Question

When a solid melts, its temperature remains constant. Explain.

Answer 1

Melting point:

• The solid-state convert to a liquid state once reaches its melting point.
• No changes in temperature.
• Reason: The heat energy supplied once the solid starts melting is used up as latent heat of fusion.
• For example, the melting point of ice is $0°\mathrm{C}$.
• The solid ice melts to form liquid water at $0°\mathrm{C}$. Because it gains latent heat of fusion energy and the temperature remains constant.

Latent heat of fusion:

• Also known as enthalpy of fusion is the amount of energy that must be supplied to a solid substance (typically in the form of heat) in order to trigger a change in its physical state and convert a solid into a liquid (when the pressure of the environment is kept constant).

Hence, a solid substance converts to liquid once it reaches the melting point and its temperature remains constant.