electrolysis of aqueous solutions

• What is the first step in an investigation?

  Develop a hypothesis
• What is a hypothesis?

  An idea to be tested with scientific knowledge
• What is produced at the positive electrode during electrolysis?

  A non-metal
• Why do unreactive metals produce metal at the negative electrode?

  They have a greater tendency to gain electrons
• What prediction can be made about copper chloride electrolysis?

  Chlorine will be produced at the positive electrode
• What points should a plan for the investigation address?

  • Apparatus to use and setup diagram
  • Solutions to test
  • Testing and identifying products
  • Hazards, risks, and precautions
• What is the connection setup for the electrodes in an electrolysis cell?

  Positive electrode to positive terminal
• How many solutions should be tested in the investigation?

  At least five solutions
• What are some suitable test solutions for electrolysis?

  Copper sulfate, sodium chloride, sodium nitrate
• How can gases produced during electrolysis be collected?

  In stoppered test tubes
• What test indicates the presence of hydrogen gas?

  Lighted splint goes out with a pop
• What test indicates the presence of oxygen gas?

  A glowing splint relights
• What test indicates the presence of chlorine gas?

  Damp blue litmus paper turns red and bleaches
• Why is it important to examine electrodes during electrolysis?

  To see if a metal has been deposited
• What harm can copper sulfate solution cause?

  Skin and serious eye irritation
• What precaution should be taken when handling copper sulfate solution?

  Wear gloves and eye protection
• What is a risk associated with a dc electricity supply?

  Electric shock
• What precaution should be taken to prevent electric shock?

  Ensure electrodes do not touch
• What should be included in the results table for observations?

  • Electrolyte
  • Observations at positive electrode
  • Observations at negative electrode
• Why is it important to analyze the results of the investigation?

  To identify patterns and support the hypothesis
• What points should be addressed in the evaluation of the practical?

  • Do results agree with predictions?
  • Actions taken for accurate results
  • Possible improvements to the method