Which process requires energy removal for a vapor to condense into a liquid?

The process that requires energy removal for a vapor to condense into a liquid is known as the latent heat of condensation. When a vapor cools down, its molecules lose energy, which allows them to transition from the gaseous state to the liquid state. This phase change involves the release of heat, termed "latent heat," because it does not result in a temperature change for the substance; instead, it reflects a change in its phase.

During condensation, the molecules lose kinetic energy, leading to a reduction in the distance between them and allowing intermolecular forces to pull them closer, thus forming a liquid. This process is critical in many applications, including refrigeration and air conditioning systems, where removing heat from the refrigerant as it transitions from vapor to liquid is essential for efficient cooling.

The other choices refer to different thermal processes. The latent heat of fusion pertains to the energy absorbed or released during the transition between solid and liquid states, while the latent heat of vaporization is related to the energy required for a liquid to become a vapor. The heat of compression involves increasing the temperature of a gas through mechanical compression but does not directly involve condensation.