A-LevelChemistryReaction kineticsFeb/Mar 2016Paper 1 Q341 Mark
A chemist puts a sample of dilute aqueous hydrochloric acid into beaker 1. She adds a sample of zinc and measures the rate of production of hydrogen gas. She then puts a different sample of dilute aqueous hydrochloric acid into beaker 2. She adds a different sample of zinc and measures the rate of production of hydrogen gas. The rate of the reaction in beaker 2 is greater than the rate of the reaction in beaker 1. Which factors could help to explain this observation? 1 The reaction in beaker 1 has a higher activation energy than the reaction in beaker 2. 2 The zinc in beaker 1 is in larger pieces than the zinc in beaker 2. 3 The acid in beaker 1 is at a lower concentration than the acid in beaker 2.
A1, 2 and 3 are correct
B1 and 2 only are correct
C2 and 3 only are correct
D1 only is correct
✓ Correct Answer
The correct answer is C: 2 and 3 only are correct
📋 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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