Chemistry Regents Practice Test 2025 – The All-in-One Guide to Exam Success!

A catalyst plays a crucial role in chemical reactions by increasing the rate of the reaction without being consumed in the process. This is achieved through providing an alternative pathway for the reaction that has a lower activation energy compared to the uncatalyzed reaction. As a result, more reactant molecules possess the necessary energy to overcome this lower energy barrier, leading to a higher frequency of successful collisions and a faster reaction rate.

In addition, because catalysts are not consumed, they can participate in multiple reaction cycles, enabling them to facilitate the reaction multiple times without any depletion. This characteristic makes catalysts essential in various industrial processes and biological systems, where they help to achieve desired reaction rates without requiring significant changes in temperature or pressure.

Other options describe roles that do not accurately represent the function of a catalyst: lowering the temperature, providing energy, or changing the products are not functions of catalysts. Catalysts do not alter the thermodynamics of the reaction or the nature of the products formed; they only affect how quickly equilibrium is reached.