${{C}_{P}}-{{C}_{V}}=R\Rightarrow {{C}_{P}}=R+\frac{3}{2}R=\frac{5}{2}R$ $Q=n{{C}_{P}}\Delta T=\frac{5}{2}nR\Delta T\Rightarrow 15000=\frac{5}{2}\times 10\times \frac{25}{3}\Delta T\Rightarrow \Delta T=\frac{6\times 1500}{125}=72K\Rightarrow \Delta \theta =72{}^\circ C$  $W=-nR\Delta T=-\frac{2}{5}Q=-\frac{2}{5}\times 15000=-6000J\Rightarrow \left| W \right|=6000J$