A-LevelChemistryGroup 2Oct/Nov 2023Paper 1 Q221 Mark
The table gives some data for compounds of two elements from Group 2 of the Periodic Table. Element calcium has decomposition temperature of carbonate/°C 840, solubility of sulfate in mol/100 g of water 4.66 × 10⁻³, solubility of hydroxide in mol/100 g of water 1.53 × 10⁻³. Element Z has solubility of hydroxide in mol/100 g of water 2.00 × 10⁻⁵. What is the missing data for element Z (decomposition temperature of carbonate/°C and solubility of sulfate in mol/100 g of water)?
A350, 1.83 × 10⁻¹
B350, 7.11 × 10⁻⁵
C1100, 1.83 × 10⁻¹
D1100, 7.11 × 10⁻⁵
✓ Correct Answer
The correct answer is A: 350, 1.83 × 10⁻¹
📋 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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