322as08_lq1_key

322as08_lq1_key - CHEMISTRY 322aL April 7 2008 SPRING 2008...

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Unformatted text preview: CHEMISTRY 322aL April 7, 2008 SPRING 2008 FIRST LAB QUIZ BY Bagfi NAME l.(lO) 2 (12) Lab time 3.(12) T.A. 4.(10) 5.(10) 6. (6) TOTAL (60) This test comprises this page and six numbered pages. If a question says to answer in fewer than a certain number of words, DO SO. Deduction for wordiness. TAs will have quizzes at office hours and make-up lab. Tuesday morning lab convenes at 9:30. For grading questions, please see your TA first. - 1' p57 fi = l0 1. (2) A 19/35 female (outer) standard taper joint has a 1.0 mm thick wall. Calculate its Outside Diameter (OD) at its narrow eize4gigggs 4 - .. 3““ Y7 I'm/"00W .Efl *(m 70")th 3/5?me ‘00“ nick—MM W (nun mud. {oil , a OD 2 </€.s'+ 1.0]Mu 2. (2) An O-ring's size is given as "8.5 x 10.5" [millimeters]. If possible, calculate its thickness. If not possible, tell why not using < 10 words. ) 0% to = 1.0 mm =? oucch fl ¢ ft = [.0 um-ftnub X—xedz'm 0: C9: m‘ckw ‘il'd‘mj 3. (2) Complete the following sentence, dgfiining the boiling point (in general) of a liquid, A, in <12 words. The bp of A is ... 0 A? “(AFC/t1. 10 m? (a k m “if V ..“gv‘agm pm. of A m gfiferm/ 4. (4) Below is the distillation curve for a 100 g of a solution of L (lower boiling) and H. There is no azeotrope in this system. O ...-III..-III-IIIII-III-I-II-II In III-lIII-IIll-III..-III-IIII-III-Il-IIIIII-I‘ll..- IIIIIIIIIIIII-III...III-IIIIIIII-II‘I-UIIIII'-flfl'll III-IIIIIIIII-IIIIIIIIIIIIIIIII-I'a 7 VJ I. III! I". l '14!- , 'AIIiIlIlI-I-ll-I __ 80o III-IIII-IIII-IIIII-III-IIIIIIII-7.IIIIIIIII-III...- l-IIIIIIIIIIIIIIII-II-IIIIIIII Il-‘II-IIIIII-II-II-I III-IIIIIIIIIIIIlI-IIII-IIII-IIII All-IIIII-II-I-IIII 7L4 1 “(L . III-III- IIIII-IIIIIIII-IIIIIII- III-III. III-III.- ” III-III. III-IIII-III-II III-IIhlIIII-III Ill-II- ‘ III-III. III-.- III-..- IVAN-III... III-II- IIIIIIIIIIIII-II-IIIIIII-I-l" ‘Il III-II-IIIIIII-III- IIIIIIIIIIIIlI-l-—::;—--—--IIIIII \IIIIIIIIIIIIIIIII '-"::__._--uni-II-IIIIIII-III-I-Il IIInIIIIIIIIIII-II ' III-IIII.-III-IIII-IIII-I-I-II-IlIII-IIIIIIII-I-IIII III-III...III-Il-IIIIII-IIl-II-II III-IIIIIIII-IIIIII III-IIIIIIIIII-III-IIIII-I-I-II-l III-IIIIIIIIIIIIIII III-III...III-IIIIIIIIIII-II-IIIIIIII-uI-III-IIIII | III-IIII-IIII-II-II-IIII-IIIIIIII III-“IIII-II-III From the curve, L's bp is original mixture was about -2- 5. (2) Both Water and Acetic Acid have strong H-bonding in the liquid state. W has an abnormally high Asvap, but AA's Agvap is abnormally low. Using <25 words, explain this difference in terms of the nature of their 1mm. { 0.) kcw Wacmfu/ If uu‘al but norma 6. (3) A pure organic liquid shows strong :C=O, i.e. carbonyl, ab- 0 sorption in the IR. But the spectrum also shows that all the \\- H's in the compound are bound to sp3-carbon. Name or draw two ~ \ . . _ ’Q 2 { ’Cégfln—tgl—nw func‘tlonal groups excluded b this result ('1 Q0334 (mow/r. 46,4 I, gion 41441;, 6K54IEJGL p " E"dU"‘/(§ai/1\ 44‘.La£4fthe:}/) \ 7. (2) An aqueous solution containing 20.549 isopropyl alcohol (IPA, {Na .__..,d = 0.782 'is "salted out". The fiper Layer weighs 18.0 g, and e on its dens1ty of . 9/ , is 80% IPA. Calculate what fraction of the original 20 g IPA is in the UL. ” our («a/J {K-Oa fall/L K 0.3 2/4146, fro/7 JD. 99/51 jig” - v 8. (3) de C, MW = 108, d = 0.80, is steam distilled a external 760 torr. If P°W<aterl = 600 torr at the mixture's bp, calcu— late the volume ratio in the distZ'llatel‘fi ("u (\uuevw 0.80 )C x. M (760*6OOJ‘M‘C' [0% acwlea (.OJJMJU‘ I «Le. 9. (2) W(ater) and odorous cpd D are mixed. Two liquid phases exist at equilibrium—-one is 1.0 mole 1; D, the other is 5.0 mole % 244,0 iF W. Assuming that in each phase, Raoult's Law applies to the majority component and Henry's Law to the minority one, give {w Ptotal for the D—rich phase, in terms of P°W and P°D. d Ptot, D-rich phase = f {’ M "17/ 10. (2) A ha fi—saturated Org Solution contains 3.0 g W per L. A certain Drying Agent system has relative humidity = 5.0%. A small excess of DA is added to the wet OS. Calculate the 1 A de’fiafd OS ‘1‘” red 0‘“- 03W : 3~0 {rd/LO! K ’§.1 Q30J%°S [91‘ 6.0): 2) Six hundred grams of an 08 contains 3.00 wt % W. For a DA of capacity 0.40 g w per g DA, calculate how much DA is needed to dry the 08. For this calcn, assume all the W is removed. 11. ( o/«u ($00,147; @ Jw = (900305 X W: (@360 flak @ amp W” :M 12. (6) For cpd F, KVB/VA, (i.e., z) = Calculate the fraction of F unextracted [FUE = 1/(1 + (z/n))n] for (a) use of B all at once, and (b) use of B so FUE is minimized. Take e3 = 20. (a)(2) (b)(2)y . (I me— -.~ _.——, m“ r .4“; (7+ at)“ ll - / - .L— '/(0 N3) 26 g m moo“) 1 ‘ (emf/u, 0.001%. ) (c)(2) As 2 increases, the FUE for (b) compared to (a) (circle one)-- decreases, which is better decreases, which is worse. increases, which 18 oet er. increases, which is worse. 13. (2) J has mp = 100°, and L has mp = 130°. The most probable mp for a mixture of 90% J and 10% L is (circle one answer)-- 75° 99° 103° 115° 127° 135° -4- 14. (2) A certain sample X, of mp = 75—80°, is suspected to be either largely cpd M or largely cpd N (but could contain neither). A mixture melting point with pure M of mp = 82—83° is 68-69°; a mmp with pure N of mp = 90—91° is 73—79°. Tell what these :L‘pb47 data say about the likely composition of X; give reasoning. \ 0W WOW?“ Mf Mhov A) St‘nr—e «fit»: @th $2 M 20} MA & 15. (5) A solid sample comprises 9.0 g P and 5.0 g Q, whose solubili— ties in a solvent S are independent. The solubility of each in hot S is 5.0 g per 100 g S. In cold S, P's solubility is 1.0 g per 100 g S; Q is four times as soluble. (a) 3) The entire sample is dissolved in 200 g hot S; the solution is then cooled. Calculate how much of each substance precipi- tates; put a number in each blank. (b)(2) After (a), one can get more pure P by boiling down the fil- trate and then cooling again. In <15 words, tell why one should not reduce the solvent volume below a certain amount; you need NOT calculate the amount. r; AA (M m Moll/wax ma (ma/fl” Q cm Wit/«10$. 16. (3) Glucose (dextrose, grape sugar) has mp ~148°. Addition of 0.28 9 water to 1.0 9 glucose depresses its mp to 70°. Re- C) state these data in solubility terms. Refer to a temperature, the nature of the solution (dilute, conc, saturated), and give ‘fibr ‘\" solution composition as the mass ratio of glucose:water. “3°22?” Alf 19", w o’afuM/lll/ [$3] 71% 50144 km Loyflumh 4.}? (J =1 .27, 3.37 JCQC‘JO A I l Mif/OS' l 17. (10) Recall the preparation of n-BuI: / acetone 47 a n—BuBr + NaI —————>- n-BuI + NaBr MW = 137 EN = 150 MW = 184 ~VVA ‘1 = m ‘ Z (‘V’ (a) (5) Suppose one starts with 4.31 mL n—BuBr and ® Calcu- late how many g g-BuI corresponds to a 75% yie a . “t0 “Mk firm! -: 0.0+0 Mm(-¢)°l/H?" me, = 7'”? " 2(9Wgtr6’nf Br (b) (5) (S)-s_e.Q-BuBr (the SM) . (S)-CH3CH2-éH-CH3, reacts with NaI in acetone, giving NaBr and (R)—§_e_g-Bu_‘[.v But with AgNO3 in 95% EtOH, the SM gives, besides AgBr, mostly the {39311119 £51191, CH3CH2-CH(OEt)—CH3. Explain these results, using chemical equations and not more than 35 words of meaningful commentary. CUl'flA #6 N03 [W 3001 “'P&Il/€7 @ flufqou/ (‘mfi'ui Salve;qu M éckcra/ CaV/qocd- (SMIIWQQA Tedd/T Wu'fk “‘WWQ _ 6 - Iq<7 jg ;:,é; (l) n—Bu—Br —-——> fn/fif' + (9'; + 178 i _ (2) NaI —---> + /I‘ + 164 ‘3-5‘ (3) %;BG¢ + /ZA ---—> n-Bu—I - 171 18. (6) Note the data below: (4) 5&4 + r‘ ----> NaBr - 174.5 (5) NaCl --—-> Na+ + C1' + 183 (6) g-Bu-Cl --—-> n—Bu+ + C1“ + 185 N (a)(3) Calculate 13Goverall for the reaction: n-Bu-Br + NaI -—-) n—Bu—I + NaBr, showing your calculation. C gwmmwa, dove MM 0/ ~09) )yiM dUW NW) N f AE'S :: AaoUM/) (b)(3) Keq for the reaction of (a) above is >100, but its rate is near zero without the solvent acetone. Tell in <25 words, hog acetone facilitates the reaction nithgut changing (kg overall. No credit for tautology, e.g., "it's catalytic", "it helps the reaction“, “goodness is better than evil because it's nicer". CVYWLéf [MIL/7' 6f Salve/252% @ MW]. ,4“? M I? m. M, twat WW Lemma! [MZR w‘w Vagrcsfi!) 36W“. ...
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322as08_lq1_key - CHEMISTRY 322aL April 7 2008 SPRING 2008...

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