Chemistry - Thermochemistry Question with Solution | TestHub

Combustion Reaction: $C{H}_4(g)+2O_2(g)\to C{O}_2(g)+2H_{2}O(l)$

Energy to Break Reactant Bonds: $4\times {\epsilon }_{C-H}+2\times {\epsilon }_{O=O}=4X_1+2X_2$

Energy Released Forming Gaseous Products: $-(2\times {\epsilon }_{C=O}+4\times {\epsilon }_{O-H})=-2X_3-4X_4$

Resonance & Phase Change Contributions: Resonance stabilizes $C{O}_2$ by $-R$, and condensing $2H_{2}O$ from gas to liquid releases $-2Y$.

Total Enthalpy ($\Delta H_c$): $4X_1+2X_2-2X_3-4X_4-R-2Y$