Because (H/P) T = -C P J T , the change in enthalpy of a gas

Because (∂H/∂P)_T = -C_P μ _{J −T} , the change in enthalpy of a gas expanded at constant temperature can be calculated. To do so, the functional dependence of μ _{J −T} on P must be known. Treating Ar as a van der Waals gas, calculate ΔH when 1 mol of Ar is expanded from 325 bar to 1.75 bar at 375 K. Assume that μ _{J −T} is independent of pressure and is given by μ _{J −T} = [(2a/RT) − b]/C_P,m, and C_P,m = 5/2R for Ar. What value would ΔH have if the gas exhibited ideal gas behavior?