The heat combustion of acetylene, C₂H₂(g), at 25°C, is -1299 kJ/mol. At this temperature, $\Delta$H°_f values for CO₂(g) and H₂O(l) are -393 and -286 kJ/mol, respectively. Calculate $\Delta$H°_f for acetylene.

Question

Quizplus · Accepted Answer

The heat of formation of acetylene can be calculated using the equation: ΔH°_combustion = ΣΔH°_f(products) - ΣΔH°_f(reactants). Rearranging gives ΔH°_f(acetylene) = ΣΔH°_f(products) - ΔH°_combustion. Substituting the given values: ΔH°_f(acetylene) = [2(-393) + (-286)] - (-1299) = 227 kJ/mol.

The Heat Combustion of Acetylene, C2H2(g), at 25°C, Is -1299 Δ\DeltaΔ

The Heat Combustion of Acetylene, C₂H₂(g), at 25°C, Is -1299 $\Delta$