Which system condition typically requires the addition of latent heat?

The correct answer is the addition of latent heat during evaporation. When a substance, such as water, transitions from a liquid to a gaseous state, it absorbs heat from its surroundings in the form of latent heat. This process requires energy because the molecules must overcome intermolecular forces to transform from a more ordered liquid state to a less ordered gas state.

During evaporation, water molecules at the surface gain enough energy to break free into the air as vapor. This energy exchange is critical, as it results in the cooling effect often associated with evaporation. For example, when sweat evaporates from the skin, it removes heat from the body, leading to a cooling sensation.

In contrast, the other conditions listed do not involve the addition of latent heat in the same way. Condensation releases latent heat as gas particles convert back to liquid, while compression and expansion processes typically deal with changes in pressure and volume rather than phase transitions involving heat absorption.