Practice question

MCQ

Question

Calculate Δ H for C₂H₂(g) + 2H₂(g) → C₂H₆(g) using: Δ Hf° (C₂H₂,g) = 226.7 kJ/mol, Δ Hf° (C₂H₆,g) = -84.7 kJ/mol.

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311.4 kJ/mol 142 kJ/mol -311.4 kJ/mol Correct -226.7 kJ/mol

Δ H = Δ Hf° (C₂H₆) - [Δ Hf° (C₂H₂) + 2 × Δ Hf° (H₂)] = -84.7 - [226.7 + 0] = -84.7 - 226.7 = -311.4 kJ/mol.

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