Thursday, February 10, 2011
Organic Test 1
After taking the first Organic Test I realized the hardest point for me was when the compound was given and we needed to construct either a H NMR, C NMR, or a mass spectrum of the compound. Being able to determine where exactly the peaks are suppose to go is the most difficult for that. However, one thing that I felt that would have been on the test but wasn't was radical halogenation since radical halogenation reactions occur with racemization at a stereogenic center and predicting the stereochemistry of the reaction products. In addition to this, I thought there might have been a question about chlorination versus bromination. Even though alkanes can undergo radical substitution reactions with both the Cl(2) and Br(2) chlorination and bromination both exhibit two differences which are: the fact that chlorination is faster than bromination and even though chlorination may be unselective and yielding a mixture of products; bromination is consistent for selective and only yielding one product. So with this I thought there might have been a problem where you had to draw the major product formed for when a cycloalkane is heated with Br(2).
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I agree with you on your first statement that drawing H NMRs and Mass Specs were difficult. I think this was due to the fact that we had had no practice drawing them before, and also because of the time constraints. I do not, however, really agree with the test question that you thought would be on the test. After asking around, I found that many people thought there would be a question about Cl2 and Br2 in terms of what the ratios of their peaks are. I don't think thats an adequate test question; I thinks it's just something to take note of and keep in the back of your mind. Your question is more complex, takes more thought, and it is a good question. The focus of this test was on spectrums and how to read them or understand how they work. Your question seems more like a reaction question, which I don't feel was the major focus of this test. Good question, but not for this test. =)
ReplyDelete-The High School Chemist
I agree with you about the test being very hard and I also thought that drawing HNMRs and CNMR were very difficult as well. However, your test questions would've not been a choice of mine; I would've liked to have had a question like Cl2 and Br2, but didn't expect it to be on there at all. Also Dr. Mullins gave us a website: http://www.wfu.edu/~ylwong/nmr/c13/ if you need help with Carbon Nuclear Magnetic Resonance, because you never know it could possibly show up on the next test. There also was a lot of questions I thought would be on the test that wasn't like problems 15 and 16 on sapling, where it ask you to tell how many unique HMNR and CNMR signals exist for each compound, but instead there hardly wasn't anything about signals on the test. Overall, I agree with you about the difficulty of this test, but I agree with Don about the focus of the test was on spectrum an how to read them and your question doesn’t really go by that. I hope you did well though!
ReplyDelete-Alexia