METHOD OF INITIAL RATE PROBLEMS
For each of the sets of data below, determine the rate law and rate constant (with units).
A+BP
1.
Expt #
[A] (M)
[B] (M)
1
2
3
0.273
0.273
0.819
0.763
1.526
0.763
2ClO2 (aq)  2OH  (aq)  ClO3 (aq)  ClO 2  (aq)  H 2O(l)
2.
Expt #
1
2
3
[OH-] (M)
[ClO2]
(M)
0.060
0.020
0.020
0.030
0.030
0.090
Initial Rate
(M/s)
0.0248
0.00276
0.00828
NO +O2  NO2 + O
3.
Expt #
1
2
3
4
5
Initial Rate
(M/s)
2.83
2.83
25.47
[O2] (molecules/cm3)
1x1018
1 x1018
1 x1018
2 x1018
3 x1018
[NO] (molecules/cm3)
1 x1018
2 x1018
3 x1018
1 x1018
1 x1018
Initial Rate (molecules/cm3s)
2.0 x1016
8.0 x1016
18.0 x1016
4.0 x1016
6.0 x1016
4. (CH3)3CBr + OH-  (CH3)3COH + BrExpt #
1
2
3
[OH-] (M)
0.10
0.10
0.20
[(CH3)3CBr] (M)
0.10
0.20
0.10
Initial Rate (M/s)
0.0010
0.0020
0.0010
5. 2A + 2B  C + 2D
Expt #
[A] (M)
[B] (M)
1
2
3
0.100
0.200
0.100
0.100
0.100
0.200
Initial Rate
(M/s)
0.000040
0.000160
0.000080
6. H2O2 + 3I- + 2H+ I3- + 2H2O
I
II
III
IV
[H2O2] (M)
0.100
0.100
0.200
0.400
[I-] (M)
0.000500
0.00100
0.00100
0.00100
[H+] (M)
0.0100
0.0100
0.0100
0.0200
Rate (M/s)
0.137
0.268
0.542
1.084
METHOD OF INITIAL RATE PROBLEMS
Answer Key (note that the reactants may be written in any order and it is acceptable to omit any
reactant that is zero order)
1. rate = 38.0 M-1s-1 [A]2[B]0
2. rate = 230 M-2s-1 [ClO2]2[OH-1]1
3. rate = 2.0x10-38 (molecules/cm3)-2s-1 [O2]1[NO]2
4. rate = 0.010 s-1 [(CH3)3CBr]1[OH-1]1
5. rate = 0.040 M-2s-1 [A]2[B]1
6. rate = 2740 M-1s-1 [I-1]1[H2O2]1[H+]0