## Catalyst vs Intermedaite

Arrhenius Equation: $\ln k = - \frac{E_{a}}{RT} + \ln A$

Andrew Nguyen 2I
Posts: 68
Joined: Fri Sep 29, 2017 7:07 am

### Catalyst vs Intermedaite

How do you distinguish between a catalyst and intermediate given reaction mechanisms? Can someone give an example with both also?

Ju-Wei Wang 1I
Posts: 31
Joined: Fri Sep 29, 2017 7:05 am

### Re: Catalyst vs Intermedaite

A catalyst is present as a reactant in the first step of a given reaction mechanism and is not consumed in the reaction. An intermediate is a species that plays a role in a reaction but does not appear in the chemical equation for the overall reaction; it is produced in one step but is used up in a later step.

In the example that we did in class:

NO(g) + (1/2)O2(g) → NO2(g)
NO2 → NO(g) + O(g)
O2(g) + O(g) → O3(g)

NO is the catalyst and NO2 and O are the intermediates (get used up in the reaction)

Wayland Leung
Posts: 51
Joined: Sat Jul 22, 2017 3:00 am
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### Re: Catalyst vs Intermedaite

Do we put catalysts in the overall rate law or do we leave them out just like we leave intermediates out of the rate law?

Riya Pathare 2E
Posts: 74
Joined: Sat Jul 22, 2017 3:01 am
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### Re: Catalyst vs Intermedaite

We leave the catalysts out of the rate laws because they only change the activation energy and have no other role in creating the products.