A-LevelChemistryChemical energeticsMay/June 2025Paper 3 Q212 Marks
You will determine the enthalpy change for the reaction of aqueous citric acid with aqueous sodium hydroxide to form aqueous sodium citrate. The procedure involves two experiments using solid citric acid. FB 4 is citric acid, C6H8O7. Use this for Experiment 1. FB 5 is citric acid, C6H8O7. Use this for Experiment 2. FB 6 is 2.00 mol dm⁻³ sodium hydroxide, NaOH.
📋 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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