A-LevelChemistryReaction kineticsMay/June 2021Paper 5 Q114 Marks
Hydrogen peroxide decomposes slowly at room temperature to give water and oxygen. 2H2O2(aq) → 2H2O(l) + O2(g) The initial rate of this reaction can be increased by the addition of a metal oxide catalyst. A student is asked to investigate which metal oxide catalyst is best at increasing the initial rate of this reaction by using a method which involves the collection of oxygen. The student is provided with the following metal oxides: copper(II) oxide, iron(III) oxide, manganese(IV) oxide, nickel(II) oxide and titanium(IV) oxide. The student is also provided with an excess volume, of a known concentration, of aqueous hydrogen peroxide and any laboratory equipment needed.
📋 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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