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• What is the role of manganese dioxide in the decomposition of hydrogen peroxide?

  Catalyst
• What is the purpose of catalysts in chemical reactions?

  Provide an alternative reaction route
• How do catalysts affect the activation energy of a reaction?

  They lower the activation energy
• What are the word and chemical equations for the reaction involving manganese(IV) oxide and hydrogen peroxide?

  • Word equation: Hydrogen peroxide → water + oxygen
  • Chemical equation: 2H2O2 → 2H2O + O2 (MnO2 is a catalyst)
• What apparatus can be used to measure the volume of gas produced during a reaction?

  A gas syringe or water-filled measuring cylinder
• What does the term 'half-life' refer to in a reaction?

  The time taken for reactant concentration to half
• How can you find the half-life of the decomposition of hydrogen peroxide?

  1. Set up apparatus to collect gas
  2. Record volume of O2 at intervals
  3. Plot graph of [H2O2] against time
  4. Use graph to find half-life values
• What formula can be used to calculate [H2O2] from the volume of oxygen collected?

  [H2O2] = (40 - V(O2)) / 240
• Why is it important to quickly put the bung in the conical flask after mixing H2O2 and the catalyst?

  To prevent oxygen escape during reaction
• Why might the volume of gas be measured in a burette instead of a measuring cylinder?

  To obtain more precise measurements