A catalyst is something present in a reaction that is not consumed. It works by lowering the activation energy needed for the reaction. It isn't necessarily a chemical, though. It can be an element, chemical, heat, or UV light, just to name a few.
A substance that speeds up a chemical reaction is known as a CATALYST.
catalyst
An enzyme speeds up a chemical reaction.
Catalyst
catalysts
enzyme
Hydrochloric acid
It speeds up the reaction by lowering activation energy.
an enzyme speeds up a chemical reaction.
Catalyst
yah
Catalysts