Question

Explain the physical significance of Van der Waals Parameters.

Answer 1

Hint: Van der Waals equation is also known as Van der Waals equation of state for real gases which do not follow ideal gas law.
Ideal Gas Equation= $PV = nRT$
Van der Waals Equation= $\left( {p + \dfrac{{{n^2}a}}{{{V^2}}}} \right)\left( {V - nb} \right) = nRT$

Complete step by step answer:
The Van der Waals equation is an equation of state for a fluid composed of particles that have a non-zero volume and a pairwise attractive inter-particle force (such as the van der Waals force). The equation is
$\left( {p + \dfrac{{{n^2}a}}{{{V^2}}}} \right)\left( {V - nb} \right) = nRT$
P stands for pressure.
V stands for volume.
n is the no. of moles of the gas.
R is the universal gas constant.
T is the temperature.
Significance of constant ‘a’: ‘a’ is the magnitude of intermolecular attractive forces between the particles.
Significance of constant ‘b’: ‘b’ is the volume excluded by mole of particles


Note:
Units of Van der Waals Constants-
Unit of “a” is $atm\,li{t^{2\,}}\,mo{l^{ - 2}}$
Unit of “b” $litre\,mo{l^{ - 1}}$
Van der Waals Forces: The weak intermolecular forces that are dependent on the distance between atoms or molecules are known as Van der Waals Forces. Due to Interactions between uncharged atoms/molecules these forces are formed.