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Phase change is the change of the state of matter. Basically, there are three states of matter: solid, liquid, and vapor. The transition from solid to liquid or liquid to vapor, for example, is referred to as phase change. These phase changes are associated with the temperature. For example, liquid changes to vapor at its boiling point.

Heat transfer is the transfer of thermal energy due to a variation in temperature. So, heat transfer can use temperature change and phase change.

The two factors on which the energy required for a phase change depends are the mass of the substance and the latent heat of vaporisation or fusion. It is mathematically expressed as;

\[\begin{array}{l}{\rm{Q = m}}{{\rm{L}}_{\rm{v}}}\\{\rm{Q = m}}{{\rm{L}}_{\rm{f}}}\end{array}\]

Here,

\[\begin{array}{l}{\rm{m = mass of the substance}}\\{{\rm{L}}_{\rm{f}}}{\rm{ = Latent heat of fusion}}\\{{\rm{L}}_{\rm{v}}}{\rm{ = Latent heat of vaporization}}\end{array}\]

So, the mass of the substance and the latent heat of fusion or vaporization can also change temperature and phase.