Suppose you have measured the kinetics of the reaction, 2 A + B → C + 2 D at room temperature using the method of initial rates.

Question

A table summarizing the results of four different experimental trails is shown below:

Experimental	Initial A	Initial B	Initial rate
Trial	(M)	(M)	(M s-1)
1	0.15	0.30	0.000673
2	0.30	0.30	0.001347
3	0.15	0.15	0.000168
4	0.45	0.45	0.004545

Based on these data, if you assume the rate law is of the mathematical form,

rate = k A^x B^y

the value of x is __ and the value of y is ___.

Answer 1

I think I've already answered this, but here goes again.

To find the order for A, we can compare trial 1 to 2 where A doubles, B remains constant and the rate doubles. This tells us the reaction is 1st order in A

To find the order for B, we can compare trial 3 to 1 where B doubles, A remains constant and the rate increases by 4 times. This tells us the reaction is 2nd order in B.

So we can write the rate law as:

Rate = k[A][B]2 ... so x = 1 and y = 2