Question

Arrange in order of increasing expansion on heating: liquids, solids, gases.

Answer 1

Molecules are tightly packed in solids as compared to liquids and gases, similarly, molecules of a liquid are bound more as compared to gases. That's why when solids are heated they expand less as compared to liquids and liquids expand less as compared to gases. In gases, molecules are not bound at all, so they expand maximum upon heating.

Hence, the order of expansion can be written as: Gases > Liquids > Solids.