How does solid melt?
Molecules in a solid are held by strong intermolecular bonds. For solid to melt, these bonds have to be broken. The thermal energy supplied will break the intermolecular bonds between the molecules of the solid. When the intermolecular bonds are broken, the molecules can move out of their fixed positions.
Solidification and freezing point:
It is the reverse of melting. Pure substance will solidify/ freeze at temperature which is equal to its melting point, 0°c (Freezing point of water). Melting point is also the freezing point.
Boiling and Condensation
When a liquid is heated and changes into vapour at a fixed or constant temperature, its change of state is boiling. Reverse of boiling is condensation. It is the change in state from vapour to liquid when it is cooled at constant temperature, thermal energy is given out during condensation.
How does a liquid boil?
At boiling point, thermal energy is supplied to the liquid, but there is no rise in the temperature. Thermal energy is used to separate the molecules as well as to push back the surrounding atmosphere.The molecules will then be further apart with little intermolecular forces of attraction between them, causing a change of state.
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