What is the heat required to change a unit mass of a liquid to vapor without temperature change called?

The heat required to change a unit mass of a liquid to vapor without a change in temperature is known as latent heat of vaporization. The process involved here is specifically related to the transition from liquid to vapor, which occurs at a constant temperature when the liquid reaches its boiling point.

Evaporation refers to the gradual transition of liquid to vapor, typically occurring at any temperature, but it can result from surface molecules escaping into vapor. While evaporation involves heat transfer, what distinguishes it in this context is that it is not an instantaneous or uniform process, making it different from boiling.

Boiling, on the other hand, specifically describes the transition of liquid to vapor at a fixed temperature, which is characterized by the formation of bubbles within the liquid. This process occurs throughout the liquid as heat is applied, and it is here that the latent heat of vaporization is also absorbed.

Vaporization is a broader term that encompasses both boiling and evaporation as modes of changing a liquid to vapor.

Fusion refers to the change from solid to liquid, which is unrelated to the vaporization process.

So, the distinction lies primarily in the specific nature of the processes. In the context of defining the heat required at constant temperature for a phase change specifically from liquid to