Determine overall reaction order

Question

The rate equation for the reaction, P + Q à 2R + S, is found to be:

Rate = k [P]²[Q] 

where [P] = 0.0120 M and [Q] = 0.0350 M, the rate of reaction was 0.450 ´ 10^-4 M/s. 

Answer the following questions. Show your working and state the units clearly.

q1:

State the order of reaction with respect to P and Q. Hence, determine the overall order of the reaction. (3 marks)

Answer 1

P + Q ==> 2R + S

Rate = k[P]²[Q]

The order with respect to P is second order in P

The order with respect to Q is first order in Q

The overall order is third order

You didn't ask for the value of k, but if you need to find it, it is as follows:

0.450x10^-4 M/s = k[0.0120 M]²[0.0350 M] = 5x10^-6 M³k

k = 4.50x10^-5 M/s / 5x10^-6 M³

k = 9 M^-2s^-1