Question

In thermodynamics, the $P-V$ work done is given by $w=-\int dV{P}_{ext}$. For a system undergoing a particular process, the work done is,

$w=-\int dV(\frac{RT}{V-b}-\frac{a}{V^2})$

This equation is applicable to a

• A. System that satisfies the van der Waals equation of state.
• B. Process that is reversible and adiabatic.
• C. Process that is irreversible and at constant pressure.
• D. Process that is reversible and isothermal.

Answer 1

Answer: (A), (B), (D)

Process that is reversible and isothermal.

$w=-\int P_{ext.}dV$

From van der waal equation of state for one mole gas.

$(P+\frac{a}{V^2})(v-b)=RT$
$P=[\frac{RT}{V-b}-\frac{a}{V^2}]$

For reversible process

$P_{ext}=P_{gas}$
$W=-\int (\frac{RT}{V-b}-\frac{a}{V^2})dv$
So, process is not applicable only for irreversible process.