1. The problem statement, all variables and given/known data 1. According to the mechanism below, what is the correct expression for the rate of consumption of A? In the mechanism, M is a molecule that collides with A and A* is a highly-energized form of A. Step 1 (reversible): A + M <---> A* + M rate constants k1 and k-1 Step 2 (irreversible): A* ---> C rate constant k2 Rate = k1 [A] [M] / (k-1[M] + k2) Rate = [A] / [C] Rate = k1k2 [A] Rate = (k1 [A] [M] + k-2[C] ) / (k-1[M] + k2) Rate=k1k2 / (k-1+k-2) Rate = (k1+k2-k-1-k-2) [A] Rate = k1k2 [A] / (k-1+k2[M]) Rate=k1+k2-k-1-k-2 Rate = [C] / [A] 2. Relevant equations 3. The attempt at a solution Sorry, I didn't show my work before. But anyways, I eliminated some choices because I know they're wrong. I tried submitting them, but it kept rejecting it, and I only have 1 more try. Anyways here is my though process. k1 is the rate constant for the forward reaction and k-1 is the rate of the backwards reaction. I'm assuming that k-2 is the rate for the backs reaction of step 2. However, it's irreversible, so I do not believe that rate constant should even exist. In step 1, M seems to be a catalyst, since the catalyst is regenerated, I assumed it won't have anything to do with the rate of consumption, as in, it just has to be present. Since step 2 is irreversible, I assumed that [C] does not play a role in the consumption of [A] as it's not an equilibrium reaction. After eliminating all choices that involve any of the above, I get k1k2[A] as my only possible choice. I don't want to submit this however cause I'm not 100% sure if my logic is correct.