Chemistry help please :)

a particular reaction is found to have the following rate law R=k[a][b]^2 how is the rate affected by each of the following changes?
a. the initial concentration of A is cut in half
b. The initial concentration of B is tripled
c. The concentration of A is doubled, but the concentration of B is cut in half
d. a catalyst is added

R = k[a][b]^2

Let k = a = b = 1 for the initial condition:

R = 1[1][1]^2
R = 1


(a) a = 1/2

R = 1[1/2][1]^2
R = 1/2

So, if [A] is cut in half, the rate is cut in half.


(b) b = 3

R = 1[1][3]^2
R = 9

So, if [B] is tripled, the rate is 9 times faster.


(c) a = 2 and b = 1/2

R = 1[2][1/2]^2
R = 1/2

So, if [A] is doubled and [B] is cut in half, the rate is cut in half.


(d) Catalyst is added

If a catalyst is added, the rate of reaction is increased.



Hope this helps...good luck!