What is latent heat best described as?

• A. Energy gained when a solid melts but temperature increases.
• B. Energy absorbed or released during a phase change without a change in temperature.
• C. Energy required to raise the temperature of a substance.
• D. Energy released when a gas condenses to a liquid with a temperature change.

Answer: (B)

Latent heat is the energy involved in changing a substance from one phase to another without changing its temperature. When a solid melts, energy is absorbed to break some of the bonds holding the particles in place, but the temperature stays the same until the entire solid has melted. The same idea applies to vaporization and condensation: energy is absorbed to overcome intermolecular forces during a phase change, or released when those forces reform, and the substance’s temperature remains constant during that transition.

That’s why this description matches latent heat: it’s about energy tied to changing the state, not about warming or cooling a substance during a temperature change. The other statements describe energy that goes into raising temperature (sensible heat) or mix in a temperature change with a phase change, which isn’t what latent heat refers to.