Question

Does an ideal gas exist in reality?

Answer 1

No. In an ideal gas, intermolecular forces are ignored except during collisions. The equation of state for a real gas, as given by J.D. van der Waals [(1837-1923) Dutch physicist], is:

`(P + (n^a)/V^2) (V - nb)` = nRT,

Where a and b are positive constants that are characteristic of a gas, n is the number of moles, and V is the volume occupied by the gas. The correction term n²a/V² accounts for the attraction between molecules, while the factor nb considers the finite volume of molecules.

The volume accessible to a molecule is (V − nb), not V (the container’s volume). Attraction between molecules reduces collisions with the container wall. As the space between molecules shrinks, the gas exerts less pressure on the container wall, resulting in lower-than-expected pressure.