Catalysts

Science

Definition

Catalysts are substances that speed up a chemical reaction without being consumed in the process. They work by lowering the activation energy needed for the reaction to occur, providing an alternative reaction pathway.

Examples

  • Enzymes in your body act as biological catalysts to speed up digestion
  • Platinum in a car's catalytic converter helps convert toxic exhaust gases into less harmful ones
  • Manganese dioxide speeds up the decomposition of hydrogen peroxide
Key Fact

Catalysts lower activation energy (Ea) but do not change the overall ΔH or equilibrium position of a reaction.

Related Terms

Activation energy Reaction rates Enzyme structure Equilibrium constant

Study This Concept

Practice catalysts with free review games in these units:

AP Chemistry Unit 5: Kinetics