A catalyst speeds up a chemical reaction by lowering the activation energy needed for the reaction to occur. Activation energy is the minimum energy required for reactants to convert into products. By providing an alternative pathway for the reaction, a catalyst makes it easier for the reactants to collide with enough energy to react.
Catalysts work by forming temporary bonds with the reactants, which can stabilize the transition state and reduce the energy barrier. This process allows a greater proportion of the reactants to have enough energy to overcome the activation energy at a given temperature.
Importantly, a catalyst is not consumed in the reaction, meaning it can be used repeatedly. This property makes catalysts essential in many industrial processes, as they can enhance reaction rates without the need for higher temperatures or pressures, ultimately making the reactions more efficient.