[cyt_91]

1. The problem statement, all variables and given/known data

a) 3 moles of carbon dioxide gas expands reversibly in a piston-container from 20 L
to 40 L in an isothermal process at 400 K. Calculate work, heat, change in internal
energy and change in enthalpy, considering van der Waals behaviour. [a = 3.59
atm L^2 mol^-2 and b = 0.0427 L mol^-1].

2. Relevant equations

(p-a(n/v)^2)(V-nb)=nRT
pV=nRT


3. The attempt at a solution

I calculated the work done by the gas to be 67.8 J.
I obtained an expression for P from VDW equation and integrate the expression for P w.r.t V from 20 L to 40 L.
R is 0.0821 in this case.

However if the gas is behaving non-ideally, how can we calculate the heat,enthalpy change and internal energy change?
Since for non ideal gas,for isothermal expansion delta U is not necessarily zero.

What difference does non-ideal behaviour bring to the calculations for heat, enthalpy change and internal energy change?

Any help is much appreciated. Thanks....