QUIZ #2
SC112, Spring 2016
Prof. M. Elert
EY
NAME ____ J'J_______________________
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R = .08206 L atm mol-I K- 1 = 8.314 J mol-I K-l
[Al
=-kt + [Ale
In [Al
k = Ae· Ea / RT
=-kt + In [Alo
t~
lI[Al = k t + 1/ [Ale
=[Alo/2k
ty,
= O.693/k
ty, = l/(k [Alo)
In k = (-Ea/R)*(l/T) + In A
1. (4 points) In the reaction
h(aq) + 2S2032- -+ 21- + S4062it is found that the h concentration decreases
from .080 M to .060 M in an interval of 15 seconds. What is the average rate of 1- production during this same
time interval, in Mis?
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Experiment
1
2
3
[NO] (M)
0.10
0.25
0.10
>
'II
Initial Rate (Mis)
24
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ISO , /
L
j(
2
48
Determine the rate law for the reaction.
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[NOJ \ J
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a.. - J..... (l.SO) .9, ,
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Vr
Mis
2NO Br(g), the following data for the initial rate of disappearance
-+
[Br2J (M)
0.20
0.20
0.40
,(1(113
L (.00/3) ~ .00 '2.6 Mis
....
2. (4 points) For,the reaction 2NO(g) + Br2(g)
of Br2 were obtained:
-::.
,10
{{ II IE".'!
i [No]'L[B 1\2.]
3. (4 points) The reaction A -+ B is first order in A with a half -life of 152 s. How long (in seconds) will it take
for the concentration of A to decrease from 0.82 Mto 0.30 M?
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S-I
4. (4 points) It takes 42.0 min for the concentration ofa reactant A in a second-order reaction A - B to drop
from 0.45 M to 0.32 M at 25°C. How long will it take for the concentration of A to decrease from 0.32 M to
0.10 M at the same temperature?
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5. (4 points) The rate constant for the reaction CH3COOC2Hs + OH- - CH3COO- + C2HsOH
is .0521 MIS-1 at 15°C and 0.184 M- 1S-I at 35°C. Calculate the activation energy Ea for this reaction, in kJ/mol.
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----120--T,( ) i f<f)
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