Which term describes the heat energy required for a substance to change its state (such as from solid to liquid) at constant temperature?

• A. Specific heat capacity
• B. Latent heat
• C. Enthalpy of formation
• D. Activation energy

Answer: (B)

Verified step by step guidance

1. Understand that when a substance changes its state (phase) at a constant temperature, it either absorbs or releases heat without a change in temperature.
2. Recall that the heat energy required to change the state of a substance at constant temperature is called latent heat.
3. Differentiate latent heat from specific heat capacity, which is the heat required to change the temperature of a substance without changing its state.
4. Note that enthalpy of formation refers to the heat change when one mole of a compound forms from its elements, and activation energy is the energy needed to start a chemical reaction.
5. Conclude that the correct term describing the heat energy for phase change at constant temperature is latent heat.