Determine the work done during an isothermal reversible

Question

Determine the work done during an isothermal reversible expansion of a van der Waals gas. Account physically for the way in which the coefficients a and b appear in the final expression. Design on the same graph indicator diagrams for the isothermal reversible expansion of

 a. A perfect gas,

b. A Vander Waals gas where a=0 and b=5.11x10^-2dm³mol^-1, and

c. A=4.2dm⁶atmmol^-2 and b=0. The values selected exaggerate the imperfections but give rise to significant effects on the indicator diagrams. Take v_i = 1.0dm³, n=1.0 mol, and T=298 K.