What is one of the primary effects of using a catalyst in a chemical reaction?

Using a catalyst in a chemical reaction primarily serves to lower the activation energy required for the reaction to proceed. Activation energy is the minimum energy that reactants must possess for a reaction to occur. By providing an alternative reaction pathway with a lower activation energy, catalysts make it easier for reactants to collide successfully, resulting in an increase in the reaction rate.

This does not change the reactants or products themselves, as a catalyst remains chemically unchanged after the reaction. Consequently, the overall energy change of the reaction remains unaffected, ruling out the options related to reducing the overall energy change or creating new substances. Additionally, catalysts do not alter the concentration of reactants; rather, they accelerate the reaction process without directly influencing the concentration dynamics.