Heat which brings about a change of state is referred to as what?

Heat that brings about a change of state is known as latent heat. This type of heat is associated with phase changes in a substance, such as melting, freezing, boiling, or condensing. During these processes, the temperature of the substance remains constant even though heat is being added or removed. For example, when ice melts to become water, it absorbs heat but does not increase in temperature until all the ice has transitioned to water. The same principle applies when water turns into steam; it requires heat energy to change state from liquid to gas without a change in temperature during that phase transition.

In contrast, sensible heat refers to the heat exchanged by a substance that results in a temperature change without a change in state. Expansive heat is not a recognized term in thermodynamics relating to heat transfer or phase changes. Conduction heat refers to the transfer of heat through a material without the movement of the material itself and does not specifically relate to changes of state. Thus, the terminology of latent heat specifically defines the heat involved in changing the state of a substance, making it the correct choice for this question.