Which statement describes an endothermic process?

Which statement describes an endothermic process?

• A. Enthalpy change is negative.
• B. Energy is released to surroundings.
• C. Enthalpy change is positive.
• D. No energy transfer occurs.

Answer: (C)

Endothermic processes absorb heat from the surroundings, so the system gains energy and its enthalpy increases. This is why the enthalpy change is positive—the defining feature of an endothermic reaction. The other statements describe different scenarios: a negative enthalpy change means heat is released to the surroundings (exothermic), energy released to the surroundings is also exothermic, and no energy transfer contradicts the idea of heat flowing into the system.

Endothermic processes absorb heat from the surroundings, so the system gains energy and its enthalpy increases. This is why the enthalpy change is positive—the defining feature of an endothermic reaction. The other statements describe different scenarios: a negative enthalpy change means heat is released to the surroundings (exothermic), energy released to the surroundings is also exothermic, and no energy transfer contradicts the idea of heat flowing into the system.