What is the term for heat that causes a change in state without a change in temperature?

The term for heat that causes a change in state without a change in temperature is latent heat. This heat is absorbed or released during processes such as melting, freezing, vaporization, or condensation, and it facilitates a transition between phases of matter—such as from solid to liquid or from liquid to gas—without altering the temperature of the substance itself.

For instance, when ice melts into water at 0 degrees Celsius, it absorbs heat but does not increase in temperature until all the ice has transformed into water. This property is crucial in applications such as refrigeration and climate control, where managing heat transfer in phase changes is necessary for efficient operation.

The other terms refer to different concepts. Sensible heat involves a temperature change in a substance that can be felt and measured. Convective heat is related to the heat transfer through the movement of fluids, and evaporative heat involves the process of liquid changing to gas, which is a specific application of latent heat during phase change. Each of these concepts plays a significant role in thermodynamics and heating systems, but only latent heat specifically describes heat that effects a state change without temperature change.