Question

which statement best describes the amount of catalyst that remains at the end of a reaction?
more catalyst is present at the end than at the beginning of the reaction.
less catalyst is present at the end than at the beginning of the reaction.
the amount of catalyst is the same at the end as at the beginning of the reaction.
the catalyst is consumed by the reaction, so none remains at the end of the reaction.

Explanation:

A catalyst is a substance that speeds up a chemical reaction without being consumed in the process. By definition, it participates in the reaction mechanism but is regenerated, so its amount remains unchanged at the end of the reaction compared to the beginning. The first option is wrong because a catalyst isn't produced in the reaction to increase in amount. The second option is wrong as it isn't used up to decrease. The fourth option is wrong because a catalyst is not consumed by the reaction.

Answer:

The amount of catalyst is the same at the end as at the beginning of the reaction.