Question
Solid fuel used in rocket is a mixture of $\mathrm{Fe}_{2} \mathrm{O}_{3}$ and $\mathrm{Al}$ (in ratio 1 : 2). The heat evolved $(\mathrm{kJ})$ per gram of the mixture is ____________. (Nearest integer)
Given: $\Delta \mathrm{H}_{\mathrm{f}}^{\theta}\left(\mathrm{Al}_{2} \mathrm{O}_{3}\right)=-1700 \mathrm{~kJ} \mathrm{~mol}^{-1}$
$\Delta \mathrm{H}_{\mathrm{f}}^{\theta}\left(\mathrm{Fe}_{2} \mathrm{O}_{3}\right)=-840 \mathrm{~kJ} \mathrm{~mol}^{-1}$
Molar mass of Fe, Al and O are 56, 27 and 16 g mol$^{-1}$ respectively.
Correct Answer
4