\(5 \mathrm{kmol}\) of Ar gas confined in a cylinder undergoes a change from an initial condition of \(20 \mathrm{bar}\) and \(350 \mathrm{~K}\) to a final condition of \(2 \mathrm{bar}\) and \(350 \mathrm{~K}\). The gas follows the equation \(P V=R T\).

Given that \(C_{P}=29.10 \mathrm{~kJ} / \mathrm{kmol}-\mathrm{K}\) and \(C_{V}=20.78 \mathrm{~kJ} / \mathrm{kmol}-\mathrm{K}\), determine the change in internal energy, change in enthalpy, heat and work requirement.