NAME:
Integrated Rate Law
1. Graph the data
2. Which set of data represents a direct relationship?
3.
4. What is the rate constant, including units, for the reaction above?
5. Determine the half-life of the reaction.
6. If another trial was performed with an initial concentration of 0.400 M, what concentration would remain after 4
hours pass?
7.
8. Write the rate law for the reaction
9. Determine the rate constant, including units
10. Determine the half-life.
11. What concentration of the reactant remains after 5 hours?
FIRST ORDER
12. N2O5 is the unstable anhydrive of nitric acid that decomposes by first-order kinetics into nitrogen dioxide and oxygen
gas: N2O5(g)  NO2(g) + O2(g). The rate constant for this reaction is 6.22 x 10-4s-1 at 45°C. If the initial concentration of
N2O5 is 0.500 M, how long will it take for the concentration to drop to 0.0500 M? ANSWER(3.7 x 103s)
13. If the initial concentration is 0.250 M at 45°C, what is the concentration after 1 hour? ANSWER(0.0266 M)
14. What is the rate constant for a first-order reaction with an initial concentration of 0.300 M if, after 158 s, the
concentration is 0.200 M?
15. In the same reaction above at the same temperature, what would the concentration be 2.75 minutes later if the
initial concentration was 1.50 M?
16. In the same reaction above at the same temperature, what was the initial concentration if after 5.00 minutes, only
0.0100 M remain?
17. The rate constant for the isomerization of cis-2 butene gams to trans-2 butene is 0.00693 s-1. What is the half-life of
cis-2 butene? (ANSWER: 100 s)
18. What fraction of the original cis-2 butene remains 5.00 minutes after the reaction? (ANSWER: 3 half lives, so 1/8)
19. If the original concentration of cis-2 butene was 3.45 M, what concentration remains 7.00 minutes after the reaction?
(ANSWER: 0.188 M).
20. The rate constant for the first order conversion of cyclopropane to propene is 9.0 x 10-4 min-1. What is the half-life of
the reaction?
21. If the initial concentration of cyclopropane is 1.50 M, what concentration remains after 51.2 hours?
22. The half-life for the first-order decomposition of N2O5 is 2.0 min. What is the rate constant for the reaction?
23. What is the concentration of N2O5 after 270 seconds if the initial concentration was 0.180 M?
24. How much time does it take for the concentration of N2O5 to drop from 0.180 M to 0.100 M?
25. The half-life for a first-order reaction is 22.7 seconds. How much time in seconds does it take for the partial pressure
of the reactant to decrease from an initial pressure of 100.00 mmHg to 10.0 mmHg?
SECOND ORDER
26. Nitrosyl chloride, NOCl, is a corrosive orange gas that is also an irritant. The gas decomposes slowly to form the
gases NO and Cl2 by second-order reaction with a rate constant, 0.020 L/mol*s. What is the concentration of NOCl
after 40 hours if the initial concentration was 0.450 M?
(ANSWER: 3.5 x10-4 M)
27. For the reaction above, how long will it take for the initial reaction of 0.038 M to drop to 0.012 M?
28. Pharmacokinetics is the study of how the body takes up, distributes, and eliminates drugs. The eliminationof a newly
designed drug follows a second-order kinetics. This new drug has a molar mass of 122.0 grams. The rate constant is
2.4 L/mol*min. If the initial dose of this drug was 0.250 grams for a 150 lbs. patient, what mass of the drug remains
after 12 hours?
29. NOBr decomposes via second-order kinetics with a rate constant of 20 L/mol*s. What is the half-life of NOBr?
(ANSWER: 5.0 s)
30. How long would it take the concentration of NOBr to drop form 0.0100 M to 0.0025 M? (ANSWER: 2 half-lives so,
15.0 s)
31. The reaction 2HI(g)  H2(g) + I2(g) is second-order and has a rate constant of 0.0796 L/mol*s. What is the half-life then
the initial concentration is 0.100 M?
32. What is the concentration for the reaction above after 375 seconds if the initial concentration was 0.100 M?
ZERO ORDER
33. A zero-order reaction has a rate constant of 0.0250 M/s. What is the half-life of this reaction of the initial
concentration was 0.50 M?
34. For the same reaction above, what will be the concentration after 15 seconds if the initial concentration is 0.50 M?
35. A zero-order reaction has rate constant of 0.0025 M. What is the concentration of A after 35 seconds if the initial
concentration is 0.50 M?
36. If the half-life of a reaction is independent of the initial concentration, what can you conclude about the reaction’s
order?
37. Answer the following questions for first, second, and zero order reactions (in that order)
a. Rate of reaction
b. Rate constant unit
c. Integrated rate law
d. Half-life