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practicelabquizkey - CHEMISTRY 322aL W W «1 556000...

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Unformatted text preview: CHEMISTRY 322aL W W «1 556000 WC’IL‘ 22-, r FIRST LAB QUIzteJ *- fumm E BY Ease Lab time fir Lei], M 61+, 7% /—-Z‘,//./7, 4. 3 ML, Ta"W 61“) 7m 9tl0)[3"/g 5.( v' This test comprises this page and five numbered pages. If a question says to answer in fewer than a certain number of words, DO SO--deduction for wordiness. Shag 39:3 for calculations. TAs will have quizzes at office hours and make-up labs, week 0 . y evening lab convenes at 7:00, Tuesday mo or grading questions, please see yo first. Me flab—mt ‘1‘/4er1¢ an 1. (2) A 19/35 female(ouifiar) standard taper joint has a wall. Calculate its inside diameter (ID) at its narrow ena.\ '9 T .7706va ()1 35‘ Mm {014 )AM ’9 “4W7 t'we/ if fflgq‘ mafia awn/1% 130 044764 1mm Jack [0 WW {WV/77%): A uavvww/ ’~ (17 “ 3JT0./))MM :l/s'f‘M‘" 2. (2) Metric O-ring size is specified as "IDxOD", both in mm. Circle the size which will just fit without stretching in a circular groove of ID a 8.0 mm and width - 1.5 mm. 3.03:9.5 6.5x9.5 8.0x9.5 9.5x11.o 3. (3) An organic liquid contains only C, H, and 0. Its IR spectrum shows inx C-H stretching above 1550 cm“1 Name or describe what functional group is indicated. Explain in <15 words. ‘ \ i “"4444 (OWfGLC/v‘ /C—-O at, 4. (2) An aq soln containing 25.0 g isopropyl alcohol (IPA, density - 0.78 g/mL) is "salted out". The 20.0 mL Upper Layer weighs 17.2 g. Using the table below, calculate ONLY what fraction of the UL is IPA. ZERO it give information not on point. is”: zblehoLn‘z, own) as —_£:Z;2223 _ (C). gé;C:) ‘7 kn [a1 3%? 03am 133 L, omm m3 )49I9M4 [y use» Md ~ iy lg ammo 4&0 . o JET mwm as 90 ‘ 7C) 3 ammo 0L0 sum 71“ 0mm ass emw eta ijn 91w 01am zuim 5. (5) Heavy water (D20), formic acid (FA, HC(O)OH), and n-BuBr all have nbp's ~ 101°; see drawing to the right. (Q In the blanks below, write A the letter of the VP vs T “/ 1”“ curve corresponding to each: «bk/L6“, ,4 fig <:_ FA -BuBr D O «Lb/Ml ‘1 2 At pressures above 760 torr the highest bp? A B C ( £:A4W /J;;;3 f9; Ct'l , e.g., 780 torr, which liquid has Circle one letter.) /tC7/u%1f; 6;?j7 ‘ 2 ' f) i llé 6. (2) Define Donna]. hailing mint (mm) by comgleting the following 4/ sentence in <15 words: The nbp of any liquid is 20 mt‘ sqflfiiww (if “if” ml; 2." fro Cm 0w: {M pay via 7éO/46 "foal/7‘ 1. fix ltfirwf 7. (3) Compound C, MW = 162, density a 1.25 g/mL, is steam distilled. Pexternal " 72° Corr; 1:H’Wmter) 3 64° Forr at 1mmixture' ‘ Calculate the volume ratio in the distillate; MWwater 2428 me/fnLc = WOW”)? 3 Wm. K £15”ch . Mt M53964.“ 710 ‘ 6:326 /e A WM (.00 i/me 3) 8. ( Mixing W(ater) and OCT gives two equilibrium phases. <51 is 99 mole 3!: W, <92 (org) is 3 mole % W. P°W ~ 6 P°OCT. After phase separation, which has the larger partial POCT, @\,(1) immediately after separation? cpl 4:2 @(2) after ~20% of each Q has evaporateef? cpl neither. Mr 9. (3) A Drying Agent forms only a dihygrate- o‘ s : em DA/DA-ZW has exam relative humidity = 10%. One adds a of DA to a (>1 1.”, , halt-saturated soln, which contains 2.0 mole 1: Water. Calcu- 44/9” ‘4; late the final w conc, in mole %. 146‘ l a; M 74 [00% M. “(W/f 9*0 Mt W” d/cJ (J o ‘ 0:) WC «152 “(4%. = 62.0%”? 0 K J 0 ML a 0 L0 w/e \ a 10. (3) The solubility of Water in an Organic Solvent is 0.30 wt % A DA has capacity 0.20 9 W per 9 DA. Calculate how muc DA is needed to dry 3.0 kg mm 03. Assume all the w is removed. W‘v‘dq Of mfm‘m 3~O 4% K :1 Lag 0 2 q‘0 (4) \ , 03 ~7 cm? /4 W4 \W 11. (2) Ethanol has nbp a 78°; it is readily available and relatively non-toxic. Tell in <10 words why it is not used routinely for extracting aqueous solutions. C 0%» (370514, wc‘rcz‘é/e wX/Zx WMMM - 3 _ M 2:13» 12. (6) For cpd F, KVB/VA, (i e., z) = 6. Calculate the fraction of F unextracted [FUR = 1/(1 + (z/n))n] for (a) use of B all at once, and (b) division of B into three equal portions. (a)(2) I (b)(2) éf‘: F“ M5 RUE“: 3 w (1*?) ( ..__. 7 (01%) J. . (c)(2) As 2 decreases, the FUE for (b) compared to (a) (circle one)-— \ decreases, which is better increases, which 1 decreases, which is worse increases, which is better I melts 78° — 83°. Mixture mp K and X a 73° — 76°- mmp J and x I a 82° — 84°. Giving your reasoning in <15 words, tell if the likely major component of x is J, K, or neither. Smut 41£W¢ ffl X M/o (W/vmi/n X), “KC/7 VMJ‘W cam/Oome 0‘. [qucc (< [owl/Ls X‘f “PJMJ 13. (3) Pure J has mp = 86°; pure K's mp a 92°- a certain sample X 14. (3) Sucrose (ordinary table sugar) has mp = 175°. When a mixture of 1.0 9 water and 9.0 g sucrose is carefully warmed from 10°, the last solid sucrose disappears at 23°. Restate these data in solubility terms; refer to a temperature, the nature of the solution (dilute, conc, saturated) and its composition in terms of wt %'s. ZERO for any reference to mp depression. 46 130. « awn/M Caz: win a/ (um/me V3 70M???) yum/nae- -4- 1;;[0 15. (4) A solid sample comprises 10.0 g M and 3.0 g N, whose solubili— ties in a solvent S are independent. The solubility of each in not S is 5.0 g per 100 g S. In cold S, M's so ubilitz is 2.0 g per 100 g S; N is twice as solub1§.=fi?c;d{ 1’ (q, «‘z‘fmof he Calculate the amounts of S needed (a) to just dis olve whole sample hot, AND (b) to just keep all the N dissolved in gold S, after boiling down filtrates to recover more M. /0 M A W 77%;?” [0035 Kb) 303,0 3 Z Lf‘fl I @514. . am 16. (2) A solid sample eated with solvent gives a colorless solution with brown goo stuck to the flask bottom. In < 12 words tell Ji fi%;i what should be done next in the recry7aallization procedure. , Jo \ karé “ fleccwag‘ ,ooowM “174/ «Ava/7:4, r ~ ‘ ‘ O/«t‘W M C” ’ » 17. (12, 4 on Recall the preparation of n—BuI: this page) acetone n-BuBr + NaI —_______>_ n~BuI + NaBr MW 2 137 FW a 150 MW a 184 ~ 0 d a 1.27 a = 1.61 {We/(’6 76 ( / MW/ (a)(4) Suppose one starts with 60.0 numfl.n-BuBr and 10.0 9 Mel. Calculate how many mL n-Bu-I corresponds to a 70% yield. 14 70% 0‘4 60 Wt [radii/x 0.70 MM/M( Mud 5M : {Flair ML MLnggqr z: O‘Oq‘px “J x Li.” ml \‘fifl: {.4 a «4L. ‘ ‘ 5 ‘ i 2 I; 17. (contd) (b)(8) Reaction AZ! fiscal). (1) n~Bu-Br ----> n—su+ + Br‘ + 178 (2) Mil ---—> Na" + I‘ + 164 (3) n-Bu+ + I‘ ——--> n-Bu-I — 171 (4) Na" + Br‘ —---> NaBr - 174.5 Sum(Br): n-Bu-Br + NaI ----> n-Bu—I + NaBr — 3.5) Keq~200 (5) NaCl ----> Na+ + or + 133 (6) n—Bu-Cl --—~> n—Bu+ + or + 135 Sum(c1): n-Bu-Cl + NaI ----> n—Bu—I + NaCl - 5.0) Keq~2000 (i) (2) Given that the rate—determining step is (X = C1 or Br): I" + n—Bu-X ———— ——> n—Bu—I + x‘ calculate 'npé"),aAE;’x_c1 -A§§=Br, assuming each term equals the dififiexgngg between the BBB of n-Bu-x and n—Bu—I. (Reverse the signs of the data above as needed.) a M AAG : [/25— 11/)«(x79'17/UflJ- W 49 (ii) (2) The rate ratio, X:Br:X=C1, is exponential inAQlG"), For this rxn, a 1 kcal/mole m inAAGif, increase; the ratio by a factor ~4.5. Calculate the rat ratio X-Br to X=Cl. wrdm = +57 = 37~3me/, ? % iHECZIC. :prlain us:1:< :SY?::% 'L Y’d‘g Wtfi < (fa/[0 (77.5‘déflm K2 Kw; T735 18. (4) Both n~Bu-Br and t~Bu—Br react readily with excess Na]: in ELQH giving ~100% yields of NaBr. Write the principal neutral ‘ organic product for each reaction: n-Bu-Br ----- --> m- 6” "I: t-Bu-sr ..... _-, , __ [ 5/1/(r‘ (% _. fifififi; om m We ‘ [/1 Ja Aa/fl/ Mr ...
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This note was uploaded on 10/12/2009 for the course CHEM 322AL taught by Professor Jung during the Spring '07 term at USC.

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practicelabquizkey - CHEMISTRY 322aL W W «1 556000...

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