A-LevelChemistryReaction kinetics9701/12 · Oct/Nov 2023 · Q161 Mark
The decomposition of hydrogen peroxide in the presence of MnO2 produces water and oxygen gas. 2H2O2(aq) → 2H2O(l) + O2(g) The volume of gas collected when 0.2g of MnO2 is added to two different hydrogen peroxide solutions at 20 °C is shown on the graph as curves X and Y. [Figure of graph with volume of gas vs time showing curves X and Y] Which row shows the conditions that will result in curves X and Y?
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Acurve X: volume of H2O2/cm³ 50, concentration of H2O2/mol dm⁻³ 0.1, form of MnO2 lumps; curve Y: volume of H2O2/cm³ 50, concentration of H2O2/mol dm⁻³ 0.2, form of MnO2 powder
Bcurve X: volume of H2O2/cm³ 25, concentration of H2O2/mol dm⁻³ 0.2, form of MnO2 powder; curve Y: volume of H2O2/cm³ 25, concentration of H2O2/mol dm⁻³ 0.1, form of MnO2 lumps
Ccurve X: volume of H2O2/cm³ 50, concentration of H2O2/mol dm⁻³ 0.1, form of MnO2 lumps; curve Y: volume of H2O2/cm³ 20, concentration of H2O2/mol dm⁻³ 0.2, form of MnO2 powder
Dcurve X: volume of H2O2/cm³ 20, concentration of H2O2/mol dm⁻³ 0.2, form of MnO2 powder; curve Y: volume of H2O2/cm³ 40, concentration of H2O2/mol dm⁻³ 0.1, form of MnO2 lumps
✓ Correct answer
C: curve X: volume of H2O2/cm³ 50, concentration of H2O2/mol dm⁻³ 0.1, form of MnO2 lumps; curve Y: volume of H2O2/cm³ 20, concentration of H2O2/mol dm⁻³ 0.2, form of MnO2 powder
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