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A-LevelChemistryGroup 2Feb/Mar 2020Paper 1 Q171 Mark

A student investigates calcium nitrate crystals by heating them in the apparatus shown. A colourless gas leaves the apparatus at Y. A flame is held to this gas. Which observations would the student make? [Figure 17.1]

Alitmus solution: changes to blue, flame at Y: flame burns more brightly
Blitmus solution: changes to blue, flame at Y: flame goes out
Clitmus solution: changes to red, flame at Y: flame burns more brightly
Dlitmus solution: changes to red, flame at Y: flame goes out

✓ Correct Answer

The correct answer is C: litmus solution: changes to red, flame at Y: flame burns more brightly

📋 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 Group 2 in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Chemistry Feb/Mar 2020 examination, Paper 1 Variant 2.

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