Use standard enthalpies of formation to determine ΔHorxn for: 2C2H2 (g) + 5O2 (g) → 4CO2 (g) + 2H2O (l)

The answer to your question is: ΔHr = - 2598.8 kJ/mol

Explanation:

2C₂H₂ (g) + 5O₂ (g) → 4CO₂ (g) + 2H₂O (l)

Enthalpies

C₂H₂ (g) = 226.9 kJ/mol

O₂ (g) = 0 kJ/mol

CO₂ (g) = - 393.5 kJ/mol

H₂O (l) = - 285.5 kJ/mol

Formula

ΔH r = ∑npHp - ∑nrHp

Process

ΔHr = 4 (-393.5) + 2 (-285.5) - 2 (226.9)

ΔHr = - 1574 - 571 - 453.8

ΔHr = - 2598.8 kJ/mol