## Catalyst vs Intermediate

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

Ishkhan 3O
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Joined: Fri Sep 26, 2014 2:02 pm

### Catalyst vs Intermediate

How can you tell the difference between the catalyst and the intermediate since neither of them appear in the overall reaction?

Kayla Denton 1A
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Joined: Fri Sep 26, 2014 2:02 pm

### Re: Catalyst vs Intermediate

Catalysts are present as reactants in the very beginning and products at the end. Intermediates, on the other hand, are not present in the initial reaction but are produced within one of the steps and then consumed within another step.

Regina Chi 2K
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Joined: Fri Sep 26, 2014 2:02 pm

### Re: Catalyst vs Intermediate

Also, catalysts are used throughout the reaction. So according to my understanding, catalysts appear in the reaction as a reactant, but also appear during the elementary steps of the reaction.

Chem_Mod
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### Re: Catalyst vs Intermediate

In general, a catalyst is consumed by a step but regenerated by a later step.

An intermediate is created by a step but consumed by a later step.

A catalyst is something added by the experimenter to the reaction to increase the reaction rate. However, we cannot physically "add" an intermediate because those are extremely unstable, temporary species.

martha-1I
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Joined: Fri Sep 26, 2014 2:02 pm

### Re: Catalyst vs Intermediate

I remember the distinction like this. A catalyst is consumed and then formed. Since catalysts are put into a reaction to speed it up, it makes sense that they are consumed first (because they are used to speed up the reaction) and then formed again later.
An intermediate is formed and then consumed. Since they are unstable molecules, they can't just be put into a reaction and because they are unstable they will be consumed in order for the overall reaction to only include stable molecules.
Hope this helps!

AKatukota
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Joined: Thu Jul 25, 2019 12:18 am

### Re: Catalyst vs Intermediate

So catalysts are in the reactants then products side. And intermediates are in the product then reactant side?

805097738
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### Re: Catalyst vs Intermediate

Kayla Denton 1A wrote:Catalysts are present as reactants in the very beginning and products at the end. Intermediates, on the other hand, are not present in the initial reaction but are produced within one of the steps and then consumed within another step.

a catalyst is one of the reactants?