A-LevelChemistryEquilibriaFeb/Mar 2017Paper 1 Q31 Mark

Two moles of compound P were placed in a sealed container. The container was heated and P was partially decomposed to produce Q and R only. A dynamic equilibrium between P, Q and R was established. At equilibrium x moles of R were present and the total number of moles present was (2+x/2). What is the equation for this reversible reaction?

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

The correct answer is D: 2P ⇌ Q + 2R.

Q: What topic does this question test?

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

AP ⇌ 2Q + R

B2P ⇌ 2Q + R

C2P ⇌ Q + R

D2P ⇌ Q + 2R

✓ Correct Answer

The correct answer is D: 2P ⇌ Q + 2R

📋 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 Equilibria in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Chemistry Feb/Mar 2017 examination, Paper 1 Variant 2.

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