What are characteristic properties of gases?

Properties of gases:
The gaseous state is the simplest of the three physical states and shows the greatest regularity in behaviour. The chief characteristic properties of gases are:
1. A gas neither possesses a definite volume nor a definite shape.
2. All the parts of a gas or a gaseous mixture have similar composition throughout.

3. Gases can expand indefinitely to fill up all the available space.

4. The molecules or atoms of a gas are in a state of continuous zig-zag motion in all directions.

5. Two or more gases mix swiftly and easily to give a homogeneous mixture.

6. On cooling and applying pressure gases can be liquefied.

7. The gases exert pressure on the walls of the container as a result of collisions of the particles against the walls of the container.