A-LevelChemistryChemical energeticsOct/Nov 2019Paper 3 Q216 Marks
In this experiment you will determine the enthalpy change, ΔH, for the reaction shown. MgO(s) + CO2(g) → MgCO3(s) To do this, you will determine the enthalpy changes for the reactions of magnesium oxide and magnesium carbonate with hydrochloric acid. Excess hydrochloric acid will be used in each reaction. You will then use Hess' Law to calculate the enthalpy change for the reaction. FA 2 is hydrochloric acid, HCl. FA 4 is magnesium oxide, MgO. FA 5 is magnesium carbonate, MgCO3.
📋 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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