Solid fuel used in rocket is a mixture of Fe_2 O_3 and Al (in ratio 1:2). The heat evolved ( kJ ) per gram of the mixture is ____ (Nearest integer)…

Solid fuel used in rocket is a mixture of $\displaystyle \mathrm{Fe}_2 \mathrm{O}_3$ and Al (in ratio $\displaystyle 1$:$\displaystyle 2$). The heat evolved ( kJ ) per gram of the mixture is $\displaystyle \_\_\_\_$ (Nearest integer)Given: $\displaystyle \Delta \mathrm{H}_{\mathrm{f}}{ }^\theta\left(\mathrm{Al}_2 \mathrm{O}_3\right)=-1700 \mathrm{~kJ} \mathrm{~mol}^{-1}$ $$\Delta \mathrm{H}_{\mathrm{f}}^\theta\left(\mathrm{Fe}_2 \mathrm{O}_3\right)=-840 \mathrm{~kJ} \mathrm{~mol}^{-1} $$ Molar mass of $\displaystyle \mathrm{Fe}, \mathrm{Al}$ and O are $\displaystyle 56,27$ and $\displaystyle 16 \mathrm{~g} \mathrm{~mol}^{-1}$ respectively