tag:blogger.com,1999:blog-16612221.post1503651298361740948..comments2024-03-19T03:14:04.172-04:00Comments on Rabett Run: EliRabetthttp://www.blogger.com/profile/07957002964638398767noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-16612221.post-70094807118482580602009-09-07T21:06:13.830-04:002009-09-07T21:06:13.830-04:00EliRabett & Tracy P. Hamilton --- I think I ha...EliRabett & Tracy P. Hamilton --- I think I have it now. Thak you!David B. Bensonhttps://www.blogger.com/profile/02917182411282836875noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-30405733270895691402009-09-07T10:30:52.355-04:002009-09-07T10:30:52.355-04:00A note to all bog whores. Eli will delete all non...A note to all bog whores. Eli will delete all non clever attempts and leave your name there as a sign of shame. <br /><br />Be creativeEliRabetthttps://www.blogger.com/profile/07957002964638398767noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-73831149813956711332009-09-07T07:26:04.217-04:002009-09-07T07:26:04.217-04:00Eli, great site, thanks - the "hot spot"...Eli, great site, thanks - the "hot spot" list actually had a few I hadn't looked at yet that might be very useful if I ever write up what I was working on on that...<br /><br />On a probably completely unrelated note, I've been looking at the issue of modeling heat absorption by the surface diffusively as an improvement over the single-time-constant (fixed heat capacity) approximation. I'm sure climate models must do something along these lines, and it's got to be a standard solved problem, but I'm having trouble tracking down an analytical solution (if there is one).<br /><br />Basically the problem is the semi-infinite one-dimensional heat equation with source at x=0 (the surface), but that boundary condition depends on a relationship between dT/dx and T at x = 0 (I think this qualifies as mixed boundary conditions - not Dirichlet or Neumann anyway). I'm feeling pretty rust on this one, if anybody has more of a clue I'd appreciate it, thanks!Arthurhttps://www.blogger.com/profile/06249922708053689717noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-57879253489578047412009-09-07T03:30:34.804-04:002009-09-07T03:30:34.804-04:00This comment has been removed by a blog administrator.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-56069919261801888272009-09-06T22:10:42.564-04:002009-09-06T22:10:42.564-04:00About C + 2H2 -> CH4, what Eli said, keeping in...About C + 2H2 -> CH4, what Eli said, keeping in mind that at higher temperatures entropy is going to kill you. deltaG is zero at 935K. Maybe the Born-Haber design would be an appropriate start.<br /><br />TP HamiltonTheChemistryOfBeerhttps://www.blogger.com/profile/04228308036995626376noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-7918550773018109002009-09-06T21:55:35.969-04:002009-09-06T21:55:35.969-04:00David, a good way to think about this is that to m...David, a good way to think about this is that to make CH4 from C and H2, you have to first break two hydrogen bonds and that costs a lot of energy. You either need a lot of heat and/or pressure or an electrical discharge or a catalyst and slightly less of the above. The role of all of these is to break the hydrogen bonds. That requires a lot of energy<br /><br />H2 --> H + H is very endothermic without a catalyst. The heat of reaction is 436 kJ/mol. <br /><br />The overall heat of reaction is easy to find since the heats of formation of C and H2 (assuming C is graphite, which is close enough) is zero and that of methane is -74.8 kJ/mole so on net you get 74.8 KJ out of the system, it is exothermic.<br /><br />C + 2 H2 --> CH4EliRabetthttps://www.blogger.com/profile/07957002964638398767noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-90946857824835788802009-09-06T20:04:18.939-04:002009-09-06T20:04:18.939-04:00I swear I've seen this site before, and have i...I swear I've seen this site before, and have it bookmarked, but not on the radar. <br /><br />And a second to Marion's Zotero. I use it a lot. Scrapbook, not so much.<br /><br />Best,<br /><br />DDanohttps://www.blogger.com/profile/03709762632849004871noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-71638387087545495872009-09-06T19:37:49.712-04:002009-09-06T19:37:49.712-04:00This is off-topic, but chemists lurk here.
I have...This is off-topic, but chemists lurk here.<br /><br />I have some carbon and some hydrogen (thought experiment only). I want the reaction<br />C + 2H2 --> CH4<br />which I suppose is exothermic, but does this require some catylist, some strting heat or other special circumstance?David B. Bensonhttps://www.blogger.com/profile/02917182411282836875noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-39922087653866468212009-09-05T23:57:00.330-04:002009-09-05T23:57:00.330-04:00Let me make a plug for Zotero, too, Eli. It's ...Let me make a plug for Zotero, too, Eli. It's the bibliography plugin for firefox. goes well with sites like that.Marion Delgadohttps://www.blogger.com/profile/09493068399042656060noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-4235574422371858532009-09-05T23:55:11.143-04:002009-09-05T23:55:11.143-04:00Thanks Eli. That's great. I've added AGW O...Thanks Eli. That's great. I've added AGW Observer to my list: <a href="http://rationallythinkingoutloud.wordpress.com/references-for-debating-climate-change-skeptics/" rel="nofollow">References for Debating Science Deniers.<br /></a> - Jerrald HayesJerrald Hayeshttps://www.blogger.com/profile/04419739299497567553noreply@blogger.com