Latent heat is associated with what type of energy change?

Latent heat is specifically associated with a change of state, which occurs when a substance transitions from one phase to another, such as from solid to liquid (melting) or from liquid to gas (vaporization). During this process, energy is absorbed or released, but the temperature of the substance remains constant until the phase change is complete. This is why latent heat is critical in understanding phase transitions in thermodynamics.

In contrast, the other options pertain to different concepts. A change of temperature refers to sensible heat, where thermal energy leads to a temperature increase or decrease without a phase change. An increase in volume can occur in various processes, but it does not directly relate to latent heat, as it doesn't necessarily coincide with a phase transition. Similarly, a decrease in density may occur due to temperature changes or phase alterations but does not define the specific process of latent heat, which is fundamentally tied to changes in state rather than changes in physical dimensions or density.