According to the mechanism below, what is the correct expression for the rate consumption of A?
In the mechanism, M is a molecule that collides with A and A* is a highly-energized for of A.
Step 1: A+M <--> A*+M : rate constants k1 and k-1
Step 2: A* <--> C : rate constants k2, and k-2
To determine the correct expression for the rate consumption of A, we need to consider the rate equations for each step of the mechanism.
Step 1: A + M ⇌ A* + M (rate constants k1 and k-1)
The rate equation for the forward reaction in Step 1 can be written as:
Rate_forward = k1 * [A] * [M]
The rate equation for the backward reaction in Step 1 can be written as:
Rate_backward = k-1 * [A*] * [M]
Step 2: A* ⇌ C (rate constants k2 and k-2)
The rate equation for the forward reaction in Step 2 can be written as:
Rate_forward = k2 * [A*]
The rate equation for the backward reaction in Step 2 can be written as:
Rate_backward = k-2 * [C]
Now, let's focus on the overall rate consumption of A. A is consumed in Step 2, so we can combine the rate equations for the forward and backward reactions in Step 2 to get the net rate of consumption of A:
Rate_consumption_of_A = Rate_forward_in_Step_2 - Rate_backward_in_Step_2
= k2 * [A*] - k-2 * [C]
Therefore, the correct expression for the rate consumption of A is:
Rate_consumption_of_A = k2 * [A*] - k-2 * [C]