Asked by Jaziya | 23rd May, 2010, 05:01: PM

Expert Answer:

van der Waals parameter a measures the intermolecular forces of attraction.

van der Waals parameter b measures the actual volume occupied by gas molecules.

The gases which have high molecular masses will have stronger intermolecular forces of attraction. Hence, the value of a will be high ofr such gases.

Also, the greater the molecular mass of the gas, more is the size of the molecules. Hence , value of b will be high for such gases.

For example: gases like hydrogen and helium have exceptionally low molecular masses. Hence, they have very small values of a and b.

Answered by  | 26th May, 2010, 11:18: AM

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