A-LevelChemistryChemical energeticsOct/Nov 2022Paper 3 Q210 Marks
Hydrated copper(II) sulfate, CuSO4•5H2O, can lose its water of crystallisation to form anhydrous copper(II) sulfate. The enthalpy change for the dehydration of hydrated copper(II) sulfate is shown in the equation. CuSO4.5H2O(s) → CuSO4(s) + 5H2O(l) You will carry out experiments to determine the enthalpy changes for the solution of hydrated and anhydrous copper(II) sulfate and then use Hess's law to determine the enthalpy change of dehydration. FA 4 is hydrated copper(II) sulfate, CuSO4•5H2O. FA 5 is anhydrous copper(II) sulfate, CuSO4.
📋 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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