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Characteristics of phase transitions

For any given substance, the specific latent heat of vaporisation ($$\ell_{\text{v}}$$) is much greater than the specific latent heat of fusion ($$\ell_{\text{f}}$$).

This is because the distance that the particles have to be separated from each other is much greater for a liquid-gas transition than for a solid-liquid transition.

Additional energy is also required to overcome the force of atmospheric pressure preventing the change of liquid to gas (atmospheric pressure has a much smaller effect on melting).

If heat is not supplied to a boiling liquid during the process of vaporisation, the liquid cools rapidly. This is because the most energetic particles are converted into vapour before the rest of the particles.

The remaining particles have a lower mean kinetic energy. This translates into a lower temperature of the liquid.