Empirical formula through reduction

• What is reduction

  Loss of oxygen from a substance
• What can you reduce to find its empirical formula?

  A metal oxide
• What are the steps to reduce copper(II) oxide?

  1. Place a rubber bung in a test tube.
  2. Weigh the bung using a mass balance.
  3. Remove the bung and spread copper(II) oxide in the tube.
  4. Re-insert the bung and weigh the test tube again.
  5. Expel air by gently turning on the gas burner.
  6. Light the gas and control the flame size.
  7. Use a Bunsen burner to heat copper(III) oxide for about 10 minutes.
  8. Turn off the burner and allow to cool.
  9. Weigh the test tube with the bung and contents.
  10. Calculate the empirical formula using the data.
• How long should you heat the copper(II) oxide?

  About 10 minutes
• What color change indicates a solid change during the experiment?

  From black to brownish-pink
• How can you control the size of the flame during the experiment?

  By changing the amount of gas flowing
• What should you do after the tube has cooled?

  Weigh the test tube with the bung
• What should you do with the data after finishing the experiment?

  Work out the empirical formula
• What equipment is needed for the copper(II) oxide reduction experiment?

  • Test tube
  • Rubber bung
  • Mass balance
  • Bunsen burner
  • Copper(II) oxide
  • Gas supply
• What is the initial color of copper(II) oxide?

  Black
• Why is it important to expel air from the test tube?

  To ensure proper reduction occurs
• What happens to the copper(II) oxide during the heating process?

  It loses oxygen and changes color
• What should you do if the flame is too large during the experiment?

  Reduce the gas flow
• What color should the copper(II) oxide turn after reduction?

  Brownish-pink
• What is the purpose of using a mass balance in the experiment?

  To measure the mass of the substances
• How does the empirical formula relate to the experiment?

  It represents the ratio of elements in copper oxide
• What should you do if you notice no color change during the experiment?

  Check the gas supply and heat settings
• What is the final step after completing the experiment?

  Record all data for analysis
• What are the safety precautions to take during the experiment?

  • Wear safety goggles
  • Use gloves when handling chemicals
  • Ensure proper ventilation
  • Keep flammable materials away from the flame