A gas has neither a definite volume nor a definite shape. Describe the molecular model to explain it.

Features of molecular model for a gas are :

1. The molecules of a gas lie much farther apart than they lie in a liquid or a solid. Thus, the density of gases is very low.
2. There is negligible force of attraction between the molecules of a gas, so they are free to move in the entire space available to them.
3. The molecules of a gas move much faster than they move in liquids, and therefore they are infact in a state of incessant random motion, moving in all possible directions at all possible speeds.
4. The molecules of a gas are far apart and there is enough space available for compression. Thus, gases can easily be compressed.
5. During motion, the molecules of a gas collide with one another and also with the wall of the vessel. In each collision, the direction of motion of the molecule changes, so the momentum changes.
6. A gas exerts pressure on the wall of its container due to the continuous collisions of its molecules with the wall.

Thus, this model concludes that a gas has neither a definite shape nor a definite volume, but it can flow and is easily compressible.