2. NATURE OF MATTER

STATES OF MATTER

On the basis of physical properties, matter may be classified into the following three states :

1. Solid State
2. Liquid State
3. Gaseous State

Comparison of the characteristics of a solid, a liquid and a gas

Gases

The molecules of a gas are free to move in all directions. The space in between them is very large. The gaseous molecules possess motion of all three types, namely translational, rotational and vibrational. The molecular forces of attraction between gases are very much weak. Hence a gas has neither a definite shape nor a definite volume.

• Gases are highly compressible
• Gases expand without limits
• Gases exert pressure on the walls of the container uniformly in all directions.
• Gases diffuse rapidly through each other to form a homogeneous mixture.