In an exothermic reaction, which statement is true?

• A. The products have higher energy than the reactants.
• B. The activation energy is extremely large.
• C. The products have lower energy than the reactants.
• D. There is no energy change.

Answer: (C)

Exothermic reactions release energy to the surroundings, so the products end up at a lower energy level than the reactants. The energy difference is given off as heat or light, which is why the surroundings often feel warmer. Activation energy is the energy needed to start the reaction and can vary; it isn’t what defines an exothermic process. There is energy change in an exothermic reaction, not zero, because energy is released. A scenario where products have higher energy describes an endothermic process, which absorbs energy. Therefore, the true statement is that the products have lower energy than the reactants.