W08 midterm2 key

W08 midterm2 key - Dr. Manashi Chatterjee 6 kg Cheflfi...

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Unformatted text preview: Dr. Manashi Chatterjee 6 kg Cheflfi 0A-Winter 2008 Last First MI - Name w Midterm # 2 Name of your TA: Bree / Eric T l ota : / 100 (50 mins) (Please Circle) Wednesday, February 27, 2008 Discussion Section - Day : Time: Chem 30 A Winter 2008 Electronegativity values for some atoms (Pauling scale) DO NOT OPEN THIS EXAM UNTIL INSTRUCTED TO DO SO Dr. Manashz' Chattery'ee Chem3 OA- Winter 2008 Q 1. (2 points) Which is the intermediate formed in the reaction of propene with Brz? a C) r /,/”\\\\ Answer is: b Q 2. (3 points) Which of the following alkenes have E configurations? c Cl cucn F Br Cl / / 2 Br /c// >c=c )c:c< >czc/ >:c H E CICHZ c: CH3 \1 H \-—OH 1 11 IH IV (a) 1, IV (b) 1, 11, IV (c) 111, IV (d) All ofthe above Answer is: b Q 3. (2 points) Which of the following alkenes is most likely to undergo rearrangement upon acid catalyzed hydration (treatment with aqueous H2804)? II III IV Answer is: 2 Q 4. (3 points) Which of the compounds has a hydrogen deficiency of 3? \ OH 1 2 3 4 (a) Only 1 (b) Only 2 (0) Only 3 and 4 (d) Only 1, 3 and 4 ’ _V Answer is ( S Dr. Manashi Chatteiy'ee Chem3 OA- Winter 2008 Q 5. (18 points) Draw the major organic product(s) generated in the reaction below. Show correct stereochemistry where ever required. I. + HCI —-—--+ H2804 (catalyst) 11_ ®iCHZCH3 + H20 III. W + HBr IV. Br "—’ C>f© + 2 CHZCIZ COOH V. g + NH3 _. Vl- \\\/\»‘f + H Br _____> B —> VII. D + r2 CHZCIZ Dr. Manashz' Chatteiy'ee C hem3 0A- Winter 2008 Q 6. (8 points) Circle the strongest acid in each series shown below. a. H20 H28 CH3CH2CH3 \ 0 CH2 AL AL H30 CH3 H30 CH3 c. CH3 CHZCH3 ClCHZCHZOH/1 CH3CH20H OH d. H 30’ : Q 7. (12 points) Write the products of the proton transfer reactions. Predict the direction of equilibrium (circle the correct arrow). pKa of acids are given below. Ll pl”) \\/. O < 9| i I. CH3 9 + H—riJ—CH3 O b. 1 33k Phenol: pKa = 9.95 CH4 : pKa = 51 CH3COOH : pKa = 4.76 CH3NH3+: pKa = 9.24 HCl: pKa = —7 H20 : pKa = 15.7 H2CO3 I pKa = Dr. Manashi Chatterjee Chem3 OA- Winter 2 008 Q 8. (10 points) Propose a step wise mechanism for the following reaction. Draw curved arrows to show moment of electrons. CH3 H O /\/\/OH 2 / H2804 o (Racemic) Dr. Manashi Chatterjee Chem3 OA-Winter 2008 Q 9. (4 points) For each molecule circle the most acidic and the least acidic protons. 1. O O Most acidic: Ha l Hb HC Ha Hc 4/ \O H” H” Least acidic: Ha Hb 6C He 2. ,,\ Most acidic: Hb Ho Ha 0 Least acidic: Ha Hb 6 \O i D Q 10. (5 points) Locate the chiral centers (stereogenic centers) in the compound shown below. Indicate them by * on the compound. Simvastatin Cholesterol lowering drug How many stereoisomers can Simvastatin have? 2 Q 11. (4 points) Identify the isoprene units in the molecules below (circle the units). Indicate the head to tail or head to head linkages by broken lines. 0 Compound A has ‘3 isoprcne units Compound B has 8 isoprene units 3 pt .5 . a p36 N arch HOHZC H2 H2 0 / O \ Dr. Manashi C hatteijee C hem3 OA- Winter 2 008 Q 12. (4 points) Given (R)—2—bromobutane has a specific rotation of -23.0°, what is the optical purity and % composition of a mixture whose specific rotation was found to be +18.4°? 8H \ H ,. , -—-—'f" 7s \0 O ‘9 fill“) Optical purity: 80V 9‘5 CO; %ofR: if) I ‘00“l @133 xmfl :7 =1 \‘ %ofS: (O'P‘ +y;\2) Q 13. (2 points) What is the correct order of stability of the following carbocations? (more stable > less stable) @ a a la ck l? 1. A)l>2>3>4 B)2>3>4>1 C)2>4>3>1 D)4>3>2>l Answer is: C Q Q 14. (4 points) Draw the structural formula for (1E,4Z)-l,5-dichloro—1,4—hexadiene. Dr. Manashi Chattery'ee Chem3 0A- Winter 2008 Q 16. (6 + 5 points) a) Draw the structure of one possibl@triacylglycerol formed from one molecule ofstearic acid and two molecules of oleic acid. b) Draw the structure of any other fatty acid that will have a lower melting point than 4 0C. O Stearic acid We” mp 69 °C 0 cI IO / 0H Oleic acid mp 4 °C 9 ..\ A ‘ ' _ \ Chfcd‘k “a” U QWM ) it" ,__ H’Q\'r0 "r (a .1 O C \-\&~()v— "‘ \Y/ "I 0 Structure of a chiral triacylglycerol kfiaocff r C13 Chkbki ac; wuefiae mam peeking cu; ~<_; —— c ~13 ecm‘cé * t V. _ . H~ Q ‘~ C; w- idem) L ‘ <1; ‘1 to .- t . -— :\/\/\/\/ Cfiaw Q '~ CA' \ \ O /\ Structure of a fatty acid that will have a lower mp (0C) than Stearic acid and Oleic acid ...
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W08 midterm2 key - Dr. Manashi Chatterjee 6 kg Cheflfi...

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