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14A2F012 . Baur CHEMISTRY 14A
LECTURE SECTION 2
FALL QUARTER, 2001 Secondmination Friday, November 16, 2001
Name—ML TA: (check one)  (LAST) (FIRST) Damian Aherne
 Mollie Cavanaugh
Natalie Gassman
Section Number Kim Miller
Will Molenkamp QUESTION N0. CREDIT m
1 IN T I 1. There are four questions. Answer each W; you may write on the backs of sheets if you need more
room, but no loose sheets of paper will be accepted. ' 2. Your work must be clearly 9193M and Lemme; credit will not be given for unintelligible responses. 3. W must be shown for all computational items; no credit for merely putting down an answer, even it
correct. 4. Make sure that all answers have the appropriate number of significant figures. 5. Give muster all answers, unless dimensionless. 6. Open book examination. Any written or printed materials may be used. 7. DO NOT LIFT THIS COVER SHEET AND BEGIN WORK UNTIL INSTRUCTED TO DO 30! II in t it n :
H. 1.008 O 16.00 Na 22.99 Cl 35.45 Cr 52.00 Br 79.90
He 4.003 F 19.00 Mg 24.30 Ar 39.95 Fe 55.85 Ag 107.87
C 12.01 Ne 20.18 8 32.06 K 39.10 Cu 63.55 . Cd 112.41
N 14.01 Ca 40.08 Zn 65.39 I 126.90
NA (Avogadro’s Number): 6.022 x 1023 Ideal Gas Law: PV = nRT R = Gas Constant: 0.0821 L atm mol1 K1
= 0.0831 L bar mol1 K1
Photon energy (Planck Law): 8 = hv = th» c(velocity of light) = 3.00 x108 ms‘ h(Planck’s Constant) = 6.63 x 1034 J5
Bohr formula: En = 2.178 x 1018 J (22/n2) 1 e.v.(electron volt) = 1.60 x 1049 J
Coulomb energy between two charges Q1 and 02;: EC = 2.31 x 1019 d nm(Q1Qp_/r) (Q in multiples of the elementary charge) The M and am are on the back of this sheet. CHECK TO MAKE SURE THAT THIS EXAMINATION PAPER HAS FOUR QUESTIONS AND FIVE PAGES 2
1 4A2F012 Name 1. (20 points) For each Of the two coordination complexes given below, you are to draw all distinct
'stereoisomers possible. Credit will be subtracted for structures which are in fact equivalent to others given
(i.e. just the same structure with a different orientation). Stategwhether each of the isomers you draw is a geometrical isomer or one of a pair of 99121 isomers.
(a) (8 points) Diamminebromochloroplatinum(lI), Pt[BrCl(NH3)2]. This is a neutral species and has a plane square geometry.
rim 4m 7w gamenew; 50/145125 ,' (Mb my  N 31
\ ?t/ 5 ’é\ Pt/
/ \ \ “*3
IS, (I  J
CIS TEM$ (b) (12 points) Diaquodiamminedichlorochromium(lll) ion, Cr[Cl2(NH3)2(H20)2]+. This ion has octahedral
geometry. (Hint: you may find it helpful to glance at Example 16.2 and SelfTests 16.6A and 16.68 on pp. 887889 of the text.) N H} ALL Tami/s : 51/
will. “to
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14A2F012 Name 2. (35 points) Below is a phase diagram for a pure substance X. For this problem, all pressures are
expressed in atm. 1000 100 PRESSURE
in ATM
a.
3 102 104 105
100 150 200 250 300 350 400 450 500 550 TEMPERATURE (K) (a) (10 points) Label the liquid, solid and vapor regions of the diagram, and circle the and label it
with a C, and circle the mom; and label it with a T. (b) (10 points) From the phase diagram, ive thﬁ following:
the temperature of the critical point [0 go the temperature at which liquid X will freeze at 1 atm pressure
the temperature at which liquid X will freeze at 1000 atm pressure m K the temperature at which liquid X will boil under 1 atm pressure £5? E
the temperature at which liquid X will boil under 103 atm pressure 2:
(c) (15 points) 1.00 mol of pure substance X is placed in a vessel of volume 10.00 liters at 400 K. Under these conditions only vapor is present.
what is the pressure (in atm) of this vapor? (5 points) . l l
P a 1g“: [hWMaU/Oﬂi’lng‘lzltot‘lﬁ “400(5) = 3,25A71Vl
10.0 suppose the volume of the vessel is reduced to 2.00 liters with the temperature still at 400 K.
Will all of substance X remain in the vapor phase or will some condense to liquid? )1 ML? IF /TkLL Rug/us? M7715: VM’oR F/fﬂﬁﬁ, Bows} LAWWM?
M2? ’72 ~ 7» La = wot . 50,, a; 570013.08/‘97‘ = lé‘lm.
, ' l 77 “37mm ‘ vy 73w
77795 a mm W ﬁts/Ame ﬂagging Avg/avg) So Smﬁlxeozpnw‘rcwm/SE, What is thenew pressure (in atm) in the vessel?
5 moﬁ ﬁmt Meaty/14v) impala w/LL 51: Pwﬁaﬂj WleéSSUzﬁ 15 54mm. 772 mvwoe szozé/Aﬂ’ 4400!) 01?. ID' A‘Wl 4
14A2F012 Name 3. (20 points) A solution of glycerol (C3H803, MW 92.1) in water is to have molar concentration 1.50 M.
(a) (10 points) Calculate the maximum volume of this solution which can be made up from 250.0 grams of glycerol. 25D 0 ‘Mﬁs
: ' ..__._—‘ I 7/ Mal/£5
m) CMW 0.P 50LUTE) _, ﬁ/
42, [ Gal11$ mu “7 ﬁ/(rom T/TH' c
z " _ L:WI/.8ll
VMH’ LmM IllD M0959" (b) (10 points) Calculate the volume of 1.50 M glycerol solution in water which should be measured out to
deliver 6.25 millimoles (0.00625 moles) of glycerol. A7: é.L§MMol/.F/ ; V'M 6,L§ MMWS
: ._____._————. 2
/, Yb lumpy ML ,: #47 ML 10,004171'. .5
1 4A2 F01 2 Name 4. (25 points) The equilibrium constant K in terms of pressures (in bar) for the gasphase reaction N204(9)_ = 2“02(9)
p is 0.98at 298 K and 47.9 at 400 K. Use this information to answer the following questions.
(a) (5 points) Is the reaction as written (reading from left to right) enmthermic or W? Explain your reas°ningmem $M/CE K Mic «M5159 A/ I 7H 1; 69 LAME/u’SPIe/wwﬁ
THE ,RELA'CTIOA/ M0 sr 6&EA/WV—A—550R8M/F [ow/ Hem W13 e/qussa W
)5 MDOTHW/g . (b) (10 points) A vessel contains N204 (g) and N02(g) at equilibrium at 400 K. The partial pressure of
N02(g) is determined to be 0.650 bar. Calculate the partial pressure of N204(g). K: 47.63: (pun? : 0'69); L— 3
~" 7’va w m = (04:? >; 8,6’2x/0 >0v003532 ' ( c) (10 points) In a separate experiment, N204(g) and N02(g) are allowed to equilibrate in a vessel at 400 K. Then the volume of the vessel is suddenly changed. Immediately after the change in volume, the
partial pressures are: P(N02) = 300 millibar (0.300 bar), P(N204) = 1.25 millibar (0.00125 bar); In which direction will reaction occur to restore the equilibrium? Explain, with brief calculation.
CALCULATE a? 1 59; PM 7 (0.3010'L _ 0
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This note was uploaded on 02/08/2012 for the course CHEM 14A 142042200 taught by Professor Lavelle during the Spring '10 term at UCLA.
 Spring '10
 Lavelle

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