Question

What is the rate constant for a reaction based on the following experimental information?

Experiment	Rate (M/s)	[A] (M)	[B] (M)	[C] (M)
1	0.3126	0.25	0.53	0.45
2	0.3126	0.55	0.53	0.45
3	0.574	0.25	0.954	0.45
4	2.3217	0.55	1.484	1.17

Answer 1

The rate law for the reaction can be written as follows,

where are the order of reaction with respect to reactant A, B and C respectively.

Using experiment entries 2 and 1, substitute the values in above rate law,

.....(1)

......(2)

Divide both the equations (2) ansd (1),

Taking logarithm on both sides we get,

Similarly, using entries 3 and 2,

(The A term is reduced to 1 due to its power zero)

Dividing both the equations, we get,

Similarly, using entries 4 and 1,

(The A term is reduced to 1 due to its power zero)

Dividing both the equations, we get,

The rate law can be written as follows,

Now, rate constant can be calculated by using any of the experimental entry,

let us put values of experiment 1 in rate law,