A-LevelChemistryChemical energeticsOct/Nov 2024Paper 1 Q91 Mark

For which reaction is the enthalpy change an enthalpy change of formation?

Q: What is the correct answer to this A-Level Chemistry question?

The correct answer is B: ½ N2(g) + ½ O2(g) → NO(g).

Q: What topic does this question test?

This question tests Chemical energetics in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

AC(g) + 2H2(g) → CH4(g)

B½ N2(g) + ½ O2(g) → NO(g)

CNa2O(s) + SO3(g) → Na2SO4(s)

DPCl3(g) + Cl2(g) → PCl5(g)

✓ Correct Answer

The correct answer is B: ½ N2(g) + ½ O2(g) → NO(g)

📋 Examiner Report & Trap Analysis

Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...

🎯 Mark Scheme Breakdown

Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.

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About This A-Level Chemistry Question

Topic

This multiple-choice question tests Chemical energetics in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Chemistry Oct/Nov 2024 examination, Paper 1 Variant 2.

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