catalyst vs intermediate

[Annabella_Amato_1I]

given the mechanism steps for a reaction, how can we differentiate between what's a catalyst and what's an intermediate?

[Victor Li 2A]

I think this topic will be covered in Wednesday's lecture, but here is how I differentiate catalysts from intermediates with mechanism steps given. First of all, both catalysts and intermediates will not appear in the overall reaction because they are canceled out in the combination/sum of the individual steps. The catalyst should appear as a reactant in the first step and as a product in the last step; this makes sense since a catalyst is involved in the reaction but is not used up/changed. The intermediates will appear in the individual steps but never as first step reactants and last step products.

[Jamie Wang 3C]

intermediates appear in the equations, but are cancelled out in the final equation, catalysts dont

[JakeSaum_1A]

This is how I understand it:
Catalysts are needed to drive a reaction. You'll typically see them in the reactants of the first step. Intermediates are produced over the course of the reaction. If you are given two steps, they will typically be in the products of the first step and the reactants of the second step. But neither catalysts nor intermediates are in the overall reaction.

I hope that makes sense!

[Neal_Agarwal_3B]

As Dr. Lavelle said in his lecture today, a catalyst is not a reactant, not a product, and not formed in the reaction. The catalyst is something that is just added and is regenerated through the reaction. An intermediate is something that is created in the reaction and therefore differs from a catalyst. I hope this helps!

[Kat Stahl 2K]

Intermediates are produced(right side) and then consumed(left side), Catalysts show up on the left first and then later appear on the right side.

[Gigi Elizarraras 2C]

Catalysts usually show up in the reactants of the first step, and intermediates are usually produced in the first step:) as well as intermediates become later reactants

hope this helps:)

[Emmeline Phu 1G]

Hi! As mentioned in today's lecture, we can determine whether something is an intermediate or catalyst by analyzing the reaction mechanism. Catalysts are always added to a reaction; thus, it should be a reactant in the first step of the mechanism. In general, intermediates usually start off as a product (are formed) and become a reactant in the next step. However, note that intermediates and catalysts are never included in the overall reaction of the mechanism and always cancel out. Hope this helps! :)

[VincentLe_3A]

A catalyst in a reaction mechanism often appears as a reactant in the first step and a product of the final step. An intermediate on the other hand shows up as a product of the first step and reactant of the second step. Both are not shown in the overall reaction equation.

[Kelly Ha 1K]

Intermediates are produced then consumed. Catalysts are present in the beginning and then regenerate at the end. They both do not appear in the overall reaction.

[Shrey Pawar 2A]

One of the UA sections I attended had a good explanation, he said that catalysts are consumed then produced, while intermediates are produced than consumed. In order words the catalyst is used up as a reactant and then is in product form in the slower step. Hopefully this helps!

[Sandy Lin 1L]

An intermediate is produced in the reaction to be then consumed in the reaction. A catalyst is present in the beginning and not consumed by the reaction, so it reappears in the end.

[claire ikemiya_2I]

Another easy way to tell I learned in highschool is that catalysts are on the reactant side of Step 1 and intermediates are on the product side.

[claire ikemiya_2I]

So for example
A + B --> C + D
C + D + E--> B +F

Overall: A + E--> F
Intermediates: C, D
Catalysts: B