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

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