Changes of state occur at particular phase transition temperatures. The heat associated with the phase transition is given by:

freezing or melting: Q = mL_{f}
L_{f} is the latent heat of fusion

boiling or condensing: Q = mL_{v} L_{v} is the
latent heat of vaporization

For water:
L_{v} = 2256 kJ/kg;
L_{f} = 333 kJ/kg; c = 4.186 kJ/(kg °C)