Thermodynamics

At 25$$^\circ$$C and 1 atm pressure, the enthalpies of combustion are as given below : .tg {border-collapse:collapse;border-spacing:0;} .tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; overflow:hidden;padding:10px 5px;word-break:normal;} .tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px; font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;} .tg .tg-baqh{text-align:center;vertical-align:top} Substance $${H_2}$$ C (graphite) $${C_2}{H_6}(g)$$ $${{{\Delta _c}{H^\Theta }} \over {kJ\,mo{l^{ - 1}}}}$$ $$- 286.0$$ $$- 394.0$$ $$- 1560.0$$ The enthalpy of formation of ethane is