Catalysts and Intermediates

[Daniel Hernandez 1G]

How can we identify what is an intermediate and what is a catalyst when we are given the elementary steps? I've seen a problem where the catalyst and the intermediate were both cancelled out of the balanced equation, so what exactly cuts a clear line between the two?

[Tatyana Bonnet 2H]

Catalysts are needed for the reaction to proceed so they would be seen first on the reactant side and then reappear as a product.
Intermediates are part of the elementary steps but not part of the overall final reaction so they would be produced first (product) and then used up as a reactant.

[jessicaosuna_1F]

Hi! So intermediates will appear first on the right side of the equation( product) then will be used up on the left side as a reactant in a later step.

On the other hand, catalysts will appear initially on the left side as a reactant and will reappear in a subsequent step as a product.

SO, while both cancel out, you have to look at which side they appear on first. If they appear first as a reactant, its a catalyst. If they appear first as a product, its an intermediate

[Sabine Salvucci 2E]

Hello! I am pretty sure that intermediates will be produced as a product then consumed as a reactant while catalysts go from reactant to product.

[Rachael Cohen 3G]

Catalysts will appear in the reactants of a step and the products of a later step. Intermediates appear in the products of a step and the reactants of a later step. Hope this helps!

[Hayden Lee 1C]

A catalyst is usually something that is used to form a product in one step and then is produced in another step. In other words, the catalyst will be a reactant in one step and the same species will be a product in another step. Simply put, it is consumed and then produced again in another reaction step. It is added to the overall reaction to reduce its activation energy; it is not a product of the reaction alone.
Intermediates will usually be a product of one of the reaction steps. After it is produced, it will likely later be consumed to form a product. Intermediates are produced by a reaction step, not added to the reaction for any particular purpose.
I know that I explained this poorly, but knowing this information really helped me identify catalysts/intermediates.

[arisawaters2D]

Thanks for this clarification! It makes sense now.

[sophia kosturos 2B]

catalysts will appear in the first step and then ultimately appear on the product's side, while intermediates will be a product in one step and then act as a reactant in a later step. So the intermediates will not show up in the final reaction.

[Taha 2D]

the intermediate shows up on the right whilst catalyst on left, both cancel out tho

[Shrinidhy Srinivas 3L]

Both intermediates and catalysts are eventually cancelled out in the overall reaction. However, you can identify an intermediate because the first time it appears in a step will be on the product side and then it will later re-appear on the reactant site. On the other hand, a catalyst will first appear on the reactant side and then re-appear later on the product side. This is because catalysts are not consumed in reactions. I hope this helps!

[Joshua_Chan_3K]

A catalyst will be one of the reactants that is also found in the end products when you put all the reaction steps together. this shows that it wasn't used in the total reaction. Intermediates are compounds that are found in the reaction steps but aren't in either the final reactants or products for the overall reaction.

[reyvalui_3g]

Intermediates appear as products as first and then are used up as reactants, catalysts show up as reactants and then become products.

[Joshua Chung 2D]

Think of it as catalysts are tools used to increase the rate, and so will exist before and after the reaction. On the other hand, intermediates are created and consumed in the reaction, so will not exist before and after.

[005502505]

Hi! Intermediates are consumed during the reaction, and thus wouldn't show up on the product side. Catalysts aren't consumed, they're merely used to lower activation energy, so they will be found on the products side at the end of the reaction. Hope this helps!

[WS405590915]

Catalysts are needed for the reaction to proceed so they would be seen first on the reactant side and then reappear as a product.
Intermediates are part of the elementary steps but not part of the overall final reaction so they would be produced first (product) and then used up as a reactant.

This was really helpful and clarified the topic for me.

Thanks

[Sarah Hong 2K]

The intermediate is produced and then used up in the following reaction. The catalyst is needed to start the reaction and is later produced in the following step.

[Justin An 2L]

The difference between a catalyst and an intermediate is that intermediates are consumed/used up in the reaction mechanism while catalysts remain unconsumed! What this means is that you'll see catalysts on the reactant side first and then product side whereas intermediates will be formed (on the product side first) and then consumed (on the reactant side for the next step of the mechanism).