Question

A + B → C Select the rate law for the reaction above using the following information: Holding the concentration of A constant and doubling the concentration of B results in the rate of the reaction increasing from 1.5E-3 M/s to 1.2E-2 M/s. Keeping the concentration of B constant and doubling A results in the rate of the reaction increasing from 1.5E-3 M/s to 3.0E-3 M/s.

Answer 1

For the initial conditions:
1.5E-3 = k A^n B^m

For the second condition:
1.2E-2 = k A^n (2B)^m
1.2E-2 = 2^m k A^n B^m
From the initial condition:
1.2E-2 = 2^m (1.5E-3)
m = 3.32

For the third condition:
3.0E-3 = k (2A)^n B^m
3.0E-3 = 2^n k A^n B^m
3.0E-3 = 2^n (1.5E-3)
n = 1

Therefore, the rate law is:
r = k A B^3.32