States of matter: describe question

Carbon dioxide, $\ce{CO2}$, in a sealed cylinder at 300 K behaves almost exactly as an ideal gas when its pressure is very low. When the same sample is compressed to a very high pressure, the actual pressure recorded is greater than the pressure predicted for an ideal gas at the same volume and temperature.

Describe how the pressure of a gas arises from the behaviour of its molecules. Describe how the two ideal gas assumptions about particle volume and intermolecular forces account for the difference between the real gas and the ideal gas at high pressure.