Introduction
Matter commonly exists in three states: solid, liquid, and gas.
To change a solid to a liquid (melting or fusion) and to change a liquid to a gas (boiling or vaporisation) requires the input of energy. This
energy breaks bonds between atoms or molecules but does not change the temperature and is thus known as ‘latent heat’.
Note: this differs from our discussion on heat capacity where added energy doesn't change the state, but does change temperature. In this
section we talk about the point where temperature does not change, but state does.
Evaporation and boiling are different actions. In boiling, the average molecular energy is at the point that state is about to change.
In evaporation, individual molecules gain enough energy to change state, despite the avergae energy around them being much lower than that required
for change of state.
The amount of latent heat required (Q) depends upon the nature of the substance (specifically, its latent heat capacity (L)) and the mass
of the substance m.
During the change of state from a gas to a liquid (condensation) or from a liquid to a solid (freezing or solidification), heat is released
due to the formation of bonds between atoms or molecules.
videos
Specific latenet heat, Fuse school
Changes of state, Fuse School
Evaporation vs boiling, Breslin science
Intra-molecular forces, Professor Dave
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