Electrolysis

• What is the aim of the experiment described?

  Investigate electrolysis of copper sulfate solution

  
• What equipment is needed for the electrolysis experiment?

  • Graphite electrodes
  • Copper electrodes
  • Crocodile clips and wires
  • Power pack
  • 250 cm³ beaker
  • 2 test tubes
  • Wooden splint and matches
  • Digital balance
  • Ammeter
  • Variable resistor

  
• What chemicals are required for the experiment?

  • Copper sulfate solution
  • Propanone
  • Distilled water
• What is the first step in using inert electrodes for electrolysis?

  Pour copper sulfate solution into a beaker

  
• How are the inert electrodes connected to the power supply?

  Using crocodile clips and wires
• What should you do after turning on the power in the inert electrodes experiment?

  Record any observations
• What happens to the mass of the positive electrode during electrolysis with copper electrodes?

  It decreases as copper ions are lost
• Why must the electrodes not touch during electrolysis?

  Current will bypass the solution if they touch
• What is the purpose of using a glowing splint in the experiment?

  To test any gas collected in test tubes
• What is the first step when using copper electrodes in the experiment?

  Measure the mass of a copper electrode
• What are the observations for the inert electrodes during electrolysis?

  • Brown/pink solid forms at the negative electrode
  • Bubbles of colourless gas form at the positive electrode
  • Gas relights a glowing splint
• What is produced at the positive electrode when using inert electrodes?

  Oxygen gas is produced
• What is the relationship between mass gained and current in the copper electrodes experiment?

  Mass gained is directly proportional to current
• What happens to the mass of the negative electrode during electrolysis with copper electrodes?

  • Copper is deposited on the negative electrode
  • Mass increases as copper atoms are formed
• What safety precautions should be taken during the experiment?

  • Wear gloves and safety goggles
  • Keep propanone away from flames
  • Clean up spills immediately
• What should be done if copper sulfate comes into contact with skin?

  Wash skin immediately
• Why is propanone considered hazardous during the experiment?

  It is flammable and requires ventilation
• What is the significance of washing electrodes after the experiment?

  To remove any residual chemicals before weighing
• What are the key points regarding the reactions during electrolysis with copper electrodes?

  • Copper electrodes participate in reactions
  • Mass decreases at the positive electrode
  • Mass increases at the negative electrode