Question

3 moles of a monoatomic ideal gas with Cv=(32)RT occupies a volume of 3.2L at a pressure of 1.9atm at point A. The gas is carried through a cycle consisting of three processes:
1. The gas is heated at constant pressure until its volume is 4.4L at point B.
2. The gas is cooled at constant volume until the pressure decreases to 1.2atm (C).
3. The gas undergoes an isothermal compression back to point A.
Find W for the isochoric process.

Answer 1

The process is represented on a P-V diagram as follows:

In the isothermal process,

initial state is: P1=1.2 atm and V1=4.4 L

final state is: P2=1.9 atm and V2=3.2

In the question work done is asked in Isochoric process, in this process volume is constant.

dV=0

So,the work done will be zero.

But if the process is isothermal

In an isothermal process, work done by the gas is:    

As the given gas is ideal:

Substituting above expression for T in the work: