What is the effect of catalysts on chemical reactions?

Catalysts are substances that increase the rate of a chemical reaction without being consumed in the process. This characteristic allows them to facilitate reactions by providing an alternative pathway with a lower activation energy.

Option C highlights that catalysts do not change the overall energy of the reaction, which is true. While a catalyst can speed up the process by reducing the energy barrier, the total amount of energy released or absorbed in the reaction remains the same. Thus, the enthalpy change remains unchanged, meaning the overall energy of the reactants and products is not affected.

Understanding this concept is crucial because it illustrates the role of catalysts as facilitators rather than participants that alter the fundamental nature of the reaction. This characteristic differentiates catalysts from reactants, which do contribute to the chemical transformation.