Using the data in the table, determine the rate constant of the reaction

Question

Using the data in the table, determine the rate constant of the reaction and select the appropriate units.

A+2B⟶C+D

[A] (M)	[B] (M)	RATE (M/s)	TRIAL
0.360	0.360	0.0224	1
0.360	0.720	0.0224	2
0.720	0.360	0.0896	3

Order:

𝑘=

Answer 1

We must first determine the order of the reaction with respect to both A and B.

Comparing trials 1 and 3, [A] doubles while [B] remains constant. The rate increases 4 fold. This tells us the reaction is SECOND ORDER in A

Comparing trials 1 and 2, [A] remains constant whlile [B] doubles. The rate remains the same. This tells us the reaction is ZERO ORDER in B

Overall order = second order

We can now write the rate law and then use any data from the table to find k:

Rate = k[A]²

0.0224 M/s = k [0.360 M]²

k = 0.0224 M/s / 0.1296 M²

k = 0.173 M^-1s^-1