Breaking bonds in a chemical reaction requires energy; this process is which?

• A. Exothermic
• B. Endothermic
• C. Isothermal
• D. Equilibrium shift

Answer: (B)

Breaking bonds requires energy to overcome the attraction holding the atoms together. The amount of energy needed to break bonds, the bond dissociation energy, is positive, meaning energy must be absorbed from the surroundings. That description aligns with an endothermic process, where the system takes in heat or energy. In contrast, exothermic processes release energy when bonds form. The other terms, isothermal and equilibrium shift, refer to constant temperature conditions and the position of balance between reactants and products, respectively, and do not define whether energy is absorbed during bond breaking. So the scenario described is endothermic.