00:01
In this video, we want to determine the rate law and the rate constant for this reaction using initial rate data.
00:07
So first, for the rate law, it's going to be equal to the rate constant times a to some order, which shows the exponential effect of the change with respect to a, and then b to some order, which shows its exponential change on the rate.
00:21
So to find the order with respect to a, we look at what is the effect if we change a and keep b constant? so we could look at trials 1 and 3 because the concentration of a is changing and b is staying the same.
00:32
In this case, the concentration doubles from 0 .32 to 0 .64.
00:36
And what's the effect on the rate? well, if we take 0 .0696 and we divide by 0 .174, that is a factor of 4 increase in rate.
00:48
So 2 to the power m, the order with respect to a, is equal to 4.
00:53
And that means m is equal to two to make this equation true.
00:56
So this is a two.
00:58
Now, we repeat that process with b.
01:00
So we want two trials where a is constant and b is changing.
01:03
So if we use trials 1 and 2, a is constant, b increases by a factor of 2.
01:08
And what happens to the rate? it actually stays the same...