Calculate Δ_fH° of octane,C₈H₁₈(l),given the enthalpy of combustion of octane to CO₂(g)and H₂O(l),-5471 kJ/mol,and the standard enthalpies of formation of CO₂(g)and H₂O(l),-393.5 kJ/mol and -285.8 kJ/mol,respectively. A)-249.2 kJ/mol B)+4792 kJ/mol C)+249.2 kJ/mol D)-4792 kJ/mol

Question

Quizplus · Accepted Answer

The enthalpy of formation of octane can be calculated using Hess's law: ΔfH°(C8H18) = ΔcH°(C8H18) - 8ΔfH°(CO2) - 9ΔfH°(H2O). Substituting the given values: ΔfH°(C8H18) = -5471 - 8(-393.5) - 9(-285.8) = -249.2 kJ/mol.

Calculate ΔfH° of Octane,C8H18(l),given the Enthalpy of Combustion of Octane

Calculate Δ_fH° of Octane,C₈H₁₈(l),given the Enthalpy of Combustion of Octane