In an exothermic reaction, the energy of the products compared to the reactants is:

• A. Higher
• B. The same
• C. Variable
• D. Lower

Answer: (D)

Exothermic means energy is released to the surroundings. Because energy leaves the system as heat when bonds form in the products, the final energy of the products is lower than the energy of the reactants. This negative energy change is why the surroundings get warmer during the reaction. If the products had higher energy, energy would have to be absorbed (endothermic); if they were the same, there would be no net energy change.