Which statement describes latent heat?

Which statement describes latent heat?

• A. Heat transmitted by radiation
• B. Heat removed
• C. Heat added that raises temperature
• D. Heat added to a substance that changes its state

Answer: (D)

Latent heat is the energy involved when a substance changes its phase, such as melting, freezing, vaporizing, or condensing. During a phase change, the temperature stays the same while the added (or removed) energy goes into breaking or forming molecular interactions that shift the substance from one state to another. This is why the statement that describes latent heat best is heat added to a substance that changes its state—the energy is used to change the state rather than to raise the temperature. For example, ice at 0°C absorbs latent heat to melt, and water at 100°C absorbs latent heat to boil; conversely, freezing or condensation releases latent heat. In contrast, heat that raises temperature is sensible heat, and heat transferred by radiation or simply removed without a phase change doesn’t define latent heat.

Latent heat is the energy involved when a substance changes its phase, such as melting, freezing, vaporizing, or condensing. During a phase change, the temperature stays the same while the added (or removed) energy goes into breaking or forming molecular interactions that shift the substance from one state to another. This is why the statement that describes latent heat best is heat added to a substance that changes its state—the energy is used to change the state rather than to raise the temperature. For example, ice at 0°C absorbs latent heat to melt, and water at 100°C absorbs latent heat to boil; conversely, freezing or condensation releases latent heat. In contrast, heat that raises temperature is sensible heat, and heat transferred by radiation or simply removed without a phase change doesn’t define latent heat.