322bs09_plq1_2_key

322bs09_plq1_2_key - CHEMISTRY 322.131.132.311. Woe was....

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Unformatted text preview: CHEMISTRY 322.131.132.311. Woe was. praczl-(Le/ {GrFIRST LAB QUIZ“ in] Jig—0.2 BY 2393 m KEY Lab time T.A. This test comprises this sheet and five numbered pages. «1- 1. (7) Recall the Grignard Synthesis of 2-methyl-2-hexanol, CH3(CH2)3C(OH)(CH3)2, from n-BuBr and acetone, CH3COCH3. (a)(3) A Grignard reaction mixture includes a little 12. State two behaviors one observes if the reaction starts rapidly without external heating. Use < 12 words total. ($369“! warm/mu; dew/Va I; or gQAA/ijuf’tflf {WM (b)(2) If the addition of n—Bu—Br is too fast, a large amJth of the "coupling side product" forms. Write a balanced equation for its formation and give the product's structure. M; Jan) might/14 3r f- n—flqgtfi‘ ., ’ 0 “ Mr WWW iii—£21836? 3rd (c)(2) Tell why the aq soln used to convert the Grignard/acetone adduct to the product should be cold, dilute, and only weakly acidic. Use <10 words. 72 worf/pMVMJL ‘ZMVJWI‘ 2. (7) Recall the Period 2 alkylation of anisole, Ph—OMe, by Ph3COH in HOAc with catalytic H2304 to give n-MeO-C6H4-CPh3. (a)( ) Put "rev(ersible)" or "irr(eversible)" in each blank: The rxn \ “l fiaQC fails in EtOH because its rxn with Ph3C+ is ( r‘k . The prep as done succeeded because rxn of Ph3C+ with HOAc is 5A9 L , and its rxn with anisole is (‘V‘V . d (b)(5) Given ratio Desired Prod to Side Prod is 50:1 at 20°, 1:1 at 80°, and is exponential in sz: Calculate T (3 sig figs) to give DP:SP = 10:1. In defining (ST, note that DP:SP goes up as T goes down. Show calCulation; 0K to take loglos = 0.70. 3. ;S) For l-hex,p~ n—C4H9CECH ----- --> 2—hexanone, n~C4H.-CO-CH3. *- here {ven tho :h its act atia ener— sis -uch hfibher t_:n is than for VC + H20, whir lead: to k: one. Exp_ain i 15 words; recall hat the.aq phas: is rearly 1-1 '"2804:H20. 60¢ rhea, - 1‘» H30®3W h {mMm/KXM. (b)(2’ A stur“t carries g-t the rxn u .i‘ all the ,- exyne Opor is ” go i. /he test; a d op of t;e - mixt wfth ',4-DN H r;- _ a-fint, oatting enly a trace 9f ppt In <y0 wo ds, fell wiat if ;/he sho 1d do.with th- rxn mixt n: t a_i why. ' 0‘ ¢(ZL/M 7" 4’ 4. (5) For drying by distillation of dilute W solns in an OS: Given y = amt W, x = amt pot soln, and r a the vapor-to-liquid w conc ratio, ln(y/yo) a r[1n(x/xo)]. For r = 10, calculate the fraction of the soln one must distill, fd (2 1 - (x/xo)), to distill 90‘ of the Water, i.e., to make (y/yo) a 0.10. In (0.!) = 10 $022) =7 “2.3 = MAGS.) -:. -~O.l3l"='? 3% : (1,77%?! (3 (3) React'wn of l hexyne with e vinyl cat'or (VC) i; s'- 1 «ant 5w, l0: w c 1’“ /O erqgg‘ 1L0?) mmfi/e. w 5. (2) For 1A a 13 a 1C: Exactly 60 mmol A produces 300 mL of a solution containing B. Reaction of 100 mL produces 15 mmol pure C. Calculate the % yield of C based A. “5% Kola—~91?me (:7 -3- p7€=ll 6. (6) Recall the isatin/acetophenone aldol condensation: O O u o CH3-C-Ph H Isatin Acetophenone MW 2 147; mp x 193-195° MW 2 120; d a 1.03 7L (IL (a) Draw the structure of cpd I, the initial aldol product. (b) Calculate the MW of cpd I solely from its stoichiometric 6413((f far relationship to the starting materials; show calculation. ‘ (c) When the (nearly) colorless soln of cpd I is warmed with (fgl aq/alc HCl, the soln turns deep red, producing cpd II. 12 words, tell what electronic structural c a) (a) / 'u'o “pk </)I( I <34 «(loaf H hange is occurring. («4 \ a}, (MKfiMAuJ‘—‘l:3 “1 €**WWJ‘“9“{%9V ‘6 w. W . 7. (5) Consider the reaction below: A + B ———————d- C + D [initial] 1.0 10.0 0 0 [equilibrium] 1 a x 10 - x X (a)(2) Calculate [A]eq for Keq a 4.00. To simplify the calculation, take x a 1.0 in all terms EXQED; 1 — x, then solve for x. (b)(3) Tell what the calculation means, given that only A is hard to separate from products. (Note that if [Ali a [311 then [C]eq = [Dleq = 2/3[A]i. and [Aleq = 1/3IAJi-) Xl- ‘ ( = W (Moo-x) ‘4 ’57 Wm" 0-47) 5L :7 x ‘— % <10fi7 (4de W ML? 2 0.03%, we 04 MR¥ML (I43;=£6’3; awe/1 SgflM'flo% 4 {W flnJacfi. PhCOOH + 16 g HOMe -———————————4- PhCOOMe + HOH MW a 122 MW a 32 MW a 98 MW a 136 bp a 66° hp a 199° d < 20 words, explain why aq Na2CO3 extracted PhCOOH, but not (CH2C12) solution containing both. Mom; 4% choo‘S’A/fl? Pkwo ml. " A} f 7. ’47 #41603 “Lu/m 0.0% /(7‘2/ {/0 Kala [a/e IU‘L («£14 (c)(2) Droplets of aq Na2C03 were removed from DCM soln of the ester just before distillation. How and why was this done? <25 wds. Auk U {0 f 00 10/? 594‘ “M/ 67 ( 71L M 4 2g“; UmCox 11 mm 1 AW Salt: Amt Home?) w 4?; PL‘CH“C\p€-<\fi l 1 ‘ IQ \Q‘Mé , fl MHZ) w < 15 words, tell why this a duction to be effici7nt. 1 Pei/L” PhxéH— (Cu/OR Egg]: :59"), \ / filling in the blanks: Compared to 2—propanol, benzoin is easil y oxi- dized because its carbinol fl, :Cfi—OH, is a to a M4040“! In two one-electron steps, the a-diketone, benzil, (write . C- +LQ\ (u (my 5,th _---,) ‘CO'CO‘ , is produced as q is reduced to Cu‘. In (re)oxidizing 2 Cu*, NH4NO3 (in excess) is reduced to NH4N02, which decomposes to. £¥q_ gas and water. One Ea to N02‘ is reduction of the brown gas -N02 by ( + (a; CH . 9; . -N02 mplete because then -¥I there is nothing left to reduce (‘4 (Kl-CM Boiling with strong producing a pungent, ' Draw ...
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322bs09_plq1_2_key - CHEMISTRY 322.131.132.311. Woe was....

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