Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
A catalyst is any substance that increases the rate of a chemical reaction by lowering its activation energy but remains unchanged itself after the reaction has occurred.
A substance that slows down or prevents a particular chemical reaction or other process, or that reduces the activity of a particular reactant, catalyst, or enzyme.