Which of the following best defines a catalyst in a chemical reaction?

A catalyst is a substance that alters the speed of a chemical reaction without being consumed in the process. Specifically, it works by lowering the activation energy required for the reaction to occur, which helps to accelerate the rate at which reactants are converted into products. This means that reactions can proceed more quickly than they would without the catalyst.

While catalysts play a crucial role in speeding up reactions, they do not affect the overall energy of the products or the reactants; thus, the energy levels remain unchanged despite the catalyst’s presence. Additionally, catalysts do not form permanent bonds with the products, allowing them to be reused in multiple reactions.

Choosing the correct definition helps reinforce the concept that catalysts facilitate reactions while maintaining their original structure and composition, making them essential in both biological processes and industrial applications.