5. Thermodynamics and thermochemistry — Chemistry STD 11 Science — Question

$C(s) + {O_2}(g) \to C{O_2}(g),\Delta H = - 394\,kJ$

$2{H_2}(g) + {O_2}(g) \to 2{H_2}O(l),\,\Delta H = 568\,kJ$

$C{H_4}(g) + 2{O_2}(g)\,\, \to \,\,C{O_2}(g) + 2{H_2}O(l)$ $\Delta H = - 892\,kJ$ Heat of formation of $C{H_4}$ is.....$kJ$