Enthalpy of bond dissociation, combustion and formationMedium

Calculating Standard Enthalpy of Formation

Consider the following cases of standard enthalpy of reaction $\left( {\Delta H_r^o\,in\,kJ\,mo{l^{ - 1}}} \right)$
${C_2}{H_6}(g)\, + \,\frac{7}{2}{O_2}(g) \to 2C{O_2}(g) + 3{H_2}O(\ell )\,\Delta H_1^o = - 1550$
$C(graphite) + {O_2}(g) \to C{O_2}(g)\,\Delta H_2^o = - 393.5$
${H_2}(g) + \frac{1}{2}{O_2}(g) \to {H_2}O(\ell )\,\Delta H_3^o = - 286$
The magnitude of $\Delta H_{f\,\,{C_2}{H_6}(g)}^o$ is ______ kJ mol^–1 (Nearest integer).

Ask about this question