A system contains \(0.15 \mathrm{~m}^{3}\) of a gas at a pressure of 3.8 bar and \(423 \mathrm{~K}\). It is expanded adiabatically till the pressure falls to \(1 \mathrm{bar}\). The gas is then heated at a constant pressure till its enthalpy increases by \(70 \mathrm{~kJ}\). Calculate the total work done. Assume \(c_{p}=1 \mathrm{~kJ} / \mathrm{kg}\). \(K\) and \(c_{v}=0.714 \mathrm{~kJ} / \mathrm{kg}\). \(K\).