What is referred to as latent heat?

Latent heat refers specifically to the heat energy that is required for a substance to undergo a change of state without a change in temperature. This change of state could involve processes like melting (solid to liquid), freezing (liquid to solid), vaporization (liquid to gas), or condensation (gas to liquid).

When a substance absorbs latent heat during, for example, evaporation, it doesn't increase in temperature during the phase change; instead, this energy is used to break the molecular bonds in the substance, allowing it to change from a liquid to a vapor. Similarly, when a vapor condenses back into a liquid, it releases latent heat. The concept of latent heat is fundamental in understanding various processes in refrigeration, heating, and phase change phenomena.

In contrast, the other options describe different types of heat exchanges: one relates to temperature changes directly (which is sensible heat), while others pertain to specific heat during combustion or a singular phase change. Therefore, the defining characteristic of latent heat is its role in facilitating a change of state while maintaining a constant temperature.