A-LevelChemistryAtoms, molecules and stoichiometryOct/Nov 2021Paper 1 Q11 Mark

Compound X consists of 40.0% carbon, 6.7% hydrogen and 53.3% oxygen by mass. What is the empirical formula of compound X?

Q: What topic does this question test?

This question tests Atoms, molecules and stoichiometry in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

ACH2O

BC2H2O

CC2H4O

DCHO

✓ Correct Answer

The correct answer is A: CH2O

📋 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 Atoms, molecules and stoichiometry in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Chemistry Oct/Nov 2021 examination, Paper 1 Variant 2.

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