91Ó°ÊÓ

One of the four fundamental states of matter, a gas is made up of particles with no definite volume or structure.

(a) When the pressure is high and the volume is small, the gas molecules collide more often with each other and the container walls, increasing the pressure exerted by the gas molecules in comparison to an ideal gas. Under these conditions, a real gas is likely to vary from ideal behaviour.

(b) The gas molecules are widely apart and have a large kinetic energy at high temperature and low pressure. Collisions are less common, there is less attraction between molecules, and there is less contact between molecules. So, under these conditions, a true gas would behave perfectly.

(c) As, the gas molecules have a smaller KE than the attractive forces at low temperatures and high pressures, they are less successful in resisting these attractions after colliding with one another. As a result, under these conditions, actual gas is predicted to depart from ideal behaviour.

Therefore, In the conditions specified in (b), a real behave gas behaves perfectly, but in the situations described in (a) and (c).