Question

Why do real gases not always behave ideally. Under what conditions does a real gas behave most ideally, and why?

Answer 1

Conditions for ideal gases are 1. There shouldn't be any repulsive and attractive forces between gas molecules 2. There is no volume for ideal gases 3. Ideal gases gain energy by elastic collisions.

All these three things are present in the case of real gases.

So they won't behave ideally always.

At low pressure and high temperature real gases behaves ideally.

At low pressure, the volume of gases becomes zero and at high temperature, there are no intermolecular forces between gases since kinetic energy is increasing with the increasing of absolute temperature .