What is a catalyst and how does it affect the rate of a reaction?

A catalyst is a substance that increases the rate of a chemical reaction without being consumed.

Catalysts are substances that increase the rate of a chemical reaction without being consumed in the process. They work by lowering the activation energy required for the reaction to occur. Activation energy is the energy required for the reactants to overcome the energy barrier and reach the transition state, where the reaction can take place. By lowering the activation energy, a catalyst allows more reactant molecules to reach the transition state, increasing the rate of the reaction.

Catalysts can be classified as either homogeneous or heterogeneous. Homogeneous catalysts are in the same phase as the reactants, while heterogeneous catalysts are in a different phase. Heterogeneous catalysts are more commonly used in industrial processes, as they can be easily separated from the reaction mixture and reused.

Catalysts can also be specific to certain reactions, meaning they only catalyse one particular reaction. For example, the enzyme lactase catalyses the hydrolysis of lactose into glucose and galactose. Other catalysts, such as platinum and palladium, are more general and can catalyse a wide range of reactions.

Overall, catalysts play an important role in many chemical reactions, increasing reaction rates and making industrial processes more efficient.