mt2au08key - Copy (2)

mt2au08key - Copy (2) - _ Callarn Midterm #2 200 points...

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Unformatted text preview: _ Callarn Midterm #2 200 points Name (PRINT) Chemistry 251 _ Autumn 2008 Kay I have neither given or received aid on this exam (SIGN) Place an X in the box to the left of your recitation section. Failure to mark your correct recitation section will result in —5 points from- your exam total: 1:30 pin—2:18 p.111. Kamala Kunchitha - atham 1:30 p.rn.—2:18 p.m. Kamala Kunchithaatham Will Henderson 1:30 p.m.—2:18 p.m. Amanda Kutney 2:30 pin—3:18 p.m. Kamala Kunchitha - atham Will Henderson Amanda Kutney 2:30 p.m.i3:18 p.111 Kamalar Kunchitha - atham 2:30 p.m.—3:1_8 pm. Will Henderson 2:30 p.m.—3:18 pin. Amanda Kutney Will Henderson 2:30 p.m.-3:18 p.111 Amanda Kutney ' Please read all of the directions for each section of the exam carefully. - ‘ There are 14 pages including this cover page for Midterm #2, please check to make sure you have all of the pages. Make sure your answers are clear. Any structures or answers that are unclear tar-ambiguous are considered wrong. If you place an X in the lower left corner of page 10 off from your exam you will receive +3 points. 0 GOOD LUCK! Do your best Page 1/14. V 00054 , 4 Callam « . Chemistry 251 Autumn 2008 0905 - Part 1. Rankiag. There will be no partial credit on Part 1 of the exam. a) Rank the following allqu halides in order of increasirig 3N2 reactivity. (1 — least reactive, 3 -— most reactive) (3 points) i t . E .3 __ /\/\Cl' b) Rank the following alkyl halides order of increasing 8N1 reactivity. (1 — least reactive, 3 - most reactive) (3 points) , Osz< Hacom . Br; ' Br ' . Br I . . a.) .i- 3 0) Rank the following alkenes‘in order of increasing stability. (1 m least stable, 3 — most stable) (3 points) .,2\- aY_ a, ' \ - 3 d) Rank’ the following nucleopbiles order of increasing strength in polar aprotie solvent. (1 ~ weakest nucleophile, 3 - strongest nucleophile) (3 points) ' ' 0 NHL! 2L0” §--|, 2. e) Rank-the following in order of leaving group ability. (1 — worst leaving group, 3 - best leaving group) (3 points). 9 ' 0 o eo—s~CH ' 9 _”_ H 3 _ 0 fi CF3 A O _ o 0 e Z , 3. - -l ' Page 2/14- Callam Chemistry 251 - - Autumn 2003 00054- Patt 2. Iteraacbemiflgr. For each of the folloufing pairs of molecules isomers (1), same molecule (S), enantioroers (E), diastereomers (D), or n in the space provided. ' (2 points each for a total of 20 points) identify them as one of the following: constitutional one of the above (N) by placing the appropriate IetteI 'Ho ‘ H 7 :t - V D - - b ' '3 ' \ ) A:kfi\ \/\E{\/ g) D " D D‘ E I D H a H .OH Br (3) X H _ h) Cl Br 0:" no: a. . . H05 F g E H ‘ H Cl/LCHZCHs fl H ' k N' . o H 9” 0H i d) Br 0 “0 H — ' m . m - H OH O 0” Cl _7 C’ CHon S E Page 3/14 Callarn Chemistry 251 Autumn 2008 ' Part 3. Stereacbemiflgr. Answer the following questions based on the information given. _ Thio-ether [(11255 2 437° 1 2) Draw the enantiomer of the molecule shown and provide the optical rotation [OLPSD in the box above. (3 points) 13) If a solution containing A and B were measured to have an optical rotation of +100 °. What is the enantiomeric excess of the solution and What is the percentage of each compound in the mixture? (4 points) ' “5‘ S0/!) A ‘ c) Thio~ethers undergo oxidation reactions with peroxyaeids to yield sulfoxides and Ia carboxyljc acid as shown in the example below: - , loo° 13?°"00 2 lBO/o €42.03). 69,2 .S. + i O ' I lSOI ' I i I \/..\/ O, -.H \/"\/ I OH Thio-ether Sulfoxide Peroxyacid Carboxyfio Acid Based on this above example, answer the question below. 2 sulfoxides of chemical formula: A . MIXTURE IS OPTICALLY ACTIVE D / ll Ml: ‘5'“ Sf!!! V Y W DmsrsranMMs Page 4/ 14 00054 ' 00054 Callam _ Chemistry 251 Autumn 2003 Part! 4. Predict the Product(s). Predict the orgamc produet(s) of _ the following reactions. When appropriate, be sure to indicate stereochemis try. Ema” than one pmdm‘ zlrfamed be run: 1‘0 z’ndz'mz‘e tbe majorpmdurt, .rtereotlromer: ampmdwed in tbe martian be new to indzkcéz‘e tbs mlafiombtp betmm them. Draw all answers in skeletal form. You will be graded on the'product you draw from the reaction no other information is needed for this question. (4 points each for a total of 40 points) Ho ‘ _/"'”'\/ NaCN, / \ ' NaOCH3 MATOR. NaSH, CH30H20H —--—-——-—+ (CH3J3COLi (CH3)3CHOH _ Page 5/14‘ Callam Chemistry .251 Autumn 2008 00054 \ . MO” H20 ' L 0 9‘ 0“ q 1 ——-——-——> i \' Chemical Formula: cameo O=§’ _ - / . + emam-H‘a WUU/ CH3 _ (\Br ____. k . Br NaOH (2 equiv.) _ A S . ______,_ f A r r K ‘ . g . _ ’ mi 7: + I ___________’ 7 1.‘ NaSH - ‘ - 2. NaOH 3. CH308020H3 Br ‘ H30 ' I ' NaSeCH3 I I / 2 I § .Br ' . ' Ill H , Se. CH3: ”‘n’ O Page 6/14 Cellam . _ _ Chemistry 251 ALI—tumn 2008 00057 Part5. Mechanism: and Energy Diagrams. Provide a mechanism for each of the reactions shown below. (10 points) a. ' ' H20, A I oar o 0‘1}; “$53 . Qr® 1:5 . H _ A _ . a ‘- H.153 b. Draw the energy diagram for the reaction in part 3 assuming the reaction is exothermic. _ Label the axes, starting material, l product, transition state, Ba; and AHD. (5 points) RXM coorwwmvs c. Draw the transifion states(s) for the second step of the reaction reaction mechanism in part a (Be sure to include correct bond angles and relative bond lengths in your drawings). (5 points) ‘~ 5a) H 90 ’— d. Provide the rate equation for the above reaction in part a. '(2 points) Rik-TE. 1 Page 5/14 Callam ' Chemistry 251 ‘ Autumn 2008 0005 Part 5. Nomenclature and Immm. I a. Draw skeletal structures for the following molecules. (4 points) I ,5wd1'methyl-cyclop entene 1 -bromo-3-methylenecyclohexme Q ‘(6 Br b. Provide IUPAC names for the £5110ng alkanes. (4 points) . 7 Br W /\‘/I\ C! 03*" Ml *ZMW (mass mama — aware MW e. Draw the enantiomer of the folloiving compound in a'Fischer projection. (3 points) I - '5“ " o H H N H ' 2 fl . [+0 H CH3 l - H a“? N Hz d. Convert the following Fischer projection-lute a staggereddash—wedged drawing. (3 points) H HO CHO H OH HO H H _H OH 'Page 3/14 CalLam Part 7.’ Prague the ngéntn . Provide the reagents or starting materials to perform the indicated transformations. More than Chemistry 251 one reaction may be required. (4 points each for a total of 16 points) Um ltNd z. /\‘/‘;t [‘BV‘L'hV' 1- (+0 r+o"‘*cpg L BV-‘z'kv C.qu Z~ +ol2, Autumn 2008 Page 9/14 '00056 ' . 00054 Callam Chemxstry 251 Autumn 2008 Part 8. 'Mecbmzz‘wl': Md Exp/ash. a. The following reaction produces two isomeric alcohols (A + B) as shown below: Provide a mechanism that accounts for the formation of both products. (12 points) J” HimH Pica-"‘46. F LOU-u m Pléox NOTOBSERVED ug/ 11+;sn' 142,0 gangst H—sm +NawH 2 NqSH 4 542,0. A may NASH f. MSH I ‘ Ms M 9 _ @ A MSFH 2:} MSM ~r— V l—9‘ PagelO/14- ‘ i9 ' . I 54 Callam ' _ Chemistry 251 _ Autumn 2008 000 c. Using Hammond’s postulate and a reaction coordinate energy diagram, explain why the following substitution reaction takes places at the 3° alkyl halide. (12 points) CI H300 ' - CH OH - 3 ° ' mam cPr’TIM ' ' 3 r . THf-YU I“ emf-60 can” Cl 4: C, ' HE C\ I ' gmoocffliamm @Jéyk lo “lino” aAK $0 CAT—ION ' ' Ffiaam Amcw q Cl: Lon KS {U ' ® ‘ ' Like annexe/nag; E 3 5' cfl-Tlofl “,7 A 7 CL EFL {U Q Lap-meg. 26‘ FOR 3" LflTlu/U' A _ fidc q: (3 coon-GK .l/U E’Nngbl-Lr Km -—-? ' d. The following alkyl halide has unknown stexe chemistry at the position indicated. Upon undergoing an E2 reaction the single product formed is the alkene shown. Indicate the stereochemistry of the starting materials that would allow for this alkene to form as the exclusive product. Draw a Newman projection dowu the cenual bond indicating the relationship between the groups to help support your answer. (12 points) emamy - E l Unknown Stereochemistry Br O 6 >L0Na - - Callam e. For the reaction of X with NaNa in ether the only with NaNg in acetone the major product is the a rationalize these observations. (12 points) or” Cl X NaNa, Ether —‘————-——>. 00054 Chemistry 251 . Auturrm 2008 product formed is inversion. However when compound Y is reaction zide with overall retention of configuration. Suggest a mechanism to \S/W’D‘ NaN3, Ether \S/W’D + \S/W \D . CI N3 N3 Y Major , fie) ‘n D - \\K D‘ . Z ' SN —9 /\l ‘1 C. ‘7. ME I \ S /\ D 3M” 3N2. T . 3 \ Ci 45C m 3 I 9 T ‘b’ - II, ['NWZIQMOLQ CULM lNMMflLELf/LM' G) N3 Page 12/14 STEP (- 'Cafi 00054 am Chemistry 251 Autumn 2008 Extra Credit -(5 points each) _ mixture that fades‘bver time. Explain the above differences in the two reactions using energy diagrams, pictures and words. N O PARTIAL CREDIT OCH3 OCHa 00:43 O /\OH O F3CAOH O 7 _ ‘ -a/\ ‘h—h‘“ 0: 7 “ «we; 0 0 O 0 HCO C C OCH HCO 0 OCH ' H30 Q 0 H3 3 _ 1 I 3 3 3 7'1/ but DRAM/«m SfiPL Wang pectQE/V’éfi NueLEePHLLE sew.me-l- 3?: CON 0 man BSCOM ES SL000 '3 CARBB . cé‘rnom (“—_“-————___—___ rn—_._.____. Le) we OBS Grit/SQ , qua] molar amounts of the given alkanes were allowed to react with C12 at 300 °C. \Which one of from the mixture? Explain using words and pictures for full credit. NO PARTIAL CREDIT 0‘. em) 4 = c, M A éoowh: g qOmMfi p. emu-q 'il 163°H)~5“=9 ‘(fzml-‘ffl: - H 2.2.. /\/ ‘L(2°l‘l’) ‘ ..._—— --—..- Page 13/14 Chemistry 251 Periodic Table I lion 3 . _ V Cr Mn 0 ' u ‘ . 508-! MB “£36 55.8!!! 585.13 . W 546 .. . my“ mum .- flKherflum nun - mm 41 42 44 45 46 47 56.996 913‘ £90! ME»? 5-; 10M? 1V2£l ' 10312 $87.87 11211 mm m team": We“ mm mm Mal-urn. mama-A gala memuy 71 T2 73 "M 75 7' 77 TB 75 80 174.9 178.49 E35 . £1 18821 | 23 ‘ 2 1 J- $96 200 9 . “mm “mm H I 6 . .-: Wm mum-n In: Inn-Dim 106 108 ‘ I if: Uunfluuflub " ' WWW” " “"33"” “'° _ . Pr Nd Sm E . " .1 "0.01 344.24 ‘- 35 15 cm ‘ianihanoids 2 93m! 5-HT" ‘ 7‘ Wum -‘ 'n . v ‘ yxw‘ ' 83 64 B5 88 57 53 r 59 70 EB E725 158.92 962.50 IE-tfi 157.26 £53.98 173.06 95 BB pram mam - ' amefldom mm belt/akin) Ian-nun chum 7. m mandala - mama 91 53 94 99 917 98 108 .‘PD‘I 102 ml '2 rm 4 L 51 gm ' (:2: *‘actinoids .} Pagg 14/14 ...
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This note was uploaded on 03/22/2011 for the course CHEM 251 taught by Professor Stambuli during the Spring '08 term at Ohio State.

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mt2au08key - Copy (2) - _ Callarn Midterm #2 200 points...

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