Calculate the standard enthalpy of formation of acetylene (C₂H₂) from its elements: 2C (graphite ) + H₂(g) ⟶ C₂H₂(g) The equations for each step and the corresponding enthalpy changes are
(a) C (graphite) + O₂(g) ⟶ CO₂(g) ΔHᵣₙ∘=−393.5 kJ/mol
(b) H₂(g) + 21O₂(g) ⟶ H₂O(l) ΔHₓₙ∘=−285.8 kJ/mol
(c) 2C₂H₂(g) + 5O₂(g) ⟶ 4CO₂(g) + 2H₂O(I) ΔHᵣₙ∘=−2598.8 kJ/mol
