Initial[A] Initial [B] Initial Rate, M/s
.740 M .010 M 3.00e-10
.740 M .030 M 8.09e-9
.740 M .060 M 6.46e-8
.740 M .070 M 1.03e-7
What is the order of the reaction with respect to the concentration of B?
3rd order
the ratio of initial rates is the cube of the ratio of initial concentrations
To determine the order of the reaction with respect to the concentration of B, we need to analyze how the initial rate of the reaction changes as the concentration of B changes.
First, let's compare the initial rate at the first two data points, where the concentration of B is different:
Initial[A] | Initial[B] | Initial Rate, M/s
0.740 M | 0.010 M | 3.00e-10
0.740 M | 0.030 M | 8.09e-9
If we keep the concentration of A constant (0.740 M) and triple the concentration of B (from 0.010 M to 0.030 M), we see that the initial rate increases significantly from 3.00e-10 M/s to 8.09e-9 M/s.
Now, let's compare the initial rate at the next two data points, where the concentration of B is different again:
Initial[A] | Initial[B] | Initial Rate, M/s
0.740 M | 0.030 M | 8.09e-9
0.740 M | 0.060 M | 6.46e-8
If we keep the concentration of A constant (0.740 M) and double the concentration of B (from 0.030 M to 0.060 M), we see that the initial rate increases again, but by a larger factor, from 8.09e-9 M/s to 6.46e-8 M/s.
Finally, let's compare the initial rate at the last two data points, where the concentration of B is different once more:
Initial[A] | Initial[B] | Initial Rate, M/s
0.740 M | 0.060 M | 6.46e-8
0.740 M | 0.070 M | 1.03e-7
If we keep the concentration of A constant (0.740 M) and increase the concentration of B by a smaller increment (from 0.060 M to 0.070 M), we see that the initial rate increases again, but by a smaller factor, from 6.46e-8 M/s to 1.03e-7 M/s.
Based on this analysis, we can see that as the concentration of B increases, the initial rate of the reaction also increases. Moreover, the factor by which the rate increases is not constant but seems to become smaller as the concentration of B increases. This non-constant increase suggests that the reaction rate is dependent on the concentration of B in a nonlinear fashion, indicating that the reaction is not first-order with respect to the concentration of B.
To find the exact order with respect to B, we can compare the changes in the initial rate as the concentration of B changes. By examining how the initial rate changes relative to the changes in concentration, we can use the method of initial rates or the method of integrated rate laws to determine the order of the reaction with respect to B.