Enthalpy and Hess's law question

Question

Determine the enthalpy of reaction for 2CH₄(g) → C₂H₄(g) + 2H₂(g) using the equations:

2C₂H₆(g) + 7O₂(g) → 4CO₂(g) + 6H₂O(l) ∆H° = −3120.8 kJ/mol

CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l) ∆H° = −890.3 kJ/mol

C₂H₄(g) + H₂(g) → C₂H₆(g) ∆H° = −136.3 kJ/mol

H₂(g) + ½O₂(g) → H₂O(l) ∆H° = −285.8 kJ/mol

Answer 1