A-LevelChemistryGroup 2Feb/Mar 2024Paper 1 Q221 Mark
The diagram shows the process of adding calcium nitrate and strontium nitrate to separate boiling tubes and heating them. Identical conditions are used. [Figure showing two boiling tubes being heated, one with Ca(NO3)2 and universal indicator, the other with Sr(NO3)2 and universal indicator] As the reactions proceed, the water containing universal indicator changes colour. Which row describes the colour change and identifies the nitrate that causes the quickest colour change?
Acolour change of universal indicator: green to blue, nitrate that causes the quickest colour change: Ca(NO₃)₂
Bcolour change of universal indicator: green to blue, nitrate that causes the quickest colour change: Sr(NO₃)₂
Ccolour change of universal indicator: green to red, nitrate that causes the quickest colour change: Ca(NO₃)₂
Dcolour change of universal indicator: green to red, nitrate that causes the quickest colour change: Sr(NO₃)₂
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The correct answer is C. This question tests the candidate's understanding of group 2 within the Chemistrysyllabus. The examiner's mark scheme requires...
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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...
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