Please help me solve this chemistry question!

Question

2 A + 2 B → C + D

The following data about the reaction above were obtained from three experiments:

Experiment: 1

[A]: 0.60

[B]: 0.15

Initial Rate of Formation of C (mole. liter-1min-1 ): 6.3x10-3

Experiment: 2

[A]: 0.20

[B]: 0.60

Initial Rate of Formation of C (mole. liter-1min-1 ): 2.8x10-3

Experiment: 3

[A]: 0.20

[B]: 0.15

Initial Rate of Formation of C (mole. liter-1min-1 ): 7.0x10-4

(a) What is the rate equation for the reaction?

(b) What is the numerical value of the rate constant k? What are its dimensions?

Answer 1

Compare Exp. 3 to Exp.1: [A] triples while [B] remains constant. The rate increases 9x , i.e from 7x10-4 to 6.3x10-3. This tells us the reaction is 2nd order in A.

Compare Exp. 3 to Exp. 2: [B] increases 4x while [A] remains constant. The rate increases by 4x, i.e. from 7x10-4 to 2.8x10-3. This tells us the reaction is 1st order in B.

a) The rate equation is Rate = k[A]²[B]

b) Rate constant calculation - Choose rate from any experiment and plug in the values and solve for k:

6.3x10^-3 M/min = k (0.6 M)²(0.15 M) = 0.054 M³ * k

k = 6.3x10^-3 M/min ÷ 0.054M³

k = 117 M^-2min^-1