# Worksheet on Van der Waals Equation

Van der Waals equation was derived by Johannes Diderik van der Walls in late 1873. He received Nobel prize in 1910 for his work on the equation of state for gases and liquids.

Van der Walls equation relates pressure, volume and the temperature of a gas taking the finite size of molecules and their intermolecular attraction.

In this article you can find some questions related to Van der Wall’s equation and their answers:

Questions:

1. The correct expression for the van der Waa1’s equation Of states is:

(a)    $(p + a/n^2 V^2)(V- nb) = \Delta nRT$

(b)   $(p + an^2 / V)(V- nb) = \Delta nRT$

(c)    $(p + an^2 / V)(V- nb) = nRT$

(d)   $(p + n^2 / V^2)(V- b) = nRT$

2. In van der Waa1’s equation of state for non-ideal gas, the term which accounts for the intermolecular forces is:

(a)    B

(b)   $\alpha/V^2$

(c)    $\alpha^2$

(d)   all

3. The constant $\alpha$ in van der Waal’s equation is maximum in:

(a)    He

(b)   $NH_3$

(c)    $O_2$

(d)   $H_2$

4. The compressibility factor of real gas is usually greater than one (Z > 1) at high temp. and high pressure. This is because:

(a)    the constant b is negligible while a is not

(b)   the constant a is negligible while b is not

(c)    both a and b are negligible

(d)   both a and b are non-negligible

5. The correct relationship between $P_c, V_c \text{and} T_c$ is:

(a)    $P_cV_c = RT_c$

(b)   $P_cV_c = 3RT_c$

(c)    $P_cV_c = 3/5RT_c$

(d)   $P_cV_c = 3/8RT_c$

6. Which of the following parameters is three times thevan der Waal constant b?

(a)    critical volume

(b)   critical temperature

(c)    critical pressure

(d)   none of these