Ace Your 2026 WJEC GCSE Chemistry Exam – Unleash Your Inner Scientist!

In an exothermic reaction, energy is released to the surroundings, so the products end up with less stored energy than the reactants. The bonds formed in the products store less energy than the bonds broken in the reactants, and the excess energy is emitted as heat, which is why the surroundings often get warmer. That’s why the correct statement is that the energy of the products is lower than the energy of the reactants.

If the products had higher energy, that would mean energy was absorbed from the surroundings, which describes an endothermic process. If the energies were the same, there would be no energy change at all, contradicting the exothermic nature. If nothing could be determined, we wouldn't have a definite statement about the energy change in an exothermic reaction.