Question

Give a definition for catalysts.

Answer 1

A catalyst is a substance that speeds up a chemical reaction, but is not consumed by the reaction; hence a catalyst can be recovered chemically unchanged at the end of the reaction it has been used to speed up, or catalyze.

Answer 2

catalysts are materials which help to change the initiation threshold of a part of a reaction. thus usually, catalysts help to reduce temperature and pressure requirements even though the reaction can be done without catalysts, it's just much harder