Chemistry - Thermochemistry Question with Solution | TestHub

$2\mathrm{F}\mathrm{e}\left(\mathrm{s}\right)+\frac{3}{2}\mathrm{C}{\mathrm{O}}_2\left(\mathrm{g}\right)\to \mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)+\frac{3}{2}\mathrm{C}\left(\mathrm{s}\right);\mathrm{\Delta }\mathrm{H}°=-234.1\mathrm{k}\mathrm{J}$…(i)
$\mathrm{C}\left(\mathrm{s}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to \mathrm{C}{\mathrm{O}}_2\left(\mathrm{g}\right)(\mathrm{\Delta }\mathrm{H}°=-393.5\mathrm{k}\mathrm{J})$…(ii)
Multiplying eq. (i) by 2 and eq. (ii) by 3 and on adding both equations, we get
$4\mathrm{F}\mathrm{e}\left(\mathrm{s}\right)+3{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3\left(\mathrm{s}\right);\mathrm{\Delta }\mathrm{H}°=(-234.1\times 2)+(-3\times 393.5)$
$=-1648.7$kJ