322af01_lq2_key

322af01_lq2_key - CHEMISTRé§2aL/325a5 #1534001 “Chu...

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Unformatted text preview: CHEMISTRé§2aL/325a5 #1534001 “Chu e31“: oui v BY 2593 FY NAME___{é—__ ‘ 1.(12)___; 2. (6) Lab time I 3.(10) T.A. 4. (7)' TOTAL 981—... This test comprises this sheet If told to use less than a certain number of words in an answer, D0 SO-—deduction for excessive verbiage. and four numbered pages. PLEA 5913; Graded quizzes‘gill be available from TAs Thu and Fri, Dec §.and fly at (check—out) labs and office hours ("special" office hours for TAs with no lab or regular office hours Thu or Fri). If you initial here ---- —-> , your quiz will be put in the Study Room, SGM 102, at 5 p.m., Fri, Dec All quizzes will be thrown out Jan 31,. _ 1 — f0 2: —:; / 1L, 1. (12) Dehydration of 4—methyl-2-pentanol, (CH3h’nCHZCH(0H)CH3, as done produces the following methylpentenes without_carbon skeleton rearrangement: 4—Me—1, 4-Me—2, Z-Me-l, and 2-Me-2. (a)(4) The differences in results using 60% aqueous H2804 compared to 70% acid occur because aggrage carbocation lifetime is longer in 70% acid. Give two reasons for (NOT consequences of) this fact: One reason is due to carbocation behavior difference, the other is due to alkene behavior difference, in the two acid solutions; Use < 20 words. (b)(4) (l) which of the above methylpentenes could come directly from the (rearranged) tertiary carbocation that forms in this sys— tem? Draw the structures of the ion and of the methylpen— tenes. (2) Circle the methylpentene(s) which must come from the tertiary carbocation. (<43 )._ g «mas/L 65g. (c)(4) A minor, rearranged alkene from 4—methyl—2—pentanol is 3—Me-27 pentene. This is the major dehydration product from an alco— hol isomeric with 4—Me-2-pentanol. This isomeric alcohol also gives a little 2-ethyl-1—butene as the only other C6H12 al- kene. ) Draw the isomeric alcohol's structure; relevant . uct alkenes are shown below. (2) By circling one of the following choices, tell which of the alkenes below arise(s) from the original carbocation formed from your answer to (1): ’V major product only minor product only neither / CH3CH=C(Me)CH2CH3 CH2=C(CH2CH3)2 major minor (H; l CL. <7+£3‘r(¥v"<; ‘1rf/LC:£%3 "”"*fi§9 -2- /isg __ 2. (6) Note the gas chromatogram of the commercial sol "Skelly B". ~. . . ‘ s :. 3 . .2 .~ : a - .‘F :'IIIIIIIIIIIIIIIIIIII ~ I .uIIIIII .: -. .‘x IIIIIIIIIIIIIIIII'VrIIIIIIIIIIIIIIIInIIIIIIIIII ,IIIIIIII 5' In... .; IIIIIIIIIIIIIIIIIIIIIIIIIIIIIInnr‘aIMIIIIIIIIIIIIIIIIIIIIIII ‘ IIIIIIIIIIIIIII IIIIIIIIIIIIIIIIII IIMIHIUI IIIIIIIIIIIIIIIIIIII ‘r+=:=== IIIIIIIIII II - ' IIIIIIIIII AIIIIDCII IIIIIIIIIIIIIIIIIIII +, I‘L_ IIIII .‘ - IIIIIIIIInIlczaIIIIIIIIIIIIIIIIIIIIII I z n.‘- -II IIIuIIIIIIIII IIIII 'i " IIIII ": IIIII :III IIIII : mfim=$ . as: mm$§.m=mwfi=m. ' IIIIII IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIII I a llIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIWI IIIIIIIIIIIIIIIIIIIIIIII II . ; III-l: Il=IIIII=IIIIIIIIIIIIIIIIIII -+t====:=:=:======ll::= III-I I IIMIIIIIHI II==:IIIIIIIIII===:=I 1“IIIIIIIIIIIIIIIIIIII III-IIII III IInIIIIIuIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIII Illllll III I IIIII II".-IIIMIIIIIIIlI-IlllllIIIIIIIIII IIIII III-- III IIIII IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIIIIIIII IIIIIIIIIIIIIII III-IIIIIIIIIIIIIIII r ._IIIIIIIIII IIIIII IIIIIIIIIIIIIIIIIII mus-"mm"- .n'wm'sflmmfl'rm:--=:'--=:----"!:=:::::- I: IMIiJEIL‘IIIIIII:I=:==f ‘ " II I. fl-ULW'IIInIII-mlmmlllu'l I 3’ GI II"..- I ‘ Il-HIIIII-II-I-l-I-I-m Ile-n‘qm'mlm-I'II-II ‘ IIIIIIIIIIIMIHI ' uIIIIII::=IIIIIIIIIIIIIIL-HZIIIIIEIIIIIIMIIIIIIIIIIIIIIIII IIII‘KJIIHEIY’TI- III-III.- Innmlflmm’nmmIflnm-I-ln-fi I'llzll- III-IIIIII-II-IIIII Immu’IIIIu‘n-Imnm—H “II-v I-“I'JI‘ HES-III- II-IIIIIIIII'I-III-I-IIIZ ‘m AI-l-l‘I-nl-IIIII-I-l'I-III-l Hill-"I'C‘flllll-I- '- III-III-III-I—Il'n'. q . "mnwlmIm-‘Inm 'III'I‘l-L‘IDVII- Ill-$.- III-II-I-I-III" “II-IMIImmn‘n-Im UIIVAv-III-VA‘IIII- ‘ III-III Ill-I'll...-IVA-IllnnI-I-IIIIIIIIIIIIIIIIIISI-IIIIIIKIIIIIIIIIK“... IllflllllllllllllwmllIll-IIIIIIIIIIIIIIIIIIInlllrilUI 'mIIIIIIIIIIIg‘II- Ill “mm-“IIIIIIIIIIIIIIIII“II-IIIIIIIIIIIl-I-In-‘II-I-‘II-I-IIII-:3 - Ill-IIIIIllll-I-II-l-I—l-I I-II-I—I I—I—l—l I—Ill-lll mu* 1-. III-I...- IIIIII-IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII7-III III-Il- IIIIIIIIIIIIIIIIIleIIIIIIIIJIIIIIIIIrSIIIIIIIIIuIIIIIIIIlIIIIIuIII lllIIIIIIKZ !IIIIIIIIll-IIIIII‘IIIIIII . “mu-ummllllflmnll' .- III-III.- IIIIIIIIIIIIIIIIIIIIIII I] ~ x 'I-gllIlI-II-IIIIIIIIIIIIIIIIIVIII-IIIIIIIII- ‘ ' A , Lam/Me, ’0») (a)(2) Which peak is associated with the component of highest vola— tility? Number «11‘ (b)(4) Recall that one estimates the areas of GC peaks by assuming they are triangular and calculating "Kb-h". Without actual getting the area, and using the baseline indicated, mark peak 4 to show how this is done; draw the height and Kb. Also gtgtg how one determines fib; use < 20 words. 7/ fCX/fibmq ' 7% t 0644 Nm% V14 Z K7W/$HA‘34/ l/Lb Am a 3 'Sfufl/W/é‘g -3- N 29/0 3. (14 pts total, 10 pts on this page) In the last experiment, Period 10, you studied the bromine— catalyzed isomerization of I, sis-X—CH=CH—X (X = COOMe) to the nggg isomer, III. The bromine-containing species, II-gauche and II-anti, are intermediates. (a)(2) Recalling the behavior of the two reaction mixtures containing 5:2, write a reasonable initiation step for the reaction. . I O (b)(53 II—anti, one conformation of the radical EH-eifi-Br,.is a key intermediate in the I e III transformation.- Draw II—anti using the framework below, and then show the mechanism for and the product(s) of, its principal chain terminating reaction. Take care to draw product stereochemistry where relevant. Use a "fishhook",\\_fl;7, to show movement of a single electron. 1 eaclx WM 02,; wad/Li? (c) (3) Based on A5 ~ -1.2 kcal for the reaction I -'> III both in D04 M0 q solution, Keq ~ 7.5. In fact, as_the reaction was done, the final amount of III was about 50 times the final amount of I. (1) What additional process that occurred "drove the reaction"? Answer in < 7 words. (2) Would running the reac; tion at 506 instead of at about 22° as was done, increase or decrease the fraction of I converted to III at equilibrium? Explain in < 15 words. 1 ,4), (ma/$11454} Km 7% Eff/r ll) Wpflfi u% flWJ,UL7afl/? (L/flsl> (Z) azcwm. [EU wen/4t 6; wdvm m 2 97 (d)(4) Suppose 120 mg Br2 (MW = 160) reacts with 15.0 mmol I (MW = 144). If all the bromine and all the I react to give only III and a product from adding Br2 to I: (1) Calculate the fraction of I converted to III, and (2) calculate the mass of the bromine-containing product formed. ' 3. (concl, 4 pts on this page) . MM( 4. A chemist plan to buy 1 k ompo C, MW her research. A company sells C qontai ' 2 (wt) % Water « for 10% less than pure C. T emist knows that 1 W reacts 'th 1 C to give DQ Ne' er D nor W is either use of C. The densities of ...
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322af01_lq2_key - CHEMISTRé§2aL/325a5 #1534001 “Chu...

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