What does the van der Waals equation of state account for in real gases?

The van der Waals equation of state enhances the ideal gas law by incorporating real gas behavior through two key parameters. The parameter 'a' accounts for the attractive forces between gas molecules, which become significant at high pressures and low temperatures, leading to deviations from ideal gas behavior. The parameter 'b' reflects the finite volume occupied by the gas molecules themselves, addressing the influence of repulsive forces that arise when gas molecules come very close to each other.

By integrating these two factors, the van der Waals equation provides a more accurate representation of how real gases behave under various conditions, particularly when the assumptions of the ideal gas law—namely that particles do not exert forces on each other and occupy no volume—fail to hold true. This makes the equation invaluable for understanding gas behavior in situations where intermolecular forces and molecular volume cannot be neglected.