322bs09_plq2_1_blank

322bs09_plq2_1_blank - CHEMISTRY 322bL/325bL...

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Unformatted text preview: CHEMISTRY 322bL/325bL —4§H4%—%97*%998 “SPRTNG_20fiB u praCtTC’Q’ rage f—QV‘ SECOND LAB QUIZ ' Ska—CI”? BY Ease NAME Lab time~_~______________‘_____ T.A. This test comprises this page and four numbered pages. [I ‘ l\, .- - izzegfwi::\ - ‘ Rbe available froh TAB as usual. fiaa”fland§Tue I} n L‘ - ' i ,1 g I » _fiw As who " ot haw.- scheduled lab; or any; houk Th or Fri will hold sp .'al office hours Nmfifiri May 1/2. If g you initial here --~-->x “'fl,ww”M . Yofir quiz will be put 3 in the gtudy roofi, SGM Jaw? 1 5:00 p.m., Mon, May 5. ¥ Quizzee3not pickéd ~¢ng Fri May ““_yill 9e thrown out. g , ~T _ 3 -1- 1. (7) Aniline, Ph—NHZ, was converted to n~nitroaniline, p—O2N-C6H4- NH2 (PNA), via acetanilide, Ph-NH-Ac, and p—OzN—C6H4—NH-Ac. d with decolorizing char- , tell what any side rxn(s) in the acetylation procedure must not do. Use < 7 words. 3C>by rapidly mixing in ACZO and then quickly adding aq NaOAc. Suppose you added 3.5 mL Aczo but forgot to get the NaOAc in advance: The hydroly- sis half—life of Ac20 at 25° is about 4 minutes. If you can add the NaOAc soln in 2 min, how much AcZO should you now add? Make an estimate, or better do a ' (b)(2) In one lab section, a bottle marked completely. Acetanilide dissolved in the rxn mixture and gave solid on pouring it into ice water, but on acidic hydrolysis, no orange-red color appeared. Identify the solid, giving your reasoning in <20 words. "Nitrating Agent" failed (3) For a general arene diazonium ion, Arnflcz 2 . (a) Draw a reso- nance structure not involving the ring which correlates with the ion's coupling with 2-naphthol. (bé In <15 words, explain how the fact that one can prepare Ar—N2 in aq soln shows that it is only a weak electrophile. 3. 2 (9) This question deals with glucosazone ( glucose phenylosazone, GPO), and its cyclization to a 1,2,3—t riazole. (a)(3) GPO is a his(phenylhydrazone), but its formation requires 3 PhNHNH2 per glucose. One PhNHNH2 (PH) reacts with the C~2 )CH—OH of glucose so that C—2 can later react with another PH to form a phenylhydrazone. Write a balanced equation, not a mechanism, showing inx the 2° alcohol/PH reaction. (b)(3) The overall scheme for GPO —————y triazole is shown below: Dissolution Step 1 Step 2 kdissoln k1 jg. Gposolid -—-——-———_. GPOin solnz—r'm ——————... P —1 The reaction was done in aq i—PrOH with Cu catalysis. Students who were impatient, enough to get vigorous boiling, Using < 25 words, explain this. vigorous conditions, things being the same 804 and aq H2304 heating stroney often got along: reaction. Consider that under more all processes should go faster, other 3 4 each is in stable equilibrium with an aq soln are as follows: (1) anhydrous a (55° - 98°), (2) a-hydrate (< 55°), and (3) (anhydrous) B (> 98°). Assume that at equilibrium at 23° the solution is 50 wt % total glucose with 8:0 = 5:3. Exactly 100 g B-glucose is dissolved completely in water. At equilibrium, there is 160 g aqu , giving reasoning and/or calculation(s): Tell how many grams of each component are in the 160 g aq solution, and state the component(s) in, and mass of, each solid phase. The a-hydrate is 10/11 glu« cose, e.g., 10 g anhydrous gives 11 g hydrate. PentaAcetate rxn mixt has a +9 0°. After treatment with cone H2804, a this is the rotation of the 90:10 a: that a—GPA is only optically active component GPA is conserved. Calcula befigre reaction with H2804 , and that total te the GPA isomeric composition (b)(3) In working up GPA rxn mixts, Ac20 to water—miscible HOAc w' Referring to the effect of T rxns compared to slow ones, than 20° water; use <20 words. -4- (7) For the glucose anomers, the equilibrium ratio is 5:3 6:0. The rate laws have the same form: rateaag = kagg[a—anomer]; switching a and 8 gives the equation for Sea. Below the k's are labeled km and k3, respectively (a)(3) Show that the rate constant Latin, kazkg, must = 5:3; recall at equilibrium, the rate for a a 8 must = the rate for B a a. aheq(mixt)‘ (4) At 40°, the solubilit ...
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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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322bs09_plq2_1_blank - CHEMISTRY 322bL/325bL...

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