Summary
Highlights
Chemical reactions occur when particles collide with sufficient energy. The rate of reaction depends on the frequency of successful collisions, and activation energy is the minimum energy required for particles to react.
Catalysts increase the rate of chemical reactions without being used up. They are important because they allow reactions to happen quickly without high temperatures, saving money, and they can be reused.
Catalysts provide an alternative reaction pathway with a lower activation energy. This means more particles have enough energy to collide successfully, which increases the reaction rate.
Catalysts are not included in chemical equations because they aren't reactants. Different reactions require specific catalysts, and enzymes are biological catalysts found in living organisms.