Which statement concerning the van der Waals constants a and b is true? (a) The magnitude of a relates to molecular volume, whereas b relates to attractions between molecules. (b) The magnitude of a relates to attractions between molecules, whereas b relates to molecular volume. (c) The magnitudes of a and b depend on pressure. (d) The magnitudes of a and b depend on temperature.

Key Concepts

van der Waals Equation

The van der Waals equation is an adjustment of the ideal gas law that accounts for the volume occupied by gas molecules and the attractive forces between them. It introduces two constants, 'a' and 'b', which correct for these non-ideal behaviors. The constant 'a' quantifies the strength of intermolecular attractions, while 'b' represents the volume occupied by the gas molecules themselves.

Constant 'a'

In the van der Waals equation, the constant 'a' is associated with the attractive forces between molecules. A larger value of 'a' indicates stronger intermolecular attractions, which can lead to deviations from ideal gas behavior, especially at high pressures and low temperatures. This constant is crucial for understanding how real gases behave compared to ideal gases.

Constant 'b'

The constant 'b' in the van der Waals equation represents the effective volume occupied by gas molecules, accounting for the finite size of the particles. It reflects the volume excluded from the available space for molecular motion due to the presence of the molecules themselves. A larger 'b' value indicates that the gas molecules occupy more space, which is significant in understanding the behavior of gases under various conditions.