A-LevelChemistryEquilibriaOct/Nov 2025Paper 1 Q121 Mark
An equilibrium can be represented by the equation shown. P(aq) + Q(aq) ⇌ 2R(aq) + S(aq) In a certain mixture, of volume 1.0 dm³, the equilibrium concentration of Q is 10 mol dm⁻³. What will be the new equilibrium concentration of Q if 5.0 mol of pure Q is completely dissolved in the mixture?
A15 mol dm⁻³
Bbetween 10 mol dm⁻³ and 15 mol dm⁻³
C10 mol dm⁻³
Dbetween 5.0 mol dm⁻³ and 10 mol dm⁻³
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The correct answer is B. This question tests the candidate's understanding of equilibria 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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