Which statement explains why product bonds are stronger and release energy?

• A. Because products have weaker bonds
• B. Because more mass is produced
• C. Because energy is absorbed during product formation
• D. Because product bonds are stronger and more stable, releasing energy

Answer: (D)

In chemical reactions, energy changes come from bond formation and bond breaking. When bonds form, energy is released; when bonds are broken, energy must be absorbed. If the bonds in the products are stronger and more stable than those in the reactants, the system ends up with a lower overall energy after the reaction. That drop in energy is released to the surroundings as heat or light. So saying product bonds are stronger and more stable explains why energy is released.

The other ideas don’t fit the observed pattern: weaker product bonds wouldn’t produce energy release; simply producing more mass doesn’t guarantee stronger bonds; and energy being absorbed during product formation would indicate an endothermic process, not exothermic.