Session Start: Wed Jun 17 07:59:55 2009 Session Ident: #Chemistry [07:59] * Now talking in #Chemistry [07:59] * chemistry.gravitywaves.com sets mode: +nt [08:55] * freddy has joined #Chemistry [09:53] * Shelley has joined #Chemistry [09:54] * kristya has joined #Chemistry [09:55] * Makala has joined #Chemistry [09:55] hello [09:56] hey [09:56] hey guys. [09:56] man im having some troubles with chapter 10 [09:57] uh oh [09:57] she said today would be a short day, so maybe you are just over thinking it... [09:57] * spike has joined #Chemistry [09:57] im having troubles with chapter 3.... LOL no im kidding. [09:57] * marygrace has joined #Chemistry [09:57] lol....i hope so [09:58] hahaa, sorry im really tired. <> ;] [09:58] it was lol.....i was talking about me over thinking it lol [10:00] hey there mary how are things going? [10:01] * KevinE has joined #Chemistry [10:01] * DrSturm has joined #Chemistry [10:03] * marygrace has quit IRC (Quit: Leaving) [10:03] Lot of people missing.....will give it another five minutes [10:03] * MikeH has joined #Chemistry [10:03] Any questions? [10:03] * marygrace has joined #Chemistry [10:03] * jicra has joined #Chemistry [10:04] will you tell us what mechanism you want us to use like last test? [10:05] Yes [10:05] For the addition of halogens to alkenes, the powerpoint shows them adding in syn fashion, but I had a note about using them in anti? [10:05] * marygrace has quit IRC (Read error: Connection reset by peer) [10:05] * KevinE has quit IRC (Quit: Leaving) [10:05] * KevinE has joined #Chemistry [10:05] Yes they add anti which we will see today, i just skipped ahead so that you would get used to drawing them anti [10:06] * jicra1 has joined #Chemistry [10:07] will the questions you assigned for chapter 10 be similar to what we will see on the test? [10:07] * Guest has joined #Chemistry [10:07] * nicole has joined #Chemistry [10:08] how much of the test will be conceptual and how much actual reactions [10:08] No, sorry for the delay was refreshing my memory on those problems [10:08] * marygrace has joined #Chemistry [10:08] It will be mainly nomenclature and reactions [10:09] 2. Will exam be cumulative? IE any competition between sn2/sn1 and e2/e1 [10:10] Things in organic chemistry are always "cumulative", in that you must remember the previous reactions, nomenclature etc [10:10] so i should not really focus on chapter 10 hw and focus more on the reactions and nomenclature right? [10:10] The only mechanisms would be Ei, E2 and HX [10:10] * jennyy has joined #Chemistry [10:10] Yes, I have decided that the only things you must know from chapter 10 are: [10:11] Definitions for Stereoselective and stereospecific, Slides 3 and 4 [10:11] Also the table on Slide # 34, also on the work sheet for chapters 9 and 10 [10:12] what happens with primary alkyl halides in weak base? That wasnt addressed in the slides [10:12] * KevinE has quit IRC (Quit: Leaving) [10:12] * KevinE has joined #Chemistry [10:12] This should make it possible for you to focus more on Chapters 8 and 9 [10:12] Don't worry about primary halides in weak base [10:13] So for Chapter 10 just the definitions for stereo-selective and -specific (Slides 3 and 4) and the table on Slide # 34 [10:14] will we also be expected to draw out isomers? [10:14] Hope this helps some as i know there are a lot of reactions to learn for the exam tomorrow [10:14] Isomers? [10:15] yes, when labeling which is the major product [10:15] i beleive there was an example is chapter 8 [10:15] Yes, my approach would be to draw all possible products then label the major one [10:15] ok [10:15] I had a dream last night that I was on a date, and all we talked about was O-Chem. [10:16] At this point it is the best method to reduce possible errors [10:16] No joke! Its intense [10:16] lol [10:16] Again I advise you to use the homework and work sheets with no notes to really judge your preparation [10:17] Watch for mistakes like incorrect numbers of carbons, carbon with five or three bonds to it [10:17] * batkins1 has joined #Chemistry [10:19] Any questions on Chapters 8 and 9 so far? [10:19] So we are all done with chapter 10 then? [10:19] trans 2 butene and cis 2 butene react with br2 to both form a meso compound? [10:20] Yes, chapter 10 basically explains the mechanisms or the why, for addition of halogens being anti, hydroxylation with KMnO4 being syn, with HCO3H anti [10:21] No trans gives a meso compound and cis a racemic, optically inactive, mixture [10:22] BTW that is beyond the scope of the exam [10:22] It is a good question but don't wnat people to worry... [10:22] for elimination do we need to make sure that the beta hydrogen is "anti" to the halide [10:22] * Makala has quit IRC (Quit: Leaving) [10:22] No, if there is elimination the beta hydrogen will be anti [10:23] i.e. dehydrohalogenation with KOH or NaOH in alcohol the beta hydrogen will be anti [10:25] when writing out the mechanism, do you want us to write out the inorganic products as well? [10:26] No, but you must use the actual compounds given in the problem not the generalized compounds that are shown in the slides [10:26] Are the only strong bases that undergo e2 KOH NaOH and salts of methanol and ethanol? [10:26] Are the only strong bases that undergo e2 KOH NaOH and salts of methanol and ethanol? [10:26] when we write out the product of a reaction, do we need to write the name of it or just the structure? [10:27] The salts of methanol and ethanol give SN2 substitution with methyl and primary alkyl halides [10:27] * Guest has quit IRC (Quit: Leaving) [10:27] Only KOH and NaOH in alcohol give 100% E2 elimination [10:28] You would only need to name the product if specifically asked to do so in the question [10:30] what happens if there are no beta hydrogens, do we assume substitution? [10:31] If there are no beta hydrogens you can't have dehydrohalogenation [10:31] on the exam will we be dealing with any carbanions or just carbcations? [10:31] The only examples I can think of would give you a carbon that has five bonds.....i.e. extrememly sterically hindered alkyl halides [10:32] We haven't discussed carbanions yet. [10:33] ok it was mentioned in chp 8 i just wanted to be sure [10:35] No we didn't discuss elimination via carbanions [10:37] Any questions on homework? [10:38] on question 8.1 (a) what would be the best way to draw out all isomers? [10:40] Just be systematic like we were for the isomers of alkanes and the monohalogenation products of alkanes [10:40] Watch to make sure you keep the same number of carbons and hydrogen in every structure and that no carbon has five bonds [10:40] will you use Tosylate (ch 8 question 5d) on the exam? [10:41] No tosylates on the exam [10:42] so in terms of freddy's question, it doesnt matter if we write the Hs out the he side or just show it in the number? [10:43] You can use condensed formulas unless you are showing geometric isomerism [10:43] sorry, i meant out to the side our just show it in the number [10:43] oh ok [10:43] * Jicra2 has joined #Chemistry [10:44] * Jicra2 has quit IRC (Quit: Leaving) [10:45] So we don't need to know anything from chapter 10 except the definition of stereoselective and stereospecific? [10:46] I will remain in the chat room for the next 15-20 minutes to answer any additional questions, after that I will be available via e-mail. [10:46] and the table shown in Slide #34 [10:46] do we need to use those reactions in a synthesis [10:47] or just know the products [10:47] what reactions? [10:47] the ones on #34 [10:48] short synthesis problems no more difficult than those seen in the hoework are always a possibility [10:48] ok and can you explain how anti addition leads to an epoxide? [10:48] you need to show syn and anti, where applicable, when drawing products [10:49] an epoxide? [10:49] yes [10:50] an epoxide is made from an alkene with the addition of PBA [10:51] it is the addition of an diradical oxygen atom [10:52] will you post this chat after you log off? [10:52] yes. [10:52] thank you for your help Dr. Sturm.....see you all tomorrow [10:53] * freddy has quit IRC (Quit: Leaving) [10:53] O.K., see you tomorrow [10:53] * jennyy has quit IRC (Quit: Leaving) [10:53] * Shelley has quit IRC (Quit: Leaving) [10:54] according to the slides it says that hydroxylation with HCO2OH forms an epoxide intermediate [10:54] * kristya has quit IRC (Quit: Leaving) [10:54] so if we saw a hydroxylation with HCO2OH reaction, would we show the epoxide as the product? [10:55] * spike has quit IRC (Read error: Connection reset by peer) [10:56] Yes so the epoxide opens up as the OH adds leaving you with an anti product [10:56] No you would show an anti diol [10:56] the epoxide is an intermediate and you can not isolate it [10:56] epoxide formation is part of the mechanism [10:57] oh i see [10:58] so when they say anti and syn oxidation that refers to addition of 2 oh groups? [10:58] yes the product of an alkene and cold KMnO4 is a syn diol, with HCO3H an anti diol [10:59] ah thank you now I understand [11:01] O.K., I am going to post this log and if you have more questions please e-mail. [11:01] * jicra has quit IRC (Quit: Leaving) [11:01] * KevinE has quit IRC (Quit: Leaving) [11:02] * DrSturm has quit IRC [11:02] * Disconnected Session Close: Wed Jun 17 11:02:27 2009