Helium weighing 16 g is expanded from 1 atm to one tenth of its original pressure at 30°C. Calculate the change in entropy assuming it to be an ideal gas (in J.K-1)

The entropy change of an ideal gas during a general process not involving any reaction or phase change is given as ΔSsys=nCplnT2T1+nRlnP1P2T1=T2;P1=1;P2=0.1ΔSsys=nRlnP1P2=4×8.314×2.303 x log10.1=76.57J=0.07657kJR=8.314J.mol-1·K-1