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Unformatted text preview: CHE 1113
TEST II
DR. POWELL
JULY 9, 2008 Please print your name on both the test paper and the Scan Tron form.
SECTION1. MULTIPLE CHOICE (4 points each). 1. The equilibrium constant, Kc, for the decomposition of COBr2 a 2 COBr2(g) H 00(9) + Br2(g) M’”“"“fﬁ
7  E ii 0\ 'is 0.190. What is Kc for the following reaction? 200(9) + ZBr2(g) H 2COBr2(g) .00361 b) 2.63 c) 10.5 d) 27.7 e) 15.5 l< [N 023 [M] 2. For the elementaryprocess N03 + CO —> N02 + 002 })\the molecularity is 4 and rate = k [N03] [CO] [N02] [CO2]
b) the molecularity is 2 and rate = k [N02] [C02]
the molecularity is 2 and rate = k [N03 [CO]
C the molecularity is 2 and rate = k [N03] [C0] / [N02] [C02]
QNhe molecularity is 4 and rate = k [N02] [CO2] / [N03] [CO] 3. Consider a chemical reaction between compounds A and B that was found to be ﬁrst order in
A and second order in B. Given the following information, ﬁll in the blank. Ex riment A ' B 7" initial rate M/s
1 1.00 M 0.200 M 0 .l’? 0
2 2.00 M 0.200 M 0.300
3 1 00 M 0. 400 M 0.600
x I Z
0 300 M/ f 172.37 _. . .
e $0.200 MI: W K [A] la. " 7170’ [I N] [0 200‘)
7.1 1200 Mlso 911K)? 0031:0100 0.600M/ _ .
gowow: :nggKo 0% (‘3'ch 4. The reaction 2A + B > CO' IS 2nd g'order in A and has a rate constant of 40 M 3' What is
the order With respect to B? I 1‘ 1 : w a) 3 @2 c) 1 d) 0 e) impossible to determine without experimental data 5. The reaction 2A + B —> C has the following proposed mechanism: Step 1: A + B —> D (fast, equilibrium)
Step 2: D + B —> E (slow)
Step 3: E + A —> C (fast) Which of the following rate laws is consistent with the mechanism? ra e—  .. I ‘ I
\Oﬁraie: Selﬁml KHV’1’KEWE3]
c)\rate= k [A]2 [B] [A] {:9 \d)rate= k[A] [B]
e) rate= k [A] [B]2 PAGE 2 6. Consider the following reaction:
2 $02 (9) + 02(9) —* 2803(9) From which of the following starting conditions would it be impossible for this equilibrium to be
established? 3x 0.50 mol 02(9) and 0.50 mol 803(9) in a 2.0L container
‘bL 0.25 mol 802(9), 0.50 mol 02(9), and 0.10 mol 803(9) in a 1.0L container
0\ \c)\0.25 mol 802(9) and 0.25 mol 02(9) in a 1.0L container
1.0 mol 802(9) in a 1.0L container
Equilibrium can be established from any of these starting conditions. 7. The decomposition of phosphine is described by the following reaction:
4PH3(9) —‘> P4(9) + 6H2(9) b If the rate of formation of H2(g) is 6.9 x 10'5 M s", then the rate of disappearance of PH3(g) is X69 x 10'5 M s" G) 4.6 x 10'5 M s" 690.3 x 10'5 M s'1 d)\2.76 x 104 M s'1
e) 'ndeterminate SECTION 2. PROBLEMS (7 points eachﬁ ( J21 I X 3 (71” (1.4 X ' 0 9 ) (I . 0‘6
8. Forthe reaction: ; U 0 000 U at U XI ,
2 CI02 (aq) + 2 0H'—> Clog(am + Clozram + H20 (I) U02 W : 2% (I. 070 0. 002’?! Experiment Cl0_2 [OH ' initial rate (M/s) a”; 51 1 0.060 M 0.030 M 0.0248 — 2 [0.020 M 0.030 M 0.00276 M ’ Z 3 0.020 M 0.090 M] 0.00828 0 H : 0,0 40 ‘: 0. 00% _ _ . o .030 ””551"
Determrne the rate of thrs reaction when [Cl02 ] = 0.1 4 M and [0H" ] = 0.145 M. (2 3
“MM/S 0.52%: 8 {0.0003 lie030] 3; Q no.00261M/s 0.02492: KoODO (’65 Y' I
00.494M/s W% 0.000l0 2 MC»
d)\0.600 Mls ‘ . _ , 6) 0.513 M/s K 3 98 O ’ ﬁggﬂggﬂ 9. Pure phosgene gas (COCI2), 0.0400 mol, was placed in a 1.50—L container‘ltwa eated to
800 K, and at equilibrium the pressure of CO was found to be 0.479 atm. What is Kp for the reaction? (R = 0.0821 L atm/mol K) 2 An 4A9
‘ +' 2 l kw  KC (RT)
:l: “18) I 0' ‘8’ . 8893924
a) 5.54 C X ~X ‘ 0 “4'7
L (33?? 520.410 09'74 *—' 0.402 d’ “"1 E0 .9 92] : W? "'V 97004201900)" e) 2.56
10. At a particular temperature an uilibn'um mixture in a 3.00—L ﬂask contains 3.50 mol HI, 4.10 mol H2, and 0.300 mol Iz. Calculate Kc at this temperature for the reaction \O I H2(g) + I2 (9) H 2H (g)
a) 2.85
@ 9.95 C l ”Tﬂlr—I __
3.33 . 
3)) 8.54 g 771 0" 1 e) 14.2 ‘ u. WI] ’ Ll .5’1 [0“] KC : ELMOFJE7JO’MJZ
" [9'01“]? PAGE3 11. Consider the following reaction. Pure N02 (9) placed in a sealed container dissociates by the reaction system shown below. The equilibrium pressure of NO(g) is 0.3500 atm.
Pm. = 1.0866 atm. What is the value of Ko for this reaction? K p :: 2N02(g) H 02(9) + 2N0(Q) I
a) 0.287 C WW _ . g _ .
93360380 9: + 0.'79+ (j. moo : Ji’ﬁUb
33.21809 3'0 Alﬂiﬁﬂé 3%: 0.92s 0 )( :10? 12. The equilibrium constant, Kp , for the following reaction is 45.9 at 763 K. A particular
equilibrium mixture at this temperature contains gaseous HI at a partial pressure of 4.00 atm and hydrogen gas at a partial pressure of 0.200 atm. What is the partial pressur .w“2
? ’ 2 ¢
1‘ “2(9) + I2(g) H 2H' (SIN/2E}! : LL%XJ
a\) 0.436 atm  >_ . r, , [0'2” ._
0.575 t ' ,  {WW ; ’ 
31.35.34“ % 5 70.0+_X+‘foo (1.7'7 we... ,_ .
\g) agggatm , . .‘ C] Uoj (0 . QOO) ( X)
. t . ' ,
am I) .7354+ti.7'7)\=—2 .00
l *‘  ' ‘e‘f‘g, ‘57} _ I .. paS‘k ANSWER THE FOLLOWING QUESTIONS bi’i 'TH'E'TEST mu:Ell—jT,‘= 0
‘ I ‘2 E! e _ (Please shqwall your work if you wish tqreceiv ny itll)  ,
l ‘ , _ . . , 55.155861: (1.92  on"!
1. How is it possible for two reactant molecules to collide with the proper orientation and still at react? (3 points)‘n(I do ml“. MM! m1, “ppm” “ML : 03‘?
0\ vm of (lay) naivmiiumme/my. 2. Kc = 55.3 for the reaction Br2 (g) + F2 (9) (9 ZBrF (g). Wh ‘ he concentration of BrF at
equilibrium if the initial concentrations of bromine and ﬂuo ' e were both 0.180 M? (5 points) . o 04‘60
if“: :3. *2". @
Q 039,010” ‘X 6” KC :(é) 4‘50 X1/ We Et/(EW‘2 lPCl3(g) +1 CI2(g) +—»\ PC5(9) ( O . igo ‘X2) 3. At 600 K the reactio 3 is at equilibrium when the concentrations of PCI3, Clz, and PCI5 are 6.00, 8.00, and 11.0 mol/ ,
respectively. Calculate the value of Kc and KD at 6 (8 oints) Kr [H0] (I IOO PAGE 4 4. a) The equilibrium constant K; for the reaction below is Look/102 at 230°C. If 3.00 moi of
H2 and 3.00 mol of F2 are introduced into a 1.00L reaction vessel at this temperature, what is
the concentration of all species when equilibrium has been established? 8 POINTS) H2<g) + F2(g><—>2HF(9) l. auxin: I Q _
M M V? dosing.” //K~2.®
1: ‘0 0.5062 3 _—_. , ' x
( 1X? X (a E 0; , " , 29X 0 l  bZ‘X/
Willem c 2r 
Z 30— DX‘JZX
loo: 5”?" __ _‘ ilo x +I0)\
deﬂgyp)’ th ' ' I part a), an “whom; Calculat o . .
equilibrium concentrations of all species. (10 POINTS) —_
C I, X ‘— X “of 2x : Q J 5/ l\ W .. ,i ______
\§;_IX BO‘X 2X (E3 31,?
' KZXXL ~ Z 1" l .ouxtoZ :. V
)7 [BQ—Xlggo f] “Kuwm )ij
lo.§/5,5x’[email protected]§o.9 The rate of a reaction is expressed in terms of changes in concentrations of reactants and
products as follows: V,”
RATE =  AINZOEJ = __A[NO.2.] = ﬂ ). UUXIUZl [2X] 2At 4At At Write a balanced uatio ' ' ‘__._ I 0 I l , if! a \/ 2 m
,. Y, . :4] lo
mm = H
WONT7'72 ﬁll/[997  W Um
uLiQIZ‘NN x — all/Ml X (9.09 axﬂ ________
"00 “Wigwam ...
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