Question

Gas exerts pressure in all directions. Explain.

Answer 1

Hint: Understand the properties of gas like shape, volume etc. Now try to understand that when placed in a close container, the molecules of gas are in constant interaction with the wall of the container. Due to kinetic energy of the gas particles, pressure is exerted. Now based on this try to form a concise explanation about the pressure applied on the walls of the container.

Complete step by step answer:
We will first see on what basis a substance is categorised as a solid, a liquid, or a gas. Two factors determine it. The kinetic energies of the particles (it might be atoms, molecules, or ions) that make up a substance. The particles move apart due to kinetic energy. The attractive intermolecular forces present between the particles tend to draw the particles together. If the average kinetic energy is greater than the intermolecular forces between the particles, a substance will not condense to form a liquid or a solid. If the kinetic energy is less than the intermolecular forces, a liquid or solid will form. The average kinetic energy of the particles in a gas is huge enough to overcome the forces of attraction between them. In other words we can also say that gas particles have very weak attractive forces between them. The molecules of a gas move apart, when they collide with other gas molecules. They bounce all around the container. Gravity also has a very little effect on them because of their small size.

So these move randomly exerting pressure in all directions.

Note: At low pressures, the gaseous molecules are relatively far apart, but as the pressure of the gas increases, the available space in which the molecules move is decreased (the intermolecular distances become smaller).