Thermodynamics

The standard enthalpy of formation $\left(\Delta_f H^{\varphi}\right)$ of ammonia is $-46.2 \mathrm{~kJ} \mathrm{~mol}^{-1}$, What is the $\Delta_{,} H^{\ominus}$ of the following reaction? \(\mathrm{N}_2(g)+3 \mathrm{H}_2(g) \longrightarrow 2 \mathrm{NH}_3(g)\)