Making oxygen gas

Preparing oxygen gas.

Apparatus and chemicals

  • Conical flask with side arm, thistle funnel, delivery tube
  • 2 gas jars/test tubes and 2 stoppers
  • Basin/trough of water
  • Test tube rack
  • Basin/trough half-filled with water, bee hive shelf (optional, but helps to stabilise test tubes)
  • Manganese dioxide/manganese(IV) oxide (3 g)
  • Hydrogen peroxide solution (20 vol)
  • Wooden Splint

Method

  1. Carefully place the manganese(IV) oxide into the conical flask.
  2. Collect 50 cm3 of hydrogen peroxide solution in a small beaker.
  3. Connect the delivery tube and thistle funnel to the conical flask with the delivery tube in a basin of water.
  4. Have three test tube filled with water also inverted in the basin of water.
  5. Carefully pour the hydrogen peroxide solution into the thistle funnel, wait 5 s then carefully place the first water filled test-tube over the end of the delivery tube. Allow the test-tube to fill with gas (when all of the water has been displaced).
  6. Leave the test-tube inverted in the water to retain the gas.
  7. Repeat step 5 until two test tubes of gas have been collected.
  8. Remove each test tube from the water as required for the following tests.

Testing the gas

To the first test-tube insert a glowing splint – record your observations. Repeat with the second test-tube of gas.