Question

Helium of mass m =1.7 g is expanded adiabatically n = 3.0 times and then compressed isobarically down to the initial volume.  Find the entropy increment of the gas in this  process.

Answer 1

If the initial temperature is T₀ and volume is V₀ then in adiabatic expansion.

V₁ being the volume at the end of the adiabatic process. There is no entropy change in this process. Next the gas is compressed isobarically and the net entropy change is