# Question #dcd39

Mar 11, 2017

The free energy change $\Delta G$ of a chemical reaction is related with Enthalpy change $\Delta H$, Entropypy change $\Delta S$ and the absolute temperature $T$ of the reaction as follows

$\Delta G = \Delta H - T \Delta S$

The combustion reaction of hydrocarbon exothermic one.
So $\Delta H < 0$ again as per given balanced equation the number of moles of gaseous product (12moles) is greater than that of gaseous reactants (9moles). So $\Delta S > 0$ and $T > 0$

So as a whole RHS $\Delta H - T \Delta S < 0$

Hence the free energy change of the reaction

$\Delta G < 0 \to \text{The reaction is spontaneous}$