5 moles of an ideal gas was initially at \(315 \mathrm{~K}\) and \(20 \mathrm{~atm}\). The expansion of gas takes place adiabatically when the external pressure is reduced to \(7 \mathrm{~atm}\). What will be the final temperature and volume? Also calculate the work done during the process, given that \(C_{P}=8.58 \mathrm{cal} / \mathrm{mol} /{ }^{\circ} \mathrm{C}\).