## Slow step

$K = \frac{k_{forward}}{k_{reverse}}$

JulieAljamal1E
Posts: 71
Joined: Fri Sep 28, 2018 12:24 am

### Slow step

In lecture on Friday, Dr. Lavelle showed us an example and asked us which step was the slow step. How do we identify which is the slow step?

Nathaniel 2E
Posts: 27
Joined: Mon Jun 25, 2018 3:00 am

### Re: Slow step

I believe you are referring to the example where we had NO2(g)+CO(g) --> NO(g)+CO(g), with the elementary steps of:
1. NO2(g)+NO2(g) --> NO3(g)+NO(g)
2. NO3(g)+CO(g) --> NO2(g)+CO2(g)

We were given that the experimentally determined rate law was rate=k[NO2]^2. Since the slow step is the rate determining step, that means that the rate law for the slow elementary step must match the overall rate law. This is true for step 1, making it the slow step.

Kathryn Wilhem 1I
Posts: 60
Joined: Fri Sep 28, 2018 12:27 am

### Re: Slow step

The slow step is the one with the slowest rate, k. The reaction can only be as fast as the slowest step, so the reaction rate becomes that of the slowest step.