Gases have following properties.
1. Since gases occupy all the available space, therefore, they do not have definite volume.
2. They do not have a definite shape.
3. The gases bubble through liquids and tend to rise up due to their relatively low densities.
4. Gases can diffuse and effuse. This property is negligible in solid, however, it operates in liquids as well.
5. Since there are large empty spaces between gaseous molecules, therefore gases can be compressed by applying pressure.
6. Gases expand either on heating or on providing more space. However, liquids and solids do not expand to such an extent on heating or on providing more space.
7. Joule-Thomson Effect:
The sudden expansion of gases causes cooling. This phenomenon is called Joule-Thomson effect.
8. The molecules of gases are in state of constant random motion. They collide with the walls of the container and exert pressure. 9. The attractive forces between the molecules of gases are very weak.