LQ1 Sp06

LQ1 Sp06 - CHEMISTRY 322aL April 3 2006 SPRING 2006 FIRST...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 6
Background image of page 7
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: CHEMISTRY 322aL April 3, 2006 SPRING 2006 FIRST LAB QUIZ KET.EE:I\T/ BY Efigfi NAME 1. (8) 2.(12) Lab time 3.(12) T.A. 4.(12) 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— i7? 1. (2) A 14/20 male (inner) standard taper joint (like those on your ‘ distillation apparatus) is made of glass 1.0 mm thick. Calcu— 0 ,9/ late its Inside Diameter (ID) at its narrow end. t‘qwlr ~3LQ»’~Q\)MM (1 T 3 /‘( [0 “Ia/é? Lud/ flak:ka :([0 MM {>(U¢(C. . 2. (2) A Circular groove in a flatAéiece of material has Outside Diameter = 12 mm, and both width and depth = 1.5 mm. Calcu— late the ID of a non—stretchable O-ring which will just fit. 13% (a —-< in (mm =7 W. 3. (2) Complete the following sentence, defiining the boiling point \ Z (in general) of a liquid, A. The bp of A is M gt? “77% “MM “4/4 (16 _( 760 Tim (Ky‘ervzo/[flrwotrt ______,___—___. 4. (2) 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. IIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIII-IIII-IIII-IIIIIIII—IHIIIIIIIIIIIIIII I II IIIIIIIIIIIIIIII "In-I 'II'IBI’II IIIIIIIIIIIIIIII v2.1 I! mt. Ifigilaizl I III lid-ll" £!I!:= 10' III-III:- -. .l'lllllll.“--.- ——-—v— ---E_—------- -—u---- .IIIIIIIIIIII III-III...'I-l'..---'-----.---‘- (0 10 30 lfiffit‘o ‘10 $0 90100 Below, circle one of the items arated by / in each set. From the curve, H's bp is @‘I / . most 84°, and the 55 original mixture was about 60 // 70 / 75 / 85 9s L. ' 2 ‘ p\7 1L 1; (’L 5. (2) Acetic Acid (AA), CH3COOH, has strong H—bonding in the liquid. (1) It has abnormally low enthalpy and entropy of vaporiza- tion; and (2) its vapor density corresponds to MW ~ double its formula weight. Correlate (1) and (2) using <15 words. War/0012 w‘ W77 /¥'bw¢&/W 1 a? Low «raw/71 a; ova (Aflm va/HHQJ 6. (3) A pure organic liquid containing C, H, and 0 shows strong C-H J! jgék absorption in the IR, but no other strong absorption above 1550 cm‘l. Name or draw two oxygen-containing groups of atoms 6"! excluded by this result. 7% /m \Czo a ~0H.d/£W (3) An aqueous solution containing 20.0 g isopropyl alcohol (IPA, 6\) Q = .78) 's "salted out". The upper layer weighs 16.0 g and is 85% IPA, based on its measured density. Calculate what the original 20 g IPA is in the upper layer. WJWW?‘ (AL [MA (606 xéo'ffdlanf/‘f Compound C, MW = 108, is steam distilled when Pexternal = 760 torr. If P°W<ater) = 600 torr at the mixture's bp, calculate the mass ratio in the distillate; mwwater = 18. 9. (2) W(ater) and odorous cpd D are mixed. Two liquid phases exist at equilibriu ——one is 1.0 mole % D, the other is 5.0 mole % (36)??? W. Assuming that in each phase, Raoult's Law applies to the szhi majority component and Henry‘s Law to the minority one, give Ptotal for the W—rich phase, in terms of P°W and P° . . D 0 W (0(a) Ptot, W—rich phase = O t a 7 + UUHJ‘*7 C/Kntfir (h)[f2zL. CQ-iuz f~ 69.1{.(1:? 15") - 3 _ fi .- IV‘VeK/ i -— 10. (4) (a) (2) A Drying Agent forms only a 2 hydrate; the DA/DA-2W has rel humidity = 5.0%. For a 3—fold DA excess added to a 3 9 W per L Org Solv mated soln, calculate the final W cone. 0 6 mm W): 3m mar 004&. I M 2 0 v [I a (b) (2) For the solution above treated with a DA of capacity 0.20 g W per 9 DA, calculate how much DA is needed to dry 600 mL W—satd 0% 08. For this calcn, assume all the W is removed. 1 Q If)” goo “L war;be (I! hm 0W- “ f“ - y .f w “00 “Hi‘LTW-W \ I For cpd F, KVB/VA, (i.e., z) = 6. Calculate the fraction of F — 1/(1 + (z/n))n] for (a) use of B all at unextracted [FUE _ once, and (b) use of B so FUE is minimized. Take e3 = 20. (a)(2) #1 :11 (b)(2) y\’——‘3()C> I {I‘M ' m” ' M “4°” (1+ é)” 12. (2) J has mp = 100°, and L has mp = 130°. The most probable mp for a mixture of 85% J and 15% L is (circle one answer)-- Ajz>{b 13. (3) 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 79—82°. Tell what these ‘ data say about the likely composition of X; give reasoning. q/fi \ [0W m/Ll‘ 4 W WWj‘flda % A7244“; WNW W 47 vi U 1 WM M (Mfm’t/h 14. (6) A solid sample comprises 10 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)(2) Calculate the minimum amount of S needed to keep all the Q in solution after cooling. Show calculation. ‘ ‘ cod ‘5 (b)(2) Remembering that it is esirable to get the entire sample dissolved, calculate how much hot S one should use initially. Jw1~€ fu/oté 6M aw, M M P :1 M mj=£ $1.005 Au/‘I c)(2) If the initial dissolution in hot S gives a colorless solution .1, with some brown goo sticking to the flask walls, tell what one :[%M:‘Mshould do nex fife Eiworgdzy; #3 Amy?“ C W m4 . '////157/T§7’élucose (dextrose, grape sugar) has mp ~148°. Addition of 1 g 7 water to 6 g glucose depresses its mp to 95°. Restate these AZ—lfl data in solubility terms; refer to a temperature, the nature I of the solution (dilute, conc, saturated), and to solution composition in terms of the mass ratio of lucose to water. fa) i" ,41‘ 750, A ref»? “('4 (%~ <TC ' -5- 16. (10) Recall the preparation of r_1—BuI: i "[6 acetone Q-BuBr + NaI —————————>- n-BuI + NaBr “a $321 (a) (5) Suppose one starts with 5.48 g g-BuBr and Calcu- late what volume (in mL) of n—BuI corresponds to a 75% - _ SUIX p , 0M1 "Inga igdfly ’ fl; — 0‘0“ wg‘tflr o-J“ fl KOJJ‘K fwd £37 {.é( (b) (5) Both t-Bu—Cl and _r_1—Bu-Br react rapidly with NaI in ethanol, giving ~100% yields of NaCl and NaBr respectively. Explain the following in mechanistic terms, using <35 words total: (1) The rxn rate of L-BuCl is independent of [I'] , while that of n—BuBr does depend on [I'] , and (2) the yield of n—Bu-I is unchanged by even a high conc of L—BuCl in the same rxn soln. t guec ,3 .W,# (Mn/14?“: 440(55fo I6) (MHZ ('ijlud/ S‘U" % flr Bw‘gh 95V§W¢Mé Odo/fl" t—C'G’f/ (IIVM($ MM- {Uo/Y wz‘fk [tile ‘1’5‘4'er 76”“ \WVM/ (57 (UL). 17. (6) Note the data below: Reaction Ag _(_k_c_a_)_1 (1) n-Bu—Br —-——> _r_1-Bu+ + Br‘ + 178 (2) NaI ——--> Na+ + I" + 164 (3) n—Bu+ + I" ----—> n-Bu-I - 171 (4) Na+ + Br' ---—> NaBr — 174.5 (5) NaCl —-——> Na+ + c1” + 183 (6) n—Bu—Cl -——-> n-Bu+ + Cl‘ + 185 n—Bu—Cl + NaI ————> (a)(3) Calculate z150verall for the reaction: Q—Bu-I + NaCl, showing your calculation. _‘lq (b)(3) Given that Keq for the reaction of (a) above is highly favora— ble, tell why alkyl chlorides are worthless in a practical sense for making alkyl iodides by the process used in this AI lab. You need not do calculations but do refer to how G changes along the reaction path. £05 {/3 £13“ Wm“ ...
View Full Document

This note was uploaded on 12/01/2011 for the course CHEM 13222 taught by Professor Bertolini during the Fall '10 term at USC.

Page1 / 7

LQ1 Sp06 - CHEMISTRY 322aL April 3 2006 SPRING 2006 FIRST...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online