A catalyst is a substance that alters the rate of a chemical reaction without itself undergoing any permanent chemical change.
A catalyst alters the activation energy for a reaction, changing the reaction profile. This means that less energy is needed for the reaction to proceed and therefore it would be easier for the reaction to take place.
There are two types of catalysts:
- Homogenous where the catalyst is in the same physical state as the reactant.
- Heterogenous where the catalyst is in a different physical state than the reactant.
The lower energy creates a pathway that needs less energy making the reaction happen faster.
The lower activation energy means that more molecules will have the necessary energy to react. With more molecules having the possibility of a reaction, the reaction will be faster.