91�ȱ�

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.