Question

A substance on heating, undergoes (i) a rise in its temperature, (ii) a change in its phase without change in its temperature. In each case, state the change in energy of molecules of the substance.

Answer 1

(i) When there is a rise in temperature, the average kinetic energy of the molecules changes. If the temperature is rising, there is an increase in the average kinetic energy of the molecules.

(ii) When the heat supplied causes no change in the temperature of the substance, the heat supplied to the substance is utilized to change the state by separating the molecules and overcoming intermolecular forces of attractions. This change increases the Potential Energy of the molecules. This heat absorbed is called Latent Heat.