catalyst vs intermediate

[Vanessa Reyes_1K]

What is the difference between a catalyst and an intermediate component?

[Yvonne Du]

A catalyst is at the very beginning of the reaction and gets used; while intermediates only join in the later time and get used.

[004932366]

When looking at the steps in a reaction mechanism, you can also distinguish the two by looking at where they end up getting placed. Intermediates aren't written in the final chemical equation because they get used up in the reaction- they become products in one step, and a reactant in the follow step (s) (product --> reactant) and get canceled out. Catalysts on the other hand do not get used up, simply lower the activation energy of the reaction, and go from reactant to product.