Mass of nitrogen gas, $m=2\times 10^{-2} \, \mathrm{kg}=20 \, \mathrm{g}$ Molecular mass of nitrogen gas $=28 \, \mathrm{g}$ Rise in temperature, $\Delta T=45^{\circ}\mathrm{C}$ Heat supplied = ? Number of moles $n=\frac{m}{M}=\frac{20}{28}=\frac{5}{7}$ For nitrogen $(\mathrm{N}_2)$ which is a diatomic gas, molar specific heat at constant pressure $C_{p}=\frac{7}{2} R$ where $R=8.3 \, \mathrm{J} \, \mathrm{mol}^{-1} \, \mathrm{K}^{-1}$ Therefore, heat supplied to the gas $\Delta Q=n C_{p} \Delta T$$=\frac{5}{7} \times \frac{7}{2} \times R \times 45$$=\frac{5}{7} \times \frac{7}{2} \times 8.3 \times 45$$=933.8 \, \mathrm{J} \approx 934 \, \mathrm{J}$