## How do you tell if something is a catalyst vs an intermediate?

$V_{0} = \frac{V_{max}[S]}{K_{M} + [S]}; K_{M} = \frac{[E][S]}{[ES]}$

John_Richey_4A
Posts: 69
Joined: Fri Sep 28, 2018 12:27 am

### How do you tell if something is a catalyst vs an intermediate?

title

Rian Montagh 2K
Posts: 60
Joined: Fri Sep 28, 2018 12:15 am

### Re: How do you tell if something is a catalyst vs an intermediate?

A catalyst is needed as a reactant in the first step while an intermediate is made in the first step (a product) and used as a reactant in the second step.

Catly Do 2E
Posts: 64
Joined: Fri Sep 28, 2018 12:24 am

### Re: How do you tell if something is a catalyst vs an intermediate?

When you are looking at the elementary reactions, catalysts are in the very first step as a reactant and as a product in the very last step too. Catalysts create a different, faster pathway for the reaction, but it is not used. Intermediates are not present as reactants in the first step but are produced and consumed within the steps. They are not present as a product at the last step either.

hanna_maillard3B
Posts: 61
Joined: Fri Sep 28, 2018 12:23 am

### Re: How do you tell if something is a catalyst vs an intermediate?

so intermediates are always found as a product in the first reaction and reactant in the second ? and vice versa for enzymes ?

Lydia Luong 4L
Posts: 59
Joined: Fri Sep 28, 2018 12:24 am

### Re: How do you tell if something is a catalyst vs an intermediate?

In the first step, a catalyst is a reactant and the intermediate is a product.

Tameen Ahmed 4C
Posts: 30
Joined: Fri Sep 28, 2018 12:19 am

### Re: How do you tell if something is a catalyst vs an intermediate?

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.

Dong Hyun Lee 4E
Posts: 68
Joined: Fri Sep 28, 2018 12:23 am

### Re: How do you tell if something is a catalyst vs an intermediate?

The catalyst will be in both the reactants of the first step as well as the products given in the last step. However intermediates are created between the first and the last step and are not present in the final products.

Anita Wong 1H
Posts: 68
Joined: Fri Sep 28, 2018 12:27 am
Been upvoted: 2 times

### Re: How do you tell if something is a catalyst vs an intermediate?

catalysts are in the reactant and intermediate is in the product side

harshitasarambale4I
Posts: 58
Joined: Fri Sep 28, 2018 12:26 am

### Re: How do you tell if something is a catalyst vs an intermediate?

How does this work when you have an enzyme.

Chase Yonamine 1J
Posts: 62
Joined: Fri Sep 28, 2018 12:17 am

### Re: How do you tell if something is a catalyst vs an intermediate?

Intermediates are consumed in the reaction

Carine Tamamian 2B
Posts: 61
Joined: Fri Sep 28, 2018 12:23 am

### Re: How do you tell if something is a catalyst vs an intermediate?

intermediates are consumed by the reaction, meaning they do not show up in the final rate law.
catalysts are regenerated at the end, and they do show up in the rate law.

Bryant Vong 2G
Posts: 32
Joined: Fri Apr 06, 2018 11:05 am

### Re: How do you tell if something is a catalyst vs an intermediate?

Intermediates are completely used up and not present by the end of the reaction

Douglas Nguyen 2J
Posts: 71
Joined: Fri Sep 28, 2018 12:15 am

### Re: How do you tell if something is a catalyst vs an intermediate?

A cool note I found while surfing the web was that a catalyst first shows up as a reactant and reappears as a product whereas an intermediate first shows up as a product and is cancelled out when it appears as a reactant in the next step.

505211599
Posts: 60
Joined: Fri Sep 28, 2018 12:28 am

### Re: How do you tell if something is a catalyst vs an intermediate?

Catalyst shows up in products and reactants but intermediated are used during the course of reaction.

CameronDis2K
Posts: 51
Joined: Wed Feb 20, 2019 12:18 am

### Re: How do you tell if something is a catalyst vs an intermediate?

An intermediate will cancel out in the overall reaction in the end (not appear), while a catalyst is not consumed in a reaction (appears in the beginning and reappears in the end).

kristi le 2F
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am

### Re: How do you tell if something is a catalyst vs an intermediate?

A catalyst needs to be there in the beginning of reaction to start reaction off. The intermediate will not appear in the beginning of a reaction because it is not a reactant. It is both formed and consumed so that it does not appear in the overall chemical equation.

MeeraBhagat
Posts: 95
Joined: Sat Aug 24, 2019 12:15 am

### Re: How do you tell if something is a catalyst vs an intermediate?

An intermediate is formed and then used up. A catalyst is what is needed to get a reaction going (so kind of like a reactant), and then it is eventually reproduced/shows up in another step of the reaction. It is never “consumed” (not the greatest word to use but...) without reappearing.