O-LevelChemistryRates of Reaction5070/12 · May/June 2022 · Q191 Mark

What is the correct balanced equation and enthalpy change, ∆H, for the complete combustion of butanol, C₄H₉OH?

AC₄H₉OH(l) + 5O₂(g) → 4CO₂(g) + 5H₂O(g) ∆H = –2676 kJ/mol

BC₄H₉OH(l) + 5O₂(g) → 4CO₂(g) + 5H₂O(g) ∆H = +2676 kJ/mol

CC₄H₉OH(l) + 6O₂(g) → 4CO₂(g) + 5H₂O(g) ∆H = –2676 kJ/mol

DC₄H₉OH(l) + 6O₂(g) → 4CO₂(g) + 5H₂O(g) ∆H = +2676 kJ/mol

✓ Correct answer

C: C₄H₉OH(l) + 6O₂(g) → 4CO₂(g) + 5H₂O(g) ∆H = –2676 kJ/mol

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Topic: Rates of Reaction, O-Level Chemistry (syllabus 5070). Multiple choice, 1 mark.
Source: O-Level Chemistry, May/June 2022 Paper 1 Variant 2, question 19.

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