is doubled; the rate is increased by a factor of 15.9/8.1, approximately 2. The rate
expressions of the two trials are:Dividing the second equation by the first,So r = k[A] [B]^2 , i.e., the order of the reaction with respect to A is 1 and with respect
to B is 2; the overall reaction order is 1 + 2 = 3.
To calculate k, substitute the values from any one of the above trials into the rate
law, e.g.:Therefore, the rate law is r = 2.0 M−2 s−1 [A][B]^2.Note, however, that this result could have been obtained more easily if we had been able to see
without cumbersome substitution that, for example, from trial 1 to trial 2 the rate is quadrupled
when the concentration of B is doubled. Therefore, the rate has to be dependent on the square of
[B].