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| JRH
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2573
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10-22-2009 11:08 PM ET (US)
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Dr. Norris, on the 2006 Exam 2, why is 10a not (E)-2-methylhex-2-ene but 7b is (E)-6-bromo-4-methylhept-3-ene?
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Peter Norris
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2574
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10-22-2009 11:11 PM ET (US)
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JRH - if you have two of the same groups on one of the alkene carbons then you can't have E and Z isomerism - switch the methyl groups in 10a and you get the same compound.
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| Kaitlin
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2575
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10-22-2009 11:57 PM ET (US)
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Dr.Norris on the 2008 exam question 7 part c how does it go from being 2,2,4,4 tetramethylpentane to a 2,4 dimethylpentane? where do the other methyl groups go?
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| Peter Norris
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2576
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10-23-2009 12:00 AM ET (US)
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Kaitlin - typo, they should be in there.
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| Aud
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2577
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10-23-2009 12:21 AM ET (US)
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I'm glad you caught that too I was super confused! Good luck tomorrow everyone!
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| Anon.
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2578
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10-23-2009 04:24 PM ET (US)
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Thank you, Dr. Norris, for emailing those flashcards. They were very helpful in studying for the exam.
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| jeff
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2579
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10-23-2009 05:55 PM ET (US)
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That didn't do so well. Time to regroup !
Anyhow... when does the answer key go up ?
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| ANON
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2580
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10-23-2009 07:32 PM ET (US)
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Dr. Norris, Don't forget to post the averages!! Thanks
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| Peter Norris
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2581
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10-24-2009 12:37 AM ET (US)
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Those summary slides seemed popular so I'll also do them for the upcoming mechanisms. Answer key is written will be posted on Monday afternoon; the average should be available sometime late tomorrow. Sunday is Liverpool-Manchester United so I want grading out of the way.
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| Peter Norris
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2582
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10-25-2009 01:37 AM ET (US)
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Grades are done and the exams will be handed back on Monday at the end of class.
High of 97, low of 17, average of 77/100 which is is very good.
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| ANON
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2583
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11-02-2009 03:23 PM ET (US)
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Dr. Norris,
Will we be getting the mechanism flashcards again?
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| Peter Norris
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2584
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11-02-2009 10:42 PM ET (US)
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Anon - hopefully when I get an hour to do them. Addition of Br2 (with and without H2O), the ozonolysis, plus the epoxidation would probably be useful.
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| Jeff
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2585
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11-03-2009 04:17 PM ET (US)
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| Kaitlin
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2586
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11-04-2009 08:01 PM ET (US)
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Dr. Norris,
im having trouble trying to figure out why a weak acid was used to wash the crude tpentyl chloride in the lab. i believe i know why we didnt use NaOH but i cant figure out why we used sodium bicarbonate instead.
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| Peter Norris
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2587
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11-04-2009 08:10 PM ET (US)
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Kaitlin - you used a weak base (sodium bicarbonate) instead of a strong base (sodium hydroxide) to avoid a base-promoted E2 reaction.
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| Kaitlin
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2588
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11-04-2009 08:12 PM ET (US)
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oh wow, i was definately thinking into that too far, thank you Dr. Norris!
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