Chapter 9, Problem 79E

At $\text{298}\text{K}$ , the standard enthalpies of formation for ${\text{C}}_{\text{2}}{\text{H}}_{\text{2}}\text{(g)}$ and ${\text{C}}_{\text{6}}{\text{H}}_{\text{6}}\text{(l)}$ are $\text{227 kJ/mol}$ and $49\text{ kJ/mol}$ , respectively.

1. Calculate $\text{ΔH°}$ for ${\text{C}}_{\text{6}}{\text{H}}_{\text{6}}\text{(l)}\to 3{\text{C}}_{\text{2}}{\text{H}}_{\text{2}}\text{(g)}$
2. Both acetylene $({\text{C}}_{\text{2}}{\text{H}}_{\text{2}}\text{)}$ and benzene $({\text{C}}_{\text{6}}{\text{H}}_{\text{6}}\text{)}$ can beused as fuels. Which compound would liberate moreenergy per gram when combusted in air?