Name: _______________________________
Determination of Rate Law and Rate Constant
1. Determine the order in the following situations
a. The concentration doubles and the rate doubles.
b. The concentration doubles and the rate quadruples.
c. The concentration doubles and the rate stays the same.
d. The concentration halves and the rate halves.
e. The concentration quadruples and the rate quadruples.
2. What does a rate law or rate equation tell us?
3. The oxidation of iodine ion by hydrogen peroxide in an acidic solution is described by the balanced
equation
H2O2 (aq) + 3I- (aq) + 2H+ (aq)  I3-(aq) + 2H2O
The rate formation of the red-colored tri-iodide ion, can be determined by measuring the rate of
appearance of color. Following are initial rate data at 25°C.
Experiment
Initial [H2O2]
Initial [I-]
1
2
3
4
0.100
0.100
0.200
0.200
0.100
0.200
0.100
0.200
From the data, determine the rate law and calculate the rate constant.
Initial Rate of formation
(M/s)
1.15 x 10-4
2.30 x 10-4
2.30 x 10-4
4.60 x 10-4
4. Initial rate data at 25°C are listed in the table for the reaction
F2 (g) + 2ClO2 (g)  2FClO2 (g)
Experiment
Initial [F2]
Initial [ClO2]
1
2
3
0.10
0.10
0.20
0.010
0.040
0.010
Initial Rate of formation
(M/s)
1.2 x 10-3
4.8 x 10-3
2.4 x 10-3
What is the rate law for the reaction? Determine the value of the rate constant.
5. The reaction of iodide ion with hypochlorite ion, OCl- (which is found in liquid bleach), follows the
equation
OCl- + I-  OI- + ClIt is a rapid reaction that gives the following rate data.
Experiment
Initial [OCl-]
Initial [I-]
1.7 x 10-3
3.4 x 10-3
1.7 x 10-3
1
2
3
1.7 x 10-3
1.7 x 10-3
3.4 x 10-3
Initial Rate of formation
(M/s)
1.75 x 104
3.50 x 104
3.50 x 104
What is the rate law for the reaction? Determine the value of the rate constant.
6. The initial rates listed in the table below were determined for the reaction of
2NO (g) + O2 (g)  2NO2 (g)
Experiment
Initial [NO]
Initial [O2]
1
2
3
4
0.015
0.030
0.015
0.030
0.015
0.015
0.030
0.030
What is the rate law for the reaction? Determine the value of the rate constant.
Initial Rate of formation
(M/s)
0.048
0.192
0.096
0.384