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AP Chemistry
Worksheet : Ch 12 : Obj. 8-14-2
Name :
Date :
A. Match the characteristics of the integrated rate laws (4 letters per blank) :
__________ 1. Zero order rate law
a. a plot of [A] vs t gives a straight line
b. a plot of 1/[A] vs t gives a straight line
__________ 2. First order rate law
c. a plot of ln[A] vs t gives a straight line
d. slope = k
__________ 3. Second order rate law e. slope = -k
i. rate = k ; [A] = -kt + [A]0
f. t½ = .693/k
k. rate = k[A]2 ; 1/[A] = kt +1/[A]0
g. t½ = [A]0/2k
m. rate = k[A] ; ln[A] = -kt + ln[A]0
h. t½ = 1/(k[A]0)
_____ 4. (T/F) For the reaction aA  bB, the rate remains constant over time. Reactant A is therefore a first
order reactant.
_____ 5. (T/F) Zero order reactions often have their rate controlled (limited) by a factor other than reactant
concentrations, such as a catalyst or adsorption surface.
6. The decomposition of hydrogen peroxide was studied, and the following data were obtained at a particular
temperature:
Time(s)
[H2O2](mol/L)
0
1.00
120 ± 1
0.91
300 ± 1
0.78
600 ± 1
0.59
1200 ± 1
0.37
1800 ± 1
0.22
2400 ± 1
0.13
3000 ± 1
0.082
3600 ± 1
0.050
Assuming that Rate  
[ H 2 O2 ]
, determine the rate law, integrated rate law,
t
and the value of the rate constant. Calculate [H2O2] at 4000. s after the start of
the reaction.
7. A certain reaction has the following general form: aA ——> bB
At a particular temperature, concentration versus time data were collected for this reaction and a plot of ln[A]
versus time resulted in a straight line with a slope value of -6.90 X 10-2 s-1.
a. Determine the rate law, the integrated rate law, and the value of the rate constant for this reaction.
b. Calculate the half-life for this reaction.
c. How much time is required for this reaction to be 87.5% complete?
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8. The rate of the reaction NO2(g) + CO(g)  NO(g) + CO2(g) depends only on the concentration of
nitrogen dioxide below 225°C. At a temperature below 225°C the following data were collected:
Time (s)
0
1.20 x 103
3.00 x 103
4.50 x 103
9.00 x 103
1.80 x 104
[NO2] (mol/L)
0.500
0.444
0.381
0.340
0.250
0.174
Determine the rate law, the integrated law, and the value of the rate constant. Calculate the [NO2] at 2.70 X 104 s
after the start of the reaction.
9. A certain reaction has the following general form: aA  bB
At a particular temperature and [A]0 = 0.100 M, concentration versus time data were collected for this
reaction, and a plot of 1/[A] versus time resulted in a straight line with a slope value of 4.15 x 10-3 L/mol • s.
a. Determine the rate law, the integrated law, and the value of the rate constant for this reaction.
b. Calculate the half-life for this reaction.
c. How much time is required for this reaction to be 75.0%complete?
10. The decomposition of hydrogen iodide on finely divided gold at 150°C is zero order with respect to HI. The
rate defined below is constant at 1.20 x 10-4 mol/L • s.
Au
2HI(g) ——> H2(g) + I2(g)
Rate  
[ HI ]
 k  1.20 x10  4 mol / L  s
t
a. Assuming that concentration versus time data were collected for this reaction, sketch a plot of [HI]
versus time, and determine the slope value of this plot.
b. If the initial HI concentration was 0.250 mol/L, calculate the concentration of HI at 25 minutes after the
start of the reaction.
c. How long will it take for all of the 0.250 M HI to decompose?
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11. The reaction A  B + C is known to be zero order in A and to have a rate constant of 5.0 x 10-2 mol/L • s
at 25°C. An experiment was run at 25°C where [A]0 = 1.0 x 10-3 M.
a. Write the integrated rate law for this reaction.
b. Calculate the half-life for the reaction.
c. Calculate the concentration of B after 5.0 x 10-3 s has elapsed.
12. The dimerization of butadiene
2C4H6(g) ——> C8H12(g) was studied at 500. K, and the following data were obtained:
Time (s)
195
604
1246
2180
6210
[C4H6] (mol/L)
1.6 x 10-2
1.5 x 10-2
1.3 x 10-2
1.1 x 10-2
0.68 x 10-2
[C4 H 6 ] determine the form of the rate law, the
t
integrated rate law, and the rate constant for this reaction. (These are actual
experimental data, so they may not give a perfectly straight line.)
Assuming that Rate  
13. A certain first-order reaction is 45.0% complete in 65 s. What are the rate constant and the half-life for this
process?
14. The radioactive isotope 32P decays by first-order kinetics and has a half-life of 14.3 days. How long does it
take for 95.0% of a sample of 32P to decay?
15. A first-order reaction is 38.5% complete in 480. s.
a. Calculate the rate constant.
b. What is the value of the half-life?
c. How long will it take for the reaction to go to 25%, 75%, and 95% completion?
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16. A certain first-order reaction is 50.% complete in 3.5 hours. What period of time is required for the
reaction to be 88% complete?
17. It took 143 s for a 50.0% of a particular substance to decompose. If the initial concentration was 0.060 M
and the decomposition reaction follows second-order kinetics, what is the value of the rate constant?
18. A certain substance, initially at 0.10 M in solution, decomposes by second-order kinetics. If the rate
constant for this process is 4.0 x 10-1L/mol • min, how much time is required for the concentration to reach
0.020 M?
19. In 6 M HC1 the complex ion Ru(NH3)63+ has a half-life of 14 h at 25°C. Under these conditions, how long
will it take for the [Ru(NH3)63+] to decrease to 12.5% of its initial value?(Assume first-order kinetics.)
20. For the reaction A  products, successive half-lives are observed to be 5.0, 10.0, and 20.0 min for an
experiment in which [A]0 = 0.20 M. Calculate the concentration of A at the following times.
a. 60.0 min
b. 20.0 min
Answers : 6. k= 8.3 x 10-4 s-1, [H2O2] = 0.037 M at 4000. s 7. k = 6.90 x 10-2 s-1 7b. t1/2 = 10.0 s 7c. 3 halflives = 30.0 s 8. k = 2.08 x 10-4 L/mol·s ; [NO2] at 2.70 X 104 s = 0.131 M 9a. k = 4.15 x 10-3 L/mol·s
9b. t1/2 = 2.41 x 103 s 9c. t = 7.23 x 103 s 10a.
slope = -1.20 x 10-4 L/mol·s 10b. 0.07 M 10c.
34.7 min 11b. 1.0 x 10-2 s 11c. 2.5 x 10-4 M 12. k = 1.4 x 10-2 L/mol·s 13. 9.2 x 10-3s-1 ; t1/2 = 75 s
14. 62 days 15a. k = 1.01 x 10-3 s-1 15b. 686 s 15c, 25% = 280 s, 75% = 1.4 x 103 s, 95% = 3 x 103 s
16. 11 hr 17. k = 0.12 L/mol·s 18. 1.0 x 102 min 19. 42 hrs 20a. 1.5 x 10-2 M 20b. 0.040 M
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