One mole of an ideal gas, Cp = (7/2)/? and Cv = (5/2)R is compressed adiabatically in a piston/cylinder device from 2 bar and 25oC to 7 bar. The process is irreversible and requires 35% more work than a reversible, adiabatic compression from the same initial slate to the same final pressure. What is the entropy change of the gas?