What role does a catalyst play in a chemical reaction?

A catalyst plays a crucial role in a chemical reaction by providing an alternative pathway with a lower activation energy. This effectively speeds up the reaction, allowing it to proceed at a faster rate. Importantly, a catalyst is not consumed during the reaction, meaning that it can continue to facilitate multiple reaction events without being depleted. This characteristic is vital as it enhances the efficiency of the reaction without altering the final products or the overall energy change of the reaction.

By facilitating the reaction mechanism, catalysts are integral in various applications, from industrial processes to biological systems, where they often speed up reactions significantly while remaining unchanged at the end of the process. This distinguishes them from reactants that undergo chemical change and are consumed in the course of the reaction.