look old.

If you have any chemist friends, offer it to them. I've got a bottle
of the stuff around here somewhere, myself - left over from some
consulting job or other.

Hmm. Anybody need a gallon or so of merthiolate tincture, I think 
I've got some in the garage near the old cans of vinyl alcohol. Sigh.

Jerry

Jerry





DOC0088

Subject:      Re: RECIPE FOR NITROGEN TRI IODIDE WANTED
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/08
Message-ID:   <406rmm$26k@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SGI.3.91.950807163302.17459B-100000@cv4.chem.purdue.edu>, 
Lev Gorenstein <lev@chem.purdue.edu> says:

>
>> Warning: Don't get iodine on clothing or cloth, it'll turn purple.
>
>Oh yeah!  Now I'm certainly sure that you are an idiot.  Of course, 
>purple clothes is the biggest danger of this process...  Hell, and we 
>hear this crap from a person from Harward...
>
>
More likely brown than purple.

Jerry




















DOC0089

Subject:      Re: Titration of Nitric Acid with Sodium Hydroxide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/08
Message-ID:   <406rve$26k@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <406bbg$sk2@earth.superlink.net>, nancy@mars.superlink.net 
(Nancy Gold) says:

>
>1) NaOH as a titrant can cause problems due to the effect of air 
oxidation
>to form carbonates.


Neat trick, oxidizing NaOH to form carbonates :)

Jerry






















DOC0090

Subject:      Re: Twink - What's in it?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/08
Message-ID:   <408bud$rph@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <95080823102915782@welcom.gen.nz>, jim.oliver@welcom.gen.nz 
(Jim Oliver) says:
>
>glhurst@onr.com (Gerald L. Hurst) wrote :
>
>GLH>In article <B.Hamilton.540.3024EE64@irl.cri.nz>, 
B.Hamilton@irl.cri.nz
>GLH>(Bruce Hamilton) says:
>GLH>>
>GLH>>In article <3vv4j3$l86@tpsun.taranaki.ac.nz>
>GLH>>Stephen Watkins <swatkins@taranaki.ac.nz> writes:
>GLH>>
>GLH>>>Could anyone tell me exactly (well, more or less) what chemicals go
>GLH>>>into correction fluid?
>
>[edited]
>
>GLH>>1,1,1-TCE was replaced because it is due to be phased out
>GLH>>under the ( ozone layer protecting ) Montreal Protocol.
>GLH>>
>GLH>TiO2 is correct, but the choice of 1,1,1-TCE had nothing to do with
>GLH>the relatively high density of the chlorinated materials. Viscosity
>GLH>and thyxotropy control are much more important factors because of the
>GLH>large difference between the density of TiO2 and any common solvent,
>
>All true.
>
>GLH>chlorinated or not. I wish I were free to discuss the technical
>GLH>aspects of type correction fluid formulation in greater detail. There
>GLH>is a great deal more art and science associated with these mixtures
>GLH>than one might suppose.
>
>Aww cummon Jerry, any half decent paint/resin/polymer/adhesive
>chemist could knock up a batch of correcting fluid. As you said
>yourself in another message :
>
>Solvent
>Resin
>Plasticizer
>Dispersing agent
>Pigment
>Toner
>
>Easy peasy. :-)
>
>It doesn't have to : Pass crosshatch tests.
>                     Last forever under sunlight + rain etc
>                     Have good gloss or be very matte.
>                     Have long shelf life (buy MORE !).
>                     Have extreme flexibility.
>                     Have good heat / cold resistance.
>                     Have good moisture transmission.
>                     Have close tolerances on P.V.C.
>                     etc etc etc.
>
>A good paint coating has to have all these things !
>
>Almost _any_ acrylic/styrene/PVC/ABS etc resin would suffice as
>binder suitably tarted up with plasticisers . Pigment grind
>tolerances could be comparitively very wide without any
>detrimental performance. Most soluble resins have good thixotropy
>in perchloroethyelene (now used in Twink), therefore no need for
>antisettle agents either.
>
>And if it does fail in service - who cares ? Not exactly a
>million dollar claim is it ?
>
>The only easier "household" item I can think of is that gunk that
>is squirted _directly_ down the toilet bowl to kill germs or
>clean "under the lip" or whatever. Become a millionaire overnight
>with that stuff.
>
>Tell us more  :-)

Golly, I didn't realize there was someone around who knows so much
more than I do about type correction fluids. Maybe I should give
back the money the Liquid Paper Corporation (Gilette) paid me
me to formulate their products.  It's a good thing their research
staff chemists didn't know how easy it is or they might have
(shudder) done the job inhouse.

BTW, there are very good reasons why most of the resins you named
are not suitable for a COMPETITIVE market and those reasons do not
apply to standard paint materials. Pigment grind  and other
properties of the TiO2 are much MORE demanding than is the case
with paints. Perchloroethylene is a very poor solvent choice; it 
was used in some other brands in the 1970s.

Isn't it funny how easy the other guy's work always seems to be?
Have you considered the possibility that correction fluids may have
their own set of criteria to be met, quite independent of those
of housepaint. I am a bit puzzled that you included flexibility
and shelflife in your list of properties not required. You might 
give those two items a few more seconds of thought.
 

Liquid Paper outsells all other brands of correction fluid combined
with annual factory sales of several tens of millions of dollars.
Perhaps you should take advantage of the situation and grab their
market with, uh, oh yeah Twink :) 

Jerry




















DOC0091

Subject:      Re: imperial units to si units conversion
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/08
Message-ID:   <406rgd$26k@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <405vv8$lbg@oban.cc.ic.ac.uk>, kz <k.zheng@ic.ac.uk> says:
>
>Dear netters,
>
>Does anyone knows of any software packages that would do
>the above conversions? 
>
>Many thanks indeed.
>
>
>My old Hewlett Packard HP41C does a pretty good job. 

Jerry





















DOC0092

Subject:      Re: sucrose density
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/08
Message-ID:   <408cfu$rph@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <95080823102915783@welcom.gen.nz>, jim.oliver@welcom.gen.nz 
(Jim Oliver) says:
>
>dpn@mailhost.tcs.tulane.edu (David P Norwood) asks :
>
>DPN>A coworker of mine needs the density of solid sucrose.
>DPN>Anybody know it?
>
>Not offhand.
>
>Get a measuring cylinder (or similar). Half fill it with water
>and note the fill point. Preweigh the whole thing. Shovel in
>sucrose until it's nearly coming over the top, the sucrose must
>be all wetted down (no air bubbles). Now reweigh it and note the
>increase in volume. Calculate the rough density by dividing the
>increase in weight by the volume increase. Density = Mass/Volume.
>
>Jim Oliver <jim.oliver@welcom.gen.nz> (3:771/370)
>
> * SLMR 2.1a * Shin: Device to find furniture in the dark ....

Is this supposed to be a joke? This technique only works with
insoluble materials.

The density of sucrose is 1.587.

I want to apologize to Mr. Oliver for my post this date re type
correction fluids (Twink-What's in it). I thought Mr. Oliver was
a chemist and commented accordingly, but now I see that this is 
not the case.

Jerry


DOC0093

Subject:      Re: Twink - What's in it?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/16
Message-ID:   <40s59d$5gc@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <B.Hamilton.570.30290F19@irl.cri.nz>, B.Hamilton@irl.cri.nz 
(Bruce Hamilton) says:
>

>I believe the original developers of computers did so solely to avoid
>Correction Fluids. They probably assumed that us chemists would
>develop a screen cleaner that would rapidly remove the correction 
>fluid without damage - we have failed them miserably. 
>
>However, I've had this * really bright * idea. - Coloured Correction 
>Fluids.  So many people use word processors that indicate attributes 
>by differing colours, and also use differing background colours, that
>the future market has to be in sets of coloured correction fluids.   
>
When I was busy developing type correction fluids (long ago), I 
assumed that the stuff would become obsolete in a year or so
because of the rapidly increasing number of word processors.
Ironically the sales have increased over the years as a result
of the increase in the number of photocopies which have to be 
altered as a result of changing prices in published price sheets.
Folks now make hundreds of copies of things we used to make in
triplicate and they usually have to make mass corrections that
don't warrant reprinting the whole batch.

Colored type correction fluid has been available for years. It
is custom formulated for executives to match the color of their
stationery.  Ah, decadence.

Although I have tested a zillion strokes of correction fluid in
the lab, the thought never occured to me to actually use the
material for my own correspondence. 

Someone remarked that type correction fluid formulations are a
low tech matter. Ain't it the truth !! As a working chemist for
many decades I have labored in rocket propellants, explosives,
coatings, plastics, pigments, forensics, general organic and 
inorganic synthesis, thermodynamics etc. and I have never done 
a thing one could consider "Hi Tech." Each year there seem to be
fewer guys around who know much about low tech subjects. I like
to think they'll miss us when we're gone :)

Jerry














DOC0094

Subject:      Re: sucrose density
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/16
Message-ID:   <40s8n1$5gc@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <95081004175915865@welcom.gen.nz>, jim.oliver@welcom.gen.nz 
(Jim Oliver) says:
>>by e-mail.
>
>Tell me, if you didn't have the figure in a book of sucrose just
>how would you determine it's density ?
>
>[Another more polite person pointed out (by e-mail) that the
>method I outlined would be better done using a solvent that the
>sucrose was insoluble in, maybe hexane or other less volatile
>solvent.]
>
Your more polite person is correct. You are trying to use the 
principle of Archimedes, but, in order to assure accuracy, you
must use a liquid which does not dissolve substantial quantities
of the solid being measured. If the solid is soluble, your 
accuracy will be a matter of the degree to which the sum of
the volumes of the components matches the volume of the solution.
The expansion or contraction of the total volume during 
dissolution will vary according to the solid/liquid combination
and the concentration.

I gather that your friend Bruce Hamilton has run the experiment
you outlined using sugar and water and that he got the value he
knew he would get based on the well-known tables of specific
gravity for sugar solutions. Is this part of a straight-faced
comedy routine by you two?  

Jerry





DOC0095

Subject:      Re: sucrose density
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/18
Message-ID:   <412qls$r50@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <B.Hamilton.571.30341CCE@irl.cri.nz>, B.Hamilton@irl.cri.nz 
(Bruce Hamilton) says:
>
>This hardly worth responding to, but just in case
>anybody seriously believes these comments...
>
>I detailed the experiment I performed.  Anyone can duplicate
>it - I performed it during a morning tea break at work. 
>If you don't get a similar answer, I'd be very surprised.
>
>I also explained why I decided to perform it -  It was not intuitive 
>to me that sensible results would be obtained. However, unlike
>some, I decided not to post until I had tried the experiment.
>I was surprised how accurate it was. 
>
OK, now try the same experiment using roughly the same technique
with,say, ethanol. Or better yet, let me dry-lab it for you and 
give the final result: density = ca 0.84 vs 0.79 handbook value.  
Or how about a thought experiment involving the measurement of 
the density of ice; the result depends on how much ice is allowed 
to "dissolve" (read melt) at 0 + deg and the range is some 10%.

Phase changes are typically accompanied by changes in the apparent 
molar volume of the substances involved. It can happen that the
change is positive, negative, large or small. In the case of
sucrose, the data indicate that the change happens to be small.
The method, however, is clearly useless for determining the 
density of materials whose properties have not already been
tabulated unless errors of 5-10 percent are considered acceptable.

>I'm glad I bothered to perform the experiment, rather than
>make disparging comments about the suggestion, I now
>know another quick and dirty non-intuitive technique for
>density.
>
The technique is indeed quick, dirty and non-intuitive.

Jerry


















DOC0096

Subject:      Re: colloidal potassium
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/27
Message-ID:   <41qjqe$1pd@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.chem.organomet



In article <Pine.OSF.3.91.950827012950.32326B-100000@plato.ucs.mun.ca>, 
Brian Watson <brianwat@morgan.ucs.mun.ca> says:
>
>
>I am interested in preparing coloidal potassium by ultrasonic dispersion, 
>for a Dieckmann condensation, and possibly for other reactions such as 
>the acyloin condensation.  I tried making colloidal potassium, using 0.3g 
>potassium in 20ml toluene in a 100ml rbf, sonicated with a 35kHz cleaning 
>bath.  I obtained negligible dispersion even after an hour and 15 min.  
>The paper I was roughly following (Tet.Let 1984 p.753) claimed to 
disperse 
>78mg potassium in 15 min, using a standard ultrasound cleaning bath of 35 
>kHz.
>
>Does anybody have any advice?  I have never used sonication before.  Are 
>factors such as position in the bath, type of reaction vessel etc 
critical?
>Also, I would be very interested in any references for the use of either 
>coloidal potassium or graphite supported potassium in organic synthesis.
>
You  didn't mention temperature, but if you have not already done
so, you need to heat the mixture above the melting point of the
potassium. If you do form the emulsion, you can expect that the
colloidal spheres of potassium may remain in the liquid state on
cooling to merely warm temperatures, that is they may supercool.

I once patented a series of dense, metallized greases prepared 
by emulsifying low melting alloys (e.g. Woods metal) with 
greases such as the silicon materials. I purchased an ultrasonic 
unit with a titanium cup for use in preparing the emulsions, but 
soon determined that ordinary mechanical mixing with good shear 
worked much better. Of course, the metals I was working with were 
much denser than potassium so your results may be different.

BTW, the dense greases (>5.5 g/cc) were intended for use in the
bearings of submersible oil well drill bearings in units 
operating under dense drilling mud, which tended to float out 
lighter greases.

Jerry
















DOC0097

Subject:      Re: sucrose density
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/27
Message-ID:   <41qmvp$1pd@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



  Article Segment 1 of 2
  
In article <B.Hamilton.571.30341CCE@irl.cri.nz>, B.Hamilton@irl.cri.nz 
(Bruce Hamilton) says:
>
>
>This hardly worth responding to, but just in case
>anybody seriously believes these comments...
>
>In article <40s8n1$5gc@geraldo.cc.utexas.edu>
> glhurst@onr.com (Gerald L. Hurst) writes:
>
>>I gather that your friend Bruce Hamilton has run the experiment
>>you outlined using sugar and water and that he got the value he
>>knew he would get based on the well-known tables of specific
>>gravity for sugar solutions. Is this part of a straight-faced
>>comedy routine by you two?  
>
>Firstly, I've mainly had contact with Jim Oliver on sci.chem,
>or email concerning the FAQ. Colleague in the same city - yes,
>friend - no.
>
>I detailed the experiment I performed.  Anyone can duplicate
>it - I performed it during a morning tea break at work. 
>If you don't get a similar answer, I'd be very surprised.
>
>I also explained why I decided to perform it -  It was not intuitive 
>to me that sensible results would be obtained. However, unlike
>some, I decided not to post until I had tried the experiment.
>I was surprised how accurate it was. 
>
>The idea of using alternative solvents does create disposal 
>problems, and the water result is probably close enough for 
>many purposes.
>
>I actually performed the experiment before I consulted
>Merck - but nobody is obligedly to believe that - I am
>as aware as anyone about the bias of knowing the answer
>in advance. If I'd had more time I would have tried the
>my suggested volumetric flask enhancement, but I hadn't
>expected the quick and dirty measuring cylinder method
>to be accurate for water-soluble material.
>
>I'm glad I bothered to perform the experiment, rather than
>make disparging comments about the suggestion, I now
>know another quick and dirty non-intuitive technique for
>density.
>
>             Bruce Hamilton


The above exchange was followed by an email dialog 
with Jim Oliver in which I continued to challenge 
and he to defend the use of the principle of 
Archimedes to measure the density of SOLUBLE solids. 
In my last message to Mr. Oliver I promised to try 
to post a clear example of the inadequacy of the 
method for even what Bruce Hamilton described as 
"another quick and dirty non-intuitive technique for 
density."

The following thought experiment using arbitrarily
selected sodium hydroxide appears to satisfactorily
demonstrate that the method is unreliable:

Dry sodium hydroxide pellets (76.5 g, 15 deg C) are 
placed a 100 ml graduated cylinder or volumetric 
flask 0f known weight. Water is added slowly with 
intermittent agitation and cooling until the 
contents are at room temperature and occupy 
100.00 ml. The mass of the added water (76.5 g) is 
determined by reweighing the filled flask and 
subtracting the sum of the tare weight and the 
weight of the sodium hydroxide. 

Using the principle of Archimedes, we assume that the 
added water occupies a volume of 76.5 ml and that the 
volume attributable to the NaOH must be 100 - 76.5 = 
23.5 ml. The calculated density of the NaOH is about
76.5/23.5 = 3.26 g/ml.

Reality check: According to the Merck Index a 50/50 
NaOH solution has a density of 1.530 g/ml, confirming 
that our 100 ml volume is correct for the 2X76.5 g of 
water and NaOH we combined in the container.

Merck also tells us that the density of solid NaOH is 
about 2.13 g/ml.  Assuming that the Merck index value
is valid, the calculated error in our measurement is
approximately (3.26 - 2.13)/2X100 = 56.5%

If this same experiment is run using a final NaOH
concentration of only 10%, it will be observed that
the specific gravity of the of the solution becomes 
1.1110 at 20 deg according to the CRC. Given that 
the mix is 90 wt. percent water the original volume 
of water added to form the 100.00 ml solution must 
be 0.9X1111.0 = 99.99 ml.


DOC0098

Subject:      Re: sucrose density
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/27
Message-ID:   <41qmvp$1pd@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
  
  
For Archimedean purposes we must assume that
the effective volume of water in the experiment 
remains constant at 99.99 ml. Under this necessary
condition, the volume attributed to the NaOH must 
be the difference between the volume of the
solution and the volume attributed to the water,
i.e. 100.00-99.99 = 0.01 ml.  The weight of the 
sodium hydroxide unnecessarily corrected for the 
slight numerical difference between the density 
and the specific gravity of water at 20 deg is
0.1X111.10X.9982 = 11.090 g.  We have only one 
significant figure left from the volume subtraction 
so it will have to suffice to say that the 
calculated density of the solid NaOH is 1X10^3, 
i.e about 1000 g/ml. 

Obviously the assumption that the effective volume
of water used in this experiment remains constant
is invalid and it follows that the Archimedean 
technique will not give reliably acceptable results 
using highly soluble materials.

The  error in the measurement of NaOH density
appears to be larger than that of most materials 
based on the limited data available in my personal
records, but other substances such as anhydrous 
MgSO4 at 20% exhibit potential errors of two or 
three hundred percent, and indeed it appears that 
the addition of small quantities of some salts
to water actually reduces the volume of the mix to 
less than that of the original pure water.

I wonder which solvent/solute pair would yield the 
largest net drop in volume? Are there pairs that 
increase in volume on mixing or is the shrinkage a 
direct reflection of the increased intermolecular 
forces that drive the dissolution?I suppose that 
an increase in volume would require the presence 
of some "structure" in the mixed phase, but this 
circumstance appears no more unlikely than the 
existence of the proposed geometric effects which 
are said to account for the unusual behaviour of 
water in the 0-4 deg C range.

Jerry










DOC0099

Subject:      Re: ethanol(spell check!!!)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/28
Message-ID:   <41sqfq$gmq@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <41siv9$ur@news2.isp.net>, <visdis@slip.net> says:
>
>Where to buy ethanol 180 or 200 proof. 
>I am an unlicensed chemist. (student)
>
Depends on where you live. Here in Texas you can buy Everclear
(190 proof, I believe) in the liquor stores. In California  
the stuff isn't legal. Hmmm, I've been a chemist for several
decades; where do I go to get a license ?

Jerry

DOC0100

Subject:      Re: A specific general chem question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/29
Message-ID:   <41u8e8$hg4@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <41u16t$an0@geraldo.cc.utexas.edu>, glhurst@onr.com (Gerald L. 
Hurst) says:
>

>>
>It is true that the calculation of molarity from molality is
>a bit difficult without handy solution density data, but the
>reverse process is a snap. Why not convert your table of 
>density vs molarity (i.e weight %) to a table of density vs 
>molality on the old PC and draw your curves or interpolate 
>from this more convenient source.  If you need to squeeze
>out the last bit of accuracy it's hard to beat picking your
>values off a carefully drawn curve. Interpolation is good
>enough for government work.
>
Hmm, that "i.e. weight %" should read "or weight %" lest I
get brickbatted by an eager grad student looking for notches
in his gun. 

I think I remember the simple conversions:

D = solution density
M = formula weight of solute
P = weight percent of solute

Molarity= 10PD/M

Molality = 1000P/[(100-P)M]

Molality = molarityX100/[(100-P)D]

If all three of these are correct, it'll be the first time
in two decades that I ran through that much math without
some egregious error so check 'em before you use 'em :)

Jerry




















DOC0101

Subject:      Re: A specific general chem question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/29
Message-ID:   <41u16t$an0@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <41tss2$g75@bubba.NMSU.Edu>, Mark R <markr@taipan.nmsu.edu> 
says:
>
>Many thanks to all who took the time to answer my last question! Here's a 
>followup that's perhaps a little more interesting:
>
>I mix a 1 molal solution of KCl at 20 degrees. To do this I combine 
>74.55 grams of KCl and 1.0018 L. of water (assuming water density of 
>0.99821 at the given temp). Can I find the molarity mathematically, or 
>must I determine the final volume by hand to get molarity? (Let's just 
>say I need a result more accurate than simply assuming 
>molality=molarity).
>
>I couldn't find any tables which give densities for solutions of various 
>molalities. This raises another question with respect to the CRC 
>molarity-density tables. Would it be more accurate to construct a 
>calibration-type curve to estimate molarities or densities not listed 
>than to simply interpolate between two given points? 
>
>Any attention to these little dilemmas (dilemmae?) is appreciated.
>
It is true that the calculation of molarity from molality is
a bit difficult without handy solution density data, but the
reverse process is a snap. Why not convert your table of 
density vs molarity (i.e weight %) to a table of density vs 
molality on the old PC and draw your curves or interpolate 
from this more convenient source.  If you need to squeeze
out the last bit of accuracy it's hard to beat picking your
values off a carefully drawn curve. Interpolation is good
enough for government work.


Jerry

DOC0102

Subject:      Re: Why thinking hurts - was Re: sucrose density
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/29
Message-ID:   <4206gr$ou0@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <B.Hamilton.572.3042B0E4@irl.cri.nz>, B.Hamilton@irl.cri.nz 
(Bruce Hamilton) says:
>

>Actual reality check. 
>
>After work today, I repeated my experiment with NaOH, using both 
>the pearl and flake forms. I used a 100ml measuring cylinder 
>filled to 50 ml mark with water. I poured in flake NaOH to the 
>85ml mark, however it did take about a minute, and considerable
>heating occured as the NaOH dropped through the water.
>The weight was 78.91 g, 78.91/35 = 2.25 g/ml. The repeat 
>using pearl NaOH to 90mls weighed 90.72 g, giving 2.27 g/ml.
>
>As Merck reports 2.13 g/ml, then the error is 
>((2.26-2.13)/2.13) x 100 = 6.1%, this somewhat different
>to your 56.5% error. 
>
>Quick, dirty and non-intuitive, but still useful....
>Others may have different opinions.
>
>                     Bruce hamilton

Say! that's really good work, a mere 6.1 % density error.
Even with temperature compensation that would still yield an 
error of well under 7%. 

I suppose if one could run the experiment even faster and
maybe use ice water it could be made even more accurate.
Having established the error at infinite time at about 56%
and the error at one minute at say 6%, what we need is a
few more points at inbetween times and perhaps shorter
times so that we can construct a time/error curve such
that one may extrapolate back to zero time and therebye
get a highly accurate value.

Do you suppose that the method works better with pelletized
and flake material than it would with typical fine granular
materials? I'll bet you could get really startlingly
accurate results with a 50 cc pressed slug of material and
a 15 second experiment.

I am learning a lot about unusual experimental methods in
this forum and I look forward more in the future.

Jerry










DOC0103

Subject:      Re: colloidal potassium
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/29
Message-ID:   <41tv3f$an0@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.chem.organomet



In article <Pine.OSF.3.91.950828212137.1297A-100000@plato.ucs.mun.ca>, 
Brian Watson <brianwat@morgan.ucs.mun.ca> says:
>
>
>
>On 27 Aug 1995, Gerald L. Hurst wrote:
>
>> In article <Pine.OSF.3.91.950827012950.32326B-100000@plato.ucs.mun.ca>, 
>> Brian Watson <brianwat@morgan.ucs.mun.ca> says:
>> >
>> >I am interested in preparing coloidal potassium by ultrasonic 
>> >dispersion . . . 
>
>                [remainder deleted]
>
>> You  didn't mention temperature, but if you have not already done
>> so, you need to heat the mixture above the melting point of the
>> potassium. If you do form the emulsion, you can expect that the
>> colloidal spheres of potassium may remain in the liquid state on
>> cooling to merely warm temperatures, that is they may supercool.
>> 
>        [Some interesting material about metallated greases deleted]
>
>Thank you for your reply.  I'm not sure I understand you correctly, 
however.
>
>There is a procedure in Organic Syntheses for making potassium sand by 
>refluxing in toluene, shaking, and leaving to cool.  Presumably the terms 
>'sand' or 'powder' mean that the potassium will settle out.  You seem to 
>be suggesting, however, that you can obtain an actual colloid this way.
>Is that really so?  (I understand 'colloid' to mean that the dispersion 
>is so fine that the solid does not settle out.  I may need to be 
corrected 
>on this point).
>
I can't say for sure what the particle size of my metal dispersions 
was, especially since I was working with greases and therefore was 
not concerned with whether or not Brownian motion would keep the 
particles in suspension in a lower viscosity medium. I did, 
however, notice that the materials behaved much like the true
micron and submicron water-in-oil (90% in 10%) explosive emulsions
(based on  aqueous ammonium nitrate/oil mixtures) with which I was
familiar. Of course, I had the advantage of using relatively
unreactive metals which coud interact passively with any 
surfactants which might already be present in grease.

I wish I could offer you a more specific reference, but I recall
that another patent issued in the same timeframe as mine (late 
'70s) on the general subject of metal-in-organic emulsions, not
necessarily greases. The work in this patent was much more
academic and thorough than my strictly practical formulation
work. Although my patent preceded theirs, they had filed earlier
and I felt that they had anticipated my work to a great enough
extent to render the commercial value of my work doubtful, and
I did not pursue the matter any farther than blending a few 
hundred pounds for field trials in an experimental bearing 
assembly being developed at the time.

I would suggest that if you have any further interest in metal
dispersions you might find that late '70s patent and read it
for the more fundamental chemistry therin. If I stumble across
my old records, I will email you the patent number and post
it for others who may be interested in this corner of chemistry.

Jerry













DOC0104

Subject:      Re: PH Question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/30
Message-ID:   <422j9c$eaq@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <420pmj$4gd@geraldo.cc.utexas.edu>, glhurst@onr.com (Gerald L. 
Hurst) says:
>
>
>pH = -log([hydronium]) = -log(10^-13) = 13
>
>That's in theory. In practice the value will be somewhat higher.

OOPS. "value" should read "value of the hydronium ion concentration"
The absolute value of the pH will be somewhat lower than 13, not
higher. 

To err is human to forgive humane,

Jerry



















DOC0105

Subject:      Re: PH Question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/30
Message-ID:   <422j9c$eaq@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <420pmj$4gd@geraldo.cc.utexas.edu>, glhurst@onr.com (Gerald L. 
Hurst) says:
>
>
>pH = -log([hydronium]) = -log(10^-13) = 13
>
>That's in theory. In practice the value will be somewhat higher.

OOPS. "value" should read "value of the hydronium ion concentration"
The absolute value of the pH will be somewhat lower than 13, not
higher. 

To err is human to forgive humane,

Jerry



















DOC0106

Subject:      Re: PH Question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/30
Message-ID:   <420pmj$4gd@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <420mhm$ja1@news.scruz.net>, chad@rebellion.com (Chad Kunsman) 
says:
>
>
>PH question:  What is the PH of a .40 M aqueous solution of HNO3??
>               I came up with .40PH where did I go wrong???

If HNO3 really did ionize 100 percent a pH value of 0.40 would
be correct. In real life the value will be considerably higher.
For purposes of a school exercise. 0.40 is fine.

>PH question:  What is the PH of a 0.050 M aqueous solution of barium
>              hydroxide???????
>              I came up with 1.3 PH????
>
>
>Write the equations necessary to depict barium hydroxide dissociating 
>in water.
>             Br (OH) + HO------- H3BrOH + OH minus Is this close.
>                   2    2

Ba(OH)2 -> Ba(+2) + 2OH(-1)  you can add "(aq)"  to each species
			     if you wish to make it clear that the
			     species are in water.

e.g. Ba(OH)2(aq) etc.	

In the following, the square brackets , [], indicate "concentration
of" or "molarity of " whatever is between them.

Since you get two hydroxyls for each mole of barium hydroxide, the
concentration of OH(-) = [hydroxyl] = 2 X 0.050 = 0.1M or 10^-1 

[hydroxyl] X [hydronium] = 10^-14   {equilibrium constant of water}

(10^-1) X [hydronium] = 10^-14

[hydronium] = (10^-14)/(10^-1) = 10^-13

pH = -log([hydronium]) = -log(10^-13) = 13

That's in theory. In practice the value will be somewhat higher.
You must have been doing something right to get 1.3 given that
the digits are correct but you have a slipped decimal place.

Remember that metal hydroxides are bases so we expect the 
pH to be above the neutral value of 7.0. Be sure to use
a lower case "p" and an uppercase H lest people confuse you
with a Ph.D :)

Homework is lots of fun, eh?

Jerry
<


DOC0107

Subject:      Re: PH Question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/08/31
Message-ID:   <423n5l$74t@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SUN.3.91.950831010817.6613D-100000@ciao.cc.columbia.edu>, 
Keith  Sheppard <ks155@columbia.edu> says:
>
>So when do concentrated strong acids become dilute? 
>
>Is 6M HNO3 or HCl or H2SO4 concentrated or dilute?
>and why?
>
They are neither concentrated nor dilute. These materials are not
"concentrated" because they contain more water than the parent
commercial materials which are generally acknowledged as
"concentrated." The reasons for labeling an acid as "concentrated"
vary from acid to acid. For H2SO4 it simply means nearly anhydrous
material. Nitric acid is given that designation at ABOUT 68% (70%)
because it forms a negative azeotrope at this level. Hydrchloric
acid also has a negative azeotrope at about 20% but the commercial
concentrated material is nearly twice this strong (38%), which
represents about as much HCl vapor pressure as can reasonably
be expected not to pop the cork.

"Dilute" is a bit harder to define and one's notion thereof may
be related to the applications one has in mind. For me acids
are reasonably dilute when they effectively start behaving
as mere hydronium ion sources which happen to be in the same
solution with whatever anion. That is, oxidizing acids such
as perchloric, nitric and to a lesser extent sulfuric stop
behaving like oxidizers and dehydrating acids like H2SO4 and
HF have their appetites for water more than satisfied.

Another chemist might think it more appropriate to classify
acids as dilute when there is enough water present to allow
the activity of the hydronium ion to approach the apparent
concentration.

I suppose we all agree that a strong acid is truly dilute when
it yields less than 10^-7 or so moles of hydronium ion per
liter and many of us would be satisfied with 0.1 - 1M.  
However, when you're nitrating an unwilling molecule anything 
short of fuming HNO3 and H2SO4 can start to look dilute.

Jerry















DOC0108

Subject:      Re: chemistry
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/01
Message-ID:   <4263i9$qcm@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SGI.3.91.950831222057.22086A-100000@cv4.chem.purdue.edu>, 
Lev Gorenstein <lev@chem.purdue.edu> says:
>

>
>Well, well, guys...  It's sad to say, but overall all the chemistry is 
>nothing more than physics of the outer electron shells...  :-)
>
True. And life is nothing more than a sack full of chemicals. I
suppose the physicists claim hegemony over the soul, it being
made of phlogiston.

Jerry





















DOC0109

Subject:      Re: dumb question : water or ice - which denser?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/01
Message-ID:   <427hci$oip@geraldo.cc.utexas.edu>
Newsgroups:   sci.physics,sci.chem



In article <427h30$oip@geraldo.cc.utexas.edu>, glhurst@onr.com (Gerald L. 
Hurst) says:

>As a child, I too was tought 

Rats, that one got away before I could change "tought" to "teached."
Anybody got a spell checker macro for my return key?

Jerry
<


DOC0110

Subject:      Re: dumb question : water or ice - which denser?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/01
Message-ID:   <427h30$oip@geraldo.cc.utexas.edu>
Newsgroups:   sci.physics,sci.chem



In article <Pine.SOL.3.91.950901103657.13432A-100000@cms1>, Anthony Potts 
<potts@cern.ch> says:
>
>The metal which was used to make type (in the good old days, when 
>I were a lad) also expanded when it froze. I do not know the 
>composition of the alloy, but it was necessary to have this 
>property so that the metal forced its way into the moulds 
>completely, to make printing neat and legible, without shitty 
>serifs or crappy qs.

As a child, I too was tought that type metal, an antimony alloy, 
expands on solidifying.  Many years later I read that this is 
not true but that the alloy merely has an exceptionally low
degree of contraction on freezing. Does anybody here have any
definitive numbers ?

Jerry

















DOC0111

Subject:      Re: dumb question : water or ice - which denser?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/02
Message-ID:   <428ml3$hft@geraldo.cc.utexas.edu>
Newsgroups:   sci.physics,sci.chem



In article <427mpb$6te@buffnet2.buffnet.net>, krieder@buffnet.net (Kurt 
Rieder) says:
>
>BTW... has anyone ever heard tin "cry"... or know what "tin cry" is ?
>
I have heard tin cry many times. I purchased several long narrow
ingots of tin along with some bismuth and lead when I was 
making low melting alloys to emulsify in silicon oil to make
dense grease. The tin rods were easily  flexed and exhibited 
virtually no springiness but gave out a sound as though they were
ratcheting into the new shape. No amount of bending back and forth
seemed to weaken the metal or reduce its pronounced cry. It is
a very impressive effect.

Jerry



















DOC0112

Subject:      Re: sucrose density
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/02
Message-ID:   <428plq$hft@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <950902110624359@welcom.gen.nz>, jim.oliver@welcom.gen.nz (Jim 
Oliver) says:
>
>glhurst@onr.com (Gerald L. Hurst) wrote :
>GLH>Subject: Re: sucrose density

>GLH>The above exchange was followed by an email dialog
>
>I intensely dislike public postings of private mail content. This
>has to be one of the worst abuses of Usenet.
>
>GLH>with Jim Oliver in which I continued to challenge
>GLH>and he to defend the use of the principle of
>GLH>Archimedes to measure the density of SOLUBLE solids.
>
>Nonense. Anyone still reading this knows that I conceeded in my
>second public posting that only insoluble solids should be used
>for the rough method I outlined. Otherwise use a suitable liquid
>that won't dissolve the material being measured.
>
>I was moved to this concession after several friendly and helpful
>posts in e-mail pointed out the potential problems.
>
Well gee, Jim, I'm sorry if you feel abused. I do apologize.
I obviously misunderstood what you were saying. Silly me, I
thought you were disagreeing and here all along you were on 
my side. Now, how are we going to convince Bruce Hamilton
that you and I (we) are right? Unless, I misunderstand him 
too, he disagrees with the position we agree on.

Jerry



DOC0113

Subject:      Re: FREON 12 Substitutes - Whadda ya know?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/03
Message-ID:   <42d9iv$ig4@geraldo.cc.utexas.edu>
Newsgroups:   <sci.engr.heat-vent-ac,rec.autos.tech,sci.environment,sci.chem>



In article <42d42n$srp@mozo.cc.purdue.edu>, ghg@cidmac.ecn.purdue.edu 
(George Goble) says:
>

>
>try this:  Take a lit cigarette, and take a butane lighter,
>push the button to release butane, but don't "flick" it
>and try to see how hard it is to ignite using a lit
>cigarette..
>--ghg
>
It is true that a cigaret will not ignite butane or any other
alkane, but there are things under the hood that can, not to
mention the flame that might be used to light the cigaret. 
Gasoline fumes around the engine can develop enough pressure
on ignition to pop the hood up, which can be disconcerting to
the driver and that same puff of energy can start a very
destructive fire.

Jerry














DOC0114

Subject:      Re: Help needed: Why is hydrogen floride toxic ?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/04
Message-ID:   <42ft0p$8i8@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <42erkr$kgv@dub-news-svc-2.compuserve.com>, 
70621.3462@compuserve.com (John S. Roberts) says:
>
>"Michael J. Shifflet" <shiffty@postoffice.ptd.net> wrote:
>

>I've handled aqueous, liquid and gaseous hydrogen fluoride without 
getting a
>burn.  It itches like hydrogen chloride if you get it on your skin.
>
You have been very fortunate. HF burns are insidious and can be
very severe, dangerous and extremely hard to heal. Anhydrous HF
can char a wooden stick. Milder concentrations often at first only
produce a slight discoloration of the skin, which is later 
followed by a rotting of tissue. I, too have been dosed many 
times with HF, but always got it off my skin in a matter of 
seconds because I have seen what it can do.

Among the worst materials I have seen for destroying tissue are
(NO2)2CFCH2OH and HgN(CF3)2. The skin goes through stages of
green and purple putrefaction in an area many times greater 
than the original area of contact.

In my next incarnation, I'm going to be a candy chemist.

Jerry
<







DOC0115

Subject:      Re: temp decrease in soda cans
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/06
Message-ID:   <42j19r$fh8@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <42i3m8$oq1@geraldo.cc.utexas.edu>, Jason Ritchie 
<jaritchie@mail.utexas.edu> says:
>
>In article Michael Gorsuch, explore@u.washington.edu writes:
>>When the CO2 was held under pressure, the CO2 molecules must have been 
>>colliding more frequently with surrounding molecules.  Wouldn't this
>have 
>>made the can feel warmer than its surroundings when it was still closed?
> 
>
>        Yes, but you then put it into your refrigerator or left it 
sitting
>exposed to the atmosphere. There should be an increase in temperature as
>you pressurize your soda, but it quickly equilibrates with the
>surroundings. So when you open it all the "hot" CO2 molecules leave and
>only the "cold" ones are left behind. This lowers the overall temperature
>of the soda system.
>
>>from the fluid when the CO2 escapes.  Where in the world is the "heat" 
>>that escapes?
>
This line of conversation assumes the original poster's statement
that the temperature of a can of cold soda drops when the tab is 
popped. This idea may be correct in the absolute sense because
the CO2 expands against the atmosphere thus losing a little heat
energy by doing a bit of PV work and there is a subsequent slow 
cooling effect from the heat of vaporization of the CO2 as it 
gradually overcomes supersaturation and volatalizes. However this
cooling effect is perhaps balanced or even outweighed by heat
transfer from the experimenters hand, not to mention the heat 
generated by the mechanical action of popping the top. 

However, I doubt that either of these heat effects would be large
enough to detected by the would-be imbiber. It's more likey that the
perceived decrease in temperature arises from agitation by the
thirsty scientist or the escaping bubbles which stir the inner, 
colder fluid around to the can surface thus creating the tactile
illusion of overall temperature drop.

Who will be the first to instrument sodapop cans so that we can
quantify the temperature change and come up with an accurate table 
of Delta H(popatop)?

Jerry












DOC0116

Subject:      Re: question re: freezing point depression
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/12
Message-ID:   <434qls$9cs@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <eifel.6.00880717@interaccess.com>, eifel@interaccess.com 
(glen) says:
>
>The equation for freezing point depression is the following:
>
>delta Tf = kf * m                                      
>       ^         ^      ^                                                
      
>        |          |        |
>        |          |        moles of solute particles/kg of solvent
>        |          |
>        |          molal freezing point depression constant
>        | 
>       freezing point depression
>
>The Kf value for water is 1.86 (K kg / mol).
>
>In the  CRC under "Concentrative Properties of Aqueous Solutions," there 
>appears values for delta Tf and m for various solutes. When I plotted a 
graph 
>to derive Kf for various solutes, I got values that differed from 1.86 (K 
kg / 
>mol). I realize that something like NaCl should give values roughly 
double 
>1.86, due to the fact that the NaCl dissolves completely. But, why would 
>something like ethylene glycol deviate from the 1.86 value. Is this due 
to the 
>dissociation of the alcohol groups in water?
>
Kf is only accurate if you use the "activity" or effective 
concentration of the solute rather than the actual 
concentration based on mass/volume.

Activity is a sort of chemical excuse for the non-ideal behaviour
of nearly all solutions except those which are very dilute. If you
plot apparent Kf versus concentration and extrapolate the curve
to zero concentration, you'll probably get answers closer to the
1.86 you're expecting.

Jerry
















DOC0117

Subject:      Re: [Q] cold trap
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/13
Message-ID:   <4371f2$stb@geraldo.cc.utexas.edu>
Newsgroups:   bionet.parasitology,sci.chem,sci.chem.analytical



In article <rose.486.3056EFC4@alf1.ngate.uni-regensburg.de>, 
rose@alf1.ngate.uni-regensburg.de (Andreas Rose        t3077) says:
>
>I study the host-finding of a blood-sucking bug (Reduviidae - 
Triatominae). 
>I want to collect odors from the headspace of a sleeping person and see 
>whether these are attractive in a behavioral test. 
>
>For the collection of the odors, I want to construct a cold trap. 

[Snip]

A dry ice-acetone trap should do the job. I would not use liquid
nitrogen because it is cold enough to condense a trap full of
liquid oxygen and solid CO2.

Jerry

















DOC0118

Subject:      Re: Aluminum plate to clean tarnish off silver works?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/15
Message-ID:   <43ba0i$2ej@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <43b71e$etq@nnrp.ucs.ubc.ca>, dcwong@unixg.ubc.ca (Donald Chun 
Kit Wong) says:
>
>There's a product being advertised around. It's a metal plate. When one
>puts it in a container water with Calgone in it, it's supposed to be able
>to convert silver tarnish (and brass, too?) back to silver. Someone has
>told me that it works, but another said it doesn't. I remember some type
>of chemical reaction that does this from Chem lecture long ago.  What is
>the actual chemical reaction? Does anyone know if this metal plate
>actually work? Thanks for any info. 
>
You can get the effect with a sheet of aluminum foil immersed in
water containing some dissolved sodium bicarbonate. The silver
sulfide tarnish common on silver is reduced back to metallic
silver. How well it works seems to depend on the exact nature of 
the tarnish - sometimes it works rather well, sometimes not.

Jerry
















DOC0119

Subject:      Re: Beginner's question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/15
Message-ID:   <43cqdu$44a@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <43cbfg$mko@news.cerf.net>, Laura Weston <ljweston@class.org> 
says:
>
 I think inorganic chemistry is easier and more intuitive than 
>organic chemistry.  BUT there are millions of others that disagree.

Millions? Everybody knows that that chemistry is merely a dumping
ground for those who lack the intellect to become physicists.
The descending order of minimum intelligence required to practice 
the chemical arts is: organic, inorganic, physical, analytical, 
management and quantum.

In the greater scheme of things the major brain power hierarchy
from top to bottom is: politician, lawyer, physicist, doctor,
used car salesman, biologist, geologist, psychologist, sociologist,
chemist and philatelist.

Others may have different opinions, but they are wrong.

Jerry














DOC0120

Subject:      Re: Beginner's question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/17
Message-ID:   <43fofu$t7u@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <43f2e6$7ii@wizard.uark.edu>, cpuyear@comp.uark.edu (Charles S. 
Puyear) says:
>
>In article <43cqdu$44a@geraldo.cc.utexas.edu>,
>Gerald L. Hurst <glhurst@onr.com> wrote:
>>
>>Millions? Everybody knows that that chemistry is merely a dumping
>>ground for those who lack the intellect to become physicists.
>
>You sir, are a pompous ass and an idiot to boot. By posting this kind of 
>nonsense you are merely broadcasting this fact to the world.
>
>>The descending order of minimum intelligence required to practice 
>>the chemical arts is: organic, inorganic, physical, analytical, 
>>management and quantum.
>
>As a theoretical (quantum) chemist, I am offended by your statement that
>my field requires less intelligence of its practitioners than any of the
>other chemical SCIENCES. (I think you listed them in an order opposite of 
that
>which you intended, although I disagree with that also. It requires an 
extremely
>clever mind to work in any area of chemistry.) Before you go shooting off
>your mouth any more, I would suggest that you actually try your hand at 
>chemical research in any of the subdisciplines. You will probably find 
that
>you are completely incapable of such work, and possibly realize (unless 
you
>are even dumber than you sound) that you are too stupid to practice any
>of the physical sciences, and that the scientific community can do 
without
>any more of your moronic ravings.
>
ooOOPs! No wonder you're offended. I got my lists mixed up. The 
one you quoted does not correspond to descending intelligence,
but to descending sense of humor.  My second (unquoted) list
of descending IQs, which terminated in "philatelist," has not
yet drawn any irate responses from the stamp collectors. 
Perhaps they didn't take it seriously :(

Jerry















DOC0121

Subject:      Re: MIT engineers; how they spend their time and how A@P
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/24
Message-ID:   <4446kq$4rb@geraldo.cc.utexas.edu>
Newsgroups:   alt.sci.physics.plutonium,sci.physics,sci.physics.particle,sci.chem



In article <443g7g$926@dartvax.dartmouth.edu>, 
Archimedes.Plutonium@dartmouth.edu (Archimedes Plutonium) says:

>
> Tell us what the total number of Coulomb Interactions there would be
>for plutonium. I need this fact to plug into Debroglie's book.
>
Mr. Plutonium, please allow me the honor of providing that
value so that you may continue your labours in the vinyard
of physics. The value you are seeking is N!/2 where N is
the total number of particles counting the nucleus as one
particle, i.e. 11!/2 for neon. I leave the calculation for
plutonium to you - it is obviously a rather large number.

Jerry



















DOC0122

Subject:      Re: nitrite to nitric oxide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/24
Message-ID:   <4444kc$4rb@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem
<A HREF="http://xp5.dejanews.com/getdoc.xp?recnum=10692059&server=db95q23&CONTEXT=878713156.1993605637&hitnum=352&AH=1">[More Headers]</A>


In article <441nub$fjo@news.asu.edu>, <A HREF="/profile.xp?author=bridges@aztec.asu.edu&ST=PS">bridges@aztec.asu.edu</A> (HARRY MOREL) 
says:
>
>
>It has been found that bacteria on the back of the tong reduce 
>nitrate to nitrite.  When the nitrite enters the anaerobic, acid 
>environment of the stomach, it is transformed into nitric oxide 
>and xxxx?
>                           ..-                       ..-
>                          :O:                       :O:
>                        .. :  ..        bacteria  .. :       ..
>                        O::N..O:-       ------>   O::N:  +   O:
>                        .. +  ..                  ..         ..
>           ..-
>          :O:   
>        .. :            +        acid   .. .             ..
>        O::N:  +        H       ------> O::N:  +         .O..H
>        ..                              ..               ..
> 
>Could neutral OH be the correct answer?  If it were, it would 
>further explain why bacteria are killed by this reaction. Could 
>someone please set the electrons right?  Much appreciation for your 
>answer.  Harry
>-- 
Are you looking for the reaction 2HNO2 -> NO2 + NO + H2O ?

Probably followed by 2NO + O2 -> 2NO2 from swallowed air.

Either of the two free radicals (NO, NO2) from these reactions 
could probably kill bacteria.

Jerry


DOC0123

Subject:      Re: Archimedes (was Re: Horst teaches . . .)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/25
Message-ID:   <445fcd$15b@geraldo.cc.utexas.edu>
Newsgroups:   alt.sci.physics.plutonium,sci.physics,sci.physics.particle,sci.chem



In article <444ug1$isk@dartvax.dartmouth.edu>, Archimedes.Plutonium@dartmouth.edu (Archimedes 
Plutonium) says:
>
> So please tell roughly what the minimum  Coulomb Interactions there
>would be
>for plutonium? I need this fact in order to plug into Debroglie's book.


95!/2, 5.16E147
			Once again I say to you
                 ninety-five factorial divided by two

516000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000 give or take a smidgeon.

Jerry


















DOC0124

Subject:      Re: WHO is MIT engineer Decobert's boss there at MIT? Govt
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/25
Message-ID:   <445djg$15b@geraldo.cc.utexas.edu>
Newsgroups:   alt.sci.physics.plutonium,sci.physics,sci.physics.particle,sci.chem



In article <444nl2$1ve@dartvax.dartmouth.edu>, 
Archimedes.Plutonium@dartmouth.edu (Archimedes Plutonium) says:
>
> Tell us roughly what the minimum  Coulomb Interactions there would be
>for plutonium? I need this fact to plug into Debroglie's book.
>
>        The book LA THERMODYNAMIQUE DE LA PARTICULE ISOLEE (OU
>THERMODYNAMIQUE
>CACHEE DES PARTICULES)  written by Debroglie, 1964
>
>  I need those Coulomb interactions to figure out the blackbody
>temperature of an electron cavity of plutonium.
>
>  So, Dirk, from Halliday and Resnick neon was computed at 2 x 10^7 but
>please tell in your superior attitude what it is for plutonium?

Mr. Plutonium, it is indeed a pleasure to be of assistance to a 
supergenius. To paraphrase my earlier posting, the value you seek
to plug into de Broglie's work is 95!/2, which is about 
5.16X10^147 (5.16E147).  Now that you have the necessary datum, 
how hot is it?

Jerry











DOC0125

Subject:      Re: Minimum Coulomb Interactions for plutonium
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/28
Message-ID:   <44daq8$gh1@geraldo.cc.utexas.edu>
Newsgroups:   alt.sci.physics.plutonium,sci.physics,sci.physics.particle,sci.chem
<A HREF="http://xp5.dejanews.com/getdoc.xp?recnum=10872422&server=db95q23&CONTEXT=878713156.1993605637&hitnum=350&AH=1">[More Headers]</A>


  Article Segment 1 of 2
  <A HREF="http://xp5.dejanews.com/getdoc.xp?recnum=%3c44daq8$gh1@geraldo.cc.utexas.edu%3e&server=db95q23&CONTEXT=878713156.1993605637&hitnum=350">(Get All 2 Segments)</A>
In article <44cmbk$li3@dartvax.dartmouth.edu>, 
<A HREF="/profile.xp?author=Archimedes.Plutonium@dartmouth.edu&ST=PS">Archimedes.Plutonium@dartmouth.edu</A> (Archimedes Plutonium) says:
>
>In article <448tro$e6g@rzsun02.rrz.uni-hamburg.de>
><A HREF="/profile.xp?author=fc3a501@AMRISC04.math.uni-hamburg.de&ST=PS">fc3a501@AMRISC04.math.uni-hamburg.de</A> (Hauke Reddmann) writes:
>
>> May I add a little bit? As I am familiar with quantum chemistry
>> computation, the fact that there are so much interactions is
>> somewhat irrelevant. When you express the Coulomb interaction
>> in the "Slater determinant" picture, you reduce the whole stuff
>> to just two sorts of operators: 1-electron and 2-electron op's.
>> And in fact, even for an actinide like plutonium, the whole
>> interaction can be expressed in simply three adjustable
>> parameters.
>
>  Hauke, thanks, you appear to be a sort of my own guardian angel of
>sorts.
>
> Halliday and Resnick say that neon has a minimum of 2 x 10^7
>independent pairs of charges whose Coulomb interactions must be taken
>into account.
>-----------
> <<A HREF="/profile.xp?author=11MAY199412262849@csa5.lbl.gov&ST=PS">11MAY199412262849@csa5.lbl.gov</A>> Scott I Chase and Thomas S. Zemanian
><<A HREF="/profile.xp?author=ts_zemanian-110594082225@ts_zemanian.pnl.gov&ST=PS">ts_zemanian-110594082225@ts_zemanian.pnl.gov</A>>   both said it was N x
>(N-1)/2 or 20 x 19/2 = 190.
>  And this answer of 190 is what several physics professors here at
>Dartmouth gave me as an answer and it seems to be the most preferred
>answer by physics professors -- 190 for neon. But I do not like it for
>I believe by instinct, by intuition that no atom of neon with 10
>protons and 10 electrons can hold-up with just 190 things going on.
>------------
>  But, another poster says this. In article
><447olq$mj4@ux.accesscom.net>
><A HREF="/profile.xp?author=jim.goodman@accesscom.net&ST=PS">jim.goodman@accesscom.net</A> (Jim Goodman) writes:
>
>> >For n particles, there are (n 2) two body interactions.
>> (n 2) = n!/(2!x(n-2)!), best I can do with a typewriter.
>> see <<A HREF="http://www.accesscom.net/sawf/">http://www.accesscom.net/sawf/</A>>
>-----------
>  And another poster says this. In article
><4446kq$4rb@geraldo.cc.utexas.edu>
><A HREF="/profile.xp?author=glhurst@onr.com&ST=PS">glhurst@onr.com</A> (Gerald L. Hurst) writes:
>
>> Mr. Plutonium, please allow me the honor of providing that
>> value so that you may continue your labours in the vinyard
>> of physics. The value you are seeking is N!/2 where N is
>> the total number of particles counting the nucleus as one
>> particle, i.e. 11!/2 for neon. I leave the calculation for
>> plutonium to you - it is obviously a rather large number.
>-----------
>
>  And I said this in 1994, that the reason for 2 x 10^7 for neon was
>because of the four quantum numbers (n, L, M_L, m_s) such that for neon
>it is (2^20 x2 x 2 x2)
>
>-----------
>
> So, who is correct and more important how do you get your answer,
>explain it? Please just do not give a formula for so many people now
>have given so widely different answers. I want to know the why and
>wherefor also so that I can be sure of the Coulomb for plutonium. Is
>plutonium (188 x 187)/2  or 95!/2 or  2^188 x 2x2x2? Here I repeat
>Halliday and Resnick's orginal.
>
>PHYSICS, part 2, extended version, 3rd edition 1986, Halliday & Resnick
>
>pages 1190-1191
>
>ATOMS BEYOND HYDROGEN. At the beginning of this chapter we described
>how the hydrogen atom potential energy function (Eq. 51-1) is inserted
>into the Schroedinger equation and how that equation can be solved to
>yield quantum numbers and wave functions. All of our results so far,
>then, apply to the hydrogen atom only. What about other atoms?
>   For atoms with substantially more than one electron the potential
>energy function that we must substitute into the Schroedinger equation
>involves the Coulomb interaction between many pairs of particles and
>can rapidly become hopelessly complicated. In neon, for example, it can
>be shown that, including the nucleus and the ten electrons, there are
>no fewer than about 2 x 10^7 independent pairs of charges whose Coulomb
>interactions must be taken into account if the Schroedinger equation is
>to be solved rigorously. At this level of complexity rigorous solutions
>are not possible, and we must rely on methods that are both approximate
>and numerical.
>--- end of quoting Halliday & Resnick ---














DOC0126

Subject:      Re: Minimum Coulomb Interactions for plutonium
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/28
Message-ID:   <44daq8$gh1@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
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  <A HREF="http://xp5.dejanews.com/getdoc.xp?recnum=%3c44daq8$gh1@geraldo.cc.utexas.edu%3e&server=db95q23&CONTEXT=878713156.1993605637&hitnum=351">(Get All 2 Segments)</A>
Mr. Plutonium, I am partly responsible for the confusion here.
There are a number of ways of looking at the interactions
of particles in an atom, but if we are here looking for
the number of distinct pairs with coulombic interaction then 
it would not be 2 x 10^7 but N(N+1)/2 where N is either 11 or
twenty for neon, depending on whether you count the nucleus 
as one charged particle or as 10 particles (protons).

Although the N(N-1)/2 figure looks rather small compared to the
full factorial numbers which describe the number of permutations
of particle strings (or sequences) involving all the particles 
(or better, their states), remember that it only refers to
COULOMBIC interactions, not to all interactions. Anyway, the
coulombic pair interaction number for plutonium is either
95(95-1)/2 or 188(188-1)/2 depending on the viewpoint.

I suspect that the Halliday & Resnick chapter erred in 
using the 2 x 10^7 figure for the number of binary coulombic
interactions.

Jerry












DOC0127

Subject:      Re: ALUMINUM BOMB
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/30
Message-ID:   <44iqdc$d77@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.engr.mech,sci.physics



In article <emilsson.812436676@aries>, emilsson@aries.scs.uiuc.edu 
(Tryggvi Emilsson) says:
>
>tims@megtas.lsid.hp.com (Tim Shipe) writes:
>

>The oxide film on Al is pretty tough. It is one of the metals recomended
>for use with fluorine.I once passed some fluorine gas over a scoop of 
aluminum
>powder.Nothing happened.I tried the same treatment on other 
materials.Magnesium
>powder,silicon carbide,Teflon,most any organics,and even GLASS ,ignited 
or
>exploded on contact.
>
When I was developing a synthesis for N2F2, I had to prepare 
cold traps with a layer of AlCl3 sublimed onto the inner 
surface. I made the salt by reacting Cl2 with thin Al foil 
heated in the glass trap with a hot air blower. Under these 
conditions the aluminum stays bright for a prolonged period 
of time until the chlorine finds the first chink in its Al2O3 
armor, after which the reaction procedes at great speed.

In pilot plant production, I always handled fluorine in monel 
or stainless steel systems with a bit of copper here and 
there, but much of this work was at moderately high 
temperatures (200 C) and high pressure (2400 psi). I never 
considered aluminum. I wonder if it would withstand this 
environment? Kinda makes me shudder to consider Al in contact 
with the ClF5 we were making at the time, but who knows?

Jerry


DOC0128

Subject:      Re: question!!!!!
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/09/30
Message-ID:   <44ioh5$d77@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <DFp4sC.F2u@cunews.carleton.ca>, dreynold@chat.carleton.ca 
(Derek Reynolds) says:
>
>
>What is the difference between the terms
>
>Adsorb.....and.....Absorb?
>
Substances are adsorbed ONTO the surfaces of other materials 
but are absorbed INTO other materials. A monomolecular layer
of water on steel is said to be "adsorbed" whereas the 
moisture in a typical fabric, i.e. cotton or Nylon, is largely 
absorbed inside the fibers as indicated by the swelling of the 
latter.

Jerry


















DOC0129

Subject:      Re: Impact of chemistry on philosophy?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/03
Message-ID:   <44qnl8$mei@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <44pc3l$f9f@lunen.gac.edu>, mmenge@pepperoncini.gac.edu 
(Matthew P Menge) says:
>
>        I was wondering if chemistry has made any impact on philosophy.  
 
>Physics and biology, for instance have both made impacts on philosophy.  
 
>In biology there was the theory of evolution, for instance, and in 
physics  
>there was the theory of relativity, among others.
>
I am neither historian nor philosopher, but it seem to me 
that the concept of entropy, arising from chemical 
thermodynamics and the consequential view of time as an
arrow rather than a (classical physicist's) pendulum, has 
an ongoing influence on philosophical thought or at least
it does when I'm in my armchair thinking up long rambling
sentences.

Jerry














DOC0130

Subject:      Re: what is flash point?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/03
Message-ID:   <44qp8c$mei@geraldo.cc.utexas.edu>
Newsgroups:   sci.engr.chem,sci.chem



In article <44pivb$5b9@news.nd.edu>, ruiyun wu <rwu@darwin.cc.nd.edu> 
says:
>
>dear netters:
>
>can anyone tell me how flash point is defined? and how can I figure out 
the
>flammibility from it?
>
>And by the way, do you think n-decane (as solvent) under 100C and 1 
atomsphere
>is dangerous?

The flash point is the lowest temperature at which the 
equilibrium vapor above a liquid in air will ignite in 
the presence of a spark or flame. In other words if a 
liquid is at or above its flash point in, say, an 
ashtray and you wave a burning match over it a few 
millimeters from the surface, the vapor will flash.

There is a second, higher temperature called the fire
point, which is the minimum temperature at which a 
liquid will continue to sustain combustion of its vapor 
once ignited. In other words, if the liquid in your 
ashtray is perhaps 20 degrees above its flash point, 
the vapor will not merely flash, but continue to burn. 
Remember that the concept of fire point only works for 
pools of liquid. If the liquid is wicked into a fibrous 
material, the difference between the flash point and 
the fire point becomes vanishingly small.

N-decane has a flash point of 46 deg C. Therefore, the 
vapor above the liquid is susceptible to ignition at 
that temperature or above. A spark of 0.3 millijoule 
(not much) is enough to ignite it.

In the U.S, the term "flammable" usually means that 
the substance being described has a flash point below
100 deg F (37.8 deg C). N-decane would be considered
"combustible" at least with respect to normal ambient
conditions and it would be so labeled for shipping.

Jerry













DOC0131

Subject:      Re: what is flash point?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/07
Message-ID:   <456gs5$826@geraldo.cc.utexas.edu>
Newsgroups:   sci.engr.chem,sci.chem



In article <456aa6$hqp@steel.interlog.com>, RFalkiner 
<falkiner@interlog.com> says:

>there are several ASTM ISO etc tests for measureing flash point         
>
>it roughly coincides with the LEL lower explosive limit
>
>for hydrocarbons

How rough is the coincidence and why is it rough?


Jerry





















DOC0132

Subject:      Re: definition of isodesmic???
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/08
Message-ID:   <457rm2$73v@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <VSUMMERS.95Oct7192052@polaris.cv.nrao.edu>, 
vsummers@polaris.cv.nrao.edu (Vince Summers) says:
>
>As I have been informed...isodesmic is the approximation of a
>structure by considering energies of `equivalent' pieces.  Ex. a
>benzene  is equivalent to 2 H3C=CH-CH3 groups minus 8 -H bonds from a
>methane.
>That is if no resonance or other properties were involved.  Thus you
>can
>determine roughly resonance, etc.  Someone else may put this more
>succinctly.
>Vincewq
>
I really don't know about such stuff, but it would seem
to me that benzene's energy would be more like that of three 
H3C-C(H)=CH-CH3 molecules minus the energy of three ethane 
molecules with the difference in energies being largely a 
function of what we used to be allowed to call resonance 
energy before the quiche and trail mix-eating quantum
physics guys made it non OC (orbitally correct).

Anyhoo, I would like to know if it is CC (chemically correct)
to call the above method ) an "isodesmic" operation or 
approximation. I've been doing this sort of thing in the 
closet for years, not knowing that it had a name and that I 
was not alone :)

Jerry






DOC0133

Subject:      Re: what is flash point?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/08
Message-ID:   <457g53$so7@geraldo.cc.utexas.edu>
Newsgroups:   sci.engr.chem,sci.chem



In article <4572i1$n36@steel.interlog.com>, RFalkiner 
<falkiner@interlog.com> says:
>
>glhurst@onr.com (Gerald L. Hurst) wrote:
>>
>> In article <456aa6$hqp@steel.interlog.com>, RFalkiner 
>> <falkiner@interlog.com> says:
>> 
>> >there are several ASTM ISO etc tests for measureing flash point       
  
>> >
>> >it roughly coincides with the LEL lower explosive limit
>> >
>> >for hydrocarbons
>> 
>> How rough is the coincidence and why is it rough?
>> 
>They are essentially the same thing, but the answer you get depends 
somewhat 
>on the hardware configuration used in each particular test. 
>
>you have to think of flash point as a "benchmark" type of test.  it 
>represents the temperature where the equilibrium vapour of a liquid 
becomes
>"flammable or explosive" under normal conditions.  

Then under "normal" conditions the may be said to coincide
exactly.

One could argue for mixtures that the flash point is actually
a continuous series of values which varies as the mix 
evaporates, whereas the LEL represents the lowest vapor
concentration, having the same molecular ratio of non-air
components as the parent condensed phase, that will flash. 
On the other hand, it can be argued that such a value would 
be pretty much worthless in the real world where the partial
vapor pressures of mixture components may span several orders
of magnitude.

Sounds like F.P. and LEL probably coincide nicely for pure
compounds but have a less intimate relationship for mixtures.

Jerry













DOC0134

Subject:      Re: what is flash point?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/10
Message-ID:   <45d9r8$s6u@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <895849388wnr@fats.demon.co.uk>, Richard Bettis 
<rbettis@fats.demon.co.uk> says:
> 
>Flash point is temperature measurement
>LEL is concentration measurement
>
>little coincidence there!

Certainly, there is. Thunder and lightning are not the same thing
but they do tend to coincide. Of course it might be said that it
is no mere coincidence that the flash point and the LEL coincide
with each other under certain circumstances.

Jerry




















DOC0135

Subject:      Re: what is flash point?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/10
Message-ID:   <45d9ap$s6u@geraldo.cc.utexas.edu>
Newsgroups:   sci.engr.chem,sci.chem



In article <45bhfp$fde@zephyr.grace.cri.nz>, B.Hamilton@irl.cri.nz (Bruce 
Hamilton) says:
>
>glhurst@onr.com (Gerald L. Hurst) wrote:

[snip]

>>Then under "normal" conditions they [Flash point and LEL] may be 
>>said to coincide exactly.
>
>Definitely not.
>
>There are a wide variety of Flash Point procedures,

[snip]

There are indeed, but not all of them would be really very
"normal" considering we were discussing the original poster's
parameters, which referred to equilibrium vapor, i.e. closed
cup run infinitely slowly or thereabouts. 

>>One could argue for mixtures that the flash point is actually
>>a continuous series of values which varies as the mix 
>>evaporates.
>
>Flash Point is just that. [snip]
>
I'm glad I got it right:)

Jerry




DOC0136

Subject:      Re: what is flash point?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/12
Message-ID:   <45i1bq$4b0@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <479783410wnr@fats.demon.co.uk>, Richard Bettis 
<rbettis@fats.demon.co.uk> says:
>
>> Thunder and lightning are not the same thing
>> but they do tend to coincide. Of course it might be said that it
>> is no mere coincidence that the flash point and the LEL coincide
>> with each other under certain circumstances.
>> 
>> Jerry
>>
>OK. There is a coincidence. 

I'm pleased you see it.

>Is there any coincidence between brighter lightning 
>and brighter thunder? Or louder lightning and louder thunder? 

Hmm. I am unaware that there is any such thing as bright thunder
or loud lightning except in some allegorical sense. I suppose
there may be some incidence of coincidence between loud thunder
and bright lightning, but you'd have to ask a meteorologist.

>Just because two 
>things happen at the same time, even for the same reason, doesn't mean 
>they are 
>the same thing.

I'm pleased with your paraphrase of my first sentence above.

>If you corner a car too fast, the tyres screech. However, if you make a 
>screeching noise, your car doesn't turn.

These observations suggest that there is probably a relationship
between the screeching of the tires (tyres) and the cornering
but no apparent relationship between the tires and my voice.
The cornering and the tire screech seem to have same  sort of  
relationship as lightning and thunder, i.e. the latter does not
cause the former, and, although they are related to each other 
they are not related to my voice.

>All I'm saying is that you *cannot* compare temperatures with 
concentrations.

That sounds reasonable, but you CAN compare incidences of two things
(coincidences) that regularly happen at the same temperature such as 
a vapour reaching its LEL and its flash point simultaneously. The 
vapour flashes, inter alia, because it has reached its LEL just as 
loud thunder peals because the bright lightning bolt has just struck. 
Thus in each case the two phenomena are different but coincide.

>The two are not related at all!
>
Ahh. But if the flash point and the LEL are not related at all, then
it must be a COINCIDENCE that they seem to occur at the same 
temperature.

Jerry





















DOC0137

Subject:      Re: Nitrogen Triiodide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/13
Message-ID:   <45klb3$979@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <45jhcn$55g@pulp.ucs.ualberta.ca>, dabell@gpu.srv.ualberta.ca 
(Darcy Abell) says:
>
>Phred PSmIth, Galactic Gadabout <JXC35@psuvm.psu.edu> wrote:
>
>>Not that NH4I3 is that stable.  One would get a big pile of damp ammonia
>>triiodide in the filter, but getting it to wait while it all dried out
>>would never work: it would just explode in small bits as it dried out.
>
>This is not the case.  If it is left alone while drying you can dry a
>substantial amount.  Once it is dry, it will go off VERY easily
>though.  How stable the clump is depends alot on how finely divided
>the iodine was.  

I believe you folks are talking about nitrogen triiodide, NI3:xNH3
rather than ammonium triiodide, NH4I3. The latter is relatively
stable whereas the former is a very sensitive primary explosive.

Jerry















DOC0138

Subject:      Re: H2O Bridges
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/16
Message-ID:   <45sm9h$cgj@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <45sfm2$8l4@vixen.cso.uiuc.edu>, misterc@ux7.cso.uiuc.edu 
(Christopher Clayton) says:
>
>syed shah <shah@shelx.uni-ac.gwdg.de> writes:
>
>>Does anybody know of compounds with bridging water molecules?
>
>        What about polymerized water?  I heard about that a couple of 
years
>ago...fascinating topic!  ;)
>
Oh, yeah, polywater, the stuff they use in cold fusion cells
to generate the phlogiston.

Jerry



















DOC0139

Subject:      Re: Hints on building a freeze dryer
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/25
Message-ID:   <46koq2$a9c@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.physics,sci.cryonics



In article <46itn4$8id@ixnews3.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>
. Vacuum gas conductance varies as the fourth power of tubing 
>diameter.  Think about it.)
>
Can you, please, explain why the conductance varies so much
with diameter in a reasonably good vacuum?

Jerry



DOC0140

Subject:      Re: Where did the MOLE come from?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/25
Message-ID:   <46ks3h$a9c@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <5BAnAzl.tinkerbelle@delphi.com>, Kimberly Lewis <tinkerbelle@delphi.com> says:
>

>Ok--what Ireally meant to say was why did they name it the "mole" ? I
>know where it came from + stuff..just not why it's called that =)
> 
Don't you suspect that they shortened the phrase "(mole)cular weight."

Or better yet, "The weight of a compound numerically equal to its
(mole)cular weight or at least its empirical formula weight expressed
in whatever units my country and/or discipline have decided are
standard."

More succinctly put, the term "mole" is short for "stone (mole)cular
weight," with the various values being based on the standard mole
of carbon, i.e. 12 stone (168lbs). Stone units are particularly
useful for calculating reaction rates because a rate of one stone
molecular weight (mole) per fortnight is precisely equivalent
to one pound of carbon per day if you happen to be reacting
carbon.

Obviously, many countries which were conquered by Napoleon now
use other systems of measurement, and there is nothing wrong with 
their continuing to do so, if they wish, providing we remember
that, although the Teutonic fortnight also has forteen days (Heute
in vierzehn Tagen), their weeks are 8 days long (Heute in acht
Tagen). Those of you who have mastered 18th century apothecary 
weight systems will have no trouble converting moles per fortnight
into units of kilograms per Germanic week, in case you need to
communicate with a chemist in, say, Austerlitz.

Jerry


DOC0141

Subject:      Re: Weighing metals (Jason)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/26
Message-ID:   <46netd$5hp@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <46n1jm$3ps@nnrp2.news.primenet.com>, mattstr@primenet.com (Matt Strandberg) says:
>
>You're going to have to learn to use your resources better, if you want
>to succeed in Chemistry...use your periodic table! 
>it has the atomic mass number right on it...and you do mean "mass"; weight
>is gravitational pull; mass remains constant.  :)
>
Oh, I don't know. A lot of otherwise pretty sharp chemists use
the terms "molecular weight," equivalent weight," and "atomic weight"
when they are conducting experiments here on planet earth. Sometimes
they will even be heard to utter phrases like "This sample of
unknown metal has a weight of exactly one gram," but we wiser heads
know that the proper wording is "This sample of metal exerts
a force of 981 dynes on the pan of the balance."

Actually there is absolutely nothing wrong with letting force
and mass be equal numerically. We just have to agree that in
Dr. Newton's "F=MA" one gram of force accelerates one gram of 
mass at 981 cm/sec^2. 

Sheesh, speaking of weight, I need to get away from this 
computer and shed a few poundals or slugs or whatever.

Jerry










DOC0142

Subject:      Re: Chemistry Problem..(Please help!)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/28
Message-ID:   <46sip9$mop@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <46sat0$9t1@news2.isp.net>, Al Oyafuso <oyafuso@slip.net> says:
>
>Hi!  I am currently REALLY stuck on this problem. Can someone help me 
>out ASAP?  Anyone info will be gretly appreciated.  I also need to be 
>shown how the problem was solved.  Thanx a great deal.
>
>Problem:
>    You find an unknown metal.  It's mass is 218.413 grams.  You place 
>this metal in a large beaker of water and heat the water to boiling.  
>Let teh water stay boiling for about 10 minutes.  In the meantime, 
>measure out 500.0 grams of new water and pour it into a styrofoam cup. 
>You find that its temperature is 22.3 degrees Celcius.  You now take the 
>hot metal and quickly remove it from the hot water and put it in the 
>water in the styrofoam.  The temperature of the "styro" water rises 
>until it reaches 38.9 degrees Celcius.  It then starts getting cooler 
>again and then eventually returns to 22.3 degrees Celcius.  Using this 
>data, calculate the Specific Heat of the metal.
>
Sounds dangerous to me. With a heat capacity that high it's probably 
an alloy of beryllium and lithium and you shouldn't be dunking it
in hot water.

(specific heat of metal) * (mass of metal) * (change in temp. of metal)

equals minus

(specific heat of water) * (mass of water) * (change in temp. of water)

I'll bet you didn't read your book.


Jerry


DOC0143

Subject:      Re: Hot Water
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/29
Message-ID:   <470vvl$dsr@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



  Article Segment 1 of 2
  
In article <4707k4$eva@ixnews5.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>
>Dear Tom,
>
>The question was trivial.  Art lies in finding hidden assumptions and 
>ramming them down a TA's throat.  Given the ACS goal of 30% "minority" 
>degree conferral (not 30% more, 30% absolute!), and the unemployment rate 
>among new BS grantees at 70% in 1994... I would not even hallucinate 
>hiring a generator of "gentleman's Cs."  I want the most extreme, 
>meanest, toughest, most recreative nerds, propellerheads, and rocket 
>scientists.  I want the most powerful mentalities.  I want labs filled 
>with alpha geeks.  If management cannot herd cats, we get better 
>management.
>
>Haven't you ever done a bomb calorimetry experiment?  The answer requires 
>correcting for heat lost to the environment, typically by calculating the 
>power input to hold waterbath constant temperature by an electric heater, 
>and extrapolating forward.
>
>Remember - diamonds can only be synthesized at extreme high pressure and 
>temperature.  It is irrefutably proven in every elementary physical 
>chemistry text.  A number of companies are making a few $hundred million 
>every year because some socially crippled ouch bag with an IQ hovering in 
>the stratosphere realized the hidden assumption of "at equilibrium."  CVD 
>growth of diamond does not take place at equilibrium.
>
>Mediocrity is a vice of the doomed.
>
Uncle Al, you have a point, but it might be better made if you
quoted a few lines to let us know from what source and by what route
your inspiration flowed. 

I'll bet you are referring indirectly to the post which began:

>>Problem:
>>    You find an unknown metal.  It's mass is 218.413 grams.  You place
>>this metal in a large beaker of water and heat the water to boiling.
>>Let teh water stay boiling for about 10 minutes.  In the meantime,
>>measure out 500.0 grams of new water and pour it into a styrofoam cup.
>>You find that its temperature is 22.3 degrees Celcius.  You now take the
>>hot metal and quickly remove it from the hot water and put it in the
>>water in the styrofoam.  The temperature of the "styro" water rises
>>until it reaches 38.9 degrees Celcius.  It then starts getting cooler
>>again and then eventually returns to 22.3 degrees Celcius.  Using this
>>data, calculate the Specific Heat of the metal.
>>
Although it is obvious that the kid is looking for someone to
do his homework, we might do better in the long run with a reply
like this:

The metal starts out at 100 deg C because it is coming out of 
boiling water. The water in the cup starts out at room temperature,
22.3 deg C. They both change temperature and both wind up at about
38.9 deg C at least in the short term before the whole assembly
slowly cools down to room temp again.  If you were looking for 
really great accuracy, you would measure the temperature of the
cup/water/metal against time as it cooled down to room temperature,
plot the data on graph paper and extrapolate back to the instant
you plunked the metal into the cup. If you were to do this, you
would find that the temperature was in fact slightly higher than
the 38.9 deg you've quoted. Since you did not mention any other 
data, I will assume that your teacher is not expecting you to
work with this slightly more accurate value and just go on with 
the 38.9 deg you have specified.

The metal goes from 100 deg to 38.9 so the change is 100-38.9=-61.1 deg
The water goes from 22.3 deg to 38.9 so its change is 38.9-22.3=16.6 deg

Water has a specific heat of very nearly 1.00 cal/deg/g (that is 
calories per degree per gram). Therefore, the number of calories 
absorbed by the water from the metal is 

16.6deg*500g*1.00cal/deg/g = 8,300cal

The amount of heat lost by the metal must equal the heat gained by
the water so we can use the same equation we used for the water, except
that we substitute X for the unknown specific heat of the metal and
use the appropriate values for the temperature change and the weight of 
the metal.

61.1deg*218.413g*X = 8,300cal

















DOC0144

Subject:      Re: Hot Water
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/29
Message-ID:   <470vvl$dsr@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
  
  
Solving for X gives: X = 8,300cal/61.1deg/218.413g = 0.622cal/deg/g

This answer would be a little bit low because it does not take into
account the heat capacity of the styrofaom cup or the loss of heat
during the time between the immersion of the metal and the 
measurement of the temperature of the temporarily more or less 
equilibrated mixture.

Only a metal or alloy with a very low average atomic weight would have 
such a high specific heat.

I personally don't find the question "trivial." It merely reflects
a level of education most Ph.D.s passed through early on their long 
path to underemployment :)

Jerry

















DOC0145

Subject:      Re: QUESTION: (bio)chemistry of popcorn
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/29
Message-ID:   <46up8d$635@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <46qf0n$5aa@wn1.sci.kun.nl>, jasperf@sci.kun.nl (Jasper Faber) says:
>
>
>Can anybody tell me what the (bio)chemistry op popping corn
>is. Why is the process so fierce? What is happening? Is 
>popping also possible with other kinds, like rice or wheat?
>
I'll leave it to others to tell you that popcorn pops because
the shell retains water until it yields under the increasing
vapor pressure of the entrained water allowing the softened,
hydrolyzed starch/water composition to  expand suddenly and 
solidify as the superheated water flashes and cools the  
mixture.

But I can say that there ARE other poppable grains such as milo.


Jerry
















DOC0146

Subject:      Re: Where did the MOLE come from?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/29
Message-ID:   <470tvr$dsr@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4705ea$6a9@news.isbe.state.il.us>, Tom Dearing <tdearing@isbe.state.il.us> says:
>

>>A much more important question would be, 
>>why is the abbreviation for mole mol??  
>>Who in their right mind thought this would save time, ink, paper etc.  
>>Does anyone know of another equally silly abbrev. only one letter less than 
>>the full word?
>
>I agree with this one! Anytime I'm working problems involving moles I just can't 
>quit when I get to the l and the **** e slips in on me.  This gives me a terrible 
>complex about not being a legitimate chemistry teacher and giving my students the 
>incorrect symbol.  Oh well I guess that is something I'll have to deal with.
>-- 
The first people to use the the word that sounds like "mole" were
Germans. They abbreviated "Molekuel" in shuch a way as to retain
the long o sound in their language, and "Mol" did the trick
very nicely. They couldn't possibly have used the spelling "Mole"
because the Germans have nothing to do with mexican dishes and they
certainly did not want to feminize the abbreviation for a neuter
word.

Back in those turn-of-the-century days we English speaking people
were still metaphorically swinging from in the chemical trees
babbling "combining weight" when this laconic Teutonic triumph
occurred. The first translator had a hard choice to make: to
retain the form or the sound of the new term. He knew that most
Brits and Amis would frown at anything that wasn't some sort of
alcohol ending in "ol."  He probably surmised that the british
might use a long "o' like the Germans, but he also reasoned that 
the Americans would balk and blurt out a sound like "moll" with 
all its unscientific connotations and invitations to double 
entendre.

Finally, he considered the fact that the Americans were the sort 
of people who mispronounce and misspell good German words like 
"Wolfram" so badly that they come out "tungsten." and, with, a
stroke, he wrote "mole," thus preserving a semblance of the sound 
if not the form of the original utterance.

If you find yourself on the edge of schizophrenia using "mole"
when you think you should be typing "mol," just throw in a few
other foreign mots like "Gestalt" and "Weltanschauung" and your 
readers will simply think you are terribly erudite, but 
patriotic.

Jerry









DOC0147

Subject:      Re: thermochemistry question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/29
Message-ID:   <46v3cc$dc9@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <46umko$37n@hopi.dtcc.edu>, m6337@hopi.dtcc.edu (CHRISTOPHER M. MALINOWSKI) says:
>
>Please help me!
>I'm  really stuck on this one problem, if anyone could please email an 
>answer directly I'd greatly appreciate it.  
>Here it is:
>
>Given the following data:
>        H2 (g) + .5 O2 (g) => H2O (l)
>                                change in H = -285.8 kJ
>        N2O (g) + H2O (l) => 2HNO3 (l)
>                                change in H = -76.6 kJ
>        .5 N2 (g) + 1.5 H2 (g) +> HNO3 (l)
>                                change in H = -174.1 kJ
>Calculate the change in H for the reaction:
>2N2 (g) + 5 O2 (g) => 2N2O5 (g)
>
Your equations are nonsense. If you expect to have anyone
help you with your homework, at least have the courtesy to  
spend enough time to present the questions and data
accurately.

Jerry











DOC0148

Subject:      Re: thermochemistry question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/30
Message-ID:   <471l6n$5fs@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <470ki9$5vq@zippy.cais.net>, alchemst@pacificnet.net (John Milligan) says:
>
>In article <46umko$37n@hopi.dtcc.edu>,
>   m6337@hopi.dtcc.edu (CHRISTOPHER M. MALINOWSKI) wrote:
>>Please help me!
>>I'm  really stuck on this one problem, if anyone could please email an 
>>answer directly I'd greatly appreciate it.  
>>Here it is:
>>
>>Given the following data:
>>       H2 (g) + .5 O2 (g) => H2O (l)
>>                               change in H = -285.8 kJ
>>       N2O (g) + H2O (l) => 2HNO3 (l)
>>                               change in H = -76.6 kJ
>>       .5 N2 (g) + 1.5 H2 (g) +> HNO3 (l)
>>                               change in H = -174.1 kJ
>>Calculate the change in H for the reaction:
>>2N2 (g) + 5 O2 (g) => 2N2O5 (g)
>>
>>The section this falls under the "Hess's Law" chapter in _Chemistry_ in 
>>Zumdahl.  I have the answer (it's in the back of the book), but I just 
>>don't know how to do the problem.
>> 
>>Thanks in advance!
>>Mal
>>
>Since the other responses were of little or no use, I'll give you a hint.  You 
>need to find a way to add the correct equations, which I assume are in your 
>book, to get the final equation.  The way in which you add the first three is 
>the way you add the delta H's to get the enthalpy change for the last 
>equation.  
>
>The correct equations are:  
>
>        H2 + 1/2 O2 ---> H2O       dH = -285.8 kJ
>
>        N2O5 + H20  ---> 2 HNO3    dH = -76.6 kJ 
>
>        1/2 N2 + 3/2 O2 + 1/2 H2 ---> HNO3      dH = -174.1 kJ 
>
>Reaction is 
>        
>        2 N2 + 5O2 ---> 2 N2O5    dH = ???
>
>Keep in mind that if you reverse an equation that its dH changes sign.  If you 
>multiply an equation by a number the dH gets multiplied by the same number.  
>
>Hope this helps.  
>
It's terribly nice of you to help the youngsters copy their
equations from the book to the computer and it is even nicer
that you fill in the blanks where they have left out 
information.

I really don't know what equations they were given, but based
on real life reactions and the hints given in the original
post,  I surmise that they were, or should have been given
equivalent, but less convenient multiples of the following  rather
commonly known reactions

1.	6H2 + 3O2 -->6 H2O

2.	2 N2 + 6H2 --> 4NH3

3.	4NH3 + 8O2 --> 4 HNO3 + 4H2O

4.	2N2O5 + 2 H2O --> 4 HNO3

Add  2 and 3, then subtrct 1 and 4 and rearrange to get:

5.	2N2 + 5O2 --> 2N2O5







DOC0149

Subject:      Re:solubility of gasses in liquids:QUESTION
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/10/30
Message-ID:   <471ri0$5fs@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <todda.1.30944B9D@coral.indstate.edu>, todda@coral.indstate.edu says:
>
>If gasses are more solubile in liquids at lower temperatures why does the 
>carbon dioxide dissolved in any carbonated drink come out when it is poured 
>over ice.  It is getting colder so the carbon dioxide should become more 
>solubile not less solubile.    

Colder or not, the CO2 is still supersaturated in solution and the
ice provides nucleation points where that gas can expand.

Try to imagine the mechanism of expansion in the absence of nucleation
sites. The CO2 molecules would have to randomly collide to first
form molecular scale bubblets which would have to grow by diffusion
from the liquid until they were large enough to generate Brownian
motion-defeating lift. Long before they reached this size, the 
enormous surface pressure of the submicroscopic bubbles would
drive the gas back into solution.

In this world, if you're a bubble, you gotta be big to survive
and in order to get big you've got to nucleate.

Jerry












DOC0150

Subject:      Re: *so* sorry and glad
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/03
Message-ID:   <47bsch$8as@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <478cr5$cct@hopi.dtcc.edu>, m6337@hopi.dtcc.edu (CHRISTOPHER M. MALINOWSKI) says:
>
>First of all I'd like to thank the people who took the time to help me 
>with the thermochemistry problem I put on here about a week ago.  
>Secondly I'd like to thank the people who decided to flame me about 
>the problem I put on because it was missing a variable which anyone with 
>even the slightest amount of brain power could fill in, that is if they 
>weren't too busy chastizing someone and trying to teach them some 
>ill-begotten lesson.  The reason I'm thanking them, is because if I do 
>decide to become a chemist I will not want to end up like them.
>Thanks again!
>Mal
>
>-- 
>"Those who forget history are doomed to repeat"

Gasp!!! I was shocked to learn that someone in this forum
had the gall to actually CHASTIZE a teenager for one tiny
little mistake in copying his homework assignment onto the
net.  If I were you I would immediately contact the ACS and 
file a formal complaint.  

BTW, was the single "variable" you missed the "5" in N2O5 
or the missing "O2" in the equation for producing nitric 
acid from the elements, or are you referring to the 
incorrect coefficient for hydrogen in the same, unbalanced
and incomplete reaction, or are you simply referring to the 
general imbalance of two of the equations?

I suspect that many chemists in this forum have forgotten
how difficult and time consuming it is to copy a couple of
equations from a textbook such as:

0.5N2 + 0.5H2 + 1.5O2 --> HNO3 

and

N2O5 + H2O --> 2HNO3

without wasting valuable time in checking all those boring
coefficients and subscripts. The very next time you are faced
with such a problem and don't have the time or inclination
to work the thermodynamics out for yourself, just log onto
sci.chem and type:

N + H --> HNO

NO + HO --> HNO

And let somebody else sort out the details:)

Jerry

Those who do not dot their i and cross their t
are full of sh??
<
DOC0151

Subject:      Re: Copper + Silver nitrate-----> *Please Help*
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/03
Message-ID:   <47dm5p$eia@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <47cadl$soq@ixnews7.ix.netcom.com>, e-mail@ix.netcom.com (None ) says:
>
>
>    Hi, 
>        I know this question is probable very simple and a waste of
>your time but please humor me and write back. The reaction 'copper +
>silver nitrate ----> Silver + copper nitrate[Cu(NO3)2].' In this
>reaction silver is produced but this silver is in an impure form.
>Can anyone tell me what impuraties are in the silver, how they got
>there, and most importently how to remove the impuraties.
> Thanks for your help, sorry about the spelling errors.
>   
Please tell us how you know that the silver is impure.

Jerry



















DOC0152

Subject:      Re: Additive to make paint glow
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/04
Message-ID:   <47f61g$glu@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <47eher$3bo@supreme.pcug.org.au>, Thomas Huljev <thohul@pcug.org.au> says:
>
>Can anyone help me with this.

The classic pigment is zinc sulfide doped with a little copper
salt. Don't grind the material too fine.

Jerry




DOC0153

Subject:      Re: exothermic reactions
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/04
Message-ID:   <47f5jq$glu@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <47dp23$f3g@dim.intersurf.net>, smiller@intersurf.com (Scott Miller) says:
>
>glhurst@onr.com (Gerald L. Hurst) wrote:
>
>>In article <47bqup$djq@numbat.devetwa.edu.au>, Clinton Smith <smithc@devetwa.edu.au> says:
>>>
>>>i would like to demonstrate an exothermic reaction:
>>>would potassium permangante and glycerine be appropriate for a small 
>>>experiment?
>>>
>>Why not just strike a match or flick your Bic?
>
>>Jerry
>
>
>Um, that would be combustion, huh?
>
>Yeah it's exothermic, but it's also destructive.
>
>My lab students always get a kick out of dissolving NaOH pellets
>(although that's a pretty caustic reaction).
>
>Scott

I see, you don't like combustion because it is "destructive."
By that I assume you mean you'd like something a little less
exothermic, a bit more reversible and not too caustic.

OK, have your students make little plaster of Paris balls.
They can dehydrate them in an oven at a modest 130 deg C
then let them cool in a jar. When a drop or two of water
is added to a ball it will warm up noticeably and the 
balls can later be recycled by heating. You might add
a bit of cobalt chloride to the balls so that you get 
the blue-pink color change along with the harmless 
thermal effect.

I have another demo in which the balls turn incandescent
but, sigh, it's destructive.
>
Jerry















DOC0154

Subject:      Re: Endothermic Reaction
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/05
Message-ID:   <47j9cq$4cb@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <47j14h$2bd@mozo.cc.purdue.edu>, Brian <bussb@elmail.cc.purdue.edu> says:
>
>Hey everyone...
>
>I had a question.  Does anyone have an idea for an endo thermic reaction 
>that uses easily obtainable reactants.  Basically what I need this for is 
>to cool some ni-cad batteries I use in RC vehicles.  The reaction would 
>have to be contained in an enclosed bag or capsule.  If the reaction you 
>have in mind produces some gas and therefore cannot be contained in a 
>sealed container, this would also be OK.  Most importantly though, the 
>reactants or products shouldn't be toxic or harmful.  ANY ideas on this
>would be greatly appreciated.  Thanks for your time.
>
You might try ammonium nitrate and water. The dissolution of
AN in water absorbs a great deal of heat. The combination
is often packaged and sold for use as an emergency cold pak.

AN is cheap, but you can recover the solid by simply evaporating
the water whenever the relative humidity is below about 60% or
otherwise by warming the solution.

Jerry












DOC0155

Subject:      Re: thermochemistry question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/06
Message-ID:   <47m6p9$q02@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <BOSSE.95Nov6102500@prima.met.kth.se>, bosse@met.kth.se (Bo Sundman) says:

>Anyone who knows how N2O5 is actually produced (if it is ...)
>
It is made by dehydrating nitric acid with P2O5. It exists in 
two solid forms and can be distilled under rather extraordinary 
conditions.

The equation N2 + 5/2O2 --> N2O5 is merely the formal, if hypothetical
reaction associated with the heat of formation of the compound.

Jerry
<





















DOC0156

Subject:      Re: Dancing mothballs?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/07
Message-ID:   <47ohel$gep@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <47o23d$34v@curly.cc.emory.edu>, nmukund@curly.cc.emory.edu (Nancy E Mukundan) says:
>
>I, also, learned that the active ingredient in mothballs
>is naphthalene.  Recently, someone told me it is some
>other compound, but I don't recall what that is.  Anyone
>know about this?
>
p-dichlorobenzene, as I recall.

Jerry


DOC0157

Subject:      Re: sodium hypochlorite (bleach) and organic impurities?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/09
Message-ID:   <47scb7$c01@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <1995Nov9.054656.7280@galileo.cc.rochester.edu>, gl002c@uhura.cc.rochester.edu (G. Lane) says:
>
>I believe (don't ask for a balanced reaction) that sodium hypochlorate
>(chlorox bleach, an important chemical in the industrial revolution)  acts
>as a solid and portable form of chlorine, or in general just oxidizes very
>well.

The solidity of sodium hypochlorite is somewhat questionable.  The
Industrial Revolution may have to settle for an aqueous solution.

> living things don't like getting oxidized, and tend not to survive. 

This is particularly true of rapid oxidation above about 500 deg C.

Jerry



















DOC0158

Subject:      Re: Caloric Value
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/13
Message-ID:   <4864ci$40f@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.engr.chem



In article <481to6$1da$1@mhade.production.compuserve.com>, Johan Reynaert <101353.3201@CompuServe.COM> says:
>
>Hi,
>
>Who can explain to me the difference between the higher and lower 
>caloric value of natural gas.
>
Natural gas from different sources contains varying amounts of
such gases as ethane, CO2, nitrogen, and even helium. 
Increased amounts of ethane raise the volumetric caloric content 
while the other gases reduce it by simple dilution.

Jerry





















DOC0159

Subject:      Re: Coulombic forces
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/13
Message-ID:   <486j27$cgd@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



.
>
>The inverse square law applies for two point charges.  The
>inverse first power law applies for the force between two
>infinite parallel plates (I believe then that the charges
>are those on each of the parallel plates).
>
What rule applies to two parallel charged lines?

Jerry


DOC0160

Subject:      Re: delta H question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/13
Message-ID:   <486tqa$gm6@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <486soq$gm6@geraldo.cc.utexas.edu>, glhurst@onr.com (Gerald L. Hurst) says:
>
 then another 540 cal/mole to change the water 
>to steam.

OOoops. I meant to say 540 cal/g times 18g/mole or roughly
9720 cal/mole to change water to steam. Never believe
the numbers we post, just pray the principles are half
right :)

Jerry

DOC0161

Subject:      Re: delta H question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/13
Message-ID:   <486soq$gm6@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <486ifg$3dh@madeline.INS.CWRU.Edu>, Robert Kanar <rck2@po.cwru.edu> says:
>
>hello, i am a student in a first year chem course in college and my 
>professor posed this question, which we are supposed to find the solution 
>to "any way we can." i was wondering if anyone here could please help me 
>with it. 
>
>"How would one find the delta-H of a reaction if the reactants are at 25 
>degrees C and the products are at 100 degrees C ?"
>
>we have a chart that has the values of the delta-H-of-formations at 
>standard states, and the basic formulas, but no one knows how to deal with 
>the variation of the temperature. i'm guessing that calculus is involved 
>somehow, could someone please explain? thanks !!
>
>You simply need to use heat capacity data to calculate the
amount of energy it takes to raise the temperature of the 
reaction products from 25 to 100 degrees, plus any heat 
required for phase changes. If the product were water  
at 100.1  deg C and atmospheric pressure, it would take 18 
calories/deg/mol times (100 - 25)deg to get the liquid up to 
the 100 mark, then another 540 cal/mole to change the water 
to steam and then a tiny amount to heat the steam 0.1 deg. 
(Cp, the heat capacity of steam, times moles of steam times
0.1 deg) Thus the total change in enthalpy would be the 
original value for the standard  reaction plus the three
quantities we just calculated for each mole of water.

The same principle applies for whatever products and whatever
phase changes may occur in warming up your products. 

You won't need calculus this time, because you are dealing 
with a small temperature range and the heat capacities
can be considered as constants. When you deal with larger
temperature ranges, get ready to use those tall esses.

Notice that we use Cp, the heat capacity at constant pressure
rather than Cv, the heat capacity at constant volume. We do 
this so that we don't have to correct our energy values for
the PV change that occurs when we heat our materials. That's
why it's so convenient to talk about total enthalpy change
rather than total energy change.

Jerry












DOC0162

Subject:      Re: odor of acetamide?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/14
Message-ID:   <489dcv$c88@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <488geh$af1@brahms.udel.edu>, sunrise@brahms.udel.edu (Adam Le Halberstadt) says:
>
>Can anyone out there tell me what acetamide smells like?I have a 
>bottle of acetamide crystals that smell like glacial acetic acid.  
>However, the merck index states that acetamide when pure has no odor, and 
>has a mousy odor whem impure.  Is this acetamide contaminated, or is the 
>label wrong?  Thanks for your help.
>
I remeber my first whiff of slightly impure acetamide 40 years
ago quite well. The odor was, indeed faintly like that of a
mouse nest - nothing more. Yup, I've smelled it since then, and
it hasn't changed. Acetamide does hydrolyze to acetic acid (or a 
salt thereof) in the presence of acid or base, but the reaction 
is usually described as occurring in hot water.

Jerry


















DOC0163

Subject:      Re: Quiz question - please help
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/16
Message-ID:   <48eplb$3e2@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <48e4ht$d1p@news.nsysu.edu.tw>, "Robert M. A. Hsu" <RobertH.bbs@bbs.nsysu.edu.tw> says:
>
>afelton@ix.netcom.com (Andy Felton) wrote:
>>On 14 Nov 1995 21:25:29 GMT, iaotb@inet.uni-c.dk (Torsten Brinch)
>>wrote:
>>
>>>Lubosh.Hanuska (ljh655@anugpo.anu.edu.au) wrote:
>>>: This must be a trivial question for those who know a bit (not like me) about 
>>>: chemistry:
>>>: What is the common name of NaCl ?
>>>
>>>:-)
>>>This is just ordinary tears (dry).
>>>
>>>Seriously: NaCl = salt
>>>
>  Just to clear up any confusion, any binary compound with a metal as one 
>of the elements is a salt (is this correct?).  
>
>
>Not really.
>As I know, SALT is defined as compounds whose aqueous solutions have 
>conductivity. For example, NH4Cl is a salt but it's not binary and 
>without a metal.  However, Fe2O3 is a binary compound and with a metal 
>but never considered as a SALT.
>That's what I know.
>
It might be better to think of a salt as an ionic compound which
can be formally thought of as the product a reaction between an
acid and and a base with the elimination of water.  Ammonium 
chloride, for instance, might be be formed by the reaction NH3 + 
HCl --> NH4Cl, but we consider it the salt of the hypothetical
reaction NH4OH + HCl --> NH4Cl + H2O.

You might then consider Fe2O3, not as a salt but a base, or in
its hydrated form as either an acid or a base.

Keep in mind that these concepts are matters of convenience 
for chemists. The properties of a metal oxide are not inherently
distinct from those of materials we more readily refer to as
"salts."  This particular view is widespread because we tend to
orient our thinking around the protonic theory of acids for
routine work-a-day chemistry.

Jerry











DOC0164

Subject:      Re: Quiz question - please help
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/16
Message-ID:   <48gaou$sin@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <30AB5E68.5FB3@esvax.dnet.dupont.com>, John Kirchstein <kirchste@esvax.dnet.dupont.com> says:
>
>The common name for NaCl is Halite --- This is the mineral rock 
>salt.

I believe the more common name for NaCl is "table salt."

Jerry




DOC0165

Subject:      Re: Liquid Paper Solvent
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/20
Message-ID:   <48on45$qqn@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <48nq32$ovd@muss.CIS.McMaster.CA>, u9301134@muss.cis.McMaster.CA (C. Base) says:
>
>
>Could anyone tell me what the solvent in Gillette's Liquid Paper(tm) is? 
>It used to say 1,1,1-trichloroethane on the label, but now all they say is
>that a Material Safety Data Sheet is available (in Canada, at least).  To
>the average Tom, Dick, and Harry, this is useless.  Is it still Cl3C-CH3? 
>-- 
I'm the guy who put the 111 in Liquid Paper, but the general 
formulations anticipated later switching to other materials
in case 111 was found to have unanticipated problems. If I
knew what they are using, I couldn't tell, but I don't so I'll
surmise that it is an HFC - that's what I would use :)

Jerry



















DOC0166

Subject:      Re: Question...
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/20
Message-ID:   <48om37$qqn@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



X-Newsreader: WinVN 0.92.6+

In article <48i9n5$3qr@news.ysu.edu>, av256@yfn.ysu.edu (Brian Travers) says:
>
>
>I would greatly appreciate it if one of you kind folks could help me out...
>
>Question:  I make water "hard".  My solubility in water decreases
>as the temperature increases.  I am found on the bottom of
>your teapots.  I am also used as an antacid.  What compound am I?
>
I think the questioner is perhaps a little mixed up. CaSO4 is
known for its unusual decreasing solubility with increasing
temperature, at least at moderately elevated temperatures.
However, it is CaCO3 which is an antacid, but, as far as I know,
the solubility of this material increases slightly with temperature.

I suppose CaCO3 might appear less soluble because of possible
formation from the more soluble bicarbonate in hot water.

Any of these calcium salts impart the quality of "hardness" to 
water.

Jerry










DOC0167

Subject:      Re: U-In8: First Commercial Cold Fusion Cell?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/21
Message-ID:   <48s25k$ov3@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <48r28u$1f9@ixnews3.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:

[re yet another cold fusion breakthru]

>I'll give you 100-1 odds against, just after I liquidate in my mortgage 
>equity and life savings, and you put up 1% in escrow, with a deadline.
>
>At 10,000-1 odds it would would still be, in the words of science fiction 
>novelist Frank Herbert, "a Wreave bet."
>
Uncle Al, I think you're on to something here. The only problem is
figuring out how to convince the indefinitely expectant true 
believers. They will keep it "on the verge" of success long after
other religions have given up waiting for their respective Messiahs.

Jerry


















DOC0168

Subject:      Re: Swallow Me
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/22
Message-ID:   <4904ou$i3p@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <744677514wnr@fats.demon.co.uk>, Richard Bettis <rbettis@fats.demon.co.uk> says:
>
>caesium (this is the correct spelling, perhaps Americans don't use the 'a' 
>because they feel that 'a' is unservicable - as in u/s of a)
>
>from the Latin: caesius,  blue-grey. (as in the colour of Caesium)
>
>(presumably Chemists find this hilarious, they've got to get their kicks within 
>their limitations I suppose)
>
Americans spell cesium as they please. They capitalize "USA," but
not "Chemist" or "Cesium." You may presume what you wish, but I 
doubt that many chemists or chemical engineers here or in the UK
find any humor in the ingestion of any alkali metal.  It IS
interesting to note that the thread caught your attention and led
you to comment on American spelling and your impression of the 
nature of chemists' humor.

If you wish to become an American chemist, you can go back to school 
and pick up a few courses prior to emigrating. You could also continue 
your studies in the USA, but you might be required to pass an English 
language proficiency test before being accepted into graduate school.
Judging from your few lines of prose. it would appear that you could
pass with flying colors after a little study and practice.

Jerry
<







DOC0169

Subject:      Re: Swallow Me
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/24
Message-ID:   <493d0u$n2k@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <DIIGqx.ICx@uns.bris.ac.uk>, ch3106@irix.bris.ac.uk (J. Spashett) says:
>
>PS  On spelling I don't care how people spell stuff.
>
>But what I *hate* is being told by IUPAC that I have to spell Sulphur as
>Sulfur.  I mean come on!
>
Yeah, but I really draw the line at "Fosforus" and "fenolfthalein."

According to IUPAS (International Union of Pure and Applied Semantics),
the correct spelling  of "IUPAC" is "UICAP" because adjectives should
follow nouns. Actually, the word-order rule-making organization 
recently renamed itself "UISAP" for obvious reasons. The Germanische
Union fuer die Reinigung der Muttersprache (GURM) and  the Union fuer 
die sofortige Hinauswerfung von verdammten Fremdwoertern und weitere 
Reinigung der Germanischen Sprachen (USHVFWRGS) have objected to the
implementation of rules based on Romantic language constructions.

Jerry
<














DOC0170

Subject:      Re: Swallow Me
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/24
Message-ID:   <495eso$spd@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <735613793wnr@fats.demon.co.uk>, Richard Bettis <rbettis@fats.demon.co.uk> says:
>

>After all, even Americans can get into graduate school (well, American graduate 
>schools at least.)
>> 
>> Jerry
>
>(shouldn't that be Gerry?) <grin>
>> 
Some of them get into Cambridge.

Gerry





















DOC0171

Subject:      Re: Air Fuel Mixture Ionization
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/11/29
Message-ID:   <49gvhi$sdt@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,alt.engr.explosives



In article <49fbks$fl1@cobia.gulf.net>, Chuck Thigpen <cthiggy@gulf.net> says:
>
>I am in no way a chemist.  However, I am a mechanical engineer looking
>to find a way to ionize an air & fuel mixture using electricity.  Would
>it be possible to ionize this mixture using an electromagnetic field?  
>Or am I just out to lunch.  What other ways could I ionize this mixture?
>Thank you.
>
You will have no problem getting the mix to ionize at low
pressures. A Tesla discharge against a glass tube of the 
materials will do the job. However, at any pressure, your
fuel and oxidizer won't take long to react with one another,
probably explosively. You could say that the sparkplugs in
your car ionize fuel/air mixtures at least in the vicinity 
of the electrodes.

There have been some gadgets on the market which claim to 
preionize fuel/air in cars or to create a "corona" effect.
I knew a mechanical engineer who strapped  one on his car
and believed he derived better milage from that P.T. Barnum
device.  

"Positive ion" generators were also very popular at one time. 
I knew a fellow , who had one in his horse trailer and one in 
the cab of his pickup. He was sure they made both himself 
and the horse run faster. In fact, he was so convinced about 
the merits of these "pizza pans on a stick" that he boasted 
openly about how he had conned the unsuspecting inventor out 
of the patent rights for a measley $20K.

Hmm. Come to remember, this was the same guy who also prided 
himself for having relieved another gullible inventor of a
priceless piece of technology for another $20K. This time it
was a system for cleaning up oil spills by sprinkling
radioactive powder on them so they'd polymerize. Once the 
slick was solidified, you could just roll it up. I guess 
this also involved ionization.

I always thought I, too, should have let myself be cheated out
of one of my great inventions, but somehoe I never got around
to it.

If you're sure you want to ionize fuel/oil mixtures, give me 
a call :)

Jerry










DOC0172

Subject:      Re: Bubbling in soda.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/02
Message-ID:   <49p2nn$i1l@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <c17cb$161f1e.4c@news.rmci.net>, jvinson@rmci.net (John W. Vinson) says:
>
>dwilkins@northernnet.com (Don Wilkins) wrote:

>>For the benefit of Mr. Vinson. I would like to offer a short Bavarian
>>poem. For him I think it is particularly appropriate.
>
>
>>  Fuer d'Flh gibts a Pulver
>>  fuer d'Schuach gibts a Wix
>>  fuer'n Durst gibts a Wasser
>>  bloss fuer d'dummheit gibts nix
>>      (anon.aus Bayern)
>
>
>True true... a rough translation:
>
>For the flu give a powder
>For the (shower?) give a (raincoat?)   < not in my Cassell's; Beyrich?
>For a thirst give some water
>But for stupidity, there's nowt!
>John W. Vinson --------------------- 74222.2372@compuserve.com
>Wysard of Information        Scientific Information Consultant
>
Greek scholars disagree - why shouldn't we?

For fleas there's a powder
for shoes there's a polish
For thirst there's water
But for stupidity there's naught

The attribution to Bavaria is absurd. No Bayer would think
of water for thirst, at least never in a Schnaderhuepferl.

Jerry





















DOC0173

Subject:      Re: Bubbling in soda.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/05
Message-ID:   <4a0av0$dbd@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SOL.3.91.951203150423.8736F-100000@gladstone>, Michael Newmen <miken@gladstone.uoregon.edu> says:
>
I do have a question though about the responsibility of chemists
>in a world all to eager to use chemicals.  I recently saw a list of 
>instructions on how to make exploasives, timing devices, and how to use
>them.  Tell me, at what point to we have to draw the line between the
>free exchange of information and censoring that which is dangerous to
>society?

One sees a lot of explosive "recipes" on the usenet, but I doubt
that many of them are posted by chemists. Most of the garbage
appears to be infinitely recycled methods which drift farther
from reality as successive generations of wannabe teenybombers
add their personal inexperience.


Jerry

















DOC0174

Subject:      Re: Chemie und deutsch
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/17
Message-ID:   <4b1s7q$ll1@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4aunpa$qrd@due.unit.no>, Martin Ystenes <ystenes@kjemi.unit.no> says:
>
>tice@nai.net (Bradley D. Tice) wrote:
>>German was easy to learn. The basic words are very similiar to English.
>>And there's only twelve ways to say "the." 
>
>der, die, des, den, dem, 
>
>Where are the 7 others?
>
Der has 4 applications: feminine and plural possesive, dative
feminine, nominative masculine; die has 2: feminine and plural;
des has 2: dative masculine and neuter; den (2) may be dative plural
or accusative masculine and dem (2) is either dative masculine or
dative neuter.

That makes twelve. There are arguably fewer or more depending
on one's viewpoint. For instance "die" could be said to
be 3 kinds of nominative plural. I counted it as only one since 
the rule is easily remembered.

I would guess that having five words representing 12 concepts
might be harder on the student than 12 differently spelled
words.  I suppose this is a question that might be more easily
answered by a first-year German student.

Jerry (Ico)







DOC0175

Subject:      Re: SEMTEX - what is it?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/19
Message-ID:   <4b537i$k9@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,alt.engr.explosives



In article <4b4pf4$qnp@bcarh8ab.bnr.ca>, yshan@bnr.ca (Yogi Shan) says:
>

>I find it strange that PETN would be mixed with
>RDX.  _Plastique_ is _plastique_.  RDX (the 
>explosive in C4), I understand is more expensive
>than PETN, and would require a separate 
>production line.
>
You are right, Yogi. PETN and RDX are so similar in their explosive
properties that it would be foolish to mix the two and thereby
double the risk of some chemical incompatibility unique to one or 
the other.

By coincidence, it happens that I have prepared and tested plastic
explosives that have about the same composition as the material that
is now called "Semtex." The compositions are very similar to 
C-4 in look, feel and performance.

In the US, RDX has been viewed as a "military" explosive. PETN,
was considered more as a "commercial" explosive, partly
because of its private industrial manufacture and widespread 
use in detonating cord. RDX, of course, works just as well in det
cord and is the basis for the military version. Industrial
use of RDX is mostly limited to surplus powder which is cast
into primers in admixture with TNT..

If you ask US military folks why they use RDX rather than PETN,
they will usually cite the somewhat lower density and greater
sensitivity of PETN. Besides, it's a habit and it costs the 
taxpayer more :)

Jerry (Ico)

DOC0176

Subject:      Re: Freezing hot water
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/20
Message-ID:   <4b7s4o$76i@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4b7pil$fnu@usenet.ucs.indiana.edu>, "John C. Huffman" <huffman@indiana.edu> says:
>
>hhowe@trgnet.com (Harold Howe) wrote:
>>Why does hot water freeze faster than cold?
>>
>>Harold Howe
>Actually it doesn't.  Water with disolved gases will freeze at
>a lower temperature however, and hot water will contain fewer
>disolved gasses.  Therefore, the hot water may appear to
>freeze faster, especially if the freezer is only a few 
>degrees below 0C.

I believe that the freezing point depression by dissolved
air is considerably less than 1/100 deg C, which would
not seem likely to make a noticeable difference in the
freezing rate with a temperature differential of a few 
degrees.

Jerry (Ico)















DOC0177

Subject:      Re: Freezing hot water
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/20
Message-ID:   <4b7q6p$76i@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4b7jri$sk8@insosf1.netins.net>, hhowe@trgnet.com (Harold Howe) says:
>
>Why does hot water freeze faster than cold?
>
I've never actually encountered frozen hot water - it was always
been quite cold :)

Perhaps you mean to ask why initially hot water in an ice-cube
tray sometimes freezes before a similar tray of cold water
under the same conditions.

In some cases, when there is a substantial layer of frost
on the metal conducting heat to the evaporation coils, the 
warmer tray melts the layer away and allows the tray to
contact the very cold and highly thermally conductive metal.

Removing the frost layer is like opening a door for the
heat to move through by conduction.  Once the thermal
barrier is gone, the water which was warmer up to about 
that point rapidly becomes colder than the initially cold 
water which continues to rest on umelted frost and therefore
loses heat more slowly.

Jerry (Ico)










DOC0178

Subject:      Re: SEMTEX - what is it?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/21
Message-ID:   <4baa9h$bk5@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,alt.engr.explosives



  Article Segment 1 of 4
  
In article <B.Hamilton.627.30D794F7@irl.cri.nz>, B.Hamilton@irl.cri.nz (Bruce Hamilton) says:
>
>In article <4b537i$k9@geraldo.cc.utexas.edu>
> glhurst@onr.com (Gerald L. Hurst) writes:
>>In article <...>, yshan@bnr.ca (Yogi Shan) says:
>[ my earlier cite to C&EN, noting that Semtex had
> both RDX and PETN deleted ]
>>>I find it strange that PETN would be mixed with
>>>RDX. 
>...
>>You are right, Yogi. PETN and RDX are so similar in their explosive
>>properties that it would be foolish to mix the two and thereby
>>double the risk of some chemical incompatibility unique to one or 
>>the other.
>
>>By coincidence, it happens that I have prepared and tested plastic
>>explosives that have about the same composition as the material that
>>is now called "Semtex." The compositions are very similar to 
>>C-4 in look, feel and performance.
>
>Well, as promised, I looked it up. Experience tends to make me 
>very suspicious of Gerald's assertions :-)....
>
>From:-  "Analysis of Semtex Explosives" J.R.Hobbs.  
>Chapter 39. p.409-428 in " Advances in Analysis and 
>Detection of Explosives" edited by Jehuda Yinon
>Kluwer Academic Publishers   ISBN 0-7923-2138-3  (1993)
>
>Table 1.  Summary of Semtex Analysis
>
>Name                 Semtex H               Semtex A
>% PETN                 49.8                   94.3
>% RDX                  50.2                    5.7
>Dye                  Sudan I                Sudan IV
>Antioxidant         N-phenyl-2-            N--phenyl-2-
>                    naphthalamine          naphthalamine
>Plasticizer        n-octyl phthalate       n-octyl phthalate
>                    butyl citrate           butyl citrate
>Binder             styrene-butadiene       styrene-butadiene
>                      rubber                   rubber
>
>Table 2.  Gravimentric Analysis
>Sample size           1.0194                   1.1061
>Weight oil            0.0811                   0.0994
>% oil by weight       7.9                      9.0
>weight rubber         0.0920                   0.1036
>% rubber by we







DOC0179

Subject:      Re: SEMTEX - what is it?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/21
Message-ID:   <4baa9h$bk5@geraldo.cc.utexas.edu>


  Article Segment 2 of 4
  
  
ight    9.0                      9.4
>weight explosives     0.7029                   0.7029
>[ rest of table omitted ]
>
>Note that other  chapters highlight the fact that Semtex H was the
>explosive used in mainland UK. There is an excellent, droll
>chapter " The Semtex H Story" by A.W.Feraday,OBE - head of
>Forensic Investigations, Forensic explosives Laboratory. He
>describes all 58 incidents involving Semtex, and notes they killed
>284 ( of which 270 were at Lockerbie, and 11 at the Deal barracks),
>whereas 3288 incidents involving other explosives killed 107. He
>was emphasising that Semtex is not unusual. In one " own goal "
>in a car three terrorists were putting the finishing touches to a
>300 ball bearing / 85gram Semtex claymore mine intended to
>disrupt an anti-Khomani meeting, when it exploded. The driver's
>surname was Fooladi, :-) - he was the only survivor, 10 years at
>her Majesty's pleasure... He also notes the various names of
>the manufacturer - initially the Semtin Glass Works, then the
>Eastern Bohemian Chemical Works, then Synthesia. 
>
>Another paper also notes that ICAO have insisted that volatile
>taggants be added to involatile plastic explosives at manufacture,
>and EGDN ( ethylene glycol dinitrate ) is now added to Semtex H. 
>Several papers also note that various batches contain various
>levels of impurities and compositions, but all consider Semtex H 
>to have a minimum of 21.5% RDX and a maximum of 64.5% PETN
>with around 14% of rubber and oil. There are a couple that note
>that Semtex A1 is predominantly PETN, but as the above analysis
>indicates it still has both, although I suppose some people may
>ignore the few % of RDX. I've no idea of the relative volumes, but
>th4e above articles indicate that H was the common terrorist 
>material of concern
>
>I will add bits of this to the FAQ, with the reference. I suspect
>the earlier reference I cited may be more comprehensive ( and
>it's the same author ), but it's not accessible to me. 
>
>                 Bruce Hamilton
>
Bruce and I have indeed had our discussions in the past 
regarding a minor difference of opinion about the suitability of
using the principle of Archimedes to measure the density of
very water-soluble solid materials. Bruce may like to tell you
which side of that argument he supported.

So, we have found some analyses of materials said to be
"Semtex-X" that contained anywhere from 21 to 64 percent PETN
with the balance RDX and inerts. You don't suppose these could 
be the result of the extreme financial problems in the old 
eastern block, especially in the period 1993? 

The Russians and Poles, etc are very good at the science of
high explosives so they know that it is unwise to specify
the unessary use of two components in an explosive mix
where one will do. Not only does it increase the likelyhood
of chemical incompatibility, but it puts your manufacturers
in the position of having to carry double inventories, which
is a hell of a stupid thing to do when you are dealing with
national defense.

We have already discussed the fact that there is little 
difference in the performance of plastique made from RDX
or PETN. I suspect that the Semtex being glommed onto by
terrorists is a kitchen sink material made up of whatever
proportions of HEX types they can find.  If comrade Vladimir
gets Col Khadaffi's order for a few tons of plastique, and 
Vlad finds he is out of PETN from the Chernobyl plant, does
he apologize and not fill the order because he doesn't have
the "minimum" 21 percent PETN? Or does he simply manufacture
"Semtex U," short for USA, a material remarkably like C-4?

As long as these guys can get their hands on either PETN or
RDX individually or in a mixed ordnance scrap pile, they will
continue to manufacture "Semtex" and people will continue
to ask "What is the composition of Semtex?"  I would be
willing to bet that there is plastique "Semtex" out there 
adulterated with TNT, HMX (They should be so lucky) and tetryl 
as well and probably a good bit of it cut with inerts to the
cap-sensitivity limit..




















DOC0180

Subject:      Re: SEMTEX - what is it?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/21
Message-ID:   <4baa9h$bk5@geraldo.cc.utexas.edu>


  Article Segment 3 of 4
  
  
According to your gravimetric analysis table II, the total
explosive contents of Semtex "A1" and "H" respectively
are 64 and 69%. The corresponding oil/rubber contents are
17 and 18% for totals of about 81 and 87%. Based on the ratios
in table 1, the RDX woiuld be 5.7*.64 = 3.6 percent which is
far less than the material not accounted for.

Three or four percent sounds like an amount which can be
assigned to residue from not cleaning the mixer between batches.

There is not a great deal of difference in the explosive 
performance of RDX and PETN, but there are valid military
reasons to prefer the former (sensitivity, stability). There
are are also good reasons to use PETN in commercial 
applications - it is powerful and cheap. Now, the old Eastern 
Block's ordnance was second to none in those areas where they
had the necessary skills, and they definitely knew at least as
much about explosives as we do.

Most explosives chemists are very used to the idea of 
interchanging RDX and PETN in various commercial formulations 
depending on the price of the materials. In this country we 
use RDX for primers when the government deigns to sell off old 
surplus material. If I had an order for 1000 1lb 50% cast 
primers, but only 250 lbs each of RDX and PETN do you suppose 
I would make up two batches of 500 lbs each or one batch of 
1000 lbs. Regardless what went in, the customer would probably 
think of it as "pentolite." For the quarry operator, no harm
done, but Uncle Sam wouldn't buy it. 

A military formulator, whether here or in Poland would not
make a plastic explosive from PETN if he/she had access to ample
RDX unless the object was to save money, in which case he/she
would simply use PETN. The use of a PETN/RDX mixture would be 
an expedient measure when supplies were short and the customer
was desperate or not too particular, as in the case of Middle 
East terrorists. Adding 5% RDX to a PETN formulation would
produce undetectable performance changes, but it would make
good sense if you had some surplus RDX available, commercial
access to all the PETN your rubles can buy and willing buyers
other than your own fussy military.

Note that the analyses indicate an excessively high proportion
of inert materials, way beyond the less than 10% required to 
impart adequate plasticity.  Looks like somebody has their
thumb on the scale, doesn't it? Or do you suppose the Eastern
armies don't object to carrying around a little totally useless 
baggage in combat? It is more likely that the high inert values 
are a reflection of the fact that terrorists will buy anything 
that goes "boom" most of the time.

I understand that they are giving away a free sample of "red
mercury' with each case of Semtex. Perhaps we can have a debate
about the precise composition of the former sometime.

For those of you who like pigeon holes and lables, we could make 
a sliding scale for "Semtex" formulations using all the letters
of the alphabet to designate closely the percentages of RDX as a 
function of total explosive content and number designators to
represent the percentage of inerts. On a ternary graph this
would produce a large area of compositions with a single dot on 
the RDX/inert axis labled "Semtex C-4."

Should you ever need to order some Semtex for a demolition job,
be sure to nudge the salesman and tell him you want the good 
stuff. Else what you get will be just about any composition up
to, but not including C-4 or Detasheet.

Bruce admonishes:

>Experience tends to make me very suspicious of Gerald's 
>assertions :-)....

Bruce does a lot very good work in providing an excellent chemistry 
FAQ and he knows more about gasoline than any three other chemists 
I've met. If he says my assertions are suspicious, he is probably
right, especially if he knows as much about military explosives as
he does about hydrocarbon mixtures.
<




















DOC0181

Subject:      Re: SEMTEX - what is it?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/21
Message-ID:   <4baa9h$bk5@geraldo.cc.utexas.edu>


  Article Segment 4 of 4
  
  
All I know is what I picked up walking by the door where the 
smarter guys were discussing explosives. Bruce is much more 
academically inclined than I am. The result may be that he
sees "Semtex" as a necessary specifier for a poorly defined 
continuum of formulations with sub-classifications "A" and 
"H" which are also indefinite compositions.

My relatively non-academic brain revolts at this concept and
insists that there really isn't any such thing as "Semtex"
except insofar as we choose to use the term for any plastique
which is analyzably not C-4 or C-3.  Of course, there may be an
"original Semtex" which actually had a specific composition.
If there was, then what we need is the original official spec 
sheet, not an analysis of something we found in a bomb at the
embassy.  

I have this dream in which they find a brief case bomb 
containing a plastic explosive which is not C-4. Analysis
shows it to be form of Semtex. I read the analysis and realize
that it is material I made 20 years before "Semtex" was 
invented and that was left in some long-abandoned storage magazine 
which has fallen into the wrong hands. I keep my mouth shut.

One of the doors I passed in the old days belonged to Israeli
security people. They invited me in, touched a pea-sized ball
of dynamite to my palm and then showed me how their detection
instruments went wild in the vicinity of my subsequently 
cleaned hand. This was a truly impressive demonstration of their
ability to detect the EGDN used in nearly all dynamites.

It would not surprise me at all if they and others fearing
terrorist attacks wished EGDN into the formulations as an easy
way to make them detectable with existing equipment. If I were
selling such equipment, I might be tempted to lobby for rules
requiring the addition of EGDN to plastique, but I'd hate to
have to manufacture the material.

Is EGDN addition really a good Idea? I don't think so. EGDN is 
chemically and physically unstable compared with any military
explosive and it is a vasco-dilator that can put you in
the hospital if you handle it too much as in molding a plastic
explosive. In this country we have gotten rid of all our
NG/EGDN explosives plants save one for good reasons. Who now
wants to actually manufacture and transport EGDN purely for
use as a taggant? Those who sell off the shelf dynamite 
detectors, of course - now that terrorists are unlikely to use 
dynamite.

Mind you, all I know is what I heard walking by the doors and
my perspective on matters such as explosives nomenclature and
acceptable formulations may be warped by too little time spent
in the library and too much spent in the hallways.

Jerry (Ico)

What do you get when you combine a gram of Semtex, a gram of
red mercury and a gram of polywater in a cold fusion apparatus?
A lot of hot air.



















DOC0182

Subject:      Re: calcium carbonate in iron pipes question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/21
Message-ID:   <4bb2c6$ra@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <dAO2wkOJGzxX084yn@world.std.com>, moroney@world.std.com (Michael Moroney) says:
>
>In article <4b7m1n$lea@news.asu.edu>,
>bridges@aztec.asu.edu (HARRY MOREL) wrote:
>> 
>> Why does a white substance (calcium carbonate?) deposit on the 
>> inside of iron pipes over the years?  Why doesn*t the calcium, (or 
>> magnesium) carbonate remain dissolved in the water?
>
>If you're talking about hot water pipes, calcium carbonate, unlike most
>chemicals, is less soluable in hot water than it is in cold.
>
>There may also be a reaction where calcium bicarbonate reacts to form
>calcium carbonate, CO2 and water, the CO2 either escapes or reacts with
>iron to form its carbonate, and the calcium carbonate precipitates.
>I am unsure about this last part.
>
I seem to recall it being calcium sulfate which has decreasing
solubility with rising temperature, at least for high water
temperatures.

Also, I believe that the observed modest solubility of calcium 
carbonate is mostly due to the formation of bicarbonate by
CO2 in equilibrium with air. Upon heating, the CO2 concentration
is lowered with the result that calcium carbonate precipitates
giving the illusion of a negative temperature coefficient of
solubility.

Jerry (Ico)

*Experience tends to make me very suspicious of Gerald's assertions :-)*
--Bruce Hamilton


DOC0183

Subject:      Re: Thermal decomp of Ammon Phosphate ?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/23
Message-ID:   <4bfu3s$2pt@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4bf0e2$4re@cloner2.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>
>pietervk@vub.vub.ac.be (Pieter Vankeerberghen) wrote:
>>
>>Dear collegues,
>>
>>
>>At which temp and under which conditions
>>does mono ammonium phosphate decompose to
>>phosphopentoxide (P2O5) ?
>>
>
>
>You had better do a DSC and DTG, especially the latter.  I would guess 
>that mono-ammonium phosphate pyrolyzes into a 3-D crosslinked polymeric 
>mess of phosphorimides.  The yield pf P2O5 is probably rather small.
>
Gee, Uncle Al, I would have predicted simple dissociation at around
300 deg (very approximate guess) to ammonia and phosphoric acid.
Then H3PO4 dehydration at higher temperatures to give first the 
related acids, then P2O5 and its cousins at even higher temps.

I would like to learn more about these "phosphorimides." Would
they form in a building fire situation? what are their general
properties?

Jerry







DOC0184

Subject:      Re: Elevation of boiling point?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/27
Message-ID:   <4bsl7f$j80@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <30E238FA.1ADA@imaginet.fr>, Albert CAU <art@imaginet.fr> says:
>
>Mohan Kalyanaraman wrote:
>> 
>> dear group,
>>             Why does water come to a boil on adding tea bag to hot
>> water? is it related to elevation of b.p?
>
>Hi ,
>
>If you observe water boils when you add tea bag, that means the adding of 
>tea bag produces an exothermic reaction that is enough strong to induce 
>the boiling of water.
> If you want to know more about, you could measure the variation of 
>temperature after you first boiled the water to prepare tea: this 
>temperature curve will give you precious indications : the boiling point 
>of water with tea bag.

It seems more likely to me that the boiling is induced by the
air bubbles introduced with the tea bag. They act as nucleation
sites for steam from the slightly super heated water.

Jerry











DOC0185

Subject:      Re: Elevation of boiling point?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/28
Message-ID:   <4bumeh$q16@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <DKAwo8.2CI@rug.nl>, bram meijboom <meijboom@chem.rug.nl> says:
>
>mmmmm.......
>
>Are you sure it's boiling of the water??????
>As far as i'm concerned it simply the air inside escaping.
>If a tea bag is trown into the water the paper absorbes water and is 
>less permeable. So the air inside heats up, increase of presure and if 
>the presure is high enough air bubles out.
>looks like boiling i'd say. 
>
You can bet on the boiling.  Throw a tea bag in 80 deg water and 
what happens? It soaks up water and eventually sinks as air is 
pushed up and out. Now, as Martin Ystenes says, heat some water to 
the edge of boiling in a microwave or better yet, heat some 
recently boiled water. Now try to slip in a tea bag without the 
water boiling over.

Anyone who has worked with boiling chips in a few hundred bumpy 
distillations can testify to the idea of nucleation.

Jerry



the microwave








DOC0186

Subject:      Re: PRAYER, Tue 26 Dec 1995 Overdose sermon
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/29
Message-ID:   <4c1ghn$ftn@geraldo.cc.utexas.edu>
Newsgroups:   sci.bio.misc,alt.sci.physics.plutonium,sci.physics,sci.astro,sci.chem,sci.math,misc.invest.stocks,sci.bio.food-science



In article <4bvk49$db2@dartvax.dartmouth.edu>, Archimedes.Plutonium@dartmouth.edu (Archimedes Plutonium) says:
>
>In article <4bsjmj$7c6@dartvax.dartmouth.edu>
>Archimedes.Plutonium@dartmouth.edu (Archimedes Plutonium) writes:
>
>> Any reader out there ever have a caffeine or chocolate overdose? I
>> understand caffeine is an alkyloid with a nitrogen compound and that it
>> is like throwing gasoline onto a fire? In overdose, caffeine is a
>> dangerous stimulant. Anyway I suspect my science and engineering and
>> math will not suffer or abate at all, and perhaps the flow and
>> importance will increase.
>
> I just learned from the Encycl. Brit. that cup of coffee has about
>100mg of caffeine and a can of cola about 40mg and a cup of tea about
>40mg also.
>
>No mention of a 100 gram chocolate bar how much caffeine? Are Encyc
>Brit. data correct for it seems to me that coca cola has about the same
>caffeine per equal volume than does coffee?
>
>And today I learned that there is another variety of alkyloids called
>theophylin in tea which is similar to caffeine but a stronger
>upper/stimulant. Does tea have both caffeine and theophylin in
>combination? Is a decaf tea meaningless because of the theophylin still
>there? Perhaps that is why Britian is addicted to tea time because of
>the theophylin which the populace subconsciously craves for the
>addiction and which is stronger than even coffee caffeine.
>
>Does carob have caffeine or one of these alkyloids? Carob makes for a
>nice chocolate replacement.
>
>Is caffeine chemically similar or similar reactions as to nicotine?

Archimedes, in addition to caffeine and theophylline there is an isomer
of theophylline known as "theobromine" which should interest you. 
Theobromine is found in rather large quantities (1.5-3%) in the
cacao bean. Coffee, tea and chocolate each contain all three 
alkaloids in different proportions but respectively the predominant 
species are caffeine, theophylline and theobromine.

The physiological effects of the trio are similar in some respects,
but quite different from nicotine, which has a more dissimilar
structure.

The solubilities of the three differ greatly in various solvents,
but in general caffeine is more soluble than the other two. Thus,
I would not rely on a caffeine extraction process to remove the
other two unless they specifically say it does on the label.

A mild caffeine overdose can cause jitteriness, cold sweat and 
nausea. I have experienced the symptoms myself after imbibing 
too much strong coffee on an empty stomach.

I believe I recall reading that carob's claim to fame is that
it does not contain caffeine. However, since it tastes so good,
there's bound to be something wrong with it :)

Jerry




















DOC0187

Subject:      Re: blue sky & ozone
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/29
Message-ID:   <4c1sve$qvc@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <1995Dec29.033407.31270@news.bogo.co.uk>, wheatley@mail.bogo.co.uk (Nigel Wheatley) says:
>
>soma@news.dorsai.org (*selah*) wrote:
>>
>>Someone told me the sky is blue because of ozone.  Is this true?  If not,
>>could someone explain to me why the sky is blue?
>>
>
>The sky is blue due to the scattering of light by dust particles in the upper
>atmosphere.  The same phenomenon (Rayleigh scattering) is responsible
>for red sunsets.  I usually fall down on a good explanation of Rayleigh
>scattering (perhaps someone else could add one), but it is NOTHING to do
>with ozone!
>
Both liquid and solid oxygen are pale blue. Does it not follow
that the sky is blue because gaeous oxygen is also faintly blue
and very abundant?  When you're in the midst of an Oklahoma
dust storm, the sky turns orange, not a deeper shade of blue.  The
sky is bluest when the air is cleanest, as after rain storm when
the dust has been washed from the air.

Jerry












DOC0188

Subject:      Re: Decomposition of Ammonium Nitrate
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/30
Message-ID:   <4c2f6h$92t@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4c226m$ntr@usenet.ucs.indiana.edu>, "John C. Huffman" <huffman@indiana.edu> says:
>
>mdudley@brbbs.brbbs.com (MARSHALL DUDLEY) wrote:
>>If you heat ammonium nitrate it decomposes. I believe that 2 NH4NO3 will
>>decompose into 2 N2, 4 H2O and O2.  Is this correct?  If this is correct,
>>then at what temperature does decomposition take place?
>>
>>Marshall
>
>At ca. 210C decomposes mostly into H2O and N2O.  Remember Texas City?

At 210C, yes, but in the texas city explosion it is more likely
that the reaction looked something like this:

8NH4NO3 -> 5N2 + 4NO + 2NO2 + 16H2O

Not counting the loss of nitrogen oxides to fuel impurities.

A trace of organics would have had an enormous effect on the
energy release. Both the above equation and the low temperature
decomposition to N2O yield only about 130 kcal/kg (approximate)
whereas the mixture with 5.7% fuel oil delivers over 1000 kcal/kg.

Like gunpowder, AN does not explode to yield its lowest energy
products. In the presence of fuel oil though, not only the 
theoretical maximum energy increases but also the efficiency in
producing the optimum low-energy products (H2O, N2 and CO2).

Jerry (Ico)





DOC0189

Subject:      Re: blue sky & ozone
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/31
Message-ID:   <4c4uce$k13@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4c3lck$1h6@news.kth.se>, tomas_e@physchem.kth.se (Tomas Eriksson) says:
>
[Snip, snip, snip]

>it's 
>the individual gas *molecules* in the air; you could say that the colour 
>of the atmosphere is mainly due to the nitrogen in the atmosphere.

Yeah, and you COULD say it is blue because of the oxygen. Either
way the bottom line is that air is blue and that's why the sky
is blue.  If you look at a Dewar of liquid oxygen, it is pale
blue. Why is it so difficult to believe that the ocean of oxygen
above us is not also "blue."  If the blueness were purely the result
of diffraction by non-air particles then one might concede that
air were not blue. But if the blueness is the result of light being 
kicked around by air molecules per se, then the first answer to the 
question "Why is the sky blue?" should be "Because air is blue." 
The second answer would then be "Air is blue because oxygen (or 
nitrogen or both) is (are) blue." The third answer could then dive 
into the area of mechanism, e.g., molecular diffraction.


Must we always obfuscate to clarify?











DOC0190

Subject:      Re: blue sky & ozone
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1995/12/31
Message-ID:   <4c7105$sbt@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4c67qr$enj@news.kth.se>, tomas_e@physchem.kth.se (Tomas Eriksson) says:
>
[Snip]

Sorry, in my last post I used the phrase "molecular diffraction" 
when I meant "molecular scattering" as opposed to dust scattering.

I understand the Rayleigh scattering arguments, but I am still 
concerned by the question of whether gaseous oxygen is indeed
colorless like nitrogen. Both solid and liquid oxygen are blue
for whatever reason. Has it been shown that this blueness (of
whatever origin) is completely lost when the gas volatilizes?
Perhaps you are aware of some spectrophotometric work that has
shown this to be the case.

In a later article, Lloyd R. Parker says:

	Dust scatters light, and blue, with the shortest wavelengths, 
	is scattered most.  When the dust is high, you see the blue.  
	When the dust is low, the blue is scattered away from you and 
	you see the complement,	orange.

Can you comment on this dust scattering phenomenon?

Jerry









DOC0191

Subject:      Re: blue sky & ozone
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/01
Message-ID:   <4c8400$jho@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Melissa.Hines-3112951939330001@galadried.chem.cornell.edu>, Melissa.Hines@Cornell.edu (Melissa A. Hines) says:
>
>In article <4c7105$sbt@geraldo.cc.utexas.edu>, glhurst@onr.com (Gerald L.
>Hurst) wrote:
>
>> In article <4c67qr$enj@news.kth.se>, tomas_e@physchem.kth.se (Tomas
>Eriksson) says:
>> >
>> [Snip]
>> 
>> Sorry, in my last post I used the phrase "molecular diffraction" 
>> when I meant "molecular scattering" as opposed to dust scattering.
>> 
>> I understand the Rayleigh scattering arguments, but I am still 
>> concerned by the question of whether gaseous oxygen is indeed
>> colorless like nitrogen. Both solid and liquid oxygen are blue
>> for whatever reason. Has it been shown that this blueness (of
>> whatever origin) is completely lost when the gas volatilizes?
>
>
>Spectroscopy of O2 gas:
>
>1st allowed @ 36096 cm-1 = 277 nm <-- UV, no way is this visible
>
>2nd singlet-triplet (forbidden) @ 13195 cm-1 = 758 nm <-- near IR/deep, deep red
>                                                         (invisible to most)
>
>1st singlet-triplet (forbidden) @ 7918 cm-1 = 1.3 um <-- near IR
>
>The color of the sky has nothing to do with absorption by oxygen. It has
>to do with Rayleigh scattering. For a very cogent discussion of this, see
>J. D. Jackson, Classical Electrodynamics. pp. 422-425.
>
>Enough already,
>
>Melissa

Melissa, it may be enough for you. I still wonder if the scattering
of very visible blue light does not imply that the unscattered light
has a reddish tinge or whatever you get when you subtract some blue.
I am not suggesting that oxygen gas necessarily "absorbs" any 
particular color.  There are many solutions you can shine a light
through and record different transmitted and scattered or "reflected"
colors with a spectrophotometer. If I ran this experiment with a
condensed dichroic material I would happily assign two colors to
the material - why are the rules different for a gas?

What I hear you saying is that if you shine a beam of white light
through air and put spectrophotometers at 180 deg and 90 deg, both
of these instruments are going to record "color," not because of
absorption, perhaps, but color nevertheless.

Liquid oxygen is blue, period. I don't know if it is blue because
it scatters blue light or because it absorbs some other frequency,
but it is positively blue. If this blueness disappears on 
volatilization, then I for one want to know what caused the color
in the first place and why it disappeared in the gas phase.

On the other hand, if the blueness of oxygen continues into the
gas phase then I want to know why we would tend to deny that the 
gas is blue, citing rayleigh scattering as though that mechanism
somehow made the blue color no longer count as such.

And finally, I would like to know if the color of the sky would
be exactly the same if we had essentially the same total amount of
atmosphere but with nitrogen replacing all the oxygen.

Jerry (Ico)










DOC0192

Subject:      Re: Nitroglycerine (medicine), storage & handling
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/04
Message-ID:   <4cfef0$cpc@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <30eafa3b.0@news.cybernet.dk>, kurir@cybernet.dk (Nancy Andersen) says:
>
>Do anyone have experince with handling and storage of nitroglycerine
>for medical use?
>
>Nitroglycerine for medical use is dissolved in ethanol, and is
>harmless until spill occur and ethanol evaporates (my idea!). Does
>anybody have any experince, and if so what to do if spill occurs.
>
If the spill is on a non-porous surface, use a large excess of 
sawdust to soak up the liquid and later burn the mixture in
the open in a thin layer and remotely.

If the spill is on a porous surface, repeated treatment with an
18% sodium sulfide (Na2S:9H2O) will destroy the NG.

Jerry (Ico)

















DOC0193

Subject:      Re: PRAYER, Sun 31 Dec 1995 Carbon in us, Carbon of Plutonium,
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/04
Message-ID:   <4ch7ur$fhd@geraldo.cc.utexas.edu>
Newsgroups:   sci.bio.misc,alt.sci.physics.plutonium,sci.physics,sci.astro,sci.chem,sci.math



In article <30EC145E.3034@algemeen.mt.wau.nl>, Marc Boncz <Marc.Boncz@algemeen.mt.wau.nl> says:
>
>After taking a glance at AP's personal homepage
>(it is on http:_//mmm.dartmouth.edu/pages/user/plutonium/)
>evrybody will be comvinced of the state of mind of this guy.
>He got no idea of what seriuos readers think of his spamming:
>
>>My newsgroup on the Internet is named "The Altar of Science & Physics is 
>>Plutonium " and aptly abbreviated
>>"alt.sci.physics.plutonium" can be telecommed here 
>>alt.sci.physics.plutonium. Warning: my web site is under continual
>>revision and often I use my newsgroup and the minor ones such as sci 
>>hierarchies as forums of discussion, hotly debated,
>>for my new ideas. 
>
>I think he uses these groups more for his hobby:
>>Some of my hobbies are bicycling and -->writing science fiction stories.<--
>
>What wonders me is what he is doing at this college. He is listed as 
>'College Staff' in this University's WWW-pages, but he seems to occupy 
>his time with making money on the stockmarkets. Wat is Dartmouth paying 
>him for? BTW: He also uses the name Ludwig.Plutonium@dartmouth.edu., or 
>at least he used it. An idea for mail&reply?
>
"Serious readers" vary in their attitude toward Archimedes. Some 
believe he adds a certain dash of color to otherwise sometimes
rather stuffy forums. 

Wonder no more. Archimedes is one of those very rare  University 
employees who actually earn their pay by hard work. He previously
used the name "Ludwig Plutonium" because it was his legal name;
now it is legally "Archimedes Plutonium," which really has a better 
ring.

Jerry (Ico)





















DOC0194

Subject:      Re: Vapour Pressure - Mixtures
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/04
Message-ID:   <4ch8u4$fhd@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4ch1kj$69s@grid.direct.ca>, tmiller@diachem.com (Tom Miller) says:
>
>It's been a long time since phys chem... how do I calculate
>theoretical vapour pressure of a mixture including a nonvolatile,
>nondissociable solute...  eg the following recipe:
>
>water     70% by mass
>ethanol  20% by mass
>sugar     10% by mass
>
Ideally, convert your mass fractions to mole fractions. The 
partial vapor pressure of each volatile component is the product 
of the respective mole fraction and the vapor pressure of the 
pure compound. Unfortunately, the water/ethanol system is nowhere
near ideal, so your calculations will be nowhere near correct.
There are tables and graphs for the water/alcohol system which
show a low boiling azeotrope at about 94% alcohol.

Jerry (Ico)















DOC0195

Subject:      Re: 'Lavalamp'- which fluids are used ?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/06
Message-ID:   <4cl5vc$1n1@geraldo.cc.utexas.edu>
Newsgroups:   can.schoolnet.chem.sr,fj.sci.chem,iijnet.chem,no.kjemi,sci.chem



In article <tice-0601960111100001@tice.nai.net>, tice@nai.net (Bradley D. Tice) says:
>
>I don't think it's water in there. I believe it's a liquid that changes
>density through electrical stimulation. It could also be temp, but I don't
>think so. I heard an interview with the inventor, he's not saying, and
>he's patented it and doesn't license it.
>
Bradley, maybe you better stick to physics. OK, I'll bite, how do
you electrically stimulate a liquid? With a cattle prod?

:-)

Jerry





















DOC0196

Subject:      Re: New definition or concept: Half-life of One single Atom
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/06
Message-ID:   <4cn1nf$7p3@geraldo.cc.utexas.edu>
Newsgroups:   alt.sci.physics.plutonium,sci.physics,sci.chem,sci.physics.particle



In article <4cn01j$9ia@ixnews8.ix.netcom.com>, quantum4@ix.netcom.com(Thomas Robertson ) says:

>>
>>>The probabilities of decay of a given atom are:
>>
>>0.5  0.75  0.125  0.0625   0.0313   0.0156   0.0078
>>  1      2       3          4             5            6            7 
>   
>I presume there is a typo in the second calculation where you should
>have put 0.25 instead of 0.75.
>
It should be "probability of survival" with the second figure as
0.25, else we need also to  subtract each of the figures from
1.0000 to get "probability of decay."

Jerry


















DOC0197

Subject:      Re: New definition or concept: Half-life of One single Atom
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/06
Message-ID:   <4cmppe$qi1@geraldo.cc.utexas.edu>
Newsgroups:   alt.sci.physics.plutonium,sci.physics,sci.chem,sci.physics.particle



In article <4cmg44$kc7@news.acns.nwu.edu>, "Todd K. Pedlar" <todd@numep1.phys.nwu.edu> says:
>

>Not really - the figures which you have quoted are first of all the 
>probabilities at N half-lives that the atom has not yet decayed.  
>Secondly, all you've done is shown an approximation to the MAXIMUM life 
>of an atom, not really its "full life."  Technically, the maximum lifetime
>for a given atom would be infinite.  What is the meaning of "full life",
>anyway?  If you were to choose a single atom to observe until it decays, you
>might find that it "lives" 30 seconds or 30 billion years.  Is its full
>life 30 seconds or 30 billion years?  In my opinion, the most meaningful
>statistic for a single atom is probably the "mean life", which is simply 
>the average lifetime of a given atom.  This is equal to the half-life
>divided by log(2), or 0.693.  There is a simple derivation of this, which
>can be found in any nuclear physics text, such as Introductory Nuclear 
>Physics by K. Krane.  
>
Not really. The figure  you quote for the "mean life" is actually
the "mean future life." Any real sample of U238 atoms with a mean 
future lifetime of of 0.693 half-lives already has an age of many
half-lives. You might say the majority of the existing atoms have 
a long history and a short future :)

Jerry










DOC0198

Subject:      Re: Fresh water from sea water - new economical process
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/07
Message-ID:   <4cplad$q44@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.engr,sci.engr.chem,sci.chem,sci.misc,sci.research



In article <4cpelm$t8n@ixnews8.ix.netcom.com>, ferrad@ix.netcom.com(Adrian Ferramosca ) says:
>
>There are a few sceptics out there, notably glhurst and oakes.
>
>I did not say that I have been theorizing about this process.  This
>phenomenon does actually happen.  I have done experiments and have
>obtained yield and purity figures.  What I have done in the patent is
>merely tried to create a commercial process to exploit this behaviour,
>which could potentially be much cheaper the reverse osmosis.  I have my
>own ideas to explain the mechanisms, but ... read my lips ...  it DOES
>happen, try it sometime.
>
We sceptics don't doubt that you can separate salt from water
by freezing. But the handwaving, smoke and mirrors about the water
vapor in the escaping CO2 carrying away enough heat to freeze the
solution from which it came does not compute thermodynamically.

Furthermore, you tell a completely different story in the patent
abstract, which says:

  *A solute can be separated from a solute/solvent solution by 
  dissolving a gas-forming material into said solution and then 
  adjusting the temperature, pressure and solute concentration 
  of the resulting solution such that a Joule-Thompson free 
  expansion of the gas-forming material released from the
  solution will produce a three-phase separation of the 
  components of said solution.*

The US Patent Office does not require a correct theory to issue
a patent. But when you tell them that a processt works by the 
Joule-Thompson effect of CO2 and then tell sci.chem it works by a
water vapor mechanism, you're gonna have credibility trouble
with the chemists.

Jerry





















DOC0199

Subject:      Re: Magnesium
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/07
Message-ID:   <4cpb0v$iak@geraldo.cc.utexas.edu>
Newsgroups:   rec.pyrotechnics,sci.chem



In article <AD15506B9668120E0@ao067.du.pipex.com>, oleum@spuddy.mew.co.uk (Nick Hiams) says:
>

>>>Um, you are ignoring the 64 kcals/mole that it requires to break the H2O
>>
>>It's mol, not mole.
>
>If you're that picky, then it's preferably 270 kJ mol-1.
>
>(At least in the *real* scientific/metric world that most of us live in:*)
>
>--TheAlchemist

Not really. You label yourself as an amateur with a comment like
that. The "real world" is chock full of tables of data in calories.
Most experienced chemists learned their trade long before it
became fashionable to use Joules to accomodate the physicists and
ease the pain of conversion to mechanical units.

After the SI conference in 1960 there was a general feeling that
all other units were dead because the delegates from 36 countries
had met and more or less so decided. The momentum was so strong
that by 1973, when Lange's 11th edition came out, the conversion
tables only gave factors for translating to SI units.  Now take
a look at the 13th edition. The complete tables are back
so that one can readily convert form calories to ergs or BTUs.

This apparent backsliding was undoubtedly the result of gripes
by "real world" chemists who were not about to toss all their 
reference works into the trash bin. International committees meet
all the time to decide everything including the fate of nations,
but the world has a way of going on about its business as usual.

Don't misunderstand me. The Joule is a perfectly fine measure of
energy. But many of us who speak SI fluently prefer to communicate 
in our native dialect. And for those of you who don't understand
the language there's always Lange's 11th edition.

Let a few more generations of chemists pass and about the time 
the average US citizen begins to think metric, the SI system will 
be the colloquial form. Then some committee somewhere will be working
to replace it with something more modern.

Jerry (Ico)

Jerry










DOC0200

Subject:      Re: Fresh water from sea water - new economical process
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/08
Message-ID:   <4cpnh0$s2f@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.engr,sci.engr.chem,sci.chem,sci.misc,sci.research



In article <4cpimp$447@ixnews8.ix.netcom.com>, prakash2@ix.netcom.com(Prakash R. Shah ) says:
>

>
>Didn't some explorer find that out a long time ago?  He found that the
>glaciers and stuff were freshwater even though the seawater was salty. 
>I'm not sure about this, though.  But if we do use this method, we'll
>be using up seawater just like we use up freshwater today, although
>there is a lot of seawater.

Don't worry about the lost seawater. Someone will undoubtedly open
a seawater recycling plant before the ocean levels drop more than
a few feet. 

Jerry



















DOC0201

Subject:      Re: Fresh water from sea water - new economical process
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/08
Message-ID:   <4cqcs9$bbo@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.engr,sci.engr.chem,sci.chem,sci.misc,sci.research



In article <4cq1aa$93a@cloner3.netcom.com>, ferrad@ix.netcom.com(Adrian Ferramosca ) says:
>
>I agree, if you're talking steady state.  But it does occur, and the only
>explanation I can put forward is that the kinetics of the process dictate that
>the energy of the system gets temporarily shifted towards the departing gas
>phase.  Eventually, if left to reach steady state, it will distribute evenly,
>and return to the 'can' and cause the ice to melt.
>
You're not going to beat thermodynamics with a kinetic stick. If 
"the the energy of the system gets temporarily shifted towards the 
departing gas phase," then you have harnessed Maxwell's demon and
perpetual motion is just around the corner. All you have to do is
let that energy segregated in the escaping gas flow through a heat
engine on it's way back to the can.

What you are suggesting is that you suspend the second law for a
little while, but its OK because you pay back the temporary loan 
of free energy later. That's a neat trick: borrow heat then pay
it back through an engine, then borrow again and so on ad infinitum.

>>Furthermore, you tell a completely different story in the patent
>>abstract, which says:
>>
>>  *A solute can be separated from a solute/solvent solution by 
>>  dissolving a gas-forming material into said solution and then 
>>  adjusting the temperature, pressure and solute concentration 
>>  of the resulting solution such that a Joule-Thompson free 
>>  expansion of the gas-forming material released from the
>>  solution will produce a three-phase separation of the 
>>  components of said solution.*
>
>This is patent attorney speak - he was hit on this Joule-Thompson
>thing.  I am a chemical engineer, what I stated as:
>1.  dissolve CO2 into seawater at an elevated pressure
>2.  cool it to just above freezing
>3.  instantaneously drop the pressure to atmospheric
>4.  ice forms
>5.  remove ice
>6.  melt ice
>7.  drink water
>
>was translated to the above.
>
You're telling us that you let a patent lawyer stick a bogus 
theory into your patent. What earthly reason would he have for
doing that? Patents do not require a scientific theory of why
they work, and the existence of a credible theory actually
weakens the claims of novelty in terms of an invention not
being obvious to one of ordinary skill in the art. A patent
attorney would prefer an invention which works by a mechanism
nobody can explain. A smart lawyer would hardly volunteer
a worthless theory.

>>The US Patent Office does not require a correct theory to issue
>>a patent. But when you tell them that a processt works by the 
>>Joule-Thompson effect of CO2 and then tell sci.chem it works by a
>>water vapor mechanism, you're gonna have credibility trouble
>>with the chemists.
>
>I won't get into the chemist / chemical engineer debate, but I thought
>they might be interested.  This is an item of primarily chemical
>engineering interest, so I don't expect much response from that side.
>
Whoa!! This is not a debate between chemical engineers and 
chemists. The tools of the two trades may be different, but
both rely on the same fundamental science. If it doesn't work
thermodynamically for a chemist, it won't work for an engineer
either.

Jerry (Ico)








DOC0202

Subject:      Re: Ozone layer/Dobson Units
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/08
Message-ID:   <4cs2of$bgr@geraldo.cc.utexas.edu>
Newsgroups:   sci.physics,sci.environment,sci.geo.meteorology,sci.chem



In article <ahansen-2708561251080001@mtshasta20.sisnet.ssku.k12.ca.us>, ahansen@sisnet.ssku.k12.ca.us (Amy Hansen) says:
>
>Hello my name is Amy and I am a physics student attending Mt. Shasta High
>School.  In my physics class the students are required to find data over
>the internet and to form a question, hypothesis, research it etc...
>   
>I found some really interesting data on the Ozone content at different
>stations accross the world.  If interested in viewing the web sight the
>address is;   http:// www.cmsl.noaa.gov/dobson_homek/dobson.HTMl
>
>Anyway the data is measured by using a dobson unit.  I have tried to
>research what a dobson unit is but haven't been able to find anything. 
>Does anyone know?
>
>I was also wanting to know more information about the ozone and how it is
>affected by the seasons.  If anyone can help me I would greatly appreciate
>it. 
>
Amy, Dobson units are derived by measuring the intensities of two
wavelengths in the absorption band of ozone. The ratio of these
two intensities as measured by a spectrophotometer provides a
basis for the calculation of the ozone content of the atmosphere.

Jerry (Ico)










DOC0203

Subject:      Re: Fresh water from sea water - new economical process
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/09
Message-ID:   <4cuknp$84r@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.engr,sci.engr.chem,sci.chem,sci.misc,sci.research



In article <4cuhnt$571@dawn.mmm.com>, cewright@mmm.com (Carl Wright          cc0197) says:
>
>Adrian Ferramosca (ferrad@ix.netcom.com) wrote:
>: There are a few sceptics out there, notably glhurst and oakes.
>: 
>: I did not say that I have been theorizing about this process.  This
>: phenomenon does actually happen.  I have done experiments and have
>: obtained yield and purity figures.  What I have done in the patent is
>: merely tried to create a commercial process to exploit this behaviour,
>: which could potentially be much cheaper the reverse osmosis.  I have my
>: own ideas to explain the mechanisms, but ... read my lips ...  it DOES
>: happen, try it sometime.
>
>You have just discovered for yourself the process of crystallization, 
>whereby materials may be purified.  My daughter (6th grade) is doing
>this for her science fair project.  Try the same thing with some water
>having red dye added to it instead of being carbonated.  That's the 
>trouble with many great ideas, they've been done before.
>
You underestimate the breadth of the claims being made for this
invention. The inventor says he is not merely purifying salt water
by freezing but that he is achieving the freezing of large amounts
of water by flashing off relatively small amounts of CO2.

In other words he claims a spontaneous process which goes up the
free energy hill, at least temporarily, because of the kinetics
of the process. The novelty of the claims may be judged by the
fact that standard enthalpy change for his process can at best
account for the freezing of about 2 percent of the mass of the
salt water.

Jerry


DOC0204

Subject:      Re: Red Mercury
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/09
Message-ID:   <4cujib$84r@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <ftn_2.200.235.0_13e0c998_Thallion@synchron.ct.se>, thallion@synchron.ct.se (Thallion) says:
>
> 
> YS> It appears that there is colorable evidence
> YS> that "Red Mercury" is an actual substance,
> YS> and a strategic one at that.
>
> Sw> I have seen this so called 2020 (refering to its density) on a TV
> Sw> recording. According to the formula it is a free radical. Who ever
> Sw> invented this (meta?) stable substance should apply for the Nobel
> Sw> Price in both physics and chemistry! I don't belive such a substance
> Sw> excist.
>
>According to a documentary I saw once, the data on the compound was the
>following; they didn't show it explicitly, but it was readable on some
>papers on some professor's desk if the VCR was paused.
>
>   Melting Point: -37.87?C
>Molecular Weight: 756.61 u
>         Density: 20.20 Kg/dm3
>          MC (?): 196.0127 ? 2%
>         Formula: Hg2Sb2O7
>
>Can someone synthesize this compound, and see if it is red? :)
>
Salts of the general type M2As2O7 are known where M is a divalent 
metal. There seems to be no reason why the mercuric salt should 
not exist, but one would hardly expect it to have a low melting
point or a density anywhere near 20. Whatever MC is, they certainly
seem to know how to measure it accurately.

Jerry (Ico)


DOC0205

Subject:      Re: Fresh water from sea water - new economical process
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/10
Message-ID:   <4cvqfr$4lq@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.engr,sci.engr.chem,sci.chem,sci.misc,sci.research



  Article Segment 1 of 2
  
In article <4csu4a$aa@ixnews8.ix.netcom.com>, ferrad@ix.netcom.com(Adrian Ferramosca )
says:
>
>He won't give up, will he ...
>
>In <4cqcs9$bbo@geraldo.cc.utexas.edu> glhurst@onr.com (Gerald L. Hurst) writes:
>>
>>In article <4cq1aa$93a@cloner3.netcom.com>, ferrad@ix.netcom.com(Adrian
>Ferramosca ) says:
>>>
>>>I agree, if you're talking steady state.  But it does occur, and the only
>>>explanation I can put forward is that the kinetics of the process dictate that
>>>the energy of the system gets temporarily shifted towards the departing gas
>>>phase.  Eventually, if left to reach steady state, it will distribute evenly,
>>>and return to the 'can' and cause the ice to melt.
>>>
>>You're not going to beat thermodynamics with a kinetic stick. If
>>"the the energy of the system gets temporarily shifted towards the
>>departing gas phase," then you have harnessed Maxwell's demon and
>>perpetual motion is just around the corner. All you have to do is
>>let that energy segregated in the escaping gas flow through a heat
>>engine on it's way back to the can.
>
>No, I'm not saying that you get it all for free, but unsteady state effects can
>shift equilibrium.  Nothing ever occurs at steady state.  If you can harness the
>articial separation of energy, you can get in this case the required product,
>and do whatever you want with the higher energy stream.  You will obviously not
>get back anywhere near the energy put in, but the idea here is to keep the low
>enthalpy product, we don't need the high enthalpy one!  Let the product warm
>itself up of its own accord.
>
Sorry you think I'm being stubborn. It's just that I seem to have
persistent doubts about spontaneous processes which result in a
net decrease in entropy, even if they occur only for a few minutes.

Let's look at your process in its simplest form. You have a can
of carbonated salt water similar to a salty diet Coke. You chill
it down to its freezing point at say -2 degC.  Let's assume we're
dealing with one liter of solution with a rather high (compared
to Coke) equilibrium CO2 pressure of 4 atmospheres.  Let's
further make the (incorrect) assumption that when we pop the lid,
the CO2 is going to bubble off instantly leaving us with a residual
CO2 pressure of one atmosphere.

The solubility of CO2 in a liter of water is about is about  1.85
liters/atmosphere and a one-molar slt concentration will vave
little effect on this value.  If the CO2 pressure drops from 4 atm to
1 atm absolute, the Amount of CO2 released  at about -2 deg will
be about

1,85liter/atm*3atm*1mole/22.2liter = 0.25 moles CO2

The enthalpy change for CO2(Aq) -->CO2(g) is about -4.85 Kcal/mole

hence the volatilizing CO2 should absorb about 4.85Kcal/mole*0.25mole
= 1.25 kcal.

Water requires the loss of about 0.080 Kcal/g to freeze, hence the 
amount of ice created by the escaping CO2 should be about

1.25Kcal/0.080Kcal/g =  15.6 g or about 1.6% of the original water.

Now let's look at the contribution of water vapor in removing heat 
from the solution. The vapor pressure of water at -2 degC is about 
4mm. If  the vapor entrained by the escaping CO2 reaches saturation 
then the 0.25 moles of the former should carry with it approximately 
4/760*0.25 = 1.3exp-3 moles of water vapor. Multiplying this value 
by the ratio of the heat of fusion to the heat of vaporization yields
1.3exp-3moles*540cal/g/80cal/g = 8.8exp-3 moles of ice or about 
0.16grams, an insignificant amount even compared with the merely 
small (15.6 grams) amount produced by the CO2.

At this stage we see that the expected thermodynamic changes can only
account for enough energy transport to freeze about 1.6 percent of 
the water.  Clearly an economical process will require freezing at 
least the bulk of the fluid, let us say certainly no less than 50 
percent or in the current example no less about 500 grams.





















DOC0206

Subject:      Re: Fresh water from sea water - new economical process
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/10
Message-ID:   <4cvqfr$4lq@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
  
  
If the carbon dioxide and water vapor could leave the solution at 
a higher temperature than the liquid we could theorize that by 
some quirk of kinetics the warm gas could carry away the necessary 
amount of heat. This is only a pipe dream though because in order 
for it to happen the net sum of q/T for the liquid and gas phases 
would have to be negative, that is the entropy of the liquid would 
go down more than the entropy of the gas went up.  Unless we are 
to break the second law, it is a no go.

The alternative, which has been suggested by the inventor, is to 
have more energy removed by water vapor (since we have much more 
water than CO2). If the water is to carry off more heat, it has 
to be vaporized to a partial pressure greater than its equilibrium 
vapor pressure of 4mm and maintained at -2 deg (or slightly lower 
as the solution becomes more concentrated) at least until it is no 
longer in thermal contact with the liquid.  In other words we have 
to produce a mix of CO2 and water vapor at -2 deg or less which is 
in a metastable supercooled state with respect to the water vapor.

The amount of water vapor in the CO2 required to carry away the
latent heat of fusion of the freezing water  is readily calculated 
by multiplying the 500 g of ice desired by the ratio of the heat 
of fusion to the heat of vaporization

500g*80cal/g/540cal/g = 74 g of water vapor  or 74g/18g/mole = 4.1 
moles.

Our product gas the consists of 4.1 moles of water vapor mixed with
only 0.25 moles of  CO2, all at -2 degC.

Ignoring the relatively minor CO2 content, we have an astounding 91
liters of ice cold super-cooled steam - the same as if we had been
able to cool 125 liters of regular steam through 102-103 degC without
it condensing.

Imagine now that as expected this cold steam is unstable and reverts
to its natural state of water and hot steam.  As the cold steam 
condenses it forms water which is heated at the rate of  18 
cal/deg/mole by the vapor which is surrendering about 9.72 kcal/mole. 
The process goes on until 

[(4.1-N)*8.2cal/deg+N*1cal/deg]*102deg=9720*Ncal, 

that is until the amount of heat provided by N condensing moles out 
of 4.1 provides enough heat to warm up both the condensed (N) and
uncondensed (4.1-N ) moles of water to 100degC. The only new data 
here are the heat capacities of liquid water (18cal/deg/mole) and 
water vapor (Cp = 8.2 cal/deg/mole)

If I did the math right, N (the amount of water condensing) is only 
0.33 moles so the final equilibrium mixture consists of  O.33 moles 
(6 grams) of boiling hot water and 4.1-0.33 = 3.8 moles (68 grams, 
116 liters) of live steam.

These calculations are only approximate, but they lead me to believe
that if the proposed desalination process works as described, the
next cold Coke you open may blister your face with a blast of steam.

If you find any mistakes in the math, be advised that I was just
testing you.

Jerry (Ico)















DOC0207

Subject:      Re: Fresh water from sea
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/11
Message-ID:   <4d1ogo$f7c@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



  Article Segment 1 of 2
  
In article <8B892C5.00EE001827.uuout@digitec.co.za>, brian.tinniswood@digitec.co.za (BRIAN TINNISWOOD) says:
>
>Hello Alan,
>
>On 06 Jan. 96  17:24 Alan \"Uncle Al\" Schwart wrote to All...
>
> AS> Has somebody worked out the thermodynamics and the material unit
> AS> processes?  I'm talking rigorous differential equations, not
> AS> back-of-the-envelope approximations.
>
>Don't make me laugh! Too many good ideas have been lost by getting
>ourselves drowned in a sea of  higher mathematics. Why don't we do lab
>scale testwork, then bench scale then finally pilot work before we make 
>any judgements?
>
>Remember, science is a set of *arbitary* rules that only approximate 
>nature. Remember also, that the models we devolope are very often 
>constrained by tight assumptions or parameters, and very often 
>these models have been proved to be inaccurate or downright wrong.
>
>Lets do the test work, then the mathematics and *then* we will be 
>in a better position to make a sound judgement of any new idea.   
>
I don't think so.

We have developed mathematical and conceptual models precisely
in order to give us the ability to predict the outcome of
experiments we have not run. Obviously, our models are always
inexact to some degree and in some cases downright wrong.

The art in science is to be able to judge well the reliability
of our theories. When a law has been tested and retested like
the second law of thermodynamics, the burden of proof falls on
whoever proclaims they have found a loophole. Most often these
would-be lawbreakers assert that they are merely skirting the
law, not defying it.

Shall we run into the laboratory to test every claim of every
inventor of every patent? There are more than 5 million of these
documents extant. There are not enough laboratories in the world
to test every outrageous claim to new technical breakthroughs.

Take the example of cold fusion. Millions of dollars worth of
resources have been poured into answering the simple question
about whether the phenomenon exists at all. Yet after years
of research by various people world wide, there are still
two entrenched warring camps arguing about simple energy
balances. Are they getting more energy out than they put in?

Here we are dealing not with esoteric nuclear energy theories
but with a classical physico-chemical process. If the inventor
can explain how his invention works within the framework of
accepted simple thermodynamic and kinetic theory that is
fine. However, if he is saying that he has discovered a 
PVT process which cannot be readily explained in terms of
accepted theory, then it is up to him to show why others should
expend the time and effort to confirm his results. So far
all we have heard is that "something else" is happening
to remove the heat. Whatever we might assume is occuring
short of the simple disappearaneof that energy from the
universe should be manifesting itself in measurable and
measurably hot products of which we have neard nothing

If the sudden release of a little carbon dioxide from cold
water can freeze 25 or 50 times as much water as is predicted
by the accepted value of the heat of solution then the 
importance of the phenomenon far exceeds that of a new 
desalination process.  The very fact that the inventor sees 
only his immediate invention suggests to me a lack of 
appreciation of more revolutionary aspects of the supposed 
process.

Before we rush into the lab or pilot plant, let's ask the
proponents of the new process to give us some accurate
experimental data on mass flow, composition and temperatures.
If their data support their novel conclusions, more power 
to them and may they win a Nobel prize. Believable and 
detailed data, if supportive of the theory, will send 
experimenters galore into the laboratory to chase the elusive
Eldorado of free (or at least cheap) energy transfer.


















DOC0208

Subject:      Re: Fresh water from sea
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/11
Message-ID:   <4d1ogo$f7c@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
  
  
Personally, I think their thermometer is off a few degrees
and they are unknowingly super-cooling the Coca-Cola. In
my own limited experience of several decades drinking
soda pop, I have observed that as the liquid approaches
0 degC the pressure of the CO2 drops to the point where
one gets only the gentlest of little "pops" when the 
cap is removed. It is when the soda gets either super-cooled
or actually well frozen that the eruptions occur and in the 
former case give the illusion that the escaping gas freezes
the liquid rather than merely initiating the process.

Jerry (Ico)





















DOC0209

Subject:      Re: Fresh water from sea water - new economical process
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/11
Message-ID:   <4d3tcl$qpo@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.engr,sci.engr.chem,sci.chem,sci.misc,sci.research



In article <4d27no$c49@ixnews8.ix.netcom.com>, ferrad@ix.netcom.com(Adrian Ferramosca ) says:
>

>Freezing is the changing of state from liquid to solid of a homogeneous
>compound due to a reduction in temperature.  Crystallization, on the
>other hand, is the combining of aqueous ions into a solid, due to
>removal of solute.  The only connection is the solid, the process is
>very far removed.  In the former, the same molecules transform from
>liquid phase to solid, in the latter, a combination of aqueous ions
>forms a new component which can crystallize out.
>
Is this your personal definition of "crystallization"? There are
a few of us who interpret the word as simply describing any
transition to the crystalline state.  Among us few are the
various dictionaries of the English language.

Jerry

















DOC0210

Subject:      Re: Fresh water from sea water - new economical process
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/11
Message-ID:   <4d2lgo$1kf@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.engr,sci.engr.chem,sci.chem,sci.misc,sci.research



In article <4d2i8f$d5f@dawn.mmm.com>, cewright@mmm.com (Carl Wright          cc0197) says:
>  The coke 
>example that you used is the one that got me started also.  In the 
>coke example, the material in the bottle doesn't freeze because it 
>contains dissolved material (CO2) which lowers the freezing point
>of the mixture below zero degrees Centigrade.  When the bottle is 
>opened, the CO2 escapes and the freezing point of the resulting 
>solution is exceeded.

I snipped most of your article because I agree with it. 

I just wanted to point out that the CO2 does not act as much
of a freezing point depressant because it is present at a molal 
concentration well under 0.25. The fraction of a degree F.P. 
average change from partial volatilization could, however, act 
as a nucleation starter, particularly if augmented augmented by 
strong localized cooling at bubble interfaces. That is assuming 
that the coke is super-cooled before the lid is popped.

You are certainly correct in equating the process to conventional
purification by crystallization.

Jerry











DOC0211

Subject:      Re: What is the difference between KEROSINE oil and ODORLESS MINERAL OIL
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/11
Message-ID:   <4d2mt1$1kf@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4d2m4v$p1b@news.asiaonline.net>, susana@asiaonline.net (susana chan) says:
>
>On 7 Jan 1996 23:31:16 GMT, you wrote:
>
>
>>I have a lamp that came with oil that is odorless. The lamp is a fine piece
>>of glass art. it is like a klein bottle, and totally transparent. The inlet
>>for oils is open, and there is no mechanical part, not even a screw. After
>>several years, the oil has not evaporated. The oil is odorless. Now I know 
>>that traditionally such  lamps use kerosine oil. I wonder where to get this
>>odorless oil. What is it? Some people say that it is deodorised kerosine 
>>oil. I wonder what is difference between a deodorised kerosine oil and
>>non-deodorised one. How to deodorise kerosine oil?
>
>>Please contact via email.
>>Thanks a lot!
>
>>lbliao
>
>
>I have the same problem as you. I have put the same question in the
>newgroup just at the end of 1995 but I can't get any answer. If you
>get any method to deodorise the kerosine, please teach me.
>On the other hand I found fuming sulphuric acid may be used to wash
>the kerosine but I have not tried. It is harmful to breathe that acid.
>Take care.

Let me tell you what little I know. 

Sulfur compounds seem to be the culprits in hydrocarbons. They are
removed along with nitrogen compounds by passing the petroleum
vapors over catalysts at high temperatures. My guess is that 
odorless kerosene and mineral oil are probably also treated with
activated carbon.  You can get at least most of the way there
by buying 1-k kerosene aka k-1, which is specified by kerosene
heater manufacturers.

Anyway, truly odorless kerosene or its near equivalent odorless #2
diesel fuel oil are available commercially at a reasonable
price. The materials are used, inter alia, to make ANFO
for blasting minerals intended as additives for cattle food.
It seems the cattle or at least their milk consumers do not
like the taste of kerosene.

Jerry (Ico)











DOC0212

Subject:      Re: 12 Yr Old Son Science Exp. - Need Help!
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/13
Message-ID:   <4d95di$74d@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4d8rlt$r20@ixnews6.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>

>    2) Capillary water, as trapped between two microscope slides pressed 
>together under water or in the minute interstices of a finely porous 
>solid, can equilibrium melt as low as -40 degrees celsius.  The surface 
>properties of water are very much different from its bulk properties 
>(e.g., surface tension).  Trapped in very thin layers, a few micrometers 
>thick or less, there is >no< bulk water.  Capillary water has very 
>different physical properties.
>
This freezing point depression in capillaries is extremely
interesting and new to me. Could you please elaborate on the 
subject? I wonder if such a phenomenon might have misled
the would-be discoverers of polywater. 

I would have assumed that any effect on the FP would be just
the opposite because of the tension on the water and the 
potential molecular aligning effects of a polar surface. That's
twice I've been wrong in the last 2 minutes :)

Jerry (Ico)
<











DOC0213

Subject:      Re: Endothermic Reactions
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/13
Message-ID:   <4d7otf$aqg@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4d7met$c7e@cloner2.ix.netcom.com>, aryal@ix.netcom.com(PAM HOFFMAN ) says:
>
>I haven't had much luck in my search for endothermic reactions. I would
>like to find a relatively simple reaction which would freeze water at
>ambient temperatures.  I believe there is one which involves using a Ba
>salt compound, but as yet it remains a mystery.  Any assistants would
>be greatly appreciated.
>    
Why not simply the "reaction" of salt with ice to form salt water. 
It is so endothermic that it is widely used to make ice cream.
Im sure you have been told you can also use the dissolution
of ammonium nitrate in water to freeze water on the outside of 
the beaker.

Jerry



















DOC0214

Subject:      Re: Fresh water from sea water - new economical process
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/13
Message-ID:   <4d96m8$cp8@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.engr,sci.engr.chem,sci.chem,sci.misc,sci.research



In article <4d916s$cjk@mozo.cc.purdue.edu>, bianchi@widget.ecn.purdue.edu (Marcus V Bianchi) says:
>
>I don't see much of a problem in this discussion, other than the fact that
>crystallization happens during the freezing of a salt solution.
>
>Anyway, I believe there has been a point missing here: the phase diagram of
>a water-salt mixture.  It is pretty simple to show in such a diagram the 
>reason for the purity of the crystal phase, if the salt concentration is
>small (which is the case for sea water).  The crystal formed in such 
>situation has pure water on it and the solute segregates in front of the
>solid-liquid interface.  It is the purification process that we have been
>discussing here.
>
>Does this help?
>
What you say is true, but it has not much to do with the heart 
of the ongoing discussion. The question is whether CO2 rapidly
escaping from seawater can freeze substantially more water than 
can be accounted for by the accepted heat of solution of the 
escaping CO2 and the heat of vaporization of the calculated 
equilibrium water vapor entrained therein.

One side of the argument holds that the standard thermodynamic
values for heat extraction are much lower than the actual 
results because of some unspecified or unknown kinetic effect.
The other side opines that the kinetics cannot result in
more heat separation between the phases without violating the
laws of thermodynamics. 

Take a seat and take a side, if it please you.

The discussion of "crystallization vs freezing" was a side issue,
it being universally agreed that freezing water segregates dissolved
salts.

Jerry (Ico)




















DOC0215

Subject:      Re: What is the difference between KEROSINE oil and ODORLESS MINERAL OIL
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/13
Message-ID:   <4d7o5l$aqg@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4d7hqu$51r@scoville.wsrcc.com>, alison@wsrcc.com (Alison Chaiken) says:
>
>What exactly is mineral oil, anyway?  Dictionary says, "a light
>petroleum distillate."  Does that mean that it's whatever combination
>of distillates are readily available and cheap at the time of
>bottling?  It seems surprising that mineral oil is non-toxic if it's
>petroleum-based.
>
In the broadest sense mineral oils are simply hydrocarbon oils 
derived from petroleum as opposed to vegetable (or animal)
oils which are basically triglycerides. 

Petroleum products often contain poisonous components including
an array of aromatic materials and sulfur and nitrogen 
compounds. The "mineral oil" we see in the drug store is what 
the british call "petrolatum oil," a highly purified, mostly
aliphatic hydrocarbon oil which is usually clear as water
and virtually tasteless and odorless.  A cousin to this material
is petroleum jelly or petrolatum, which is made mostly of
aliphtic hydrocarbons of higher molecular weight.

Jerry (Ico)












DOC0216

Subject:      Re: oklahoma explosive
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/13
Message-ID:   <4d94l9$74d@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4d8mp1$r20@ixnews6.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>
>The nature, and hence geometry, of the OK City explosion is open to 
>question.
>
>Ammonium nitrate/fuel oil emits a vast red-brown plume of NOx when it 
>pops.  I did was involved in oil shale work in 1970 for Occidental 
>Petroleum, in Colorado.  It took three days to ventillate the galleries 
>after a blast.
>
>The OK City explosion was heard 40 miles away.  Official truth claims up 
>to five tons of ANFO in the device.  How is it nobody witnessed/recorded 
>a 400 foot NOx geyser?  Where are the residues from  the blast?  Analysis 
>of hydrocarbon deposits could fingerprint the source of the diesel (or 
>whatever).

The amount of visible or at least noticeable NO2 varies greatly
with the exact oxygen balance. One sees the clearest orange-brown
vapor from the venting of underground shots in wet conditions. 
Surface shots always produce a great cloud of dust into which
NO2 can blend to simply look like more dust, especially in
Oklahoma, where dust storms look like NO2 gas attacks. Many
times, NO2 is not even visible from clean surface shots.
>
>Two seismic waves were recorded.  Had the device been a fuel/air bomb, a 
>"small" charge would rupture the vessels and nebulize/disperse the fuel 
>cloud.  Detonators would then trigger the vapor/mist cloud in air, and 
>KABOOM!  As air is the oxidizer, the device would scale down to about 
>500-700 lbs tops with no residues and no plumes.  Of course, such a 
>device would require non-trivial design and computer modeling (commonly 
>only available to a government).
>
The number of events recorded by seismometers is a highly debated
topic among the cognoscenti. There is no really persuasive evidence 
for more than one blast, (at least that I have seen). I've
also listened to the two tape recordings of the event from near
and far. Some say they hear two events; I hear only one.

>Had it indeed been a fuel/air munition, the inverse square law would NOT 
>obtain!  The very large projected area of the cloud before detonation 
>would not be a point source, it would approximate a plane wave detonation 
>- NO initial decrease in power with distance, then a much slower decrease 
>than inverse square.  Even a line source only decreases linearly with 
>distance.

If the explosive had been a fuel-air mix, there would have been no 
crater. There is no basis at this time for suspecting that FAX was 
involved. 
 
>One last thought.  How is it that all "targeted" government personnel  
>were evacuated shortly before the blast, leaving children, innocents, and 
>a Dept. of Agriculture office to be slaughtered?
>
Just who were these "targeted" personnel and how do we know
they were targeted?  Who targeted them? Neither McVeigh nor any
hypothetical "insiders" have have yet testified on this subject.  

Uncle Al, it is a big grin to learn that you are a conspiracy buff.
If you find any real evidence for any of the above disputed 
opinions, please let me know. I like a good conspiracy just as well 
as the next guy :). Maybe we'll get some more facts on which to
base our theories from the criminal trial (in April?).

Jerry


Jerry (Ico)











DOC0217

Subject:      Re: normality
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/14
Message-ID:   <4dbno6$sjc@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <shogun.21.006BE0FA@interaccess.com>, shogun@interaccess.com (Kevin Squires) says:
>
>In article <4d9ibb$14fp@bigblue.oit.unc.edu> kferri@email.unc.edu (Karen Ferri) writes:
>>From: kferri@email.unc.edu (Karen Ferri)
>>Subject: normality
>>Date: 14 Jan 1996 00:22:03 GMT
>
>
>>Please pardon this basic question, but I can't recall the facts from my 
>>college days and I can't find it in my old chemistry books:
>
>>What is the definition of normality?  I need to make a 10 N (not M) NaOH 
>>solution, but can't remember this definitiion.
>
>In addition, normality finds its usefulness in titrations.  However, I also 
>have a simple question: For a 1 M H3PO4 solution, what would the normality be 
>(by definition).  I understand that with strong base, all 3 protons would be 
>pulled off, eluding to a normality of 3N, but the last, in particular, proton 
>is hard to remove.  Does this have any effect on the defined normality of the 
>solution?

You might look at my previous article on this subject. "Normality"
very much depends on what reactions are involved. For instance,
acetic acid contains 4 hydrogen atoms but only one of them is
measurably ionizable. In practice, because of the formal 
classification of all three hydrogen atoms as ionizable, you would
normally label a bottle of 1 molar H3PO4 as 3 normal for the
benefit of visiting chemists. However, in your own mind, you might 
reasonably consider it as 2 normal for purposes of your own 
titrations.

Jerry (Ico)


DOC0218

Subject:      Re: normality
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/14
Message-ID:   <4daa8c$5gh@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4d9ibb$14fp@bigblue.oit.unc.edu>, kferri@email.unc.edu (Karen Ferri) says:
>
>
>Please pardon this basic question, but I can't recall the facts from my 
>college days and I can't find it in my old chemistry books:
>
>What is the definition of normality?  I need to make a 10 N (not M) NaOH 
>solution, but can't remember this definitiion.
>
You certainly came to the right forum with this question. Your
mailbox should overflow.

In the case of sodium hydroxide solution the normality and
molarity are the same because each mole of NaOH provides
one mole (or equivalent) of hydroxide ion. 

We arrive at a value for normality by looking at the number of 
equivalents each mole represents from the perspective of whatever 
reaction we are interested in.  We multiply the number of 
equivalents per mole times the molarity to get the normality.

Let's take HNO3 as an example. If we are dealing with an acid
base reaction we would say that one mole of the acid yields
one mole of hydronium ion so one mole is one equivalent and thus
the molarity and normality are equal. If we were using the 
same compound as an oxidizer such that the nitrogen went from
the 5+ oxidation state to the elemental nitrogen state of zero,
we would multiply the molarity of a solution by 5 to get the
the normality or number of equivalents per liter for oxidation
purposes. 

Most often we use normality to describe solutions of acids and
bases. This makes it very easy to figure out the number of
equivalents per mole. We merely count the active hydrogen
atoms in a molecule of acid or the number of hydroxyl radicals
associated with a molecule of base.

Jerry (Ico)


















DOC0219

Subject:      Re: Oxygen & hydrogen combine??? What exactly happens?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/15
Message-ID:   <4dd458$rqd@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <1996Jan15.055131.2397@news.bogo.co.uk>, wheatley@mail.bogo.co.uk (Nigel Wheatley) says:
>

>You would be quite surprised exactly how much energy!  The enthalpy of
>formation of water is -286 kJ/mol (this is the amount of energy given
>out to produce one mole of water from hydrogen + oxygen: the minus
>sign signifies that energy is given out).  The heat capacity of steam
>is 33.6 J/K/mol, ie. it requires 33.6 J to raise the temperature of 1
>mole of steam by 1 K.  This means that enough energy is given out
>in the reaction to produce water to raise the temperature of the
>product to nearly 9000 K !!
>
>Well, it doesn't quite because all the many asumptions I've used in
>that back-of-the-mouse calculation wouldn't hold at 1000 K let alone
>9000 K, but it is little surprise that it soon gets to be a runaway
>chain reaction!
>
>Other loss of energy, other than heat and light, comes in the work
>required for the expanding gas to push back the atmosphere, and in the
>kinetic energy of the expanding gas:  it is this kinetic energy which
>results in the thrust to the Shuttle.
>
You might note that the work expended against the atmosphere
is already compensated for in your heat capacity figure which is 
C(p). One important reason the reaction won't get as hot as 
calculated lies in the fact that the heat capacity of steam is 
considerably higher at elevated temperatures where additional
degrees of freedom kick in.  Also, of course, water dissociates 
into its elements way below 9,000 K.

Jerry (Ico)



DOC0220

Subject:      Re: Water injection into
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/15
Message-ID:   <4de96p$k4o@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <8B8E27B.06230067AA.uuout@execnet.com>, billc@execnet.com (BILLC) says:
>
>RRJ>Water injection was used (and still is on some old engines) in turbo jet
>RRJ>engines to increase the thrust on takeoff.  The Boeing KC135 was an example
>RRJ>of a aeroplane using this technology.  The water has the effect of cooling
>RRJ>the gas streem and increasing thrust through expansion.  The water injectio
>RRJ>systems made the engines much noisier.
>
>Please, how does cooling a gas stream "increase thrust through
>expansion"?
>
Good question. The only mechanism I can think of is one in
which the water is flashed into steam by the heated metal
of the engine. One can extract some useful work from energy
stored in heated mass. A good example might be the little 
mining locomotives which run for a long time using an injection
of very hot water under high steam pressure.

Jerry (Ico)















DOC0221

Subject:      Re: oklahoma explosive
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/15
Message-ID:   <4de8o0$k4o@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <877251112wnr@fats.demon.co.uk>, Richard Bettis <rbettis@fats.demon.co.uk> says:
>
>Is there *nothing* that 'Uncle Al' isn't ignorant about.
>
>You could make a building destroying fuel/air weapon for less than the cost of 
>the anfo. FAW's are designed for destroying buildings.
>
>(actually, I work on the 'accidental' scenario of a liquefied gas fuel leak. 
>Its like FAW's only morally defensible!)
>
>I would suggest that 'Uncle Al' might try some simple fuel/air experiments in 
>his back-yard, only I'd probably get sued by his neighbours!
>
What part of Al's post did you find inaccurate? His remarks 
concerning FAE seemed quite correct to this reader. Making
a reliable fuel-air device requires a great deal of design
and test work. If it were a trivial exercise, air blast
weapons would not have relied exclusively on condensed 
explosives for most of this century. The comment about the
existance of two seismic waves may or may not be correct,
but that is a subject which remains open to debate.

Jerry (Ico)





Jerry (Ico)





DOC0222

Subject:      Re: resistance of solution
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/15
Message-ID:   <4dd4bb$rqd@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4dcs39$2i8@hemp.imel.kyoto-u.ac.jp>, yoshihar@bird.scphys.kyoto-u.ac.jp says:
>
>  I am measuring resistance of aqueous 
>solution of KCl.But it increase as time 
> goes. What is wrong? Or if it is not
>wrong ,which point should I use as a 
>result?  Thank you.
>
I trust you are using high frequency alternating current
to avoid the build up of counter EMF by electrolysis
products. You should expect constant values with 
such apparatus.

Jerry (Ico)




















DOC0223

Subject:      Re: ammonia powder
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/16
Message-ID:   <4dfsr9$nbb@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4dflv1$f77@grid.direct.ca>, tmiller@diachem.com (Tom Miller) says:
>
>jzhou@nyx.cs.du.edu wrote:
>>I have a recipe which calls for the use of "ammonia powder"...
>
>Post the recipe, its purpose, its origin & date of publication... a
>few clues will improve your chances of a quality reply.
>
I got a request from alt.chinese.txt et al to take them off
the distribution list for this thresd unless we post in 
chinese. Sounds like a good idea to me.

Jerry (Ico)





















DOC0224

Subject:      Re: 35% of h2o2 means how many volumes ?????
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/17
Message-ID:   <4djtfi$edn@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SGI.3.91.960117022208.18374J-100000@cv4.chem.purdue.edu>, Lev Gorenstein <lev@chem.purdue.edu> says:
>
>On 16 Jan 1996, Christophe Morin wrote:
>
>> 
>> Je pense qu'il suffit de calculer la molarite de la solution et de 
>> rapporter cela au volume molaire degage par la decomposition de l'eau 
>> oxygenee. le ratio donnera le nombre de volumes
>>  (je ne suis pas le specialiste demande mais j'espere que cela aidera 
>> quand meme).
>
>Ce n'est pas vrais.  Le "volume" la est le ratios de volumes de H2O and 
>H2O2 pour la preparation de la solution. 
>
>God, sorry for my poor French and let me switch to English.  This
>suggestion is not correct.  I mean - it's possible to turn it Christophe's
>way, but I bet that the original sence was different.  All it takes is to
>say "Take 1 volume of H2O and X volumes of H2O2".  Since the densities of
>H2O and H2O2 are quite different (1 and 1.46g/ml, respectively), one needs
>to know if the requested 3% is percent by volume or percent by mass,
>before getting this number X. 
>
>If it's by volume, then the answer is quite simple - 35% is roughly 1/3,
>so you take 1 volume (part) of H2O2 and 2 parts of water.  If you need
>more precision, solve the equation
>
>                            X
>        Volume % = 0.35 = -----
>                           X+1
>
>If it's by mass, you have to play a little harder ball:
>
>                           X*1.46
>        Mass % = 0.35 = ---------------
>                         X*1.46 + 1*1
>
>
>Et voila.
>         Lev.


That's not how it works, Lev. The "volume" referred to is the
STP volume of oxygen gas liberated by one volume of H2O2 solution,
at least for weak solutions which have a density of approximately 
1.0.

100 volume H2O2 solution is equivalent to 30% H2O2 where the
percentage is expressed as weight/volume, e.g., kg/L.  Watch out 
because some references express the percentage in the more 
conventional form of weight/weight. The Merck Index, for instance,
says that 30% by weight H2O2 is 100 volume material. Since the
liquid has a density of 1.11, this means the yield of oxygen
is almost exactly 100L/kg rather than 100L/L.

Kingett's Chemical Encyclopedia  says the percentage should be 
calculated as w/v rather than w/w, but fails to note that this
could lead to some confusion if one selected the wrong units
for w and v :)

I would judge that the best bet is to use the system suggested
in references such as *Industrial Chemicals* - John Wiley & Sons.
Here the strength is expressed in weight percent and the "volume"
strength is v/v. Of course you need a table of densities (sigh)
to figure out that 100 volume H2O2 is actually 27.5% by weight,
not Merck's 30%. Incidently, just to make it a little harder,
the eighth edition of Merck printed "30% H2O" rather than 30%
H2O2.

Welcome to the US.

Jerry (Ico)

Where is the SI when you need them? Busy making us shift from
dynes to Newtons :-<




DOC0225

Subject:      Re: Cyanide ingestion
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/17
Message-ID:   <4djpus$edn@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4dj1c4$maq@ixnews4.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>
>Small amounts of ingested cyanide bind to small amounts of cytochrome at 
>the terminal end of the respiratory chain.  It also gets metabolized to 
>thiocyanate, which then depresses thyroid function.
>
>People who suffer chronic ingestion of members of the cabbage family are 
>ingesting rather large amounts of thiocyanate.  The depressed thyroid 
>function resulting leads to behavioral torpor, obesity, and lowered 
>intelligence.
>
>Brussels sprouts not only taste awful, they destroy your mind and body - 
>dispite being cruciferous vegetables harboring the cure for cancer and 
>the FDA.
>
That is very interesting. At least in the "old" days, the colleges
at Cambridge served brussel sprouts in hall each day for about
six months of every year. The other six months it was leathery 
green peas.  East Anglia is known as the "Brussel sprout capital
of the world."  BTW, the students apparently were immune to the
obesity enhancing effects, generally being notoriously thin.

I wonder how much smarter and scrawnier those Cambridge graduates 
might have been if they had refused the sprouts.

Jerry (Ico)








DOC0226

Subject:      Re: Picric acid safety
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/18
Message-ID:   <4dm8u2$3t4@geraldo.cc.utexas.edu>
Newsgroups:   alt.engr.explosives,sci.chem



In article <4dh1up$m95@news.ox.ac.uk>, mert0236@sable.ox.ac.uk (Thomas Womack) says:
>
>Gerald L. Hurst (glhurst@onr.com) wrote:
>: In article <4dbnde$7ov@zinc.compulink.co.uk>, mark@murder.compulink.co.uk (Mark de Roussier) says:
>
>: We froze the tube above the valve with liquid nitrogen poured 
>: on a fiberglas wrapping and then cut and flared the tube and 
>: installed a new valve. The frozen ClF5 seal wasn't a perfect 
>: fix so a few drops escaped and burst into flame on contact 
>: with the concrete floor.
>
>: BTW, it is nice to be able to talk about ClF5 these days. Back
>: then it was a classified and otherwise unknown compound which
>: we called "compound A" in the cloak-and-dagger atmosphere of
>: those cold war space race years.
>
>What on earth do you use ClF5 for? I can see it's a good oxidiser and 
>fluorinator (to put it mildly), but I can't see a use for it in the space 
>race. And how did you classify the interhalogen compounds? 'oh, chlorine 
>doesn't react with fluorine, and if you try to perform the reaction the 
>CIA will come and imprison you'? :)
>
Now I know why we called it "the other place."

Most large rockets are propelled by binary propellants, e.g., a
fuel and an oxidizer such as liquid oxygen and kerosene (kerosine).
About the highest specific impulse is delivered by the combination
of liquid fluorine and liquid hydrogen, both of which are devils 
to handle. ClF5 is a liquid under pressure and chemically 
(energetically)about as close as one can get to liquid fluorine.

ClF5 was, I assume, discovered during work under a government 
contract, I would guess at Rocketdyne. It was classified by the 
simple expedient of only disclosing its existence to people who 
had an appropriate security clearance. Such individuals had 
signed an agreement not to divulge classified information, often 
for 12 years, until automatic declassification.

In the case of ClF5, it was unlikely anyone would stumble onto
it in the lab, because, in typical fashion, many theoretical
chemists knew good reasons why it couldn't exist as a stable
molecule. Also, the conditions required to synthesize the 
material were rather extreme considering the nastiness of the
starting materials, and thus it was not too likely anyone would
stumble onto the compound.  Of course, it was known to all that
chlorine reacted with fluorine to give ClF and ClF3. BrF5 was
known, but was often justified in chemists minds by the larger 
bromine atom.

I believe there were two pilot plant scale methods of
manufacture: The batch process which I developed at Aero-Jet 
General, and a continuous process developed at Rocketdyne. I do 
not know how successful the latter was, but I can imagine they 
had their difficulties along the way:) My plant made a total 
of about four tons of the substance before we finished the
contract and shut that juggernaut down.

If the stability of ClF5 appears obvious today, that obviousness
is probably augumented by a few temporal diopters.

Jerry (Ico)

















DOC0227

Subject:      Re: Amonnium Nitrate (& other people's problems)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/19
Message-ID:   <4dovv3$rkj@geraldo.cc.utexas.edu>
Newsgroups:   rec.pyrotechnics,sci.chem



  Article Segment 1 of 2
  
In article <spiegl.822037845@lobster>, spiegl@lobster.cig.mot.com (Mark Spiegl) says:
>
>So why does the addition of certain phase stabilizers - KN, ZnO, NiO, 
>dinitramides, etc - make AN less susceptible to swelling, sintering and 
>powdering. My laymans (and possibly incorrect) understanding is that the 
>addition of of these phase stabilizers raises the temperature of the 
>phase3-phase4 transition into a range which is unlikely to occur during 
>normal handling and storage. Is this correct? How do the catalytic effects 
>of water which you described play into this? 

Obviously, I can't speak for every proposed mechanism, but many of 
them have been held to be ineffective invalid in later literature
or in the unpublished reports of industrial chemistry labs.
.
Many of the claims concerning "phase stabilization" simply do not
work as advertized. However, it is true that certain additives
retard the end effect, swelling. My GUESS is that additives
change the behaviour of the surface by competing for water or
aqueous solution with the AN. Most additives are put on the
surface of the AN so that their concentration is very high where
the competition is needed. Clay is frequently added as a 2%
coating to improve flow and inhibit sticking. Clays can also
act as pourous agents to help wick moisture away from prill
contact points. Remember that clays (bentonite, China clay) are
often used to crosslink aqueous gels and are among the most water
adsorptive materials. Other additives may act as surfactants, 
lowering the surface tension of water and therby again reducing 
capillary bridging contact.

I've studied a few additives on my own. It was once indicated
to me that guar gum might inhibit swelling, but was a bit 
expensive. Thinking by analogy, I tried a series of multiweek
tests using ordinary wheat flour as a dusted coating. Sure
enough, the samples swelled much less than the controls. It 
seems likely that those tiny, heterogeneous particles of
insoluble carbohydrate worked by the mechanism of binding
surface moisture.

It is rather easy to see how early researchers might happen
to try some relatively esoteric compound like acid magenta
and discover "unique" properties of stabilization. People,
including my researcher friends with the guar, often do not
try the obvious because we are sort of programmed to expect 
more if the method involves the rare or the expensive.

An example: Many years ago there was a major explosives
company which manufactured a water-base ammonium nitrate
gel explosive which incorporated a very small quantity of
ammonium perchlorate (sensitizer), a relatively expensive 
ingredient as commercial explosive ingredients go.

When the formulation was called to my attention because of
a material availability problem, I got a big grin by 
sending the client a memo which said: 

	You are putting AN, sodium nitrate and ammonium
	perchlorate in your formulation. Ammonium
	perchlorate is much more expensive than sodium
	perchlorate. If you use sodium perchlorate in
	place of ammonium perchlorate, you can get exactly
	the same final composition (mix of ions) at a lower 
	price and with fewer supply problems. In particular,
	you can use raw sodium perchlorate liquor, which is
	even cheaper, because the manufacturer doesn't have
	to dry it.

The research group at that company had over 50 scientists and
technicians working on a daily basis on explosives formulation 
and manufacturing problems. The tip I gave them might have come
off of an early page in a freshman chemistry text. The people I
was helping were nothing less than well educated and competent,
but in the press of solving difficult problems they had  all
overlooked the cheap, easy and obvious solution to an ongoing
problem in a major tonnage mainline product.


DOC0228

Subject:      Re: Amonnium Nitrate (& other people's problems)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/19
Message-ID:   <4dovv3$rkj@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
  
  
Second example: Also many years ago, a large explosives company
had designed a delay primer which was initiated by a line of
detonating cord through a tube along the cylindrical side of
the charge. A delay cap was located in the body of the charge
and required the conduction of the shockwave from the cord via
a low-energy shock tube such as Nonel. The problem was that
Nonel and its patent belonged to someone else.

I suggested to the research group: "why don't you just use a
hollow tube?"  It worked. As it turned out, for distances of
several inches, a hollow tube with no explosive on its surface
(a la Nonel) will happily transmit a more than adequate amount
of shock energy around a couple of right angle bends and still 
reliably initiate a delay element. Had there been no anticipated 
trouble getting and using Nonel, that's what would have been 
used at greater cost. Had this happened, it would be taken for
granted still today that an explosive coating was necessary.

Why did these simple solutions come from a consultant and not
from within the groups working daily on the problem? The answer
to that question is simply that any consultant has the advantage
of fresh perspective on OTHER PEOPLES PROBLEMS. Where consultants
need help is in the swamp of their own personal jungles.

It helps also to remember that simple information is more highly 
valued when you have to pay an expensive consultant for it.I have 
also earned my wages by simply advising management to listen to 
the advice of one of their own employees who had been trying 
unsuccessfully to get their attention for a long time.

I suppose it is human nature to undervalue or ignore that which
isn't expensive, difficult or rare and to try to apply quantum
mechanics where Popular Mechanix will suffice. I know that I
have been guilty all my life of overlooking the obvious.

Jerry (Ico)



















DOC0229

Subject:      Re: CaHCl
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/20
Message-ID:   <4dpu05$na6@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <DLFnr8.n2s@rug.nl>, DeAx (hm...) says:
>
>Uhhhhhhh,
>
>A little bit of nonsence?????????????????
>
>Could you immagine a stable species containing Ca(2+) H(+) and only one Cl(-)?
>
No, but Ca(2+), H(-) and Cl(-) doesn't really bother me. At least
as a thought experiment, I see nothing glaringly wrong with
reacting calcium hydride and calcium chloride to get a double
salt.

Jerry (Ico)




















DOC0230

Subject:      Re: Fresh water from sea water - new economical process
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/22
Message-ID:   <4e105s$90r@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.engr,sci.engr.chem,sci.chem,sci.misc,sci.research



In article <4e0jp7$dg0@columbia.acc.brad.ac.uk>, ajkamphu@bradford.ac.uk (AJ KAMPHUIS) says:
>
>Gerald L. Hurst (glhurst@onr.com) wrote:
>
>: The question is whether CO2 rapidly
>: escaping from seawater can freeze substantially more water than 
>: can be accounted for by the accepted heat of solution of the 
>: escaping CO2 and the heat of vaporization of the calculated 
>: equilibrium water vapor entrained therein.
>
>Has anyone considered the temperature decrease due to adiabatic 
>expansion (of the CO2), as an additional source of cooling

There is no need to. That energy is included in the enthalpy
change. Remember that DeltaH = DeltaE + Delta(PV).

Jerry (Ico)

















DOC0231

Subject:      Re: low temp flames?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/22
Message-ID:   <4e0vj7$90r@geraldo.cc.utexas.edu>
Newsgroups:   rec.pyrotechnics,sci.chem



In article <4drtj2$6pc@ccnet3.ccnet.com>, berniew@ccnet.com (Bernie Willis) says:
>
>Michael Freiert wrote:
>> i know some liquids burn at low temperatures (ie 70-110 F of
>> around 30 C for you metric people)
>
>At what point do we draw the line between burning and simply oxidizing?
>
If it isn't hot enough to be capable of producing black body
visible light, it isn't burning or deflagrating. Dull red light
emission begins around 500 deg C.

Now try the more difficult task of defining the difference between
simple oxidation and combustion. I would say that combustion
(which includes burning and deflagration as a subset) usually but
not always connotes the emission of light, but not necessarily in
the form of black body radiation.  Cool flame combustion may be
luminous below 300 degC. Combustion appears also to be a useable
term where there is no (visible) light emission but the combusting
substance disappears as a result of the reaction. A hypothetical
example of such a reaction would be one which otherwise had
the properties of cool flame combustion but lacked the specific
electron transitions resulting in luminosity. All forms of combustion
require thermal feedback from the energy of their reactions to 
sustain them in the absence of insulation and usually in the presence 
of substantial gas flow or reaction zone movement.

Simple oxidation may be thought of as occurring at the
temperature of the surrounding environment without feedback from the 
heat of reaction raising the temperature significantly above 
that of the environment..

The reaction of unsaturated oils in a pile of rags is a form of
oxidation which does rely reaction energy feedback without
producing visible radiation until the rags burst into flame.  We
call the entire process autocombustion, but the initial reaction
is virtually the same as the drying of oil-base paint, which
hardly qualifies as "combustion." We can at best now invoke the
fact that the substrate is not "consumed" in the initial reaction
to avoid the "combustion" classification.

There are also numerous cases of catalytic oxidation which
may occur with or without light emission. In describing these
reactions, the distinction between oxidation and combustion
seems extremely arbitrary since it depends often on merely
how far we turn the feed valve - enough to make the catalyst
glow or not?  It might be argued that the dividing line in this
sort of process is set by whether or not the energy feedback
is a primary agent in determining the reaction rate.

I guess it boils down to the frequently encountered principle
that we know it when we see it, but it's hard to define
unambiguously.

Please do not succumb to the temptation to invoke Webster
as the FINAL authority in this discussion. Dictionary definitions
are rarely adequate to describe technical shades of gray.
Words have a way of  gathering different connotations in different
areas of the arts and sciences. We sometimes need to listen to
hear what they seem to mean in our art, and then sometimes
create new conceptual fine structure  by mutual  agreement.

I have not defined "combustion," and the related terms above.
I have merely tried to describe what the terms mean to me,
along with some of the ambiguities. Others will surely have a
different perspective.  The initial authoritative tone above
was adopted to ensure some combative spirit in the replies :)

Jerry (Ico)
<








DOC0232

Subject:      Re: Solubility of NO2 in water
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/23
Message-ID:   <4e25cs$arg@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.engr.chem



In article <31046700.6941@superlink.net>, Eric Lucas <lucas@superlink.net> says:
>
>Frank Koch wrote:
>> 
>> Hello!
>> 
>> Who can help me?
>> 
>> I am looking for the solubility of NO2/N2O4 in water. I need values for
>> different temperatures. Perhaps anyone can deal with a Henry-consant if
>> one exists. I am not sure if the Henry-law is applicable since NO2
>> reacts with the water forming HNO3. But perhaps there is a maximum
>> concentration one can reach when NO2 is bubbled through water (and that
>> changes with the temperatures).
>> 
>
>NO2 + H2O  --->   HNO3?
>
>Does this really occur?  It represents and oxidation of N and would 
>have to be accompanied by reduction (or disproportionation).  If its 
>a reduction of water, it must be giving off H2, and I didn't think 
>NO2 had anything like the required reducing power.  If 
>disproportionation, it would have to give HNO2, but I believe HNO2 
>and HNO3 react to give a brown gas--presumably a mixture of NO2 and 
>N2O4.
>
Try it this way:

2NO2 + H2O <-> HNO3 + HNO2 at low temperatures, then on warming:
3HNO2 <--> HNO3 + 2NO + H2O Then of course the NO can further go:
3NO <--> N2O + NO2 and if there is any oxygen about:
2NO + O2 <--> 2NO2

Nice system to keep one busy.

Jerry (Ico)




















DOC0233

Subject:      Re: Blending Talcolm Powder
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/24
Message-ID:   <4e6c9s$45d@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4e68bp$9me@lijgate.lij.edu>, Kaminie Amarjit <Amarjit@lij.edu> says:
>
>Forgive my ignorance,but what is a waring blender.  Is it a regular 
>blender you use in the kitchen.
>
"Waring" is a trade name which has become colloquially generic
for all makes of high-speed kitchen blenders. The brand name
is especially common among chemists because the company also
makes stainless steel models for laboratories.

Personally, I always used Oesterizer mixers or their OEM
cousins because they have Mason Jar standard threads. This
gives one the option of using upside-down canning jars as
mixing vessels and can save a lot of trouble in clean up
when working with a lot of gunky materials. Once the material
is blended, simply screw on a lid and the product is ready
for storage. For the next batch you use another 50 cent jar.

With liquids, it helps to have a couple of spare blade 
assemblies and to buy silicone gaskets (for organics). I used
to soak my gaskets in solvent to leach out the plasticizers
and thereby avoid contamination of sensitive organic mixes.

For talcum powder, any mixer should make uniform blending
a piece of cake (easy).

Jerry (Ico)

Jerr





DOC0234

Subject:      Re: Blending Talcolm Powder
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/24
Message-ID:   <4e5vff$r1h@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4e5nh2$290@lijgate.lij.edu>, Kaminie Amarjit <Amarjit@lij.edu> says:
>
>Can someone suggest the best procedure for blending talcolm powder( baby 
>powder) with a red synthetic dye(red lake) on a home made basis.
>
>-- 
>
>This message represents the personal views and opinions of the individual 
>sender and shouldin no way be construed as an authorized  communication 
>on behalf of Long Island JewishMedical Center.
>
How about a Waring blender?

Jerry (Ico)




















DOC0235

Subject:      Re: Fresh water from sea water - new economical process
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/24
Message-ID:   <4e4rkk$7s5@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.engr,sci.engr.chem,sci.chem,sci.misc,sci.research



In article <31043335.1295186@news.rmci.net>, jvinson@rmci.net (John W. Vinson) says:
>
>ajkamphu@bradford.ac.uk (AJ KAMPHUIS) wrote:
>
>>Gerald L. Hurst (glhurst@onr.com) wrote:
>>
>>: The question is whether CO2 rapidly
>>: escaping from seawater can freeze substantially more water than 
>>: can be accounted for by the accepted heat of solution of the 
>>: escaping CO2 and the heat of vaporization of the calculated 
>>: equilibrium water vapor entrained therein.
>>
>>Has anyone considered the temperature decrease due to adiabatic 
>>expansion (of the CO2), as an additional source of cooling
>
>Youxue Zhang has an article in _Nature_ (379:57, 4 January 1996) about
>the Lake Nyos disaster in 1986.  To quote: "an estimated (1-3)x10^8 kg
>of CO2 was released during an eruption that possibly lasted as long as
>4.5 hours".  If this "new economical process" were to be working as
>well as claimed Lake Nyos would have become Nyos Glacier.  Later in
>the article, Zhang notes:  "Because of the high heat capacity of
>water, the temperature decrease due to gas exsolution and expansion is
>small (the temperature decrease is estimated as ~4 C if P(0) is 2.0
>MPa and final P is 0.1 MPa)."
>
>Perhaps the injection of some real numbers and algebra would further
>this discussion.

Careful with those quotes, John. The clipped paragraph suggests 
that I am asking whether CO2 can do what is alleged in the patent.
No way in my opinion.

What do you mean by "the injection of some real numbers and algebra"?
Weren't the thermodynamic calculations using accepted enthalpy
values for CO2 solutions "real" enough? Not one shred of 
quantitative evidnce has been published to to the contrary. What
kind of algebra do you expect to overcome the absurd conclusions
I demonstrated would arise out of the inventors claim in light
of the CALCULATED thermodynamic consequences. One of those
algebraically calculated bottom lines, based on accepted enthalpy
data, showed that if the invention works as described, The opening
of a can of Coca Cola at 0 defC would cause a serious risk of
scalding the hand that opened it. That experiment has been run 
at least several million times without any reports of live steam
rushing out of the can.

Jerry (Ico)








 

Jerry (Ico)
<



















DOC0236

Subject:      Re: Melting rate of ice cubes
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/24
Message-ID:   <4e4qc3$2qh@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



  Article Segment 1 of 2
  
In article <jbednarc-2301960941320001@mtshasta18.sisnet.ssku.k12.ca.us>, jbednarc@sisnet.ssku.k12.ca.us (Jennifer Bednarczyk) says:
>
>To whom it may concern:
>   I am a student at Mt. Shasta High School in CA.  I am trying to find
>research for my project which is 'How does the surface area of an ice cube
>affect the melting rate?'  Now the abvious answer is that the smaller the
>size of the ice cube, the faster it melts but I need background research
>to help me understand the scientific reason for this.  If you have any
>helpful information please reply to me at the following e-mail address~
>jbednarc@sisnet.ssku.k12.ca.us    Thank-you.
>                                       ~Jennifer Bednarczyk~
Try this approach:

The time it takes to melt an ice cube (T) depends directly on how 
much volume (V) of ice you have to melt and inversely on how much 
surface (S) there is present for the heat to get into the ice. The
more ice you have to melt, the longer it takes and the more 
surface the ice has, the less time it takes. We translate these
English statements into the following little algebraic equation:

1) T = K*V/S 

Where K is some constant we do not need to know the value of for
our general analysis.

An ice "cube" or any other "shape" such as, say, a pyramid or a 
horse has a very interesting individual property associated with 
it which we will call the "shape constant" (SC), such that for
any given shape, including that of an ice "cube" the relationship
between the surface of the shape and its volume is given by
the expression:

2) S = SC*V^(2/3) 
(surface = shape constant times the volume raised to the 2/3 power)

and this equation holds for any size as long as we are talking
about the same shape.

Now believe it or not, there is a good chance that your teacher
never heard of the shape constant, but it is the sort of thing
that makes people who see it say. "Hmm, now that I think of it
that equation is obviously (or intuitively) true. Sometimes they
will even try it out to see if it works for two different sized
cubes or spheres or the like. It does work. SC is equal to 6
for a cube and 4.836 for a sphere, which is as small as it gets.

We don't really care what the value for an ice "cube" is, but it
is obviously close to 6.

Now for the cool part (a little humor there).

Substitute the value of S in equation 2 for the S term in
equation 1 to get:

3) T = K/SC*V^(1/3)

Since we don't really care what the values of SC and K are,
we can simply define a new constant (A):

4) A= K/SC

And substitute it into 3 to get the very simple equation:

5) T = A*V^(1/3)

Now another nice property of any "shape" is that the length of
any arbitrary line between two corresponding parts of the 
object, such as the tips of a horses ears, is proportional to
the cube root of the volume of the horse (shape). This is 
equally true for, say, the length or width or diagonal across
the top of an ice "cube" of any shape. Let's call whatever line
we choose "L" for length, then we can write:

6) V^(1/3) = B*L where B is again a constant for any given shape. 

OK, now we simply replace the more ungainly term, V^(1/3) in 
equation 5 with its value in equation 6 (B*L) to get:

7) T = A*B*L 

And since we once again don't care what the values of the 
constants A and B are, we let their product A*B = C and substitute
this new constant into equation 7. TA DAAAA!

8) T = CL

How about that? It turns out that the time required to thaw
an ice cube of given shape is proportional to the length
(or width or height, etc.) of the cube.

So if a one-inch "cube" thaws in one hour then a two-inch "cube"
should take 2 hours, even though it is eight times as big
in volume and weight.

If you want to express this as a rate, the expression is
simply C = T/L which gives the melting rate in length
units per unit time and should be valid for all "cubes" of the
same shape.






















DOC0237

Subject:      Re: Melting rate of ice cubes
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/24
Message-ID:   <4e4qc3$2qh@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
  
  
Remember that C is a combination of several constants which
we chose to ignore as far as actual individual values go,
but if you expand your final equation back to include all
those constants you will find that that equation defines
a universal rate of melting valid for all shapes and sizes,
depending only on that original shape constant (SC) and
that other constant B, which is also a sort of "shape constant."
But unlike SC it is one which depends on your choice of arbitrary 
points on the particular shape.

Naturally, you would have to make at least one careful 
experiment under reproducible conditions of temperature,
ventilation, and even relative humidity to get the necessary
value for that original K constant.

What we have derived here is a mathematical model which we
hope will conform to reality. In practice such models work
better sometimes than others, mainly because we can never
really guarantee that "all other things are equal" in our
experiments.

The next stage would be to test the theory to see how good 
the model is.

Good luck. 

Jerry (Ico)






DOC0238

Subject:      Re: Archival Plastics
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/26
Message-ID:   <4e9tc6$lat@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4e86ct$ire@ixnews6.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>
>Mylar is Dacron or PET - poly(ethyleneterephthalate).  There is no 
>plasticizer or halogen in Mylar, it is remarkably resistant to UV 
>degradation, it is strong and tough, it has a very low gas and water 
>vapor permeability, and it heat seals - good stuff! 

"Mylar" is duPont's trade name for THEIR polyester film. Credit
should go to 3-M for this class of product as they were the 
pioneers with Skotch-pak (R). Heat-sealable? My experience is 
that despite the listings in charts of "heat-sealibility" in the 
425-450 degF range for "some" PETs, the material one ends up
using is a laminate or coextrusion with a polyethylene or
blend resin as a heat-seal coat. Again, hats off to 3-M for
this innovation of the sixties.

Jerry (Ico)

















DOC0239

Subject:      Re: Endothermic Reactions
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/26
Message-ID:   <4e9qv9$lat@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4e83b9$chq@vixen.cso.uiuc.edu>, stinky <jezek> says:
>
>I can't believe you said that, because it is absolutely, positively untrue.
>Since enthalpy for endothermic reactions is positive you need a large positive
>entropy change to overcome it.  So spontaneous endothermic reactions usually
>involve some chemical species in the condensed phase changing into some
>chemical species in the gas phase, like
> 
>              HgO(s) ------->   Hg(l) + 1/2 O2(g)
>
>and there are plenty more like that.  I found this one in a general chemistry
>text.
>
If you are referring to the article by jyri_r@madli.ut.ee (Jyri Ruut),
you better poke your nose back into that book and think again. 
What the man wrote is correct, and you picked a lousy example to 
try to disprove it. Jyri's article is quoted below for the 
benefit of those who have no idea to what you were referring.

Jerry (Ico) 

****** Begin quote:

Newsgroups: sci.chem
Subject: Re: Endothermic Reactions
Date: 25 Jan 1996 07:27:16 GMT
Organization: Tartu University, Estonia
Lines: 21
Message-ID: <4e7bck$hja@kadri.ut.ee>
References: <4d7met$c7e@cloner2.ix.netcom.com> <4d8n7a$r20@ixnews6.ix.netcom.com> <4dlspv$5q7@soap.news.pipex.net>
NNTP-Posting-Host: madli.ut.ee
X-Newsreader: TIN [version 1.2 PL2]

John Williams (j.williams@bbcnc.org.uk) wrote:


: All these examples are phase changes. Anyone got a simple *reaction*
: i.e. a chemical change takes place?


Endothermic reactions need continuous flow of energy from the outer
environment. Commonly, one gets this energy from some kind of heating
device.

Without additional energy, these reactions won't go, i.e., one can't
observe the reaction going and the temperature dropping and dropping.
Activation energy is needed to initiate the reaction and surplus amount of
energy to keep the endothermic reaction going. In addition, reaction rates
drop dramatically with decrease of temperature.







DOC0240

Subject:      Re: HELP!!!  superfluidity/liquid helium
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/26
Message-ID:   <4e9ppl$lat@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4e73cn$2832@news.doit.wisc.edu>, Netscape User <netscape-user@uwmadison> says:
>
>I guess the Utah State University does have a library with quite a couple of books 
>about chemistry. What about a visit over there and some questions following this 
>visit, if you didn't understand something? I hope you don't expect that I write you 
>a couple of pages back about this or even your whole paper???
>
Dear Netscape User,

Please see my reply to Username unless you are Username.

Jerry (Ico)
<





















DOC0241

Subject:      Re: HELP!!!  superfluidity/liquid helium
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/26
Message-ID:   <4e9ph0$lat@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4e8fn0$o41@vixen.cso.uiuc.edu>, Username <username@uimrl7.mrl.uiuc.edu> says:
>
>If your paper is really only one page you could make the whole thing up or
>just use a lot of long words that say nothing.  If you would like facts may 
>I suggest going to the library.  They have many nice books that should be 
>rather helpful.  
>Why on earth would somone post their homework on the net and expect others 
>to do it for them?  Answer:  because people on the net are so ready to show 
>"how much they know (or can read)" that they dont care that they are being 
>irresponsible by doing so.  Both the homework posters and answerers should 
>be ashamed of themselves.
>
That's a fine lecture for a fellow named "username," who doesn't
believe in quoting an introductory line. Why waste the time and
space giving us your unsolicited opinion on the shamefulness of
our exercise of the right to decide what we do and do not answer.

The question regarding liquid helium is of enough general interest
to warrant answering even if it serves some nefarious teenager's
scheme to avoid an hour of homework. At least it relates to 
physics, which is more than I can say for your whining post and
my snippy retort.

Jerry (Ico)










DOC0242

Subject:      Re: Molar masses does't work.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/26
Message-ID:   <4e9v7o$lat@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4e8m6v$bgn@hawk.pix.za>, nt000001@pixie.co.za (Nicola Toma) says:
>
>Email: nt000001@pixie.co.za
>
>Can someone please explain to me why a mixture of potassium nitrate,
>sulphur and sugar using calculated molar mases from the exation for
>its combustion reaction does not work at all?
>
>Is it because some of the sulphur forms SO2 instead of reacting with
>the potassium nitrate to form K2S to free excess oxygen.
>
>There is alot of carbon left after the reaction (if I can get it to
>react at all!) which seems to support my theory.
>
>Am I right? If so please suggest a possible solution to rectify the
>problem.
>
How are we supposed to know what proportions you used in order
to judge what is wrong? If you are expecting a simple reaction from 
this mix, you may be surprised. Have you looked at the reported
reactions of black powder? They are quite complex and the products
tend to be a gawdawful mess of things which look like they ought
to bounce down to a lower overall enthalpy state but don't. Why
should sugar be any better than charcoal? Don't hold your breath
until SO2 gives up its sulfur to form K2S. How much K2SO4 are
you expecting? CO, K2CO3, H2S, S?

Particle size and intimacy of mixing have a lot to do with it
too. The catch is that it is not healthy to grind such materials
together if you value your skin.

From a pyrotechnic point of view, why bother with this inferior
mixture?

Jerry (Ico)





















DOC0243

Subject:      Re: Vapor Pressure Determination
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/26
Message-ID:   <4e9u16$lat@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4e86jd$ire@ixnews6.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>
>For a one-shot determination, one need merely introduce a small quantity 
>of the test subject into a mercury barometer.  The bolus will float to 
>the top of the Hg column, vaporize, equilibrate at temperature, and you 
>read off the vapor pressure (there must be residual liquid phase) as the 
>difference in column height.
>
>Of course, for the SECOND sample, you must disassemble and clean the 
>barometer, and reassemble it.  You safety people will have a conniption 
>fit (or take out a hunting license).
>
If you have a friend with a vacuum line, get him to run
your vapor pressure - at least a few points for a logP vs 1/T
plot. If you do it yourself, make a mercury manometer attached
to a cold trap which can be pumped down with your volatile
material frozen down in liquid N2 or CO2 depending on just
how volatile it is. You can measure the vapor pressure by 
immersing the trap in dewars of liquid, preferably slush
baths at a whole bunch of temperatures to get a marvelous
straight line of LogP vs (1/T). You can use the mercury flask
as a reservoir if you wish, so that when you are through
all you have to do is release the vacuum and restopper the 
flask.

Jerry (Ico)








DOC0244

Subject:      Re: Why is this pH 13+?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/27
Message-ID:   <4ecged$iud@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4ebkse$9fc@treasure.coastalnet.com>, 47jv59wl@coastalnet.com@abaco says:
>
>Can anyone explain how an aqueous solution that is 99% KNO3, NaNO2, & NaNO3
>at +400F have a pH of +13?  I have a customer who says it is.  Where are the
>-OH ions coming from?  There certainly can't be enough in the water.
>
Why not pH 13? If it's 99% metal nitrates and nitrites at a 
temperature nearly 200 degF above the normal boiling point
of water, it is hardly an "aqueous" solution. A high pH just
means there is little hydronium ion present. Maybe the 
hydronium figured there was no sense hanging around after 
the water left.

A high pH simply denotes a low concentration of H+. If that low
concentration of H+ occurs in water, there is a corollary
effect that the concentration OH- must go up. Your toothbrush,
however, may well contain less than 1X10^-13 moles of H+ per 
liter of melted plastic at 400 degF, but that does not imply 
that it contains a lot of hydroxyl ion.

Come to think of it, the pH of hot mercury is probably nearly
as high as that of the space in an empty beaker :)

Jerry (Ico)










DOC0245

Subject:      Re: Who to complain to about Plutonium.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/28
Message-ID:   <4eepjg$1u9@geraldo.cc.utexas.edu>
Newsgroups:   sci.bio.misc,misc.invest.stocks,sci.bio.ethology,sci.astro,sci.math,sci.skeptic,sci.chem,rec.arts.movies.current-films,rec.bicycles.tech,alt.c



In article <822791917snz@deltrak.demon.co.uk>, Andrew Stephenson <ames@deltrak.demon.co.uk> says:

>He has his own group for his own doctrines, yet he habitually
>cross-posts them to groups where they rarely have any relevance.
>
>People who try to point out what a rotten situation this is get
>yelled at for infringing rights.
>
>The Question: What's wrong with this picture?  ;-)

What's wrong with this picture? The artist has the wrong 
perspective.  Archimedes' posts have at least a much relevance
to chemistry as those of his detractors and he is usually a 
darned sight more entertaining. Personally, I read his posts 
when it pleases me Just as I read the complaints at my 
discretion. 

I see no real harm in either his posts or yours. When the
chemistry is slow we can always tune in on the Lilliputian
war to see which end of the egg is being cracked. Then,
there is always the possibility that Mr. Plutonium's unfettered 
ideas may inspire one of us more convervative adherents of 
conventional science to take wing on a flight of fancy and
knock the socks off of academe.

One aspect of this whole debate which I fail to understand
is why it is so difficult for so many to grasp the idea that
the only freedom of speech which is worth a damn is the freedom 
to express controversial ideas. Even Big Brother usually 
allows the freedom to sing his praises.

Chemistry doesn't belong to any one group, not even chemists.
Who should decide what's proper or improper here? Other forums
develop moderated groups or exclusive email groups for those
participants who want to limit the breadth of material to which
they are exposed. Some of us prefer a more open forum where the 
rabble get to chuck vegetables at the performers. Sci.chem
is and should be such a forum.

Please do not let my comments suggest that any of you go away.
Archimedes value on this stage would be diminished by the 
absence of his devoted critics and their continuing 
frustrations and machinations.  

All that is missing is a transcript of the various conversations
which must take place among the powers-that-be at Dartmouth from
time to time.  They have a difficult problem, and I am sure many
in this forum appreciate the fact that they have thus far resisted 
invoking censorship in the face of what must be considerable
pressure from understandably offended and wannabe offended parties.
May they continue to resist. The aftermath of any move to deny
Archimedes access to this and other groups would probably leave
us all waiting for the other shoe to drop.

Jerry (Ico)

DOC0246

Subject:      Re: Who to complain to about Plutonium.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/28
Message-ID:   <4egpje$d1g@geraldo.cc.utexas.edu>
Newsgroups:   sci.bio.misc,misc.invest.stocks,sci.bio.ethology,sci.astro,sci.math,sci.skeptic,sci.chem,rec.arts.movies.current-films,rec.bicycles.tech



In article <310B9360.158E@physics.carleton.ca>, Mike Doncheski <mad@physics.carleton.ca> says:
>
>Gerald L. Hurst wrote:

>> What's wrong with this picture? The artist has the wrong
>> perspective.  Archimedes' posts have at least a much relevance
>> to chemistry as those of his detractors and he is usually a
>> darned sight more entertaining. Personally, I read his posts
>> when it pleases me Just as I read the complaints at my
>> discretion.
>> 
>
>The same could be said of you...

Myopic people are also entitle'.

>Plutonium occasionally posts things 
>of relevance to sci.physics and the rec.bicycle.* groups.  The 
>message to which Andrew Stephenson replied belonged to a thread 
>in the sci.physics.* groups (yes, I just checked this).  Mr. Plutonium 
>removed the sci.physics groups from the newsgroup: line and in their 
>place added:
> 
>           sci.bio.misc, misc.invest.stocks, sci.bio.ethology, 
>           sci.astro, sci.math, sci.skeptic, sci.chem,
>           rec.arts.movies.current-films, rec.bicycles.tech
>
I don't blame you for feeling slighted. I'm sure Mr. Plutonium would
not object to your copying his post in sci.physics. Perhaps his
"Newsgroups" line is limited or maybe he simply made an error. I'm
sure he would not deliberately omit one of his favorite forums,
especially now that you have called it to his attention.

Jerry (Ico)
DOC0247

Subject:      Re: Pressure of liquid N2 at room temprature.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/29
Message-ID:   <4ej8nv$4vb@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <USE2PCB943065871@brbbs.brbbs.com>, mdudley@brbbs.brbbs.com (MARSHALL DUDLEY) says:
>
>jvinson@rmci.net (John W. Vinson) writes:
> 
>-> I think the reason that the constants apply only up to -113 C is that
>-> this is the triple point of liquid N2.  Anywhere above this
>-> temperature there *is* no liquid phase at *any* pressure.  I suggest
>-> you investigate some other medium for your application...
> 
>Huh?  Let us do a reality check here.  The triple point of water is I believe
>.15 C.  If what you are saying is true then water could not exist at room
>temperature.  I checked my CRC and it indicates that there is NO triple point
>for N2.  I'm not sure what that means except that at extremely high pressures
>it sublimes dirctly from solid to gas like dry ice does.
> 
The triple point of N2 is -210.002 degC per Lange's 13th ed.

One of my engineers once tried to defrost a SS tank full of liquid
F2 a few decades back. As the crew dived out of the pilot plant,
one of them saw the pressure rapidly passing the 4,000 psi mark
before the explosion. The tank (cylinder) probably had a burst
strength of over 15,OOO psi, but that would have been butter for
a wall-to-wall liquid heading for its critical temperarure.

Jerry (Ico)












Jerry (Ico)


















DOC0248

Subject:      Re: What is the freezing point of water???
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/29
Message-ID:   <4ej95a$4vb@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4eit1h$ndo@central.bldrdoc.gov>, aharvey@boulder.nist.gov (3555) says:
>
>In article <310B3053.6690@Brown.edu> KJK@Brown.edu writes:
>>the celcius scale -- another of the multitudinous arbitrary scales -- is defined (or limited)
>>by the melting point and frezing point. So we ca just write:
>>
>>          _
>>O degrees = freezing/melting point of water
>>
>>            _
>>100 degrees = boiling point/condensation point of water.
>
>Actually, for those who are into to semi-trivial details, the above is
>no longer correct.  International standards now define Celsius 
>temperatures strictly as Kelvins minus 273.15 (no reference to water
>there).  And Kelvins is defined solely by defining the temperature of
>the triple point of water to be 273.16 Kelvins - the temperature scale
>is then defined strictly by thermodynamics without references to any
>properties of substances.
>
>As a result of all this, as of the adoption of the International
>Temperature Scale of 1990, the boiling temperature of water at 1
>atmosphere pressure is approximately 99.974 degrees Celsius, and the
>melting point at 1 atm. turns out to be about 0.002 degrees C.  Close
>enough to the old definitions for most purposes.
>
>Allan Harvey, Thermophysics Division, NIST, aharvey@boulder.nist.gov
>"Don't blame the government for what I say, or vice-versa."

And for those into even more trivial details, the freezing point
and boiling point of water are still 0 and 100 degC respectively
to the accuracy stated. They are also absolutely correct for those
who do not recognize "international authorities."

Jerry (Ico)

Sometimes out of step in the march of science, but always good
enough for government work.


















DOC0249

Subject:      Re: Why is this pH 13+?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/01/29
Message-ID:   <4ehlgu$3mm@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4ehaid$crd@morgoth.sfu.ca>, David Naugler <dnaugler@sfu.ca> says:
>
>glhurst@onr.com (Gerald L. Hurst) wrote:
>>In article <4ebkse$9fc@treasure.coastalnet.com>, 47jv59wl@coastalnet.com@abaco says:
>>>
>>>Can anyone explain how an aqueous solution that is 99% KNO3, NaNO2, & NaNO3
>>>at +400F have a pH of +13?  I have a customer who says it is.  Where are the
>>>-OH ions coming from?  There certainly can't be enough in the water.
>>>
>>Why not pH 13? If it's 99% metal nitrates and nitrites at a 
>>temperature nearly 200 degF above the normal boiling point
>>of water, it is hardly an "aqueous" solution.
>
>The pH of a solution is only properly defined for a truely aqueous system in which it 
>can be said that [H+][OH-]=10^-14. It may be true that at +400F and 99% alkali nitrate 
>and nitrite salts, we have a nonaqueous system. In this case, any serious student of 
>chemical equilibria would throw away the concept of pH and reformulate the equilibrium 
>problem in terms of the various species present and their free energies of formation 
>under the conditions of temperature and pressure actualy obtained.
>
>It may safely be said that the concept of pH causes brain damage in those who fail to 
>progress beyond first year chemistry.
>
You're right. I checked the pH of my melted toothbrush and empty
beaker with litmus pH paper. It turned brown in the plastic and
refused to change color in the empty beaker, so clearly the theory
does not extend to these materials. Thank you for clarifying
the matter. Now I can cancel the experiments I had planned with
the bowling ball.

Jerry (Ico)



DOC0250

Subject:      Re: Volcano
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/17
Message-ID:   <4g5inr$no4@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4g5ajg$ahn@uucp.intac.com>, mdunkel@intac.com says:
>
>Does anyone know how to prepare a "volcano"? I remember seeing it done
>some years ago and remember that it used household chemicals and was
>safe. My grandson, a budding chemist of six, expressed interes and I
>would  like to run it for him.
>
Sure.
Mix iron filings with sulfur powder and add a little water to
form a thick mud. The reaction Fe + S -> FeS will begin shortly,
generating enough heat to cause gentle steam formation with
a very satisfying "Galooop" sound of cooking oatmeal. If
you cover a cup or so of the mixture with some earth you will 
get a fine "volcano" effect.

Based on the equation above you need about a 56:32 ratio of iron
to sulfur by weight. The water serves as a catalyst and of course
as the converter of heat to mechanical energy and source of steam.

Jerry (Ico)














DOC0251

Subject:      Re: Analog of Capillary condensation
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/18
Message-ID:   <4g6fvk$749@geraldo.cc.utexas.edu>
Newsgroups:   sci.engr.chem,sci.chem



In article <31269CD4.72E4@gold.tc.umn.edu>, "Patrick K. Notz" <notz0001@gold.tc.umn.edu> says:
>
>JTW8150 wrote:
>> 
>> I am curious to know if anyone has ever heard of "capillary
>> solidification".  That is the increase in the liquid boiling point when a
>> liquid is confined in a small pore.  I think this would be the analog of
>> capillary condensation ie the increase the boiling point of a vapor that
>> is confined in a small pore such that the vapor condenses to the liquid
>> state.
>
>I am not particularily familiar with "capillary solidification" but it could be 
>the result of the pressure differential (that is, capillary pressure) across the 
>meniscus (assuming one exists).  Depending on the liquid-solid pair, the pressure 
>drop could be positive or negative giving rise to a boiling point elevation or 
>declination... this idea doesn't seem to mesh with you capillary condensation 
>idea tho.
>
I am not sure I understand what is being asked, but let me make a
stab at what I think may be some pertinent information.

Imagine water in a capillary which it does not wet, i.e., in which
it has a convex meniscus. The supface tension of the curved water-
air interface will create a surface pressure which increases in
inverse proportion to the diameter of the capillary. 

At modest diameters in the micron range the surface pressure is
of the order of a few psi or thereabouts and results in a very slight
increase in the vapor pressure of the water and a modest increase
in the boiling point. As the capillary size is reduced to, near
atomic dimensions, say of the order of 10exp-7 cm, the surface
pressure may rise to a few thousand psi. Although the vapor 
pressure is significantly higher than the normal vapor pressure
under these conditions, the net effect is to very greatly increase
the initial boiling point. However, if two segments of liquid were 
separated by either an air or vacuum space, I would expect them to 
be propelled apart against external atmospheric pressure well below 
the normal boiling point. One could say that the liquid then had TWO 
boiling points.

Suppose, however that the water does wet the capillary. Then,
we can imagine that the water column is under tension of as
much as several thousand psi. It cannot, however fly apart
because its tensile strength is still greater than the net
surface tension effects. Will the initial boiling point be
reduced? In small, smooth capillaries using very pure water,
I would guess that the initial boiling point, even under tension
would be increased rather than decreased in most cases because of 
the absence of nucleation sites and the difficulty of forming the 
initial bubble. Once a bubble was in place between two segments,
though, the pressure between the two should be reduced slightly
because of column tension, and, from the standpoint of the two 
opposing menisci, the boiling point could be said to be increased
over that of the normal liquid
 
It may be that the phenomena I have proposed above were at least
in PART responsible for the erroneous discovery of "polywater." 
This is a personal theory and welcomes criticism.

If there were phases present in the capillary near their freezing
points, the capillary pressure or tension could well be sufficient
to cause solidification. Water,for instance should freeze a little 
above zero degrees C under tension whereas most materials would
freeze at slightly higher temperatures under pressure.

Jerry (Ico)












DOC0252

Subject:      Re: HELP PLEASE!!!
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/18
Message-ID:   <4g8a24$i7l@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3127941A.20B9@cris.com>, "Paul R. Ferreira" <pferre@cris.com> says:
>
>Hi there,
>
>I'm a college student and I'm stuck with a simple problem. The problem 
>says:
>
>        For the formation of ammonia from hydrogen and nitrogen, if the 
>        ammonia concentration is increasing at a rate of 0.024 mole/L 
>        sec, what is the rate of disappearance of hydrogen.
>
>I know rate = k[conc]
>
I should probably leave this one alone since Mr. Ferreira obviously
hasn't given the problem much thought. Sigh.

N2 + 3H2 --> 2NH3

makes it pretty obvious that hydrogen molecules disappear at 3/2
the rate at which ammonia molecules are formed. Your rate equation 
and the concentrations of the molecular species have nothing to do 
with solving the problem as stated.

You are looking for a complicated answer to a simple problem.

Jerry (Ico)








DOC0253

Subject:      Re: Science Fair Cold Pack Salts
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/18
Message-ID:   <4g8d5t$i7l@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4g849e$4j6q@news-s01.ny.us.ibm.net>, schapir@ibm.net says:
>
>I'm a 7th grader working on a science fair project. I have several questions 
>reguarding salts. 
>1) What kinds of salts are used in cold packs? 
>2) How do they make the water get colder? 
>3) Why doesn't table salt make the water get colder? 
>4) Are there any salts that make the water get hotter? 

More freebee homework problems, eh? 

1) Most often ammonium nitrate, NH4NO3
2) This particular salt and numerous others require more
   energy to break up the crystal lattice into ions than
   is gained from the energy of hydration of those ions
   as they attach themselves to water molecules. The driving]
   force which causes dissolution in the face of having to
   absorb energy is the increase in entropy.
3) The hydration energy is roughly equal to the crystal 
   energy in this particular case. This also explains why the 
   solubility of salt, unlike that of AN, does not increase 
   much with temperature.
4) Yes, there are numerous salts which undergo exothermic
   dissolution. In some instances they can raise the 
   temperature enough to scald your hand. Some materials
   have such great hydration energy that they form stable
   hydrates like CaCl2:4H20 (calcium chloride). Some salts 
   will get hot by hydration without dissolving. Calcium 
   sulfate (plaster of Paris) is an example.

If you need an exothermic salt for your project, you might
consider anhydrous magnesium sulfate, which can be made by
drying Epsom salts in a hot (400 deg F) oven in a disposable 
open pan which you can cover loosely when you turn the oven
off to keep out moisture while the material cools. Once cool, 
you'll have to break up the solid fairly quickly and store it 
in a jar with a tight lid to  protect it from moisture until 
you are ready for the demonstration. This dry salt will 
happily absorb water from the air (or your hands - wear gloves) 
until it is  once again the original Epsom salts, MgSO4:7H2O. 

Do not use your Mom's good cookware for this project. The
pan must be free of holes, because the salt is going to melt
before it dries. Let a parent help you with the project, 
because they are going to be really mad if you spill hot, 
molten Epsom salts in the oven or worse, burn yourself.

Jerry








DOC0254

Subject:      Re: CO2 in coke
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/19
Message-ID:   <4galfm$b7o@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <wpenrose.265.001C22AF@interaccess.com>, wpenrose@interaccess.com (William R. Penrose) says:

>
>When you add ice, some CO2 bubbles are nucleated by irregularities on the ice 
>surface.  (If you really want to demonstrate this, add a spoon of sugar or 
>salt to a glass of coke sometime.)  Molecule-sized bubbles add more surface 
>area, so CO2 passes into them and they grow at a rapid rate.
>
Bill, I think on further consideration you might decide that
"Molecule-sized" bubbles would not help much as nucleation sites,
at least in the case of Coke fizz. Larger bubblets are more likely
to get the job done.

Jerry (Ico)
<



















DOC0255

Subject:      Re: Science Fair Cold Pack Salts
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/19
Message-ID:   <4ganbv$b7o@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4g8d64$bcc@ixnews4.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>

>The change in free energy of a system equals the change in enthalpy 
>(sensible heat) minus the change in (absolute temperature times entropy 
>(disorder)).  Ammonium nitrate marvelously disorders the equilibrium 
>structure of water.  The energy for randomizing the water molecules from 
>their lowest energy interactions comes from the average molecular kinetic 
>energy of the system - the temperature drops.  Energy is also absorbed by 
>the crystal forces in solid ammonium nitrate being broken as it goes into 
>solution.
>
Help me out here, Al. I thought the disruption of the crystal would
be the dominating energy effect here - not the "randomizing" of the
water. I guess my question is why an AN solution would be considered
any more "random" than than any other salt solution.

>Urea dissolved in water drops the temperature exceedingly well, too.
>
>>3) Why doesn't table salt make the water get colder? 
>
>It doesn't disorder the structure of water.
>
Same question again. By what yardstick do we measure this lesser
"disorder" other than by the circular reasoning that q/T is
measurably less than in the case of AN?

Being an old-fashioned guy (belated 19th century chemist), I have 
a lot of trouble dealing with the modern chemical paradigm. Your 
help will be appreciated. 

Al, your answer on this topic was directed to a seventh grade
student who would be what, 12 years old? Don't you think maybe
the reasoning was a little bit on the esoteric side for that
age group?  I hope you will be gentler with me if you decide 
to answer my query. You know I'm not so smart as I used to be
before QM and GR taught us humility.

Jerry (Ico)

















DOC0256

Subject:      Re: Explosives -- academic research and career choices
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/21
Message-ID:   <4gdvrg$n13@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <NEWTNews.824865844.31647.crobc@epix.net>, crobc@epix.net says:
>
>
>
>1.  Are there academic (graduate) laboratories that conduct 
>legitimate and safety-oriented research in explosives, such that if 
>one were interested, they could do their M.S. or Ph.D. on this topic 
>?
>Try New Mexico Tech's Energetic Materials Research and Testing
Center at <A HREF="http://www.emrtc.nmt.edu/">http://www.emrtc.nmt.edu/</A>.  Mel Cook used to head up
explosives research at the U.of Utah, so you might check there,
too. Unfortunately their web site isn't worth visiting.

>2.  Are the accident statistics for explosives researchers or 
>industrial explosives chemists much worse than those for chemists in 
>general ?
>
It depends. Most of the large manufacturers have very good safety
records. However, I have too many very dead ex-acquaintances and
ex-coworkers in the field.

>3.  Because I can imagine that it is possible to *really* counter 
>most of the hazards associated with this type of work by the use of 
>heavy sheilds and remote actuating equiptment (expensive, of 
>course), I wonder if these levels of precautions are actually used 
>or do people just put there hands right on their reaction vessels 
>and stir away.
>
It depends on what you are working with. I've blended a lot of
high explosives in a kitchen mixer on a lab bench and manufactured
class A explosives using ribbon mixers we rebuilt from food-processing
equipment. On the other hand, for nitroglycerin we bought a very
sophisticated Biazzi setup built over a swimming pool to dump the
reaction mixture into if it got too hot. The plant had escape slides 
for the monitors and looked like a layman's concept of a modern
stainless steel lab.

Frequently, manufacturing facilities are barricaded, but often as not
they are not. Lab blast shields are used extensively. One advantage
in working with explosives is that you KNOW they are explosive.
The nice thing about a simple shield is that you only lose a hand :)

Jerry













DOC0257

Subject:      Re: [Q] Best way to keep fizz in drinks
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/22
Message-ID:   <4gih9e$qp3@geraldo.cc.utexas.edu>
Newsgroups:   sci.physics,sci.chem



In article <312c5c44.167246@news.dial.pipex.com>, mreeves@dial.pipex.com (Malcolm Reeves) says:
>
>Hi,
>
>Does anyone know the best way to keep the fizz in drinks, coke/pepsi,
>lemonade etc.  A program on the TV the other day stated that in was
>best to compress the bottle to leave as little air space as possible
>and then to screw on the cap.

[snip]

> But if you compress the bottle
>won't it just expand, end result no gain?  Anyone care to answer this
>question ?
>

The program was right. Sure the bottle will gradually expand, but
all during that expansion the net rate of CO2 loss to the gas space
will be proportional to the difference between the activities of the
dissolved CO2 and the free CO2.  The instantaneous chemical activity 
of the dissolved material is independent of what's going on in the 
gas phase, but the activity of the gaseous CO2 is proportional to 
its concentration (pressure).

THe CO2 concentration in the hullage space may initially be as
low as near zero if it gets well ventilated when you take a swig.
If you squeeze that air out, the partial pressure of the CO2 will
rapidly rise to one atmosphere and an activity of unity when you screw 
the cap back on.  If you leave a large hullage space after imbibing,
that space may again be nearly pure air, in which case the liquid
will have to give up enough CO2 to create 2 atmoshpheres total 
pressure in the now relatively large hullage before the activity 
(partial pressure) of the CO2 reaches unity (one atmosphere).

The rate of loss of CO2 from the liquid in the squeezed bottle will 
be less than that in the unsqueezed bottle until such time as the 
partial pressures of CO2 in the two containers are equal. 

These approximations neglect the slight reduction in absolute
pressure greated by the elasticity of the bottle.

From a practical standpoint, the other two measures which help
keep the fizz in the Coke are:  1) to to cool the beverage to the
lowest possible non-freezing temperature before opening it and 2)
to agitate the liquid as little as possible before opening it.

It also helps if, before popping the lid, you slowly rotate the 
container end over end a couple of times, without sloshing, 
to allow the escape from the liquid of any entrained nucleating
bubblets which may have formed when your mate tossed the bottle to 
you:)

Jerry (Ico)



DOC0258

Subject:      Re: Does Heat Speed Up or Slow Down a Chem
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/23
Message-ID:   <4glh2j$83q@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4gk4p4$8b8@mserv1.dl.ac.uk>, ijb@mserv1.dl.ac.uk (I.J. Bush) says:
>
>
>Heating up a system will always increase the speed at which equilibrium
>is reached. Why ? 

Can you not think of a scenario or three in which equilibrium 
is attained more slowly at higher temperatures? Consider
heterogeneous systems in which phases play a role in determining 
reaction rate. 

Jerry (Ico)






















DOC0259

Subject:      Re: Minority Postdoctoral Fellowship Opportunity
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/23
Message-ID:   <4gj7co$g3f@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem.organomet,sci.chem



In article <4gg8ob$2mb@mailhost.zeneca.co.uk>, Geoffrey Cooper <geoffrey.cooper@uawrc.zeneca.com> says:
>
>Dear Rob,
>     If you waste your time responding to "Uncle" Al's blatherings, 
>remember the saying "I refuse to have a battle of wits with an unarmed 
>man".  Al is a flaming moron, apparently with endless time on his hands.
>     I would like to see this group become moderated to restrict it to 
>chemistry issues.  This would keep the "Uncle" Als to a minimum.
>
Well, Geoffrey, if they ever do decide to make this a moderated group,
how do you know that Uncle Al will let you post?

The following list is of short quotes abstracted from your other 
four postings to the sci.chem group this month:

	The comments about slimeball behavior should rightly 
	be addressed to Mr. Lloyd Parker this time.  Tom's 
	slimeball behavior was addressed in my earlier post.  
	Birds of a feather!  Maybe you all would like to move 
	out of America,

	One wonders if you have a life, or if you spend your 
	time in the sort of mental masturbation that seems to 
	characterize your all-too-abundant postings.


	Maybe you're John Doe #2 from OK city!  It sure seems 
	to fit	Irrational hatred of the bogeyman government, 
	affinity for terrorism when it fits your bill, apparent 
	association with cult groups.

	Yes, please!  Let's hear some organic chem instead of 
	the political nuts ranting and raving.

It appears that Uncle Al is just one of a number of people whom 
you don't like very much. Do you also do chemistry or only ad 
hominem social, psychological and political commentary?

Jerry (Ico)

















DOC0260

Subject:      Re: Minority Postdoctoral Fellowship Opportunity
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/23
Message-ID:   <4gk498$3gu@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem.organomet,sci.chem



In article <312D3D92.4A29@ix.netcom.com>, Geoff Cooper <gcooper1@ix.netcom.com> says:
>
>Gerald, You're right. 
  
Yes, I am.

[Irrelevant personal opinions of Uncle Al's political opinions
snipped]

>But what matter that to someone like you who already has all the 
>answers?

I'm disappointed. That teensy bit of temper barely deserves
the following update of quotable ad hominem quotes. Oh well,
at least you are seven for six in posts containing SOME ad hominem
remarks unadulterated by any chemistry. Here they are in poor
chronological order:
	
	Tom's slimeball behavior was addressed in my earlier post.  
        Birds of a feather!  Maybe you all would like to move 
        out of America,	[Indirect reference]

	The comments about slimeball behavior should rightly
        be addressed to Mr. Lloyd Parker this time.  

        One wonders if you have a life, or if you spend your 
        time in the sort of mental masturbation that seems to 
        characterize your all-too-abundant postings.

        Maybe you're John Doe #2 from OK city!  It sure seems 
        to fit  Irrational hatred of the bogeyman government, 
        affinity for terrorism when it fits your bill, apparent 
        association with cult groups.

        Yes, please!  Let's hear some organic chem instead of 
        the political nuts ranting and raving.

	Al is a flaming moron, apparently with endless time on 
	his hands.

	But what matter that to someone like you who already has 
	all the answers?

We know it is tough being a college student or tyro working
scientist and not having the time to play with the big boys, 
but in two or three decades, who knows? Maybe you'll be a second 
Uncle Al and a master of sarcasm as well.

By the way, your comment that "unreliable science is useless 
science." needs a little rethinking. That is a layman's 
concept of perfectly structured "science" which is built on
such a firm foundation that its paradigms lead unerringly
upwards. It is precisely the "unreliable" areas of science
that are most exciting and it is in the closer examination
of the things that seem to bend the rules that we will find
the next theory or invention. "Reliable science" is what we
better call "engineering."

Jerry 

Troll, troll, troll your gloat slyly down the scheme, Verily,
verily, warily, warily, things aren't what they seem.- Ico
<















DOC0261

Subject:      Re: Copper/Cupric Oxide Question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/24
Message-ID:   <4go28c$qv0@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4gm3cp$dp7@cobain.rowan.edu>, kilroy@copland.rowan.edu (Dr Nancy's Sweetie) says:
>
>"Bright copper kettles".  Shouldn't these also form
>a layer of cupric oxide, and shouldn't that also be toxic?  It seems odd
>to make food preparation containers out of a material which supposedly
>forms toxins.  It seems extra-odd that people don't get sick after eating
>food cooked in such pots.
>
I should have added in my prior response that a little copper can
sometimes be beneficial in cooking.

Lined copper (tin) is the preferred cookware of great chefs unless 
they can afford silver. These metals have high thermal conductance
which assures uniform heating across the cooking surface. There are 
cases where untreated copper is used in food preparation. Egg whites 
beaten in a copper bowl, for instance, produce a superior meringue.

Jerry (Ico)
















DOC0262

Subject:      Re: Copper/Cupric Oxide Question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/24
Message-ID:   <4go1m9$qv0@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4gm3cp$dp7@cobain.rowan.edu>, kilroy@copland.rowan.edu (Dr Nancy's Sweetie) says:
>
>But today, my wife happened to be singing "My Favorite Things" from
>`The Sound of Music'.  In particular, the first stanza got my attention,
>because it mentions "Bright copper kettles".  Shouldn't these also form
>a layer of cupric oxide, and shouldn't that also be toxic?  It seems odd
>to make food preparation containers out of a material which supposedly
>forms toxins.  It seems extra-odd that people don't get sick after eating
>food cooked in such pots.
>


DOC0263

Subject:      Re: Does Heat Speed Up or Slow Down a Chem
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/24
Message-ID:   <4gmeon$t6i@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4gldu2$cot@lll-winken.llnl.gov>, shaw@s119.es.llnl.gov (Henry Shaw 510 423-4645) says:
>
>In article 6jn@reader2.ix.netcom.com, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> () writes:
>> Heat may speed up a reaction, slow it down, or have no effect upon it at 
>> all.  It depends upon the thermodynamics of the reaction.
>
>
> The equilibrium state may change as a function of temperature, but
>heat will *always* speed up the rate of a fundamental reaction.
>
What is a "fundamental" reaction? If an overall reaction slows
with increasing temperature does that automatically qualify it
as "non-fundamental"?

>>
>> In general, hotter means faster, doubling reaction rates near room temp 
>> for every 10 celsius rise in temperature.
>
>
>You can't make a general statement like this. 

The heck you can't. Competent chemists have been using this
approximation as a first estimate for thought experiments
for a long time. The fact that the statement doesn't 
qualify as a fundamental law does not mean that it has 
no utility - especially for explaining the typical behaviour 
of simple homogeneous reactions and a lot of heterogeneous
phenomena.

Jerry (Ico)




DOC0264

Subject:      Re: [Q] Boiling water at low pressure
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/24
Message-ID:   <4gmf2g$t6i@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <312E9040.7E3B@indiana.edu>, "John C. Huffman" <huffman@indiana.edu> says:
>
>The answer is in your cookbook.  When cooking at high elevations, most
>often there are instructions to add salt--this is NOT for flavor, but to
>raise the boiling point. It is indeed the temperature that cooks the egg.
>Calculate the boiling point at 29,000 ft and then figure how much salt 
>would be necessary to raise the temperature accordingly.
>-- 
Yuck. Who would add 50 grams of salt to a liter of water to 
raise the BP by half a degree C?? It would be easier to lug 
a pressure cooker to the top of Mt Everest than enough salt
to do much cooking.

Jerry (Ico)




















DOC0265

Subject:      Re: [Q] Boiling water at low pressure
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/24
Message-ID:   <4go7te$23c@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4go647$qv0@geraldo.cc.utexas.edu>, glhurst@onr.com (Gerald L. Hurst) says:

>
>Notwithstanding the rhetoric, the practical use of salt to raise
>the boiling temperature of water for cooking purposes at 29,000
>feet is a joke. Saturated NaCl is about 6.5 molar so the increase
>in boiling point would be about 3 deg C. At the top of Mt Everest

Pardon me, I forgot to count my ions. The maximum increase in
boiling temperature should be roughly 7 degrees, not 3 degrees
for saturated salt water - raising the boiling point on Everest 
to the high 70's. Still can't brew a decent cup of tea at that
altitude even if you don't mind a little salt :)

Jerry (Ico)



















DOC0266

Subject:      Re: [Q] Boiling water at low pressure
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/24
Message-ID:   <4go647$qv0@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <312F19EE.3377@indiana.edu>, "John C. Huffman" <huffman@indiana.edu> says:
>
>Gerald L. Hurst wrote:
>> 
>> In article <312E9040.7E3B@indiana.edu>, "John C. Huffman" <huffman@indiana.edu> says:
>> >
>> >The answer is in your cookbook.  When cooking at high elevations, most[snip]
>> >--
>> Yuck. Who would add 50 grams of salt to a liter of water to
>> raise the BP by half a degree C?? It would be easier to lug
>> a pressure cooker to the top of Mt Everest than enough salt
>> to do much cooking.
>> 
>> Jerry (Ico)
>
>How fast does salt diffuse through an egg-shell?  Shucks, I always salt
>my hard boiled eggs anyhow.  And don't forget, the question was " asked 
>us if it was possible to hard-boil an egg on top of Mt. Everst"  He 
>didn't say anything about eathing it :-)  You go ahead and carry your 
>pressure cooker.

Notwithstanding the rhetoric, the practical use of salt to raise
the boiling temperature of water for cooking purposes at 29,000
feet is a joke. Saturated NaCl is about 6.5 molar so the increase
in boiling point would be about 3 deg C. At the top of Mt Everest
the boiling point of water would be around 70 deg C so those 
three degrees would hardly do the trick, would they?

So instead, you decide to use a more soluble salt and finally
succeed in raising the temperature of your fused mixture to
100 degrees. Ooops, the egg cracked and exploded because of
the differential pressure across that salt-proof shell (about
10 psi at 29,000 ft) and you, Dr. H, wound up with egg on your
face :)

Jerry (Ico)




















DOC0267

Subject:      Re: Does Heat Speed Up or Slow Down a Chem
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/25
Message-ID:   <4goq52$ch1@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4gok49$9le@pulp.ucs.ualberta.ca>, ssia@pop.srv.ualberta.ca (Sam Sia) says:
>
>In article <4glh2j$83q@geraldo.cc.utexas.edu>, glhurst@onr.com says...
>>
>>In article <4gk4p4$8b8@mserv1.dl.ac.uk>, ijb@mserv1.dl.ac.uk (I.J. Bush) 
>says:
>>>
>>>
>>>Heating up a system will always increase the speed at which equilibrium
>>>is reached. Why ? 
>>
>>Can you not think of a scenario or three in which equilibrium 
>>is attained more slowly at higher temperatures? Consider
>>heterogeneous systems in which phases play a role in determining 
>>reaction rate. 
>>
>>Jerry (Ico)
>
>So are you saying the Arrhenius equation is false?
>
Not unless I'm speaking sotto voce and and am going deaf.

Take the hypothetical reaction:

FP + O2 + xH20 --(NaCl)-> Fe2O3:xH2O 

This reaction can be observed to accelerate greatly as a result
of a temperature drop of only 20-30 deg C.  The increase in rate
as measured by the amount of Fe2O3 produced per year apparently
arises from phase changes taking place in one of the reactants,
and that phase change more than offsets any accompanying modest
drop in temperature.

Actually it is not just Ford pickups that rust more quickly
in the cold high RH environment of the northeastern US. Out
in the southwestern states where the absolute humidity may be 
just as high or higher and salt and alkali are often abundant,
those same vehicles may be virtually rust free.

The point is that the Arrhenius equations describing a reaction
may have to be rewritten if one of the reactants acts as more
than merely a species which can be fully characterized by a 
concentration figure.  Of course, if you have an unlimited
supply of Arrhenius equation parameters at hand, you can 
calculate most anything to within the limits of (delta t)(delta E).

Some reaction rates may seem to depend on the mood of the Maxwell 
demon who is opening and shutting the little door between the 
reactants.  Under such circumstances I recommend the use of
Ico's famous fudge factors for the normalization of intractable
yellow gunk.

BTW, for the sake of consistency the term "rate" as used herein
refers the the instantaneous value of dPR/dt where t is time
and PR is the magnitude of the pile of rust.

Jerry (Ico)





















DOC0268

Subject:      Re: [Q] Boiling water at low pressure
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/25
Message-ID:   <4gor2j$fm5@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4gomti$cg4@news.aladdin.co.uk>, tonywilk@aladdin.co.uk (tonywilk) says:
>
>"Michael R. Jones" <mrjones@niia.net> wrote:
>
>*snip*
>>...hard-boil an egg on top of Mt. Everst [el. 29 029 ft].
>*snip*
>
>Hmm... seems like a chance to look at it sideways....
>
>The question doesn't _specifically_ state you have to boil it
>in water does it? 
>Why not just boil it in something who's boiling point will be
>around 100C at that altitude ?
>
>Preferably something non-toxic :-)
>
>Would Glycerine (or a mix with water) do the trick ?

It would if you don't mind a face full of hot glycerine
when the occassional egg blows up. With a little bit of
luck you may avoid this if the shell is undamaged, thanks
to the good structural engineering of the shell. But don't
bet on it. I understand they used to boil a lot of rotten
eggs in oil.

Jerry
<






DOC0269

Subject:      Re: Does Heat Speed Up or Slow Down a Chem
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/26
Message-ID:   <4gt4od$eis@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
  
  
Now let's assume that A is a catalyst for reaction 2 and C is
a catalyst for reaction 3. Also assume that the equilibrium in 
reaction 1 is strongly influenced by temperature.

If you have a mixture of A,B,D and F, can you unequivocally say
that both reactions 2 and 3 will accelerate with temperature?

Jerry (Ico)



DOC0270

Subject:      Re: Does Heat Speed Up or Slow Down a Chem
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/26
Message-ID:   <4gt4od$eis@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



  Article Segment 1 of 2
  
In article <4gsk22$nvl@larry.cc.emory.edu>, lparker@larry.cc.emory.edu (Lloyd R. Parker) says:
>
>: Take the hypothetical reaction:
>
>: FP + O2 + xH20 --(NaCl)-> Fe2O3:xH2O 
>
>: This reaction can be observed to accelerate greatly as a result
>: of a temperature drop of only 20-30 deg C.  The increase in rate
>: as measured by the amount of Fe2O3 produced per year apparently
>: arises from phase changes taking place in one of the reactants,
>: and that phase change more than offsets any accompanying modest
>: drop in temperature.
>
>Huh?  Could it be that salt is only used when it is cold?  Sorry, this is 
>NOT an example of lower temperatures causing a faster reaction.  If you 
>place the same truck with the same amount of water and salt at high 
>temperatures, and keep the salt in contact with the metal just as long, 
>the rusting will go faster.  (Frozen salty slush stays in contact with 
>the metal longer than salt water.)
>
>: Actually it is not just Ford pickups that rust more quickly
>: in the cold high RH environment of the northeastern US. Out
>: in the southwestern states where the absolute humidity may be 
>: just as high or higher and salt and alkali are often abundant,
>: those same vehicles may be virtually rust free.
>
>Keep the salt and water in contact with the metal as long and compare.  
>And I've seem rusty cars in coastal areas quite a lot.
>
>If you were being facetious, I apologize, but it seems you're serious.

I an quite serious. Of course they add salt (CaCl2) to roads
in some areas, but that has nothing to do with this discussion.
Hold the ambient salt and absolute humidity constant but lower
the temperature, and in certain instances the rate of rusting
will increase, not decrease.

What reason is there to doubt this statement other than mere
adherence to the dogma that "all reactions increase in velocity 
with temperature." Is it not generally true that various corrosion 
and other degradation reactions occur more slowly in Egypt than in 
Ireland, and is it not true that this difference is at least partly
attributable to the difference in relative humidity? RH is an 
inverse function of temperature at constant AH (absolute humidity, 
water vapor concentration) is it not? Does it not therefore follow 
that we should expect some reactions to increase in rate if a fall 
in temperature produces higher RH.

Imagine that you work in an un-air-conditioned labortory in, say, 
Dallas and one of your jobs is to grind samples of ammonium nitrate 
into a fine powder. All of the surfaces in that lab become coated
with a fine lawer of AN dust, but the metallic surfaces remain
bright an shiny all day long. When you return to the lab the 
following morning the metalwork is uniformally covered with a
patina of orange rust. You polish all the metal back to its 
original sheen and once again it stays bright all day. Next morning
it's all rust again.

Remember, this is Dallas, not Hell - although some might argue
about the distinction in summer.

Your problem is simple. The humidity (AH) is pretty much constant
but the RH is cycling a little above and a little below about
60% - above during the day and below during the night. Ammonium
nitrate has the inconvenient property of being deliquescent
below about 60% RH and so each night the salt liquifies and
acts as a corrosion accelerator. The next morning it recrystallizes
as the temperature rises and the rusting slows to a crawl.

I chose a reaction in which one can actually see the surface change
which affects the reaction rate in the opposite direction from that
expected for the temperature change. However any heterogeneous
reaction may involve surface phenomena which are not visible, but
which have a profound effect on overall reaction kinetics.

Let's look at a generalized reaction scheme - this time without 
regard to whether the reaction mixture is homogeneous or 
heterogeneous:

1)  A + B<--->C  k = f(T)

2)  D-->E

3)  F-->G














DOC0271

Subject:      Re: Does Heat Speed Up or Slow Down a Chem
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/27
Message-ID:   <4gu3tk$bea@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4gtft4$e58@lll-winken.llnl.gov>, shaw@s119.es.llnl.gov (Henry Shaw 510 423-4645) says:
>
>> >In article 6jn@reader2.ix.netcom.com, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> () writes:
>> >> Heat may speed up a reaction, slow it down, or have no effect upon it at 
>> >> all.  It depends upon the thermodynamics of the reaction.

>> >> In general, hotter means faster, doubling reaction rates near room temp 
>> >> for every 10 celsius rise in temperature.

>You can't make a general statement like this. 

[My disagreement snipped]

>I didn't say it had no utility, but unless the person using this
>rule of thumb is also aware of its limitations, it could lead someone
>astray.  For instance take these two simple bimolecular gas reactions:
>
Pardon the snipping of the previous messages to the original and your
last. I am merely making the point, in the first quoted paragraph, that 
the original poster (Uncle Al) qualified his use of the "reaction rate 
doubles (or triples) for every 10 degrees" phrase adequately.

No chemist is going to seriously try to tell anyone that all
reactions follow this rule any more than one would suggest
that arthritis is a good weather indicator.  My prior arguments
were devoted to the idea that increasing temperature may even
decrease the rate of an overall reaction so I hardly need to be 
told that the rule of thumb is not a substitute for the science 
of chemical kinetics.

I think we can all rest assured that Al knew the limitations
of the rule at the time he published it and that he chose not
to elaborate beyond saying, in effect, that it might not work
at all or might even work backwards. 

The only disagreement you ran into was my statement that one may
indeed quote the old saw if one wishes to and that a very great
number of outstanding chemists have done so with as much or as
little qualification as they thought appropriate under the
circumstances.

Jerry (Ico)














DOC0272

Subject:      Re: Does Heat Speed Up or Slow Down a Chem
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/28
Message-ID:   <4h0fan$mv0@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4gv5um$dde@curly.cc.emory.edu>, lparker@curly.cc.emory.edu (Lloyd R. Parker) says:
>
>Sorry, but you're varying the amount of a reactant, or at least a 
>catalyst.  That's what affects the rate of your reaction.  Keep RH 
>constant and let the temperature vary and see what happens.

You should be sorry. If you keep the RH steady and vary the 
temperature then it is YOU who is varying the amount of one
of the reactants.  It is the AH not the RH which must be held
constant if you wish to maintain a constant amount of water.
More accurately, we should let the total water present remain 
constant at the expense of a microscopic drop the AH, But you 
know how difficult it is for me to split hairs.
 
>: Let's look at a generalized reaction scheme - this time without 
>: regard to whether the reaction mixture is homogeneous or 
>: heterogeneous:
>
>: 1)  A + B<--->C  k = f(T)
>
>: 2)  D-->E
>
>: 3)  F-->G
>
>: Now let's assume that A is a catalyst for reaction 2 and C is
>: a catalyst for reaction 3. Also assume that the equilibrium in 
>: reaction 1 is strongly influenced by temperature.
>
>But (1) is a fast step and builds up a constant amount of C.  As soon as 
>some is used by (3), the equilibrium in (1) shifts to make more.

If you like, (1) can be a fast step, but since C is a catalyst,
it does not get used up. Furthermore, we have already stipulated
that the equilibrium constant for (1) does indeed vary sharply
with temperature, so under the variable conditions we are are
interested in here, C is most definitely not constant, but
also not "used up."
>
>: If you have a mixture of A,B,D and F, can you unequivocally say
>: that both reactions 2 and 3 will accelerate with temperature?
>
>Unless you can prove by an actual example that the Arrhenius equation 
>fails, yes.  A higher temperature leads to more energetic collisions, so 
>more collisions have sufficient energy to overcome the activation energy 
>barrier.
>
The Arrhenius equation has absolutely nothing to do with this
thought experiment and it does not have to be held "incorrect"
to to make the premise true that:

	Either reaction 2 or reaction 3 MAY (or may not) slow  down 
	with increasing temperatures as measured by the decrease in 
	the rate of production of either E or G respectively or by 
	the decrease in rate of loss of either D or F respectively. 

It is not always necessary to break a law to get an unexpected
result. We are not here trying even for a loophole, but merely
pointing out that the fact of raising a closed system's reaction
temperature is not a guarantee that a given specified net reaction 
will proceed more rapidly.

Some may prefer to shrug and say that "this doesn't count" because 
some "fundamental" reaction behind the scenes is always obeying
Arrhenius' law, but that does not alter the fact of our observation
of the end result, which outside of academe, may sometimes be
equivalent to "the bottom line."
	
One little added thought: If B in (1) is nothing, then A = C,
but they are the same species in the same total amount, differing
only in phase. Phase transitions are notoriously temperature
dependent as is exemplified by water in the 99 - 101 deg C range.
Other phase changes may be just a sharp, but less obvious. Thus 
the admonition to be especially wary of the kinetics of any reaction 
involving such sometimes subtle transitions. 

>: Jerry (Ico)


DOC0273

Subject:      Re: How to melt magnesium ?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/28
Message-ID:   <4h0qi7$aqb@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.engr.chem,sci.engr.metallurgy,rec.crafts.metalworking



In article <4gul4a$egr@news.knoware.nl>, Klaas van Ditzhuyzen <klaas@uniface.nl> says:
>
>I want to try melting magnesium.
>I don't have exotic equipment like a vacuum furnace or a professional
>lab, but just a simple workshop with a propane torch.
>But an attempt to melt Mg on the air will ignite it.
>So I thought about melting under a salt-bath. Then the salt mixture
>should have a low s.g. (less than liquid Mg == 1.6) and a melting
>point under 600 deg C. An NaCl / KCl mixture is too heavy and the
>Mg will float on it.
>Does somebody know such salts (or other ideas to melt Mg in an
>ordinary garage) ?
>
No problem. Put the magnesium in a suitable crucible, turn the 
crucible upside down in second, larger crucible containing the salt 
of your choice and then melt the latter. The  magnesium, when
it melts by contact with the hot liquid salt, will float happily on 
that denser, molten material, fully protected from the air.

If the salt won't float on magnesium, then magnesium will float on
the salt.


Jerry (Ico)










DOC0274

Subject:      Re: What is the temprature at which paper burns?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/29
Message-ID:   <4h2rmn$ioo@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.engr.chem



In article <3133F803.41C6@iil.intel.com>, "Opher D. Kahn" <okahn@iil.intel.com> says:
>
>If you know, please tell!
>
Ignition temperatures in general are hard to pin down and are
usually expressed as a relatively broad range. Paper, wood and
the like are particularly difficult to quantify because the
ignition temperature often depends greatly on their history
as well as on their specific composition. 

If a piece of wood is left in contact with a lightbulb for
a period of weeks or months, it may eventually become so
active that it bursts into flame when the surface that was
adjacent to the bulb comes into contact with air. 

In the old days, when chemistry was more of a hands-on science,
many students learned about pyrophoric versions of materials
which are normally considered stable with respect to combustion
or at least spontaneous combustion. I am here referring to
such materials as iron and lead.

Even the simplest of substances, such as hydrogen gas, may 
exhibit unpredictable behaviour with respect to ignition
temperatures depending on its environment and the recent 
history of that environment insofar as invisible sometime
transitory surface effects may be present.

Jerry (Ico)






DOC0275

Subject:      Re: liquid heavier than water?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/02/29
Message-ID:   <4h356a$vl@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4h2kb8$n7a@ixnews2.ix.netcom.com>, oldetyme@ix.netcom.com(BILL CARMICHAEL ) says:
>
>I am looking for a non-flammable liquid that is or could be dyed blue
>that is heavier than water.It cannot mix with the water as the water
>must float on top of it. We are wanting to use it in water globes for a
>two tone effect. Any ideas?

One of the phthalate esters might do the trick. Dibutyl phthalate
is a little denser than water, has low toxicity and should take
a number of dyes nicely. The other lower phthalate esters are
even denser but perhaps not quite as benign or as readily
available.  Possibly even a short-chain fatty acid might work,
but I think I'd go with the phthalates.

Jerry (Ico)



















DOC0276

Subject:      Re: non exothermic
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/01
Message-ID:   <4h5jjr$gvs@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <9602291926.0RAUI00@cornucopia.digital.net>, cathy.hettinger@cornucopia.digital.net says:
>
>
>I realize I am being awful simplistic here.  But, I realize you are generally
>talking about endothermic reactions. 

Could you tell us what posts you are responding to?

Jerry (Ico)



DOC0277

Subject:      Re: How to melt magnesium ?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/02
Message-ID:   <4h97pu$b0i@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.engr.chem,sci.engr.metallurgy,rec.crafts.metalworking



In article <1996Mar1.144251.21352@roper.uwyo.edu>, jimkirk@uwyo.edu (James Kirkpatrick) says:
>
>In article <31358ed8.213163@news.northernnet.com>, dwilkins@northernnet.com (Don Wilkins) writes:
>|>... The magnesium is indeed oxidized when it reacts with
>|>nitrogen.
>
>Please explain the reaction.  If you have elemental magnesium, and
>elemental nitrogen, how on earth can you get an oxidation reaction
>without oxygen!!??
>
3Mg + N2 --> Mg3N2

Not so stable as MgO, but holds together up to 800K.

Jerry (Ico)



















DOC0278

Subject:      Re: [Q] Boiling water at low pressure
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/02
Message-ID:   <4haiia$1nl@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4hagkf$hou@news.aladdin.co.uk>, tonywilk@aladdin.co.uk (tonywilk) says:
>
>"Michael R. Jones" <mrjones@niia.net> wrote:
>
>>   As the origional poster, I would like to thank all of you for helping 
>>me.  My mail server is ill, so if you mailed me and I haven't responded, 
>>my mail server is messed-up.  
>*snip*
>>     ...     if a pressure cooker can't be found, that one use a 
>>different substance to boil.  I will suggest mercury or oil.
>*snip*
>
>Practically I wouldn't suggest mercury for 3 reasons:
>
>        1. it would be _very_ heavy to carry
>        2. it is toxic
>        3. It would be almost impossible to force an egg under
>           the surface of a container full of mercury without
>           breaking the egg.
>           Because of the density of Hg is so high, even
>           metal coins will float on the surface.
>
>I would stick to using a light oil (e.g. cooking oil)
>
What measures will you take to prevent the egg from exploding
if you heat it in oil above the ambient boiling temperature
of water at the top of the mountain?  I am wondering if you and 
the original poster, having read all the postings on this topic,
have learned or know something that I missed. 

Jerry (Ico)



DOC0279

Subject:      Re: What is Baume?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/03
Message-ID:   <4hbdab$oqo@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4hb7s0$taq@news.netam.net>, pletcgm@netam.net (G. Michael Pletcher) says:
>
>I have muratic acid that contains 20% HCL and 32% Baume. What is
>Baume?
>
Degrees Baume is a measure of specific gravity originally based
on assigning 10% NaCl solution a value of 10.

In the USA the relationship at 60/60 degF is usually expressed:

sp.gr. = 145/(145-Baume)

In the present case there is something wrong because 20% HCl is
nowhere near 32 Baume. What you probably have is 32% HCl, which
corresponds to about 20 degrees Baume.

Be aware that there are a bunch of other methods for reaching 
values for Baume so your milage may vary a little in Washington
DC, Amsterdam and Germany.

Jerry (Ico)













DOC0280

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/07
Message-ID:   <4hnine$nab@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.energy,sci.mech.fluids,sci.materials,sci.physics



In article <JMC.96Mar7075624@Steam.stanford.edu>, jmc@Steam.stanford.edu (John McCarthy) says:
>
>Let me return to the topic of the thread - energy of atoms in
>molecules.
>
>I'm not entirely sure of this, so I hope someone will correctly if I
>am mistaken.
>
>Molecules have ground states and can absorb energy to go into excited
>states.  However, until a temperature considerably higher than room
>temperature is reached, molecules are almost all in the ground state.
>Hence the internal energy of molecules does not contribute to the
>specific heat of the substance below relatively high temperatures.
>
>Someone should tell us how high.
>-- 
If you track the heat capacity of a simple gas such as hydrogen
as a function of temperature from well below room temperature
up to say a theoretically extrapolated temperature of say 6,000 deg,
you will find that there is a continuousincrease in the value.

In my simple way, I assume that the major low-temperature contributions
to the value are first from rotational states as is consistent with
the relatively low frequency of infrared rotational spectra. More 
complex molecules show much higher heat capacities than simple diatomic 
molecules below room temperature, so at least a number their more 
numerous degrees of freedom must be active. For instance, C(v) for 
ethanol is nearly 5 times greater than for a monatomic gas at room T.

Presumably, the larger molecules have an easier time of it in reaching
numerous vibrational states because they do not necessarily require
intermolecular collisions to enable a new mode.

Anyhoo, it does appear that internal modes of one sort or another are
significantly active at normal temperatures albeit nowhere near as
active as at higher temps.

One incidental point is that at high pressure or low temperature
one may sometimes see increases in heat capacity on cooling, even
in the case of hydrogen or inert gases. At the other extreme, even
monatomic gasses may show increases in C(v) as a result, I assume,
of ionization.

Jerry (Ico)












DOC0281

Subject:      Re: How did he die?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/09
Message-ID:   <4hssjg$fnc@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4hsbct$ove@dfw-ixnews2.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>
>glhurst@onr.com (Gerald L. Hurst) wrote:
>>A man is found dead and badly burned in a fire. The autopsy shows
>>that although the man was a smoker, his lungs are bright red, 
>>but there is a little soot in his mouth. The DA alleges that
>>he was murdered by someone pouring gasoline on him and igniting
>>it in the burned house. Was he killed by the fire?
>
>Carbon monoxide (or hydrogen cyanide) would fill the bill.  
>Dr. Kevorkian did it.
>
>If carboxyhemoglobin or cyanide (or its metabolite thiocyanate) are not 
>found, the man was killed while well-oxygenated - homicide.

Let's stipulate that the CO saturation of the blood was only
10 percent. If it was murder, was it the fire that killed him?
How about natural causes with a cigaret or lighted match in his 
hand?

Jerry (Jerry)













DOC0282

Subject:      Re: Mineral Spirits of Kerosene
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/09
Message-ID:   <4hssrc$fnc@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4hsb79$ove@dfw-ixnews2.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>
>glhurst@onr.com (Gerald L. Hurst) wrote:
>>You are told only that they found some material that the 
>>laboratory analyst said was "mineral spirits of kerosene"
>>at the scene.  Later various people ask you as a chemist to 
>>tell them just what it was that was found. What do you say,
>>and on what do you base your opinion?
>
>Unless you can find an industrial or literature reference to "mineral 
>spirits of kerosene" you say nothing.  Professional pronouncements ex 
>cathedra carry the weight of personal liability.  NEVER defend another 
>person's work with your opinions unless you wish to tightly grasp the 
>tar baby.
>
That's fair enough, but now let's ask if anyone amongst us chemists
has actually seen an industrial reference to "mineral spirits of
kerosene" or if it is otherwise perhaps a phrase invented by the
analyst.

Jerry (Ico)













DOC0283

Subject:      Re: supersaturation problems -- help us!!
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/11
Message-ID:   <4i2a61$rnb@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4i1vui$5o7@service2.uky.edu>, rtore00@pop.uky.edu (Rob Toreki) says:
>
>In article <ekrause-2708561437390001@mtshasta13.sisnet.ssku.k12.ca.us>
>ekrause@sisnet.ssku.k12.ca.us (Elizabeth Krause) writes:
>
>> Hi!  This is Elizabeth Krause and lab partner Mandi McDowell and we have
>> some questions.  While doing a experiment on supersaturation we followed a
>> "recipe" in a high school chemistry book.  This book said that 46.5 g of
>> Sodium Acetate would dissolve completely at 20 degrees C in 100 ml.

[Snip]
>
>The Merck Index (a sci.chem standby) says 1 g of sodium acetate
>dissolves in 0.8 ml room temperature water and 0.6 ml boiling water, so
>it appears your "recipe" may indeed be your problem.  Using these
>numbers, you aren't saturated after cooling your 83 g from 50 degrees
>unless you started with 66 ml or less of water!
>
Professor, you may not be referring to the material used by these 
young folks in their experiment. The solubilities you quoted are 
those of the trihydrate. Perhaps they are using the anhydrous material.

Jerry (Ico)











DOC0284

Subject:      Re: Help with solubilities / mixed salts
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/13
Message-ID:   <4i5ltu$l5k@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,alt.engr.explosives



  Article Segment 1 of 2
  
In article <4i2iqv$kvq@news.aladdin.co.uk>, tonywilk@aladdin.co.uk (tonywilk) says:
In article <4i2iqv$kvq@news.aladdin.co.uk>, tonywilk@aladdin.co.uk (tonywilk) says:
>
>Quick background:
>----------------
>After an experiment to convert KCl to KClO4 by electrolysis
>I recovered 36g of solid, which due to starting materials
>and concentrations I am assuming contains a mixture of:
>   KClO3
>   KClO4           (OK, it might be a BIG assumption!)
>
>Attempting to simply determine the composition of this I
>Took 30g of the solid and dissolved in 405ml water.
>
>My assumption being:
>  If the whole was KClO3 (solubility 7.4g/100ml @ 20C)
>  then 30g would all be in a saturated solution at 20C
>  in 405ml of water.
>  If it were all KClO4 (sol. 1.8g/100ml @ 20C) then
>  I would have 7.3g in solution and 22.7g solid.
>
>I decided on 20C since it's easy to stabilise at that
>temp. and the solubility curve aint so steep lower down.
>
>Warmed the solution to 22C, shook it up a lot, then left 
>it for 3 hours with occasional shaking. This actually
>kept it at 20C as the ambient was 19-ish and holding
>the flask to shake it added a degree.
>
>Filtered at the pump...dried the solid = 17.1g
>So... there's 12.9g left in 405ml of solution.
>
>
>Here's the Questions:
>--------------------
>Firstly: If I have solubility data for both KClO3 and KClO4
>can I directly calculate the proportion of these 2 salts ?
>
>If (as I suspect) not... is there a general rule which 
>allows calculation of the solubilities of 2 salts in solution?
>
>I currently can't understand how to draw up a phase diagram
>showing the mutual solubility of two salts, although in trying
>to replicate a diagram for KCl/NaCl (from Perry's) I'm led
>to believe that the Cl in common has a lot to do with the
>reduction in solubility of one salt as the other is increased.
>
>Any help gratefully accepted,
>
>Yours,
>
>   Tony Wilk
>
>P.S. If poss. please include ISBN's for any book refs - 
>     saves hours in the library - ta.
>
If the composition is made up of ONLY the two compounds you expect,
it would have to be mostly the perchlorate such that there is a
healthy excess along with enough chlorate to make up the weight
total to 12.9 g in what is something over 405 ml, lets say V.

For what they are worth we can use estimated solubility constants
to guess at the equilibrium of the saturated KClO4

[K][ClO4] = M1^2 	where M1 is the estimated molarity of pure 
			saturated KClO4 and its square is the 
			estimated value of the soly constant

[ClO4]*FW1 + [ClO3]*FW2 = 12.9*V/1000  where FW1 and FW2 are the 
					formula wts of the two
					pure potassium salts.
			

[ClO4] + [ClO3] = [K]	The positive and negative ion molarities
			must add up.

This gives you three equations in three unknowns so you can
solve for the three unknowns and, at least in theory, determine
the amounts of the two salts making up your 12.9 grams of
dissolved material.

Note that there cannot be any chlorate left in the solid because
if there were, the mix would keep dissolving past the 30 g total 
mark even if saturated with KClO4. You can check this assertion
by using:

[K][ClO3] = M2^2 (M2 = molarity of saturated pure KClO3)

along with the analogous KClO4 equation above to show that for 
a saturated solution of both salts:

[K]^2 = M1^2 + M2^2

Which allows you to plug the calculated [K] back into the two
solubility constant equations of the two pure compounds to get
the concentration of each material in a hypothetical saturated
solution, if you also remember that the positive and negative ions
again will add up.

Keep in mind that we are here working with ideal concepts and
trying to apply the common ion priciple to pretty strong
solutions. Also, the already limited accuracy is totally
dependent on your compositioon being made of what you think
it is.
















DOC0285

Subject:      Re: Help with solubilities / mixed salts
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/13
Message-ID:   <4i5ltu$l5k@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
  
  
You need to begin by converting your solubilities into 
estimated molarities. I say estimated because dissolving
x grams of a salt in 100 ml of water will give you 
100+(x-?) mililiters total solution.  Here's a hint on
density estimates for KClO3: 1.011 @ 2%, 1.024 @ 4%.
Extrapolation and estimation of similar values for
the perchlorate are plenty good enough for this rough
work.

Jerry (Ico)

DOC0286

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/13
Message-ID:   <4i66ba$1af@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.energy,sci.mech.fluids,sci.materials,sci.physics



In article <4i0409$m1k@agate.berkeley.edu>, ted@physics12.Berkeley.EDU (Emory F. Bunn) says:
>
>You seem to be claiming -- again, please correct me if I'm
>misinterpreting you -- that your definition is the one used
>historically by Gibbs, Boltzmann, and that crowd.  If that's true,
>then I'm grossly misremembering what I've read about the history of
>thermodynamics.  That's possible; I'll have to go read up on the
>subject again some time.
>
Perhaps it would help to clarify my viewpoint if I post my personal
favorite definition of temperature:

	The characteristic property of the scale which I now propose
	is that all degrees have the same value; that is, that  a unit
	of heat descending from a body A at the temperature T of this 
	scale, to a body B at the temperature (T-1), would give out
	the same mechanical effect, whatever be the number of T. This
	may justly be termed an absolute scale, since its characteristic
	is quite independent of the physical properties of of any 
	specific substance.

-William Thompson, "On the Absolute Thermometric Scale founded on 
Carnot's Theory of the Motive Power of Heat and calculated from
Regnault's observations," Phil. Mag. (3) 33, 313 (1848).

If I may add a note.

Thompson had worked with Regnault the prceding year and the latter
had just published a book. Regnault had done a lot of work on
gases including building an outstanding air thermometer.

At the time the above quote was written, Thompson also mentioned
and gave credit to Joule, who had earlier developed the now
classic and simple kinetic theory of gases based on his concept
of molecules which was not widely accepted at that time.

Despite his experience with Regnault, Thompson at this time didn't 
really believe that an "ideal gas" thermometer would track well 
with his new scale, probably because the one he built with his
assistant did not. It was 3 years later when he did an about face
and recognized the ideal gas scale as being the same as his 
thermodynamic scale.

I personally suspect that his original doubts were based on
Regnault's work. Despite the fact that R had built a decent gas
thermometer, much of his work had concentrated on showing
the variations of real gases from the idealizations of Charles 
and Boyle.  Thompson may have at first been more aware of how
bad it could get rather than how good, merely becaue of the
object of the work :)

Just as Thompson based his work on the Carnot cycle, so did
Gibb's concept of entropy spring from the same source, 
independently but at roughly  the same time. Entropy descended 
readily from the Carnot reduction:

Q1/T1 = Q2/T2 

which basically says entropy is a property of state given that 
the Carnot cycle uses Q(rev).

Although I recall the above from other sources, it appears to
comport with the understanding of Wolfgang Pauli as described in 
his noted  thermodynamics lecture in which he defines S as 
int(dQ/T) after first deriving T from the Carnot relationship.

In case some of the youngsters might not know, Thompson was
later known as "Lord Kelvin," after whom the absolute temperature
scale was named.

Jerry (Ico)







DOC0287

Subject:      Re: Dehumidifier efficiency
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/14
Message-ID:   <4i7or9$n56@geraldo.cc.utexas.edu>
Newsgroups:   sci.physics,misc.consumers.house,sci.chem



In article <Uf$GUaAW2tRxEwmP@upthorpe.demon.co.uk>, Oz <Oz@upthorpe.demon.co.uk> says:
> 
>>       But on the other hand, maybe it would work best when the air around
>>it is warm, since then it will contain more water vapor, and there would be
>>a bigger temperature differential between the coils and the air.
>>       Any opinions? 
>
>It works better when the air is warm for the reason you gave.
>
Oz, it seems to me that the absolute humidity stays about the same
in the evening so the air contains just as much water unless it
actually drops below the dew point. Since the humidifier is 
essentially a Carnot heat pump, it has to pump less heat at
the lower temperature and less work is wasted cooling air molecules,
whereas the heat of condensation itself is virtually the same.

Jerry (Ico)
<
















DOC0288

Subject:      Re: Dehumidifier efficiency
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/14
Message-ID:   <4i9uti$evs@geraldo.cc.utexas.edu>
Newsgroups:   sci.physics,misc.consumers.house,sci.chem



In article <Qu3JwMA+P9RxEwF3@upthorpe.demon.co.uk>, Oz <Oz@upthorpe.demon.co.uk> says:
>
>In article <4i7or9$n56@geraldo.cc.utexas.edu>, "Gerald L. Hurst"
><glhurst@onr.com> writes
>>In article <Uf$GUaAW2tRxEwmP@upthorpe.demon.co.uk>, Oz <Oz@upthorpe.demon.co.uk> 
>>says:
>>> 
>>>>       But on the other hand, maybe it would work best when the air around
>>>>it is warm, since then it will contain more water vapor, and there would be
>>>>a bigger temperature differential between the coils and the air.
>>>>       Any opinions? 
>>>
>>>It works better when the air is warm for the reason you gave.
>>>
>>Oz, it seems to me that the absolute humidity stays about the same
>>in the evening so the air contains just as much water unless it
>>actually drops below the dew point. Since the humidifier is 
>>essentially a Carnot heat pump, it has to pump less heat at
>>the lower temperature and less work is wasted cooling air molecules,
>>whereas the heat of condensation itself is virtually the same.
>
>Eh?
>
>Most are just a fan, a fridge unit and a water container. Since the
>airflow is relatively high all are on all the time. The cost per hour
>will be largely independant of the ambient conditions.
>
>Generally I know of only two common uses for dehumidifiers as such.
>
>1) To accelerate the drying of a room or building, usually because of
>wet processes (such as plastering) or local flooding. Here the higher
>the ambient temperature the higher the absolute humidity and the greater
>quantity of water you get out per unit time by cooling the humid air by
>delta T since the absolute humidity is nothing like linear in T.
>Sticking a couple of fires in the room helps considerably. I have tried
>it and it works. Obviously if the air is close to freezing then the
>absolute humidity is very low and the walls/floors don't lose much
>moisture so their rate of drying is very slow.
>
Pardon me. I wrote "humidifier" but meant dehumidifier.

HAH! You make me laugh, Oz. We are talking about two totally
different situations and quite naturally coming to totally
different conclusions because we each interpreted the original
poster's question in accordance with our perception of his
problem.

You saw it as a problem of ofsetting the effects of moisture
introduced by the user either with wet plaster or a swimming
pool. I saw his problem as needing or wanting to reduce the
ambient humidity in a room where the moisture is  already
there as a result of whatever air mass is passing by outside.

In my scenario the absolute humidity stays about the same during
the daily thermal cycle but the relative humidity swings widely.
In your examples, a reduction in relative humidity by heating
the air will drop the relative humidity and help dry the 
plaster. In Texas, when the temperature is over 40 K and RH
around 50% we do not heat the room to drop the RH for the
sake of comfort :) I Was referring to the energy required per
liter of liquid water removed from the air at constant
absolute humidity as for instance to maintain equilibrium
with a salt solution of fixed concentration.

In a manufacturing plant or laboratory where, say, ammonium nitrate
is being handled in Dallas, the salt will stay dry during the
summer day with RH at 40-50% so little dehumidifying is needed.
However, in the early evening the temperature drops enough to
raise the RH above 60% and the AN begins to liquify, requiring
the dehumidifiers to run full tilt. In this example the efficiency
is indeed better at high temperatures as it is in drying plaster.

Jerry (Ico)





DOC0289

Subject:      Re: Help with solubilities / mixed salts
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/14
Message-ID:   <4i9vr4$evs@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <haascn-1403960753180001@n1-24-210.macip.drexel.edu>, haascn@dunx1.ocs.drexel.edu (Charles N. Haas) says:
>
>In article <4i2iqv$kvq@news.aladdin.co.uk>, tonywilk@aladdin.co.uk wrote:
>
>> Firstly: If I have solubility data for both KClO3 and KClO4
>> can I directly calculate the proportion of these 2 salts ?
>> 
>> If (as I suspect) not... is there a general rule which 
>> allows calculation of the solubilities of 2 salts in solution?
>> 
>> I currently can't understand how to draw up a phase diagram
>> showing the mutual solubility of two salts, although in trying
>> to replicate a diagram for KCl/NaCl (from Perry's) I'm led
>> to believe that the Cl in common has a lot to do with the
>> reduction in solubility of one salt as the other is increased.
>
>Tony, the problem is you need additional information, or additional assumptions.

No additional information is required in simple theory. Obviously an
accurate answer requires assumptions of ideality, but there is a 
reasonable chance that the accuracy may suffice for the application if 
the data are correct. At any rate the problem presents an ideal
opportunity to practice chemistry calculations - it is a text book
question better than most created as exercises. 

>1) if the two salts are assumed to be present as indvidual pure solids in
>separate phases, then their solubility remains unaffected by the presence
>of the other.

This is incorrect because it ignores the common ion effect.

>2) if you form a solid solution, then you need to either assume that the
>two components form an ideal solid solution, or have data on the non
>idealities.  In any event, the common definition of solubility product (as
>the product of the ion activities raised to their stoichiometric exponents
>) no longer holds, since the activity of the solid phase is no longer
>unity (and getting back to the fundamental defintion of an equilibrium
>constant, must be considered explicitly).
>
There is little chance that the two materials form a solid solution
and only a remote chance that they form a double salt.

Jerry (Ico)













DOC0290

Subject:      Re: Is CaCl2 a good humidity absorber to protect chemicals ?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/14
Message-ID:   <4ia0ct$evs@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4i9n14$1d8c@news.doit.wisc.edu>, Martin Mueller <mueller@chem.wisc.edu> says:
>
>Bob <BANCKAERT@UNICALL.BE> wrote:
>>Is CaCl2 in a plastic jar as good as silica gel to proctect
>>chemicals from humidity ?
>>
>>It is cheap and you can find it anywhere. 
>
>No, it is not in general. While silica gel is more or less inert as a 
>drying agent, CaCl2 always contains CaO, which means it is basic. 
>Therefore, it is not a good idea to use CaCl2 for acidic compounds. For 
>basic and neutral compounds it is as good as silica gel.

Martin, you lost me on this one. Why would CaCl2 contain CaO?

CaCl2 is a little too soluble to put directly into many liquids,
but it is an excellent bulk drying agent for use in dessicators
and the like. It is true that it will not reach the absolute low
humidity levels achieved by silica gel or calcium sulfate, but
it has a voracious appetite for water and yields dry enough
air for many purposes.

Jerry (Ico)











DOC0291

Subject:      Re: Making pure ammonium nitrate from fertilizer
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/14
Message-ID:   <4i7r6t$n56@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3146e496.0@news-feed.tfi.be>, Bob <> says:
>
>Is the percentage of nitrogen in the fertilizer of any importance ?
>
If you're growing crops it is.

Jerry (Ico)





DOC0292

Subject:      Re: Mineral Spirits of Kerosene
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/14
Message-ID:   <4i7qsd$n56@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4i1orb$1vc@crcnis3.unl.edu>, dshobe@unlinfo.unl.edu (david shobe) says:
>
>Gerald L. Hurst (glhurst@onr.com) wrote:
>: In article <4hsb79$ove@dfw-ixnews2.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>: >
>: >glhurst@onr.com (Gerald L. Hurst) wrote:
>: >>You are told only that they found some material that the 
>: >>laboratory analyst said was "mineral spirits of kerosene"
>: >>at the scene.  Later various people ask you as a chemist to 
>: >>tell them just what it was that was found. What do you say,
>: >>and on what do you base your opinion?
>: >
>: >Unless you can find an industrial or literature reference to "mineral 
>: >spirits of kerosene" you say nothing.  Professional pronouncements ex 
>: >cathedra carry the weight of personal liability.  NEVER defend another 
>: >person's work with your opinions unless you wish to tightly grasp the 
>: >tar baby.
>: >
>: That's fair enough, but now let's ask if anyone amongst us chemists
>: has actually seen an industrial reference to "mineral spirits of
>: kerosene" or if it is otherwise perhaps a phrase invented by the
>: analyst.
>
>: Jerry (Ico)
>
>     Did the analyst SAY "mineral spirits of kerosene" or did he/she
>TYPE it?  If the latter I might suggest that "of" is a typo and that
>the intended communication was [either] "mineral spirits or kerosene".
>                                                         --
>--David Shobe
>
>P.S. "Uncle Al" is right--if the asking is more than a casual "What
>do you think?" you would be advised to do a little "research" first:
>call the analyst and ask what "mineral spirits of kerosene" are!
>
Mr. Shobe, I am not a school boy; the question is not casual; I am
doing precisely the proper "resaerch" in the proper medium under
the circumstances and the question is NOT based on a typographical
error or other mistake irrelevant to the sense of the query.

Please note that among the present list of postings, the following
unrelated message appears under the subject title "Re: Solvent: 
Mineral spirit ?" 

	Mineral spirit  is hydrocarbon derived from kerosine with       
	initial boiling point 140 degc and final boiling point 210 degc.
	5% volume max at 150 degc 50% vol min at 180 degc.

You will note that the author believes and states that mineral
spirits are derived from kerosene. Under this scenario, the
the phrease "minerals spirits of kerosene" would be as correct
as the concept "mineral spirits of petroleum." It appears that
there may be some reason for the authors belief, possibly some
published reference, however incorrect.

Words have connotations. "Kerosene" and "mineral spirits" are liable
to be found in different locations for varying reasons. An analysis
which suggests either the equivalency of the two or the necessary
presence of one as a consequence of the presence of the other can
have severe consequences in the interpretation of the cause and
origin of a fire or in the partial identification of a composite
product. If we take the concept to its extreme, we might conclude
that "gasoline" is subset of asphalt. 

Now, if you will refer to my original posting, perhaps the nature
of my question, its raison d'etre and the reason for including
the UseNet in the field of will become evident.

Jerry (Ico)









DOC0293

Subject:      Re: Nitrogen Dioxide Question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/14
Message-ID:   <4i8m6g$jk1@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <alyy.12.0007524B@pl.jaring.my>, alyy@pl.jaring.my (Alvin Leong) says:
>
>I have a simple question.  Why is Nitrogen Dioxide, NO2 brown in color?  Is 
>the reason anything like that for the transition elements where electrons 
>shift in the d-orbitals?  If you know, please please E-Mail me at 
>alyy@pl.jaring.my and you'll make me a very happy person.  I'd like to have as 
>in-depth an answer as possible.  Thanks in advance.  :)
>
NO2 has an unpaired electron which is responsible for the color.
When the gas is cooled it dimerizes, pairing up the electron and
losing the color. Mixtures of NO and NO2 (brown) freeze to give 
beautiful a blue or turquoise solid if I remember correctly. 
The bonding in the alleged solid N2O3 must be interesting.

Jerry (Ico)



















DOC0294

Subject:      Re: Solvent: Mineral spirit ?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/14
Message-ID:   <4i7p95$n56@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SUN.3.91-heb-2.05.960312070812.14788A-100000@actcom.co.il>, Moty Gendler <levana@actcom.co.il> says:
>
>Mineral spirit  is hydrocarbon derived from kerosine with       
>initial boiling point 140 degc and final boiling point 210 degc.
>5% volume max at 150 degc
>50% vol min at 180 degc
>
Why do you say that MS is derived from kerosene? Are these two 
materials not merely basically different cuts from the distillation 
of petroleum which (at least in the US) have distinctly different 
flash points? If you have a reference describing MS as a being
derived from kerosene, I would appreciate your posting the cite.

Jerry (Ico)




















DOC0295

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/14
Message-ID:   <4i8h07$jk1@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.energy,sci.mech.fluids,sci.materials,sci.physics



  Article Segment 1 of 2
  
In article <31471D10.4F29@hermes.bc.edu>, Keith Ramsay <Ramsay-MT@hermes.bc.edu> says:

>The definition of temperature we are "selling" here has the 
>virtue of explaining the reason for this equilibrium in terms
>of the conservation of energy and non-decrease of entropy, and
>doing so without specializing to idealized systems of particles.

And how does entropy free us from particles? When we describe the 
adibatic mixing of gases or liquids,  A and B, the entropy 
increases without the least consequence to  internal inergy and
fully independently of any temperature changes. Entropy here is
associated with nothing more than the fact that the particles
of A and B are red and blue respectively in some metaphorical sense.
Nevertheless, the "spontaneous" entropy change depends on the 
existence of particles whose particulate identity may be 
conveniently awept under the rug by Sterling's approximation. It
seems that entropy, then, is a particle function even when those
particles do not differ in any but an abstract way. 

At least the relation of temperature to the hypothetical particle
in a box of kinetic theory depends only on the mass and velocity
of the hypothetical units, which means it depends only on 
mass, distance and time, not red and blue.

Note here that the ideal gas temperature scale is not derived from
the kinetic theory of gases. The latter merely provides insight
into the mechanism behind the ideal gas law. The ideal gas scale,
again,is not the basis of the thermodynamic scale, it merely 
helps to validate the derivation of the latter from the Carnot 
cycle. Finally, the carnot cycle also provided a powerful raison
d'etre for the enormously useful concept of entropy.

>> Now, the equation  dS = (delta Q)/T is certainly valid, but the
>> question many might like answered is that if it is to be used
>> as a fundamental definition of temperature, to the exclusion of
>> other approaches, how can one demonstrate the prerequisite
>> definitions of energy (Q), entropy, and the unwritten but
>> necessary "reversibility" of the underlying process with reasonable
>> simplicity and elegance - the hallmarks of the kinetic theory?
>
>I think the explanation for why entropy does not decrease is 
>pretty fundamental. The "number" of states having greater
>entropy is larger, and the state of the system tends to wander
>out to vaster pastures, as it were, and will not wander back
>(unless something like Gold's universe with a future as well as
>a past boundary condition holds in the real world).
>
Yes, but the wandering itself relies on motion which correlates
back directly or indirectly to temperature. Eventually the map
should fit the physical territory if thermodynamics is to rise
above the status of just another mathematical system. In the real
world, thermodynamic problems will continually be required to
interface with kinetic mechanisms in which T is so very important.

Most real questions of equilibrium are concerned with "what" will
happen and more often the greater question also demands an answer
to "when."

>That energy is conserved is also very fundamental. It can be
>explained in both classical and quantum physics in terms of 
>the time symmetry of the laws of nature.
>
>If an isolated system has no other conservation laws getting in
>the way, it will tend to get to the highest possible entropy
>given its energy level.
>
That is true, but that striving may leave the "temperature"
totally disinterested in the proceedings of entropy. How often
do you find a situation where a change in temperature or
temperature distribution is not accompanied by an inevitable
change in entropy. In short, entropy is far more dependent on
changes in T than vice versa.




DOC0296

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/14
Message-ID:   <4i8h07$jk1@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
  
  
>If you put two systems, each at equilibrium, side by side, the 
>combined system will tend to go toward equilibrium, maximizing
>entropy. Moving a little energy from system 1 to system 2 will
>permit the total entropy to go up if dS/dQ is greater for
>system 2 than for system 1. The only way to make energy go
>backward while keeping the total energy constant is to decrease
>entropy.

If you put two systems side by side, their temperatures will
always equilibrate  Whether their total entropy rises will depend
on other things.
>
>Now, is there a more simple and elegant explanation for why
>they tend to go to an equilibrium at the same temperature?
>Do we need to drag molecules into the picture at this stage?

Molecule per se are never required except for the eminently
practical expedient of providing a convenient reference for
establishing calibration points and physical standards for
temperature measurement. You can escape from real molecules in
thermodynamic theory, but not from red and blue particles and 
those colorful enablers of entropy dance to the tune of 
temperature.

Let me stress that I never deny that temperature can and is
sometimes defined in terms of entropy. I do however suggest that
such a definition leaves a lot to be desired when presented as
"the" definition of temperature. I am not well known for defending
the "establishment," status quo, or tradition, but this time I
gotta go with the graybeards.

Jerry (Ico)

DOC0297

Subject:      Re: Dehumidifier efficiency
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/15
Message-ID:   <4ib378$8mm@geraldo.cc.utexas.edu>
Newsgroups:   sci.physics,misc.consumers.house,sci.chem



In article <4i9uti$evs@geraldo.cc.utexas.edu>, glhurst@onr.com (Gerald L. Hurst) says:

>plaster. In Texas, when the temperature is over 40 K and RH
>around 50% we do not heat the room to drop the RH for the
>sake of comfort :) 

Those are (K)ermit degrees in Texas, roughly equivalent to (C)elsius
degrees elsewhere:)

Jerry (Ico)


DOC0298

Subject:      Re: Is CaCl2 a good humidity absorber to protect chemicals ?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/15
Message-ID:   <4iav84$8mm@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <3148389b.845515@news.rmci.net>, jvinson@rmci.net (John W. Vinson) says:
>
>Derek DeLong <delongd@umd.umich.edu> wrote:
>

>>> It is cheap and you can find it anywhere. 

>The disadvantage of CaCl2 is that, unlike SiO2, it deliquesces when it
>absorbs enough moisture (i.e. it turns to a slimy liquid).  It also
>can't be regenerated.

Sure it can be regenerated - just heat it.

It only liquifies after it has absorbed a LOT of water. Just take
it out before it reaches saturation of its lower ligand water 
capacity  (CaCl2:2H2O) and the solid hydrate then begins to 
deliquesce as the weakly-bonded hexahydrate. You can regenerate
the dessicant at 200C.

Jerry (Ico)














DOC0299

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/15
Message-ID:   <4ibc0f$8mm@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.energy,sci.mech.fluids,sci.materials,sci.physics



  Article Segment 1 of 2
  
In article <3148B6F4.35C9@hermes.bc.edu>, Keith Ramsay <Ramsay-MT@hermes.bc.edu> says:
>
>Gerald L. Hurst wrote:

>You seem to be advocating using a certain sort of definition,
>*because* it conveniently gives an important (and idealized!) 
>case "special" status, and you want to make sure people understand 
>that special case, and so on. My point is, it would all be somewhat 
>pointless if it didn't fit into a general scheme, applicable to systems 
>which are not even made of molecules.
>
If you were able to read this supposed advocacy into my posts, then 
I must have failed to express myself adequately. I suspect you have 
let other's imputations suggest that my inevitable references to 
particles in tying together the historic relationships between absolute 
temperature, the kinetic theory of gases, the ideal gas law, the Carnot 
cycle, and Claussius' entropy somehow prove that I am "advocating" 
some particular definition of entropy.

My personal image of "entropy" happens to be based on probability,
but that has nothing to do with the discussion I have been 
conducting. This thread began with a comment from John Baez which
contained a trivial typographical error and an unequivocal statement
of *the* definition of "temperature." This dictum was followed by an 
assertion from another party that that particular definition was the 
work of or had been accepted by the international committee which 
adopted the the  (Kelvin) definition of "temperature" in the late 
1800s. As the discussion grew, there was a strong argument made, 
and which is still being made, that the most generally accepted 
definition of temperature in the scientific community in the 
twentieth century is that promulgated by John Baez and not the 
definition originated by william Thompson and based on the Carnot 
cycle. 

The corollary argument arose that not only was John's definition
of temperature the primarily espoused version in the twentieth
century paradigm, but that the most widely the most generally 
repeated and often taught definition of "entropy" was something
other than the ubiquitous S = Q(rev)/T or one of its cousins.

I disagreed with all of the above. 

Now you face me with a treatise on why I am wrong in advocating
some definition of entropy related to molecules or particles.
I have done no such thing. I HAVE described other SPECIFIC 
approaches to entropy which also use other versions of the particle 
concept merely to point out that "differentiation" of some sort 
between classes or species is usually necessary in even the purely 
mathematical approaches (which I did not address). However, these
comparisons should not imply that I have held out one method as 
better than another, except to the extent that I feel any worthy 
system must eventually touch our chemo-mechanical world in some way 
to avoid the obscurity of excessive virginity.

I have argued what is and has been a segment of history for better 
or for worse. It appears for worse, for if you read the rather 
rambling prose of Doug Merritt and then interpret my writings 
through his paraphrases, every particle and molecule leaps from my 
paragraphs like the fiends of some 19th century reactionary 
Rasputin trying to subvert the purity of modern science by 
injecting unwanted and unneeded connections with the contamination 
of the physical universe at early rather than terminal stages.

I have said in my miniessays what I set out to say. You seem to 
believe that I now need a lecture on the superior qualities of
methods other than those which I described in their historical 
context. Since I have clearly failed to convey my opinions and
more importantly, my LACK of opinions on the relative merits of 
various approaches to definitions of entropy, I must resign 
myself to the fact that it will so remain.






DOC0300

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/15
Message-ID:   <4ibc0f$8mm@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
  
  
I have written an overly lengthy reply to Merritt's latest
God-Save-Baez harangue, but find that it necessarily contains no 
real substance other than oft repeated denials of authorship of 
inane ideas ascribed to me. I will not bore you further by 
publishing that poor document or any additional comments on this 
topic other than the rhetorical end marker, "Joules/K?"

Jerry (Ico)



DOC0301

Subject:      Re: liquid/solid thermometer..is it possible??
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/15
Message-ID:   <4icln5$d10@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4ibdpq$sb5@unidhp.uni-c.dk>, c948296@bohr.gbar.dtu.dk (Lars Juhl Jensen) says:
>>
>: Basicly what it comes down to I guess is this: Can a solution 
>: be made in several different percentages of purity (I guess) so 
>: that each one will have a slightly different melting/freezing 
>: point? And if so what would the possible solutions/compounds 
>: possibly be??  water mixed with varying amounts of ?? or any 
>: other compounds???
>
>: This would be for a thermometer such as the ones used in 
>: ordinary households -50 f to 150 f  or so...
>
>: thanks...its just an idea that is nagging at me...
>
>Well I think you could make a thermometer this way.  Using a
>couple of compunds with melting points in the range wanted
>and then making use of freezing point lowering for finer
>graduation (the freezing point is lowered when impurities
>are added - it does not matter what impurities).
>
>It could be fun to try actually...
>
Ammonium nitrate/water will work. It has a wonderfully steep temp/soly
curve and should do a good job between 150 and  bit below freezng.
If you gotta get down to -50 F, you might try CaCl2/water Its curve
is less steep but it will let you get your liquid very cold.
Crystallization may be a bit slow at low temperatures.

Jerry (Ico)





DOC0302

Subject:      Re: Phase Changes: water
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/16
Message-ID:   <4idg2i$1l2@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4ica7v$dfm@crcnis3.unl.edu>, dshobe@unlinfo.unl.edu (david shobe) says:
>
>Jim Goodman (jim.goodman@accesscom.net) wrote:
>: In article <1996Mar12.172012@carleton.edu>, erberl@carleton.edu says...
>: >
>: >Boiling water freezes more rapidly than water at room temperature? - a 
>: myth?
>: >Under what conditions could this ever be true? 
>
>: Somewhere there is the idea that the transfer of heat dE/dt is 
>: proportional to the the difference in temperature dT:
>
>: dE/dt = k dT
>
>: I do not remember where the idea popped up (thermo?), but I think
>: it is a misunderstanding of a valid law. For example, if we set out
>: to calculate E(t), is it linear in some parameter?
>
>  dQ/dt = k (T2 - T1),  i.e. the rate of heat transfer is proportional
>to the temperature difference is called "Newton's Law of Cooling". 
>I don't know whether it is based on a sound physical principle or is 
>just a linear approximation to a more complex formula.
>
David, mixing history and science will get you a peck of troubles
sometimes in sci.physics, but you might consider that Newton was 
75 years old when the first practical thermometer was invented.
The nature of heat as a form of measurable energy was still around
a century away when he died, so it is improbable that the conduction
law bears his name. 

The above equations look like versions of Fourier's law, remembering
that k depends on the phase of the material and is a function of P 
and T.

Jerry (Ico)
<




















DOC0303

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/16
Message-ID:   <4idu4q$1l2@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.energy,sci.mech.fluids,sci.materials,sci.physics



In article <4icclt$jsq@guitar.ucr.edu>, baez@guitar.ucr.edu (john baez) says:
>
>Exactly.  Workers in quark-gluon plasma physics would find a
>18th-century definition of temperature based on steam engines, or even
>an early 19th-century definition based on atoms and molecules, rather
>beside the point.
>
John, I understand now why you dislike historical connections 
in science. There was no 18th-century definition of temperature
based on steam engines nor was there an early 19th-century 
definition based on atoms and molecules.

[Snip]

>This tremendous generality, and the ease of deducing all the principles
>of thermodynamics within this framework, makes it vastly superior to the
>18th-century definitions formulated when people only understood a few
>special cases, such as ideal gases (which don't even exist except as a
>useful mathematical approximation).

There was no ideal gas law in the 18th century, no molecules no 
atoms, no absolute temperature scale.  Dalton and Avagadro and 
Gay-Lussac and Carnot and Thompson all developed the necessary 
intellectual ingredients in the 19th century.

That was a very nice modern definition of temperature you gave. I 
shall happily add it to my collection.

Jerry (Ico)
<




DOC0304

Subject:      Re: Immobilization of carbon dioxide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/17
Message-ID:   <4ii5bg$q8u@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.chem,sci.engr.chem



In article <Pine.SOL.3.91.960317005559.26041D-100000@james.freenet.hamilton.on.ca>, Scott Nudds <af329@freenet.hamilton.on.ca> says:
>  Loonies who insist or imply that the distribution of temperature 
>fluctuations are not known are either ignorant of the facts and therefore 
>incapable of scientific debate, or pretending to be ignorant of the facts 
>and therefore unwilling to engage in scientific debate.
>
When one lives in a period between ice ages, it is rather difficult
to determine man's contribution to the average temperature.  To
insist that one *KNOWS* the truth of the matter qualifies you for
membership in the Repent-the-end-is-near brigade.

>> Whether or not you realize it, I am not obligated to hold 
>> your beliefs.
>
>  But you are obligated to accept the scientific consensus opinion or 
>provide respectable technical reasons why the consensus opinion is wrong.
>Please do so.  If you fail, you will continue to be considered a crank.
>
The only "consensus" you have is the fraction of people who share
your beliefs. I suggest that most scientists still doubt that we
have enough data to estimate the earth's temperature fluctuations
in the absence of human contributions. Nobody is obligated to 
believe squat or prove anything. We have not yet sunk to the level
of prosecuting thought-criminals or forcing the pledge of allegiance
to anybody's pet theory.

Jerry (Ico)







DOC0305

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/17
Message-ID:   <4ignli$3m0@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.energy,sci.mech.fluids,sci.materials,sci.physics



  Article Segment 1 of 3
  
In article <314AFDAD.5E8A@hermes.bc.edu>, Keith Ramsay <Ramsay-MT@hermes.bc.edu> says:
>
>Gerald L. Hurst wrote:
>>[I wrote:]
>> >You seem to be advocating using a certain sort of definition,
>> >*because* it conveniently gives an important (and idealized!)
>> >case "special" status, and you want to make sure people understand
>> >that special case, and so on. My point is, it would all be somewhat
>> >pointless if it didn't fit into a general scheme, applicable to systems
>> >which are not even made of molecules.
>> >
>> If you were able to read this supposed advocacy into my posts, then
>> I must have failed to express myself adequately. 
>
>Oh? Note that I'm not imputing to you the claim that it should be 
>the only definition to use, ever. You have, however, advocated its 
>use rather strongly, unless somehow someone has been forging posts 
>from you.
>
>One rather key use of a definition is in communication.
>
>Earlier in the thread, you said:
>
>   The ideal gas temperature scale may now be "obsolete" for 
>   certain purposes, but it is a far better mechanism for teaching 
>   the uninitiated to develop some personal association in their 
>   minds with the interactions of material and energy at least 
>   from the macroscopic and moderately paced perspective of the 
>   older but not yet dead paradigms.
>
>Far better? Not just better, far better. I haven't seen you withdraw
>these claims.
>
You most certainly will not see me withdraw anything in the paragraph
you have quoted. The "uninitiated," who have never heard of Entropy
are hardly in a position to use a definition such as the one
recently presented by John Baez. John's definition was a humdinger,
but hardly suitable for the vast majority of students learning to
use science and mathematics as a map for the physical territory 
those students have trod but not understood to any degree.

If we were to adopt the simpler definition, which John first
suggested  T = dE/dS, a basic restatement of the second law at the
expense of teaching the historical ideal gas approach, we would
simply create even vaster hoards of semiliterate scientists and
engineers who could regurgitate but understand not at all.

Again you are in confusing an argument relating to to ORDER in which 
ideas are taught with an argument for the inherent quality of two 
definitions. The distinction is not subtle, but it appears difficult 
to grasp by many here.

Most of the arguments I have seen here which denigrate the 
importance of history are by people who have exhibited an 
astonishing ignorance of that same history.  So much is this the
case, that I now realize that most of the advocates of the
supremacy of newer definitions are abysmally ignorant of the 
fact that even those definitions rely on the dog-eared old methods
of the ideal gas law to calibrate the scales. "dE/dS" is only a
"conceptual definition." It cannot by itself produce a scale on
which you can assign a triple point to carbon dioxide unless one
uses that point as an arbitrary anchor for the system.

When I described the definition of "temperature" as it was first
proposed by Thompson and and later adopted international agreement,
I did not say "PV = nRT," but rather I described in many words
an entire scheme which takes one from the Carnot cycle, an 
expression of the second law through the theoretical ideal gas
law to the real gas thermometers which are still used today, again 
by international agreement. 

Even when one uses the most abstract of concept definitions as a 
starting point, it is the actual gas thermometer which acts as the 
basic standard for the international temperature scale (ITS) 
with its myriad of reference points. The ITS90 scale which came 
into force on January 1, 1990 is no different - it still relies
on the ideal gas law and its practical implementation in the
form of the real gas thermometer.  The gas thermometer is 
augmented by the acoustic thermometer, which again depends on
ideal gas relationships.


















DOC0306

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/17
Message-ID:   <4ignli$3m0@geraldo.cc.utexas.edu>


  Article Segment 2 of 3
  
  
You were not listening when I pointed out that the entropy concept
is contained in the carnot cycle, from whose reversible processes 
the equality Q1/T1 = Q2/T2, i.e.,constant entropy, descends and
from which process Thompson PARTLY derived the definition. Thompson 
incorporated the real gas thermometer in the overall method two years 
later and the whole schema was adopted in 1887. There have been many 
adjustments to that scale since then, but the primary standard is
still the REAL gas thermometer, still interpreted by extrapolations
of the ideal gas law to extreme conditions to remove the vestiges
of nonideality.

Again I am not arguing "PV=nRT" vs "dE/dS = T"; "PV = nRT" is merely
part of a larger system that may start with Carnot or the entropy
concept (which is inherent in Carnot) derived from some more abstract 
definition.  When Thompson finally incorporated the ideal gas concept
into his already existing CONCEPTUAL definition, he had extensive
experience in the experimental investigstion of the NONIDEALITY of 
real gases.  He and the international committee who later accepted
his system, nonideal warts and all, knew exactly what they were 
doing and why. Their example has been followed by all succeeding
international authorities for reasons which are still valid today. 

There seems to be some idea here that it is only in the recent
years that minds have expanded to the "modern" concepts which
were unknown to the generations of teachers who have taught
at least the elements of the way our latest international scales
have been defined. It is this group who have gotten swept up into
the odd notion that earlier generations were too ignorant to 
understand the finer points of good teaching methods. Perhaps this
is because you represent the first generation of college graduates
who were required only to learn their math and quantum mechanics
without any sense of either the history of their subject or the
actual mechanics of bridging from the theoretical to applications 
in the real world where measurements must actually be made.

Reread some of the posts of your supporters and note the pride they 
take in their ignorance of "ancient history."

Do you really think that Wolfgang Pauli was too ignorant to
understand modern approaches to physics when he used the classic
textbook definitions of temperature and entropy in his lectures
on thermodynamics in Switzerland? He obviously made a conscious
choice that thousands of other knowledgable scientists have made.
In so doing, he was not expressing an opinion on whether one 
definition is "better" than another, but he was definitely 
favoring one teaching approach - not for specialists but for
scientists in general and for those who would never make the grade
but would at least know from whence those numbers called "K"
originated.

Again, for those whose reading comprehension and historical
knowledge are not quite on par with their mathematical aptitude
and training, I do not have any opinion on which elementary
mathematical expression of either temperature or entropy is
"Better" or more "sophisticated." 

I do suggest that the long version of the definition of temperature,
as I have outlined it, is not only the best FIRST lesson, but should
be mandatory in addition to any other versions that are taught. If
you can succeed also in implanting more sophisticated notions, go
to it. One lesson is not learned at the expense of the other.

Our future generations will be better off if we make sure that the
current crop of scientists is the last to lack both historical
knowledge and hands-on experience. We will profit if the world's
scientists know how things are actually done and why.

When I said that I suggested that we at least look at the 
possibility that our teaching methods leave something to be desired,
I wasn't simply referring to some individual definition.

BTW, yes, William Thompson (Lord Kelvin) WAS an engineer, but he also
did a journeyman's job as a scientist.




DOC0307

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/17
Message-ID:   <4ignli$3m0@geraldo.cc.utexas.edu>


  Article Segment 3 of 3
  
  
>I also tend to think your calling the statement of another definition 
>"possibly true as a pronouncement of the latest committee" to be 
>intended to leave the impression that it is not so hot, at least from
>a longer-term point of view.

I did not call *another* definition "possibly true as as a 
pronouncement of the latest committee." I said that of *THE*
definition. My statement was too mild. The latest real 
international committees have not adopted any such definition. If
there is such a "committee" worth mentioning it is well hidden
from rank-and-file scientists. I made the mistake of assuming
that John knew something about some important formal resolution
that I did not. It appears that despite our having been told of
such a committee from the 1800's, the only real group consists
of a few current mathematicians with a proclivity for algebraic 
transposition.

The "sophisticated" definitions per se are ok until it comes to 
explaining to the students why the units of entropy in the handbooks 
are given as Joules/K, which is kind of like listing the second in 
units of joules, grams and centimeters.  This sort of thing works 
better in a mathematics book than in some pchem classes.

If I seem to be giving you folks less credit than before, it's 
because I've thought and read a bit more and looked into some
of the more far-out thermo systems without finding much 
support for your positions. In that same period I have noted that
the most vocal arguments against the classical approach come
from those who know the least about it. If I am perceived as
backsliding, chalk it up to the pull of the weight of the evidence 
that some (not all) of the arguments for more "sophisticated" 
definitions as general educational fare are the smoke of pipe 
dreams.

Jerry (Ico)




















DOC0308

Subject:      Re: Immobilization of carbon dioxide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/18
Message-ID:   <4ij672$fo8@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.chem,sci.engr.chem



In article <4iiu4v$ltr@allinux2.alliance.net>, mjones59@mail.alliance.net (MarkJones) says:
>

>Would Washingtom,  Michigan and other northern states become the Sauli
>Arabia of the USA?  I live up there and  would tell the rest of the
>desert west to go to hell just like we do when they want our water!!!
>
Relax Mark. You need to travel around a little to lose that provincial 
attitude. Some of your best friends are probably "Winter Texans,"
who will need a cool glass of water after they thaw out. When does
the secession begin :)

Does this mean we don't get to cut down all the trees and pave 
everything north of Oklahoma?

Jerry (Ico)


















DOC0309

Subject:      Re: Immobilization of carbon dioxide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/19
Message-ID:   <4il5pd$4nd@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.chem,sci.engr.chem



In article <4ij9vu$2t0@main.freenet.hamilton.on.ca>, af329@freenet.hamilton.on.ca (Scott Nudds) says:
>
>Gerald L. Hurst (glhurst@onr.com) wrote:
>: I suggest that most scientists still doubt that we
>: have enough data to estimate the earth's temperature fluctuations
>: in the absence of human contributions.
>
>  And if the nature of the debate were "in the absence of human 
>contributions", you would have a significant point.  Unfortunately the 
>debate is concerning human induced climate change, so your observation 
>has no applicability.
>
Sorry, I assumed you were looking at the problem scientifically. I
won't bore you with the details, but in general, if you wish to
measure the effect of a specific agent on a system it is necessary 
to have a reasonable measure of the base-line behaviour of the 
system in the absence of the agent.

>: Nobody is obligated to believe squat or prove anything.
>
>  Those who have no expertise and argue <against> the consensus opinion 
>are fools.  To the extent that people are not obligated to be more than 
>fools you are correct.  I would assume the above author considers himself 
>something more than a fool however.  Hence he is obligated.
>
Sounds like something that came out of a fortune cookie. You are
still using "consensus" to describe the people who believe as you
do.  Or perhaps you mean "Forty million Frenchmen can't be wrong."

Jerry (Ico)




DOC0310

Subject:      Re: Phase Changes: water
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/19
Message-ID:   <4il4pg$4nd@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <314DF632.3926@ifu.net>, Jason Tiscione <tiscione@ifu.net> says:
>
>Gerald L. Hurst wrote:
>> In article <4ica7v$dfm@crcnis3.unl.edu>, dshobe@unlinfo.unl.edu (david shobe) says:
>> >Jim Goodman (jim.goodman@accesscom.net) wrote:
>> >: In article <1996Mar12.172012@carleton.edu>, erberl@carleton.edu says...
>> >: >Boiling water freezes more rapidly than water at room temperature? - a
>> >: myth?
>> >: >Under what conditions could this ever be true?
>> >: Somewhere there is the idea that the transfer of heat dE/dt is
>> >: proportional to the the difference in temperature dT:
>> >: dE/dt = k dT
>
>You quoted the equation wrong.  dE/dT=k(T-T0) where T0 is ambient temp.
>"dT" is an infinitesimal.

I think he meant dE/dt = -(K/A)*dT/dx, where A is the cross sectional 
area normal to the heat flow along direction x. This is Fourier's law.
>
>> >: I do not remember where the idea popped up (thermo?), but I think
>> >: it is a misunderstanding of a valid law. For example, if we set out
>> >: to calculate E(t), is it linear in some parameter?
>
>> >dQ/dt = k (T2 - T1),  i.e. the rate of heat transfer is proportional
>> >to the temperature difference is called "Newton's Law of Cooling".
>> >I don't know whether it is based on a sound physical principle or is
>> >just a linear approximation to a more complex formula.
>
>Newton's Law of Cooling is a very good law.  You can add higher order
>terms to the linear dQ/dt equation but there won't be much of a deviation
>from the linear approximation.  Unless phase changes are involved, and when
>you pour boiling water in an ice cube tray...
>
For the simplified condition where dT/dx is constant then for a given
length and area, dE/dt = k(T2-T1) as in your equation where your 
"proportionality constant, k = -K*A/(x2-x1) and my big K is known as
the "coefficient of thermal conductivity." Simplified though it is, 
Fourier still gets the credit, not Newton. 

>> David, mixing history and science will get you a peck of troubles
>> sometimes in sci.physics, but you might consider that Newton was
>> 75 years old when the first practical thermometer was invented.
>
[Snip Newton, a bitter man at the mint.]

>> The nature of heat as a form of measurable energy was still around
>> a century away when he died, so it is improbable that the conduction
>> law bears his name.
>
>WRONG!  dQ/dT=k(T-T0) IS Newton's Law of Cooling.  Whether it was his
>or just named in his honor is another matter.  But, that's the name.
> 
As a general rule, laws are rarely named after people who knew
nothing of the subject matter of the law. Perhaps the people who 
named this particular law after Newton did so as a lark after a
snoot full of Bay Rum. If that is the case, then I, having no more
but no less authority (yet more sense) than they, hereby declare
that the name shall henceforth be Fourier's law. Now that you have
seen the declaration in print, it must be true. 

Jerry (Ico)

















DOC0311

Subject:      Re: Phase Changes: water
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/19
Message-ID:   <4il8j0$4nd@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <ant1820320b0EKEZ@jmwa.thenet.co.uk>, "J. M. Woodgate" <jmwa@thenet.co.uk> says:

>Nevertheless, Newton _did_ formulate his Law of Cooling as Jim Goodman
>states. It strictly applies in the case where the cooling object is in a
>continuous air-flow. In still air, the rate of cooling is proportional to
>the five-fourths power of dT, and this is (or was forty years ago) as the
>'five-fourths power law'. 

Newton may well have formulated rules giving a cooling rate with respect
to time for an object. He could even conceivably have used a Fahrenheit
thermometer in his later days. It is quite possible that someone assigned
the apellation "Newton's cooling law" to his observation and formulation.

However, the expression dE/dt requires a knowledge of the existence of heat
energy as a measurable quantity.  Fourier was only able to derive his law
because of the work of a number of people who were born long after Newton's
death in 1727. 

A "cooling law" requires only an expression of the sort dT/dt = f(T) and
the two variables can be measured using only a thermometer and a timing
device such as a clock or the human heart. The concept of energy seems very
obvious to us now, but back then "phlogiston" was not quantifiable.

In short, Newton had the tools to define a limited "cooling law," but not a 
heat conduction law. Today we would look for kinks or loopholes in a 
"cooling law" as indicative of exothermic or endothermic events in 
differential thermal analysis.

Jerry (Ico)





DOC0312

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/19
Message-ID:   <4ilqr7$lhc@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.energy,sci.mech.fluids,sci.materials,sci.physics



In article <1996Mar19.051115.8793@pmafire.inel.gov>, russ@pmafire.inel.gov (Russ Brown) says:

>>There was no ideal gas law in the 18th century, no molecules no 
>>atoms, no absolute temperature scale.  Dalton and Avagadro and 
>>Gay-Lussac and Carnot and Thompson all developed the necessary 
>>intellectual ingredients in the 19th century.
>>

>Before dancing too far on thin ice, you might want to consider
>  
>  1) L. Boltzman, Populare Schriften (1905)
>  
>  2) L. Boltzman, Weitere Studien uber Warmegleichgewicht unter
>     Gasmoleculen, Sitzungberichte der K.Wiener Akademie, and
>     his Lectures of Gas Theory (Berkely, 1964).
>
Let me guess: 

1. You're testing me to see if I know that Ludwig spelled his name
   with 2 n's ?

2. You believe that since he was born in 1844 his work on "Further
   Studies of Thermal Equilibrium in Gas Molecules," published
   postumously, proves that the ideal gas law or the absolute 
   temperature scale was developed in the 18th century?

3. You believe that 1844 was in the 18th century?

4. You were wondering if I speak German?

5. You believe that Boltzmann published a paper in 1905 on the 
   problems of dancing on thin ice?

6. You had absolutely nothing to say, but you said it anyway?

Jerry (Ico)




















DOC0313

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/19
Message-ID:   <4inc9t$24m@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.energy,sci.mech.fluids,sci.materials,sci.physics



  Article Segment 1 of 2
  
In article <1996Mar19.135921.9793@pmafire.inel.gov>, russ@pmafire.inel.gov (Russ Brown) says:
>
>No.  And you lose a point on "posthumously".  :)  
>You lose half a point for not catching the incorrect typing of "Berkeley".
>
You are quite right. I dropped the "h," which was  careless of me.
I really should take more time to proofread my postings. Ah, so you
were referring to the city in california.

>No.  The resolution of questions about scientific principles is not
>limited to historical niceties.  You seemed somewhat excited, too.

There is not and has not been any discussion of "scientific principles"
by me. This discussion deals with a matter of perspective and in 
particular with the question of whether there is only one acceptable
"definition" of the "temperature." The specific post to which you
made your less than relevant comments about Boltzmann had absolutely
zilch to do with the accuracy of my comments concerning the time
frame of the development of theories relating to ideal gases.  Once 
more we hear the endorsement of the banality of a group which actually 
takes pride in their lack of historical perspective.

In particular, references to Boltzmann and his work do not 
contribute much to the support of dogmatic argumments regarding
temperature definitions. Part of Boltzmann's fame rests on his
work on the kinetic theory of gases, which is a two-edged sword
in an argument advocating definitions based solely on his other
work on the relation of entropy to probability. Remember that 
Boltzmann's constant is also called the molecular ideal gas 
constant. How do you suppose the numerical value of his famous
constant was first determined, Bubele?

Here's are three bits of perspective from the *Encyclopedia of Physics*

	A precise distinction between kinetic theory and stastical
	mechanics cannot be made. The latter is usually more
	formalized but utilizes the same basic laws of mechanics
	and collisions. Statistical mechanics is generally regarded
	as the aspect of kinetic theory that deals with interpreting
	thermodynamic quantities like entropy and free energy by
	molecular collision analysis.

and, with regard to the derivation of the Maxwell-Boltzmann law:

	Finally recourse to Jopule's derivation is taken wherein the 
	mean molecular kinetic energy arises from

		(1/2)mc^2 = (3/2)(R/n)T = (3/2)kT

	The molal gas constant R, divided by Avagadro's number n,
	is called Boltamann's constant and is represented by k.

and, finally

	The Kelvin temperature of an ideal monatomic gas (thus of
	a real monatomic gas at sufficiently low density and
	pressure), for example, is given by T = (2/3k)E, where E is 
	the mean kinetic energy per atom and k is the universal 
	Boltzmann constant. More complicated relations hold for more 
	complicated systems; they all support the the generalization 
	that higher temperature is a macroscopic manifestation of 
	more energetic molecular and submolecular motion. This 
	generalization is for many scientists the essence of the 
	temperature concept.

>Never did.  But in 1906, he committed suicide, having become depressed
>about the scientific establishment's hostility to his work.  Buried in
>the Zentralfriehof in Vienna, his tombstone was engraved with the
>commendable (for all, even you) relationship, S = k ln(W).

Why did they bury his tombstone and if it is buried, how do you know
what is written on it?:)

Remember that k is R/N and is expressed in J/K. Wasn't it nice of
lord K to provide that K 

What conceit leads you to believe that simply because I deplore your
obvious ignorance of history and do not share your particular myopia,
that I am less capable of appreciating intellectual achievement than 
you? If they had not chisled it in stone, would the feat have been any
less admirable? Catchy epitaphs copied from the encyclopedia are not 
what I had in mind when I suggested learning a little history. 
>>
>>6. You had absolutely nothing to say, but you said it anyway?
>
>"Nothing" seemed appropriate for a conversation that had degraded to
>personal exchanges.











DOC0314

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/19
Message-ID:   <4ine48$24m@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.energy,sci.mech.fluids,sci.materials,sci.physics



In article <4im65d$no6@lyra.csx.cam.ac.uk>, dna1000@cus.cam.ac.uk (David Allsopp) says:

>>simply create even vaster hoards of semiliterate scientists and
>                           ^^^^^^    ^^^^^^^^^^^^
>>engineers who could regurgitate but understand not at all.
>
>I think you mean 'hordes', unless someone is stockpiling scientists.
>What what that about semiliteracy? 8-)

Nope, I meant "Hoards." However, I well remember the equally 
appropriate but different mental picture of the "marching hordes
of Ph.D.'s from the ancient tome entitled "The Education of T.C. 
Mits." We keep our hoards of hordes of physicists in the taxi
stations of our great nation where we have enough in reserve
for a generation to come.  I like the word "herds" or "armies"
or "marching bands" better for the ACTIVE masses symbolism, 
because of the added connotations of follow-the-leader mentality.

BTW, if you judge literacy by good spelling, then you can happily
classify me as illiterate. I have no particular facility for 
spelling and I have no inclination to waste time learning to spell
any better than I do now. I suppose I could use a spelling checker 
or at least do more proofreading, There you have good reason to
add lethargy to my personal defficiencies it pleases you.

Despite my own mediocre abilities, I can still comment to my heart's
content on the pitiful level of education among young scientists.
I am surprised that my individual shortcomings are worthy of 
comment, but if it pleases you, have at it.

Jerry (Ico)



DOC0315

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/19
Message-ID:   <4inc9t$24m@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
  
  
It is sad that you admit being drawn into a discussion merely by
the attraction of "degraded personal exchanges" when you
had nothing of value say. I have tried to turn a sow's ear
into a silk purse by usuing your vacuous post as an excursion
point for some observations on perspective. 

I do not expect you to break your lockstep with the marching band 
of the sci.physics mafia, but consider the possibility that there 
might be other valid viewpoints.

Jerry (Ico)






















DOC0316

Subject:      Re: A question about carbondioxide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/20
Message-ID:   <4inkeq$adv@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4iml22$8mb@reader2.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>
>hahnh@ix.netcom.com(Hyeok Hahn ) wrote:
>>I recently doing some project about soda(in a PET-bottle).
>>But all the hand book in our university's library didn't cover this
>>subject.
>>How can I get the concentration in atmosphere during summer day.
>>And how can I get the concentration of carbondioxide in the coke?
>>(All I could find about this concentration is that of a bear and
>>I also couldn't understand its meaning... it says " CO2 volume."
>>Thank you.
>>
>>H.Hahn
>
>A recent CRC Handbook of Chemistry and Physics will have a table of CO2 
>concentration in air by month and year.
>
>As for the CO2 in Coke... get a large balloon and weigh it.   A big 
>Mylar balloon is best because it is not elastic - it will inlfate at 
>ambient pressure.  Secure the open end of the balloon over the top of a 
>warm bottle of Coke, then open it by unscrewing (grasping it through the 
>balloon).  Shake gently then well (or drop in a magnetic stir bar and 
>have at it).  When everything comes to equilibrium, remove the balloon so 
>as not to lose gas, tie its open end into a knot, and weigh it again.
>
>Account for the CO2 still in solution at low pH at atmopsheric pressure 
>(they don't chug in all that phosphoric acid for nothing), and you have a 
>pretty good estimate.
>
It might be a good idea also to acount for the buoyancy of air,
which will give a CO2 mass value roughly roughly triple what the 
balance tells you.

Jerry (Ico)
DOC0317

Subject:      Re: Blowing Bubbles
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/20
Message-ID:   <4ipst8$c8h@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.materials



In article <4inqrr$jh2@cloner2.ix.netcom.com>, Alan \"Uncle Al\" Schwartz <uncleal0@ix.netcom.com> says:
>
>Snell <snell@csh.rit.edu> wrote:
>>I am looking for a material or chemical substance that can be used to 
>>make lighter than air bubbles that will have an exterior coat that will 
>>become solid, and still be lighter than air. IE: The bubbles, after 
>>becoming hard, must retain a positive buoyancy, as this will mostly be 
>>applied in my underwater/surface projects.
>>
>>Other factors:
>>       Cost of the material,
>>       Supply of the material,
>>       Simplicity to make bubbles using the material,
>>       Toxicity of the material used.
>>
>>Gas used inside the bubble will be helium, or hydrogen. Fire is not an issue.
>
>You can buy hollow glass or silica microspheres in several sizes and 
>wall thicknesses ( <A HREF="http://www.thomasregister.com">http://www.thomasregister.com</A> ), as well as hollow 
>ceramic or epoxy macrospheres used to make syntactic foams (can't crush 
>under pressure).  You can easily get 30% void space in cast resin.
>
>I suppose you could take the microspheres and heat them in a vacuum oven 
>to a couple of hundred C for a week or two, or in a furnace around 
>a vacuum ampoule (dynamic vacuum) to maybe 400 C tops.  The air will 
>slowly diffuse out and at those temps the bubbles should not sinter or 
>inflate. I don't think they will hit negative boyancy in air.
>
Glass microballoons already have a vacuum inside, but there is
no way anyone is going to make them air-buoyant. I you want
air-buoyancy and solidity, like Al says, you're going to need
something large like a so-called "Mylar" balloon. A glass 
sphere or the like, light enough to float in air when filled with 
hydrogen, can be made in roughly lightbulb size, but is much too
delicate and frangible to work under water. In theory, you could
scale such a balloon down to "bubble size," but such an "aerogel"
weight bubble would be a very fragile feat of advanced art.

Jerry (Ico)

















DOC0318

Subject:      Re: Immobilization of carbon dioxide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/20
Message-ID:   <4ipr10$c8h@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.chem,sci.engr.chem



In article <4iof65$1t4@phunn1.sbphrd.com>, Frank_Hollis-1@sbphrd.com (Triple Quadrophenic) says:

>And only non-fools are allowed to participate in our 
>democracy (lunatics and peers are not allowed to vote).
>
The results do not confirm the truth of the allegation.

Jerry (Ico)




DOC0319

Subject:      Re: Immobilization of carbon dioxide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/20
Message-ID:   <4inkir$adv@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.chem,sci.engr.chem



In article <Pine.SOL.3.91.960319004407.26685G-100000@james.freenet.hamilton.on.ca>, Scott Nudds <af329@freenet.hamilton.on.ca> says:
>
>
>
>On Mon, 18 Mar 1996, dcwhite wrote:
>> How would you propose we solve the carbon dioxide problem?
>
>  The first step is to admit that the problem exists.  Since I am not a 
>coward, or a fool, I took this step a long time ago.
> 
Two out of three ain't bad.

Jerry (Ico)





















DOC0320

Subject:      Re: Phase Changes: water
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/20
Message-ID:   <4io8k7$adv@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4ik6h0$1hn@crcnis3.unl.edu>, dshobe@unlinfo.unl.edu (david shobe) says:
>
>Gerald L. Hurst (glhurst@onr.com) wrote:
>: In article <4ica7v$dfm@crcnis3.unl.edu>, dshobe@unlinfo.unl.edu (david shobe) says:
>
>: >  dQ/dt = k (T2 - T1),  i.e. the rate of heat transfer is proportional
>: >to the temperature difference is called "Newton's Law of Cooling". 
>: >I don't know whether it is based on a sound physical principle or is 
>: >just a linear approximation to a more complex formula.
>: >
>: David, mixing history and science will get you a peck of troubles
>: sometimes in sci.physics, but you might consider that Newton was 
>: 75 years old when the first practical thermometer was invented.
>: The nature of heat as a form of measurable energy was still around
>: a century away when he died, so it is improbable that the conduction
>: law bears his name. 
>
>     The equation is referred to as Newton's Law of Cooling in 
>_Heat Transfer_ by Alan J. Chapman (p. 13 in 3rd ed.).  Again, I
>don't know the history.  It is an estimate of the rate of heat
>transfer from an object to its environment by all mechanisms, not
>just conduction.

David, either your author has written inacurate information or 
perhaps you have misinterpreted something. Newton did not have
the necessary knowledge of the concept of heat energy to define
a law dealing with its flow. He could certainly have measured
and described a generalization about cooling rates if he had
wished to since various types of thermometers with arbitrary
temperature scales had been invented as far back as Galileo, and
Fahrenheit had brought out his alcohol and mercury thermometers
a dozen years or so before Newton's death.

If you take the "heat" out of the story it would play better in
Peoria. Why don't you hum a few bars from _Heat Transfer_ by 
Alan J. Chapman (p. 13 in 3rd ed.) and we'll see if we know the 
tune (quote, please).


>*** radical change in subject ***
>
>    As you might guess I am new to sci.chem, and don't know what 
>rules of 'netiquette' apply.  It appears that this is *not* an
>open discussion forum, and that only certain people are allowed
>to answer questions.
>
It is a very open forum, but only I and Uncle Al and Archimedes
Plutoni are allowed to speak with authority. Sorry, just kidding.

You can say what you please with no worse consequences than being
yelled at in capital letters. If you can stand the caps you've
got it made.  If you think you've got it bad, you should see the 
lynch mob that's after me in sci.physics. Over there it's not 
just big letters - they know ascii characters that are banned in
Boston.

Jerry (Ico)





















DOC0321

Subject:      Re: [Q] Energy of atoms in molecules
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/20
Message-ID:   <4invic$adv@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.energy,sci.mech.fluids,sci.materials,sci.physics



In article <DoJJM9.8sB@midway.uchicago.edu>, meron@cars3.uchicago.edu says:
>
>In article <4inc9t$24m@geraldo.cc.utexas.edu>, glhurst@onr.com (Gerald L. Hurst) writes:
>
>        ... big snip ...
>
>>I do not expect you to break your lockstep with the marching band 
>>of the sci.physics mafia, but consider the possibility that there 
>>might be other valid viewpoints.
>
>Hey, "mafia" implies organization (as in "organized crime").  I can 
>think about various less then flattering descriptions of sci.physics, 
>but "organized" isn't one ot them.
>
Are you kiddin'? Since I posted that message I've learned that the 
Nobel committee is no longer considering my nomination, and I'm being 
sued by the Cosa Nostra for defamation.

Jerry (Ico)















DOC0322

Subject:      Re: patron saint
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/20
Message-ID:   <4iprk8$c8h@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <31507F16.7C1@chem.kuleuven.ac.be>, Peter Carly <peter.carly@chem.kuleuven.ac.be> says:
>
>Who is the patron saint for the chemists? Is there one for each 
>discipline?

Other than St. Amorphous and Pope Intractable, whose canonization
is disputed, I cannot think of any

Jerry (Ico).



DOC0323

Subject:      Re: Immobilization of carbon dioxide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/21
Message-ID:   <4iq7o3$ph9@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.chem,sci.engr.chem



In article <4ioto4$j2s@main.freenet.hamilton.on.ca>, af329@freenet.hamilton.on.ca (Scott Nudds) says:
>
>Triple Quadrophenic (Frank_Hollis-1@sbphrd.com) wrote:
>: If Gerald has some expertise (no matter 
>: how small) then he can argue against the consensus and not be classified as 
>: a fool.
>
>  If Gerald shows himself to be technically competent, then he has the 
>right to object and remain in good standing.
>
>  The probability of that is near zero however.
>
How sharper than a serpent's tooth is a zealot scorned.

Of course I'm technically competent. I took science in junior high 
and did quite well, and I know what most of the buttons on my Iron
Man watch do.

Jerry (Ico)















DOC0324

Subject:      Re: Immobilization of carbon dioxide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/21
Message-ID:   <4iq7bj$ph9@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.chem,sci.engr.chem



In article <4iotj7$j2s@main.freenet.hamilton.on.ca>, af329@freenet.hamilton.on.ca (Scott Nudds) says:
>
>Gerald L. Hurst (glhurst@onr.com) wrote:
>  Please provide a peer review reference to a Global Climate Model that 
>predicts cooling in response to increased CO2.  Please provide a list of 
>Peer review articles that predict cooling in reponse to increaed CO2.
> 
>  If there is no consensus on the quesiton of CO2 induced global warming 
>then there must by definition be an equal number of papers predicting 
>cooling as there are papers predicting warming.  The same is true for 
>Global Climate Models.
> 
>  If you are unable to provide references (and you will be), we can (and 
>will), easily conclude that your insistance that there is no consensus is 
>based either on abject ignorance of the subject or or a desire to lie for 
>political reasons.
> 
>  I await your refrences before I draw any conclusions.

It looks like you've got a long wait in store.

I suppose it saves a lot of time when you decide on the nature of 
both or all ten sides of a discussion. According to your instructions
I am supposed to take the side that CO2 in the atmosphere doesn't
tend to increase global temperatures. I'm sorry but you'll
have to keep arguing both sides of that point yourself until you
can find somebody more pliant to argue that increased CO2 is 
responsible for ice ages.

Counting the number of publications proposing some theory is a
very dodgy way of arriving at a "consensus" of what "scientists"
think. If this method worked, we could easily determine that both 
polywater and cold fusion are generally accepted. Just think how
many publications dealt with phlogiston, before it got very quiet.

Do you happen to know what concentration of CO2 climatologists
believe was typical prior to the last ice-age?

We don't merely spew out CO2, we also shove zillions of pounds
of particulates into the atmosphere. How much cooling effect is
that going to have? Maybe we're going to bring on a new ice age
and then we'll need to shove some more CO2 into the air to 
compensate.

Perhaps the increased CO2 will lead to an explosion of green carbon
dioxide-sucking monster algae which will generate so much oxygen 
that we will perish in a holocaust of fire. Then the planet can start 
all over with the freshly made gas.

So many questions and so few climatologists.

Jerry (Ico)




DOC0325

Subject:      Re: CO2 Reaction Question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/22
Message-ID:   <4itlqm$f0s@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4it1nc$e2j@newsbf02.news.aol.com>, brianburt@aol.com (BrianBurt) says:
>
>I desperately need the expertise of someone well versed in chemistry to
>answer the following question!
>
>I am starting work on a science fiction novel in which I need a very
>specific type of (hypothetical) chemical reaction to satisfy some central
>requirements of the plot.  Carbon dioxide and seawater need to be two of
>the reactants, and the reaction must:  A) be highly exothermic (the more
>violent, the better); and/or B) generate toxic product(s) (the more
>lethal, the better).  I have been using as a working premise some type of
>"mysterious" organometallic reactant/catalyst that, combined with CO2 and
>seawater, yields a carbonate (possibly calcium carbonate?) and explosive
>quantities of waste heat... but I'm not a chemist, and I don't know if
>this type of reaction is realistic or a candidate for satisfying my plot
>requirements.
>
>Any advice, guidance, or suggestions anyone out there can provide would be
>gratefully accepted and much appreciated.  (I promise to give proper
>credit in the book's acknowledgements.)  Thank you in advance for any
>input you can offer!
>
Why not?

Here's one that at least allows the suspension of disbelief.

Aluminum is added to many explosives because it reacts in such a
way as if it gobbled up the water either present in or produced by
the explosion. Some of these explosives are actually water solutions
of such things as ammonium, calcium or sodium nitrate or even the
odd perchlorate. Although  nobody knows exactly why, the 
hypothetically quite reactive mixture of aluminum and water does
not react explosively when smacked with a blasting cap or primer
unless an unspecified amount of oxidizer is added.

You can be pretty certain nobody has ever tried CO2/Water/Aluminum
powder at high concentrations of CO2 (High pressure). Since CO2
is liquifiable under pressure you can use pressure to create any
mixture of CO2/water you wish. If you say that that mixed liquid,
combined with aluminum powder, will detonate or at least explode 
under confinement, nobody can prove you wrong. You can even 
speculate that the carbonic acid present from the reaction of CO2
with water cleans the oxide film off the aluminum and sensitizes it.

If the creative license bothers you, just add some oxidizer to 
the brew, in the form of, say, ammonium nitrate and you've got
the first metallized explosive soda "POP" blasting agent.

Jerry (Ico)







DOC0326

Subject:      Re: CO2 Reaction Question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/24
Message-ID:   <4j340p$anc@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4j29ct$1lk@mojo.eng.umd.edu>, candela@Glue.umd.edu (Philip Candela) says:
>

>With regard to some other comments on this thread: note: liquification of
>CO2 at pressure does not ensure mutual solubility -over a range of T's and
>P's there is a considerable field of liquid immiscibility betweem liquid
>CO2 and liquid Water.  the addition of NaCl to this system can extend the
>immiscibility to many hundreds of degrees(C) and a few kilobars (Deep 
>ocean water at 6.7 km is at a pressure of about 670 bars).  In fact 
>natural inclusions of fluid in quartz crystals at room temperature can 
>contain vapor+liquid CO2 +liquid H2O  (the quartz xl acts as a pressure 
>vessel - the total mechanical pressure in such inclusions can be high)
>
I have a little trouble with your data. According to my references,
the critical temperature and pressure of CO2 are respectively
31 C and 72.85 atm, which, if correct, means there is no liquid
phase of CO2 above 31 C and therefore no immiscible liquid phase
"at many hundreds of degrees (C)..." At lower temperatures I would 
expect high pressure to drive the equilibrium to the carbonic acid 
side.

There are a lot of chemists working on liquid CO2 systems these
days, so someone is sure to straighten us out.

Jerry (Ico)









DOC0327

Subject:      Re: CO2 Reaction Question
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/26
Message-ID:   <4j9gck$olh@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4j8ckt$mdr@mojo.eng.umd.edu>, candela@Glue.umd.edu (Philip Candela) says:
>
[Good stuff snipped]

>I hope this clears things up.  Again, my apologies for turning an 
>interesting question re: "novels" into a lecture on physical chemistry.
>
>Any comments welcome.
>
No apologies needed. The information you provided on NaCl/H20/CO2
phases was fascinating and (to me) very surprising in terms of 
the enormous effects of relatively minor concentrations of 
salts on the critical properties of water solutions, not to
mention the CO2/H2O system. If you have some additional cites handy, 
I'd appreciate some email, but there are probably others here
who would welcome more information.

Jerry (Ico)
















DOC0328

Subject:      Re: CopperChloride
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/26
Message-ID:   <4j9ron$olh@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4j9k2t$4dj@nms.telepost.no>, Beavis <Beavis@telepost.no> says:
>
>Can anyone explain why copperchloride (CuCl2) has one copper atom and two 
>chloride atoms. One would think that since the copper atoms has only one 
>valence electron it would make pairs with just one chloride atom, just 
>like sodium (NaCl) ????
>
If it's any consolation, Beavis, copper also forms a Cu(I) chloride,
Cu2Cl2. It is able to form Cu(II) compounds by losing one
of its d subshell electrons to leave that subshell one short of
a full house. Other transition elements also dip into the d level 
form species like Ni(II) and Co(III).

Jerry (Ico)




















DOC0329

Subject:      Re: Know your limits ! (reply)
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/26
Message-ID:   <4j8dno$59h@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.geo.rivers+lakes,sci.chem.analytical,sci.geo.oceanography,sci.chem.organomet,sci.environment,sci.geo.geology,sci.geo.hydrology



In article <4j6uut$pjg@niamh.indigo.ie>, clavin.rubicon@indigo.ie (rubicon) says:
>
>While you're doing all of this learning, you might find the time to learn 
>how to spell - very usefull for getting good grades.
>
Useful(l)?

Jerry (Ico)




DOC0330

Subject:      Re: looking for info...
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/03/28
Message-ID:   <4jctee$bsp@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4jb5v2$edf@Axil.wave.co.nz>, Peter@rjhill.co.nz (Peter Robinson) says:
>
>In article <4j29nq$1m8@impsrv1.imp>, babucher@mtu.edui says...
>>
>>
>>Is there a place on the net I can telnet/www/gopher/whatever
>>to that I can use to look up information on compounds, such as
>>specific gravities, blah blah...
>>
>>Also, what would 'turpentine' be under in the CRC Handbook of Chemistry
>>and Physics?  It's not in the T's under organic or inorganics.
>
>Kia Ora Boo
>
>Turpentine isn't in the Rubber Handbook because it is not a pure compound - try 
>alpha or beta pinene which are major constituents.  Turpentine was (is?) 
>extracted from the wood of various species of pine trees, often as a by-product 
>of paper manufacture.  This form has been largely supplanted, as a paint 
>thinner anyway, by "mineral turps" which is a hydrocarbon blend with no 
>chemical relationship to the original, it's just used for the same purpose!
>
>Also look in the Merck index where you will find turpentine.

Turpentine is still around and so is "oil of turpentine" which 
is what you are referring to. Turpentine is really a gum from
which the oil is distilled, but common usage often applies the 
single word to define either material.

Jerry (Ico)





DOC0331

Subject:      Re: Immobilization of carbon dioxide
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/01
Message-ID:   <4jo42l$e9t@geraldo.cc.utexas.edu>
Newsgroups:   sci.environment,sci.chem,sci.engr.chem



In article <828294325snz@daflight.demon.co.uk>, Hugh Easton <hugh@daflight.demon.co.uk> says:
>The oceans contain
>60 times as much CO2 as the atmosphere, and all mankind's emissions to
>date amount to only about 1 percent of this. 

Do you happen to know what the theoretical equilibrium 
amounts of CO2 in the air and oceans would be if such
a hypothetical equilibrium existed under current 
temperature conditions? How do these amounts compare with
the actual distribution?

Jerry (Ico)






















DOC0332

Subject:      Re: Help with salt water density
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/04
Message-ID:   <4jvs19$lie@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.engr.chem



In article <4jv0ac$gbp@dfw-ixnews2.ix.netcom.com>, frontrec@ix.netcom.com(Sergio E Firpo) says:
>
>I would appreciate any help in determining the density of salt water
>using different salts and different concentrations.
> I know the density of sodium chloride  (NaCl2) is  2.165 g/cm3 and the
>solubility in water is 264 g/L. For Calcium Chloride the density is
> 2.16 g/cm3 and the solubility is 427 g/L. Is this data suficient? I am
>not sure if a direct sum of the fractions apply.
> 
No, the volumes are not in any way reliably additive; the densities 
of solutions must be obtained experimentally. There are existing tables
of densities for many different salt solutions. The older handbooks
are more likely to contain this sort of data than are some of the
newer ones. There are extensive tables in the chemical literature.

Here are a few values for NaCl and CaCl2 solutions @ 20/4 C
from the fourth edition of Lange's Handbook to give you an 
idea:

	%1	2%	4%	8%	12%	16%	20%
NaCl	1.0053	1.0125	1.0268	1.0559	1.0857	1.1162	1.1478
CaCl2		1.0148	1.0316	1.0659	1.1015	1.1386	1.1775

Jerry (Ico)










DOC0333

Subject:      Re: What food holds the most heat? Potato?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/06
Message-ID:   <4k4uk8$odq@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,alt.sci.physics.plutonium,sci.bio.misc



In article <4k48h3$hh3@dartvax.dartmouth.edu>, Archimedes.Plutonium@dartmouth.edu (Archimedes Plutonium) says:
>
>In article <1996Apr4.031250.24093@galileo.cc.rochester.edu>
>gl002c@uhura.cc.rochester.edu (G. Lane) writes:
>
>> Water has one of the highest specific heat capicities, food that has a lot
>> of water should retain a lot of heat.  So tubers (including potatoes) should
>> retain a lot of heat.
>> george
>
>  Thanks George, now I need to generalize that. So H20 as a polar
>molecule has high specific heat capacity.
>
>  What would be the concept of heat capacity for the elements 1 through
>100? And what element in pure form would hold the record? Is it carbon
>for I understand it has the highest melting point and is heat capacity
>related to melting point.

Archimedes, I am pleased to tell you that Carbon actually has a
an exceptionally low (molar) heat capacity of about 2 kcal and 
diamond is even lower at less than 1.5. 

The reason for my pleasure is having the privilege of announcing
that the highest heat capacity listed in my references appears to 
be enjoyed by non other than your favorite element, Plutonium.
Said heat capacity is listed as 8.48 cal/mole.

I suspect that sci.physics and sci.chem will be hearing more about
this matter in the near future.

Jerry (Ico)



DOC0334

Subject:      Re: high temp reactions
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/07
Message-ID:   <4k7qbd$ncb@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <4k6vd9$hnl@cronkite.seas.gwu.edu>, roxas@gwis2.circ.gwu.edu (Audrey Roxas) says:
>
>
>Hello all!  Just a quick question.
>
>Is it true that
>
>CaC O  +  Heat -->  CaCO (s) + CO(g)
>   2 4                  3
>
>and
>
>CaCO  + Heat (circa 850 degrees C) --> CaO(s) + CO (g)
>    3                                             2
>
>Hope I don't sound too stupid.  Later!
>
Nothing stupid about those questions.

Calcium oxalate does decompose "with little charring" as written and 
the second reaction is the method of making lime (quicklime, not 
slaked lime) for such purposes as cement manufacture.

Jerry (Ico)
<









DOC0335

Subject:      Re: Help with salt water density
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/08
Message-ID:   <4kc04a$iub@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.engr.chem



In article <4kbo32$1r6m@service.polymtl.ca>, Roger Pelletier <rpelletier@mail.polymtl.ca> says:
>
>Is there an easy way to measure the density of salt solutions at 
>temperature below 0 C with 0.02 g/cm3 precision?  It seams to me that it 
>would need costly equipments.
>
If that is all the accuracy you require for KCl solutions in the 
range -5 to 15 degC, why not simply assume that the density change
is the same as it is for pure water?

The maximum density change for water in this range occurs between 
15 and 0 and amounts to only 0.0009 g/ml. There is only a 4% change
from freezing to boiling. It seems logical to assume that you can
calculate the density of a given solution as 

D(soln @t) = D(soln @ t0)*D(H2O @t)/D(H2O @t0), t0 = reference temp.

I would be surprised if this calculation doesn't yield values
well within your desired 2% precision (and accuracy). You can 
easily check out the validity of the method by either finding
or measuring values for two or three temperatures above zero.

BTW, the logistics of measuring densities at -5 C to an accuracy
of 2% would require nothing more elaborate than a balance, a freezer, 
a couple of thermometers and some household items, if you have 
something to serve as a pycnometer or volumetric flask. For the 
limited accuracy you require, you could get a whole series of values
(V vs t) from a single volumetric flask with the neck calibrated like 
a graduated cylinder. Just measure the volumes going down in 
temperature and then going up with good insulation around the body
of the flask to slow the process down.

Jerry (Ico)

DOC0336

Subject:      Re: Semi skimmed milk
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/08
Message-ID:   <4kahuf$hnm@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Ag99jFAYy$ZxEwHy@poison.demon.co.uk>, Eric Lovett <eric@poison.demon.co.uk> says:
>
>Dear All,
>        I have recently read that heating food can destroy flavour
>components.
>        So when skimming milk, what side affects is caused to the milk.
>(eg loss of nutrional, flavours etc)

Skimming milk has nothing to do with heating. Butterfat, in the
form of cream, rises to the top of unhomogenized milk on standing and
can be literally skimmed off. You bet you lose flavour when you get 
rid of the fat, sigh.

Jerry (Ico)




















DOC0337

Subject:      Re: throwing boiling water into freezing air
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/10
Message-ID:   <4kfm0c$gof@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SUN.3.92.960409224535.8160A-100000@ruby.ora.com>, Nancy McGough <nancym@ora.com> says:
>
>I'd like to understand the chemistry of the following.
>
> You throw a pan of boiling water into freezing air
> and all the water vaporizes.
>
>Now, in order for it to vaporize it needs to absorb some
>heat, but where is this heat coming from?  Does this
>only happen in freezing air?  If so, why?
>
They lied to you. The water hits the ground, mostly unevaporated,
and then gradually evaporates by drawing heat from both the air
and the ground.

We are assuming, of course, that you did not throw the water out of
an airplane. Under such circimstances, it may well evaporate before
it lands, deriving the necessary heat from the surrounding air.

In either case, it helps if the air and/or ground is warm.

They were supposed to tell you that the water freezes before it
strikes the ground, which, again may be true if you toss it out 
of an airplane at low temperature or out of a space ship.

Sigh, they pulled the wrong leg - no bells.

Jerry (Ico)






DOC0338

Subject:      Singed Hair
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/12
Message-ID:   <4kmbc9$31l@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



When hair is exposed to flame or heat it undergoes changes including
melting and shriveling, generally referred to as "singeing." Does
anybody here know at what temperatures these phenomena occur? In
an actual fire situation, soot with its various accompanying chemicals
is produced. Do these substances lower the onset of visible changes
in the the structure of hair, i.e., do they lower the temperature
at which hair apparently undergoes physical changes associated with 
singeing?

Jerry (Ico)


DOC0339

Subject:      SONIA DIDN'T DO IT.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/21
Message-ID:   <DqA8yF.927@world.std.com>
Newsgroups:   sci.chem,sci.chem.analytical,sci.physics,misc.legal,misc.legal.moderated



Sonia climbed from the bedroom window of the burning house looking
for Uncle Bill. The frantic woman did not find him in the yard and
tried repeatedly to reenter the house to get him out.

The lady from victim aid escorted her to the hospital and then the
police force of the tiny West Texas town swooped down on her 
hospital room. The authorities leaped to the conclusion of arson
within an hour of the fire.

Forensic samples were sent to San Antonio's Bexar County labs for
analysis and they returned a positive GC-MS analysis for gasoline
on Uncle Bill's clothes.  The lab's evidence supervisor at the time 
was the infamous Fred Zain, who was said to be responsible for the 
most egregious evidence tampering spree in history.

The West Texas stone-faced jury heard enough facts and evidence to
establish Sonia's innocence a dozen times over, but they gave their
beloved District Attorney and neighbor the verdict and sentence
he wanted.  "Science" is still a holy cow in that remote village.

Sonia got 99 years. Sonia is innocent. 

With luck, we may get a third trial and if we do, it will take all
the ammunition that can be mustered to hammer home the fact that
Sonia did not kill Uncle Bill.

The case has a number of scientific issues that will call for 
clear reduction to show-and-tell for yet another jury who will be
predisposed to believe that police labs do no err even when they
fail to label their cans of evidence and have no chain of 
possession documents. If the defendent were O.J., the case
would be thrown out on a dozen grounds, but this defendent is
dirt poor.

There are currently three experts (fire/explosion/chemistry) and a 
lawyer donating time to try to save Sonia. We could use some input 
from a skilled reader of GC/MS hydrocarbon spectra to help verify 
how the charts were fudged.

The pathology in this case is abominable. Any layman could tell
that Uncle Bill probably died before the fire, but laymen have
no standing in the courts.

The combustion properties of gasoline are a factor. The D.A.'s 
case depends on a hollywood vision of what happens when gasoline
is poured on a sleeping person and ignited.

This case needs the glare of the media to force the prosecution
to present an honest case that would survive the scrutiny of 
well-trained scientists. There is a story here worthy of serious
investigative reporting.

The UseNet has the potential of helping to right a gross miscarriage 
of justice. Who can help Sonia? Sonia didn't do it.

Jerry (Ico)
<





















DOC0340

Subject:      Re: SONIA DIDN'T DO IT.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/26
Message-ID:   <4lriqn$dq7@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.chem.analytical,sci.physics,misc.legal



  Article Segment 1 of 2
  
In article <MOrtch-2604961051220001@purgatorio.chem.ualberta.ca>, MOrtch@Ualberta.ca (Mary Ortch) says:
>
>In article <4lq5ld$ci3@geraldo.cc.utexas.edu>, glhurst@onr.com (Gerald L.
>Hurst) wrote:
>
>> In article <4lo2l5$o19@access1.digex.net>, rdadams@access1.digex.net
>(Dick Adams) says:
>
>> >Gerald L. Hurst <glhurst@onr.com> wrote:
>
>> Slither back into your hole, moron. This is a serious business, 
>> you lame-brained nincompoop. This woman's life is at stake and you
>> feel you have to stick your snotty nose in and show us all how 
>> smart you think you are.
>
>Sure he was being snide, but how is this reply going to help your cause? 
>Please think before you reply.
> 
Lady, you are less snide than he but just as useless.

>> In the present case we are going to have to prove that the lady is
>> innocent. This is going to take a lot of very skilled and unpaid
>> work by a number of lawyers and technical people.
>
>Fine, but you posted a long (purple prose) piece that was utterly devoid
>of any real content to evaluate.  How are you going to get anyone on your
>side unless you can show anything that could differentiate you from a host
>of others who just want to get away with murder?
>
What I posted was an introduction to the story. The technical stuff is 
pretty meaningless unless it is explained in the context of the events 
surrounding the bits of forensic evidence which are acquired later.

>> I have studied the records and testimony of the case for many weeks now
>> and I continue to slowly piece together the reasons why the system 
>> blundered. I cannot help but wonder how often science runs amok and 
>> results in the conviction of innocent people via shaky forensics.
>
>How nice for you.  Why not post some of this for public scrutiny?  As a
>suggestion, keep your posts short and to the point.  If you have several
>different analytical questions, they should be broken in to several
>different posts.  As for how often it happens, well it certainly happens
>both ways, for example O.J. and David Milgaard.

Nice for me? How stupid and insensitive can you be? I will make my posts 
as long or as short as I deem necessary. It is incredible how nitpickers
like you and your buddy DICK love to post your useless and vacuous comments 
and suggestions. May you live long enough to find yourself in Sonia's position. 
You're damned right it happens both ways, dummy. Have you forgotten the 
principle that it is better to set the guilty free than imprison the innocent. 
I suppose you'll have to wait until it happens to you or yours to find out 
how welcome your worthless suggestions are.

As far as the exchange of detailed information, that is already occurring
18 hours a day, but you and your ilk are not included. I'm sorry I wasted 
five minutes venting at your smug and sanctimonius attitude. It is technical 
people like you who are the problem. You think that forensic problems are 
simply a set of spectra that determine guilt or innocence.

All over this country there are technicians sitting at their GC's injecting
eluted samples without the faintest notion of the history of the material
they are analyzing. The results will be sent to an insurance company or 
police prosecutor who has not the vaguest idea of the reliability of the
analysis or what it means.

For the cop who gets your report the phrase "Consistent with the presence 
of class II hydrocarbons" means they found gasoline (ASTM) or maybe it 
means they found kerosene (NFPA).

You think you've got a lot of good advice to give about limiting technical
posts to "just the scientific facts"? You've got another think coming little
missy. In this game, you need to start with a good Ph.D. and then learn
something about weaving your technical know-how into the complex webb of 
motive, social interaction and applied science.

By "applied science" I do not mean that elementary work of poking needles 
into the GC or sipping coffee while you peruse peaks and make your subjective
evaluations on the graphs the computer refuses to interpret.




















DOC0341

Subject:      Re: SONIA DIDN'T DO IT.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/26
Message-ID:   <4lriqn$dq7@geraldo.cc.utexas.edu>


  Article Segment 2 of 2
  
  
Chemistry and physics in forensic investigation require analytical methods 
that have not been reduced to routines and above all these sciences have 
to operate within and interface with the real life environment. That is why
the "purple prose" is necessary. You could spend the rest of your life
successfully working only on the "technical" problems in Sonia's case and
never help the woman one little bit.

There are very, very few people on the net who have the experience and skill
to help Sonia. I will simply have to put up with crap from you and DICK, et 
al until I find a few good men (or other women).

Jerry (Ico)





















DOC0342

Subject:      Re: SONIA DIDN'T DO IT.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/26
Message-ID:   <4lq5ld$ci3@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.chem.analytical,sci.physics,misc.legal



In article <4lo2l5$o19@access1.digex.net>, rdadams@access1.digex.net (Dick Adams) says:
>
>
>Gerald L. Hurst <glhurst@onr.com> wrote:
>
>> Sonia climbed from the bedroom window of the burning house
>> looking for Uncle Bill.  The frantic woman did not find him
>> in the yard and tried repeatedly to reenter the house to get
>> him out.
>
>Please name independent third party witnesses to this behavior!!
>
Slither back into your hole, moron. This is a serious business, 
you lame-brained nincompoop. This woman's life is at stake and you
feel you have to stick your snotty nose in and show us all how 
smart you think you are.

For those of you in the two scientific forums, I hope to publish 
details of the forensic case in an ongoing series as we try to 
illuminate the various technical misconceptions and poor theories 
that led to the conviction.

Anyone can comment on the net so it will be necessary to suffer
the idiots like DICK. I appreciate the helpful correspondence I have 
already received from technical folk who have offered their real 
skills in such tasks as interpreting GC-MS spectra and the like.

Sonia is a real person and she really is innocent of wrongdoing. 
Those among you who, like DICK, are good little true believers do not 
know that the authorities often make egregious errors in prosecution
and that our ideal of being innocent until proven guilty is not 
always followed.

Sonia is not an old friend. I reviewed her case as a favor to an 
attorney with whom I had previously worked on a civil case. After 
plowing through a thousand pages of testimony, lab reports, 
investigation reports and the like, I quite easily concluded that 
her Uncle's death was a not unexpected accident. Three other 
experienced fire investigators have looked at the material and concur.

The D.A.'s theory may have sounded good to a jury, but it did not
jibe with the simple physical rules that we chemists and physicists
are used to watching matter and energy follow.  Police investigation
does not always employ scientific methods. There is a strong tendency
for some enforcement organizations to accept their initial theories 
as laws and then procede to compress the facts into the theoretical 
mold.   

In the present case we are going to have to prove that the lady is
innocent. This is going to take a lot of very skilled and unpaid
work by a number of lawyers and technical people.

Since we cannot swat the DICKS of the net like mosquitos, I am ready to 
concede early that most of the material I have gathered relating to this 
case will have to be sent to a a few intelligent people who may be able
to offer some valuable insights.  There will be no DICKS on the mailing
list.

I have studied the records and testimony of the case for many weeks now
and I continue to slowly piece together the reasons why the system 
blundered. I cannot help but wonder how often science runs amok and 
results in the conviction of innocent people via shaky forensics.


Jerry (Ico)
<












DOC0343

Subject:      Re: SONIA DIDN'T DO IT.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/29
Message-ID:   <4m38hg$lcb@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.chem.analytical,sci.physics,misc.legal



There has been a lot of clucking in this forum about my bluntness in 
dealing with various posters, mainly students, who have commented on
such matters as the non-technical character of the "purple" prose of 
my initial post telling Sonia's story. I have received extensive 
criticism for the sarcastic dismissal of the majority of these posts.

I would like to say that I regret insulting the critics, but the truth 
is that I do not. Sonia's story is a c grade pulp fiction tale that 
would bomb in a minute as a work of fiction, but unfortunately is not
fiction but fact.

For the most part our students (and, to be fair, others) have pointedly 
focused on what a nasty old man I am with my barbed and intemperate 
replies to their clever comments about what is wrong with my style 
or my attitude.

It is unfortunate but necessarily true that there will be no public
postings of any of the technical aspects of Sonia's case. It is the 
nature of such things that they must be circulated to a small and 
select group of people with particular skills, tenacity and 
determination. I will not elaborate on this subject, but the reasons 
will be obvious to those experienced in such matters.

It is possible that I may be able make an exception in particular aspects
of the case such as the description of the prosecution's theory of the 
mechanics of the alleged crime. It might be an interesting exercise to
see how well chemists and physicists in these forums are able to
reconcile that theory with known physical phenomena.  I suppose the
decision depends on the level of expected static.

If it appears that I am impatient with the dilettante posters that is
because it really is so. My comments to these posters are mild 
reflections of my real opinion. 99 percent of everything that 
transpires in these science forums is recreational fluff. It does not 
matter much if the high schoolers get their homework done by professor 
Jones or yet another theory of the cosmos is introduced, but Sonia's 
fate matters a great deal.

If you have something to contribute, contact me by email. If you merely
wish to show how very clever you are and what a terrific sense of
humor you have, save it for discussions of relativity. I have zero fear 
that I will "chase away qualified scientists." If you have the stuff
that is needed, no amount of my curmudgeonry will keep you away; if
you don't, I hope it does.

I wish to thank those few qualified folks who have contacted me by email
and express my appreciation for the help you have offered. It is
extremely gratifying to note that these posts have mostly been by people
who do have high levels of expertise and have all been by people
sincerely trying to help Sonia. Thanks again.

The best advice I have received is not to reply at all to those who have
nothing to offer. I'll follow that advice. 

Jerry (Ico)

DOC0344

Subject:      Re: SONIA DIDN'T DO IT.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/29
Message-ID:   <4m1gi2$hl7@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.chem.analytical,sci.physics,misc.legal



In article <4luhbk$dmk@grivel.une.edu.au>, dbromage@metz.une.edu.au (David Bromage) says:
>
>Gerald L. Hurst (glhurst@onr.com) wrote:
>>As far as the exchange of detailed information, that is already occurring
>>18 hours a day, but you and your ilk are not included. I'm sorry I wasted 
>>five minutes venting at your smug and sanctimonius attitude.
>
>Maybe it's _your_ attitude that keeps respectable scientists away from you?
>
Now that IS funny. You are referring, I presume, to yourself, missy 
and DICK.

Aren't you the little student who pointed out that gasoline burns?
How will I possibly get by without the help of you three "respectable 
scientists"?

Your comments about the courts will probably lead to head-bobbing 
assent from the technical academics and uproarious laughter from 
the legal forum.

There is no way to to teach in school what you do not know.

Jerry (Ico)











DOC0345

Subject:      Re: SONIA DIDN'T DO IT.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/04/30
Message-ID:   <4m5ns0$hnc@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.chem.analytical,sci.physics,misc.legal



In article <4m50to$m28@rzsun02.rrz.uni-hamburg.de>, fc3a501@rzaixsrv1.uni-hamburg.de (Hauke Reddmann) says:
>
>Then give us DATA,DATA&DATA! (Was I redundant?)
>Your first post was much too general for any
>sensible scientific comment. Raid the court files,
>append the forensic data, stuff us with 10M of
>scenery gifs - eh, on second thought, don't -,
>but give us !!!DATA!!!
>
Sorry HR, you're not paying attention. The first post was intended 
to be precisely what it was. No scientific comment was expected.
DATA, DATA & DATA wouldn't do you the least bit of good. Like most,
you have not the foggiest idea what is involved and what is 
required to tackle this type of problem. The "science" that you and 
I practice in the normal course of research is only an element in
the analysis of a court case. If I showered you with chemical analyses 
and spectra from the case, you (or anyone else) would not be able 
reach any meaningful conclusions.

The fact that the original "purple prose" story did not elicit a
different sort of response is indication enough that you probably
cannot be of help at this stage. It is quite possible that later on
there may be some clearly defined "scientific" questions that will
be right up your alley.

Here is a general type of question which you or one of the other 
skilled scientists might like to have a bash at:

Suppose that a fire burns in a room containing various common natural 
and synthetic materials such a PE, polyurethane, PVC, ABS, nylon, 
polyester, wood, coatings and the like and that the fire burnes 
long enough to create a lot of pyrolizates. 

A technician takes a sample of partially burned material from a
location at which he suspects gasoline was poured to initiate the fire.
He neglects to take any comparative samples from other locations
in the room.

The technician subjects the sample to purge-and-trap separation 
and collection in charcoal followed by elution and GC-MS analysis.
The raw spectra show thousands of peaks which the computer sorts
out into sub-spectra, trying to eliminate all not purely CH compounds,
and it labels the subspectra as "naphthalenes," "alkyl benzenes," 
and the like but does not actually print out the mass numbers. Assume 
that the distribution of "hydrocarbons" and "alkanes" is substantially 
different from gasoline per se, containing a very much higher 
proportion of higher molecular weight materials.

The technician decides from the visual interpretation of the 
sub-spectra that the sample contains some unknown brand of "thermally 
degraded gasoline."

The question is what criteria can one apply to ascertain the credibility
of such an interpretation in the absence of any specific parameters
having been recorded by the technician to justify his conclusion. In 
a complex mixture of pyrolizates how does one quantify the reliability
of such an analysis in the absence of control samples from the same
general environment?

Finally, is it acceptable at all to test a fire debris sample for 
suspected foreign accelerants in the absence of a control sample 
from the same or nearby environment?

Jerry (Ico)














DOC0346

Subject:      Re: SONIA DIDN'T DO IT.
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/05/02
Message-ID:   <4m9bqh$59u@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem,sci.chem.analytical,sci.physics,misc.legal



In article <4m32ed$ns@s-cwis.unomaha.edu>, stone@cwis.unomaha.edu (Travis Stone) says:
>
>Gerald L. Hurst (glhurst@onr.com) wrote:
>[bitch-bitch-bitch-gripe-gripe-gripe] 

>> You think that forensic problems are 
>> simply a set of spectra that determine guilt or innocence.
>
>No....no more than most people think that lawyers are parasites who feed
>off the miseries of other people and who habitually twist the facts to
>get their clients off no matter what it takes, true as that may be.
>
Both propositions sound good to me. But what would be more useful would 
be if someone here has handy an approximate typical composition for 
untreated (no fire retardent) flexible polyurethane foam such as is 
routinely used in mattresses, furniture and the like.

I'd like to calculate the approximate heat of combustion -- unless 
someone also has some equally handy thermodynamic data.

Travis, I'm really sorry if I offended you. I had no idea you were a 
lawyer.

Jerry (Ico)










DOC0347

Subject:      Re: Unka Al groupies
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/05/10
Message-ID:   <4muo5t$cgk@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



In article <Pine.SGI.3.91.960509125808.7496I-100000@cv2.chem.purdue.edu>, Lev Gorenstein <lev@chem.purdue.edu> says:
>
>On Wed, 8 May 1996, Mark Tarka wrote:
>
>> Just in case this gets to the level of a free-speech issue...I
>> demand the right to have unprotected internet-conversations with
>> that no-good, rat-haired, anti-reality, scum o' the earth degenerate
>> known as Al Schwuartis...whatever...Uncle Al.  However, I do reserve
>> the right to ammend this post, demanding that the said Uncle Al be
>> executed (electronically speaking) forthwith (i.e. immediately).
>
>
>I was always wondering, why the defenders of free speach are so eager to 
>execute everyone whose opinion differs from theirs?  "We are for 
>democracy, so we'll lynch everybody, who's against it", right?  How nice 
>of you, Mark Tarka.  You HAVE the right to talk, but yet you'd like to 
>deny this right to Uncle Al, presenting this as "protection of a free 
>speach".  YOUR speach.  If you're so concerned about the freedom, why are 
>you jealous towards the freedom of others?  I'm not even mentioning the 
>disgusting rude language you used.  Would you please learn some manners??
>
Lev, I think you may be taking Mark's words a little too seriously.

Jerry (Ico)










DOC0348

Subject:      Re: Dangerous/Illegal Demonstrations
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/05/21
Message-ID:   <4ntld1$7kr@geraldo.cc.utexas.edu>
Newsgroups:   rec.pyrotechnics,sci.chem,alt.engr.explosives,sci.engr.explosives



In article <4nt440$jnq@mailhost.zeneca.co.uk>, Geoffrey Cooper <geoff.cooper@uawrc.zeneca.com> says:
>
>Mike Herauf <m.herauf@ix.netcom.com> wrote:
>>Carrying a gas mixture (I think H2 and Cl2) across a parking lot from the physics 
>>building to the chemistry building, a professor was preparing for the annual Chem. 
>>100 stoichiometry lesson. The balloon is usually set off with a flashbulb, showing 
>>its photoreactivity to a specific wavelength, previously not set off with a 
>>low-power laser of inappropriate frequency. However, this particularly bright day, 
>>the sunlight set it off while in transit and knocked him unconscious for a few 
>>seconds.
>>
>>I don't remember the gasses involved, would H2 and Cl2 do this?
>
>Mike,
>     Isn't it Cl2 and CH4 that make the classic photochemically initiated 
>reaction?  Our instructor set it off (within an inverted graduated 
>cylinder immersed in water) with light from a burning strip of magnesium.
>
The reactions you two are talking about both depend on photoactivation 
of a chlorine molecule followed by a chain reaction.  The reaction with
hydrogen is the "classical" one, but the mechanism is essentially the 
same.  The hydrogen-chlorine reaction is not one I would suggest relying
on not to occur in the absence of a photon or two. 

Jerry (Ico)









DOC0349

Subject:      Re: Dangerous/Illegal Demonstrations
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/05/22
Message-ID:   <4nvmh9$eo9@geraldo.cc.utexas.edu>
Newsgroups:   rec.pyrotechnics,sci.chem,alt.engr.explosives,sci.engr.explosives



In article <4nv6ff$ljv@clorox.news.pilot.net>, Mike Herauf <m.herauf@ix.netcom.com> says:
>
>Geoffrey Cooper <geoff.cooper@uawrc.zeneca.com> wrote:
>>Mike Herauf <m.herauf@ix.netcom.com> wrote:
>>>Carrying a gas mixture (I think H2 and Cl2) across a parking lot from the physics 
>>>building to the chemistry building, a professor was preparing for the annual Chem. 
>>>100 stoichiometry lesson. The balloon is usually set off with a flashbulb, showing 
>>>its photoreactivity to a specific wavelength, previously not set off with a 
>>>low-power laser of inappropriate frequency. However, this particularly bright day, 
>>>the sunlight set it off while in transit and knocked him unconscious for a few 
>>>seconds.
>>>
>>>I don't remember the gasses involved, would H2 and Cl2 do this?
>>
>>Mike,
>>     Isn't it Cl2 and CH4 that make the classic photochemically initiated 
>>reaction?  Our instructor set it off (within an inverted graduated 
>>cylinder immersed in water) with light from a burning strip of magnesium.
>>
>>Geoff
>>
>
>Very possibly. The exact reaction escapes me. What would the products of CH4 and Cl2 
>be?
>
The mechanism of the H2-Cl2 reaction is:

Cl2 + photon -> 2[Cl]

[Cl] + H2 -> HCl + [H]

[H] + Cl2 -> HCl + [Cl]

The reaction with methane would follow a simiar form with the 
appropriate methyl or substituted methyl radicals.

One might reasonably expect to get some of all the chlorine-substituted 
methane species, elemental carbon and ethane species with amounts 
depending on the ratio of starting materials and the concentration
(pressure) of the mixture.  The formation of HCl is the primary driving
energy for the reaction as the C-Cl bond is relatively weak.

Either of these two reactions would be somewhat quenched by surfaces,
but the efficiency of quenching would be very low, especially for 
surfaces with a coat of water.

Jerry (Ico)









DOC0350

Subject:      Re: Lifting capacity of helium
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/05/22
Message-ID:   <4nvon6$eo9@geraldo.cc.utexas.edu>
Newsgroups:   rec.models.rc.misc,sci.chem,rec.models.rc.air



In article <31A33271.4B113C13@MIT.EDU>, Christopher C Stratton <stratton@MIT.EDU> says:
>
>A lot of people have been replying with numbers on the order of
>25g/mole, but this assumes that the pressure inside the balloon
>is the same as outside.  Because the rubber is elastic, the pressure
>inside will have to be greater, thus the density will be higher and 
>one will not get this much lift.  I don't really know what
>the reduction would be, but I could imagine it would be as much
>as half.  Also, this effect would tend to widen the gap in available
>lift between hydrogen and helium.
>
>I think probably the best thing to do is just experiment.  You
>might get some idea from small rougly circular balloons,
>but the effect may not be of the same maginitude with larger ones.
>thus you probably won't know until you try it.
>
>It would be possible to inflate a large balloon with air, then
>measure the pressure at the neck and figure out the density
>inside from that.  This should make it possible to calculate
>the lift that would be available if the air were replaced
>with helium.
>
The pressure inside a rubber balloon is not very high, in most cases.
well below 1 psi.

For RC work one would probably prefer a so-called "Mylar" 
(Sorry, duPont. Registered trademark) balloon in which the pressure may
be set at zero if necessary.  The rupture pressure of such a balloon 
large enough to carry an RC payload would be a fraction of a psi.
For small balloons the primary correction for lift is the weight of the 
envelope.  The envelope weight of an 18" (lay-flat) Mylar balloon is
about 10 grams and the gross lift is only 13 grams (net = 3 grams).
Larger balloons, of course, have lower envelope weight ratios.

Rubber balloons are a lot lighter than the plastic ones but they lose
helium much faster.

Jerry (Ico)













 

Jerry (Ico)


DOC0351

Subject:      SONIA DIDN'T DO IT
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/06/09
Message-ID:   <4pdvs3$o5n@geraldo.cc.utexas.edu>
Newsgroups:   sci.chem



The original articles posted on this subject were not favorably received 
in sci.chem so the thread will not be posted here. Fortunately, we have 
found the needed analytical chemistry expertise elsewhere. For those 
who are interested there is a new article in sci.med.cardiology and 
sci.med.pathology. Comments for my attention should be by e-mail.







DOC0352
Subject:      Coal tar solvent naphtha compositions
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1996/11/03
Message-ID:   <55j5li$oki@geraldo.cc.utexas.edu&gt>
Newsgroups:   sci.chem

I was in the library last night looking for information on typical
compositions of coal tar naphthas in the approximate boiling point
range of gasoline. I am particularly interested in the distribution of
C3 and C4-alkylbenzene species and indan derivitives and how it
compares with typical gasoline or reformate compositions.

Unfortunately, nearly all the references on coal tars are now in
storage and not available for perusal by non-student, non-faculty 
chemists.  I guess coal is no longer a hot topic in the schools :)

Does anyone here have any such data on typical compositions or perhaps
some chromatograms or pointers to such information?  I would like to 
compare the apparent relative abundance of the various isomers.  Most 
of the literature so far within my reach gives some data for benzene, 
xylene isomers, naphthalene and methyl naphthalenes but refers to the 
inbetween stuff merely as "naphtha."

I am also interested in any studies of the pyrolysis products of other 
organic materials such as wood or plastic which yield aromatic species 
such as those mentioned above.  I would like to compare the distribution
of species in such products with those of the better characterized 
Friedel-Crafts alkylations and disproportionation reactions.

Thanks,

Jerry











DOC0353

Subject:      Re: Lye/Aluminum reactor?
From:         glhurst@onr.com (Gerald L. Hurst)
Date:         1997/02/14
Message-ID:   <5e16j5$fa0@geraldo.cc.utexas.edu>
Newsgroups:   rec.pyrotechnics,sci.chem,alt.engr.explosives



In article <5e11vv$6v4@crl13.crl.com>, gherbert@crl.com (George Herbert) says:
>
>You can use water as fuel with ClF5 oxidizer, but nobody does... hydrazine
>is much higher specific impulse.  There is a ClF5-hyd motor and associated
>upper stage that were recently developed by the DOD for high performance
>transfer stage usage.
>
It is good to hear that the early work on ClF5 has born some fruit.
I designed, built and managed the Aerojet-General pilot plant which
churned out 8,000 lbs of ClF5 for experimental purposes back in 1966.

In those days, ClF5 was unknown in the open literature.  Perhaps the
happiest day of my life was the day the program was completed and
I was finally able to shut down that monster plant which had been
running around the clock in a perpetual fog of evaporating liquid
nitrogen.

It seemed that whenever the plant blew, there was rain to ignite 
the ClF5 gas escaping from the various ruptured high and low pressure 
lines. The dripping cold liquid also put on a pretty pyrotechnic
display as it burst into white flame on contact with the concrete
plant floor.

As a reward for working 20 hours a day, seven days a week for months 
the division V.P. offered me a sincere apology for the tiny Christmas 
bonus (based solely on a low seniority level). As a consolation prize I 
was given a standing ovation (attaboy with clapping) by the fully 
assembled Aerojet V.P.s and handed an extra week's vacation.  Later, 
the V.P. of my division said to me, "You B******, you used that week 
to find another job."  He was right.  I got a super raise and a night
of unlimited banana cows by joining the new Explosives Corporation of 
America (EXCOA) as their Chief Scientist. Working with ultra-sensitive 
explosives was like a vacation after dodging hot ClF5 at at obscene
pressures.

Despite my abrupt departure from Aerojet, I really did like that
company and I understood that the boss' hands were tied by inflexible
company policy. After all, I had volunteered to take over the then 
unproductive plant after being forewarned by the previous manager 
(a once sane PhD engineer) whom I met babbling to himself in the 
hallway about needing an exorcist.  

Besides, I learned the valuable lesson that no good deed goes 
unrewarded at best or unpunished at worst :)

Frankly, I miss those early days of both the aerospace race and the
entrepeunerial explosives research nurtured by the Viet Nam problems.
Both of these situations created incredible R&D environments where 
the only limitation was the imagination. In those days science was
actually a respected occupation.  Don't get me wrong though. I 
wouldn't do it again for any amount of money.  It took an undeserved
lot of pure luck to survive the learning curve.

Jerry (Ico)


