Question

Which contains more heat, 1 kg of ice at 0 C or 1 kg of water at 0 C? Give reason for your answer.

Answer 1

water at 0°C has absorbed latent heat of fusion (334 kJ / kg) of ice while it is getting converted from 0ºC ice to 0°C water.
hence water at 0°C contain more heat

1kg of water contains more heat than 1kg of ice.

Enthalpy (i.e. heat) of water = Enthalpy of ice + latent heat

Latent heat is heat required to change​ the phase of the substance. In this case, latent heat is heat required to melt 1kg of ice at 0°C. Latent heat just changes the state/phase of the substance without changing it's temperature.

Hence, 1kg of water has more heat than 1kg of ice at 0°C