Apparatus and chemicals
- Conical flask with side arm, thistle funnel, delivery tube
- 3 gas jars with lids (or test tubes with stoppers)
- Basin/trough of water
- Test-tube rack
- Calcium carbonate small pieces 3 g
- 50 cm3 of hydrochloric acid 1 mol/dm3
- Wooden Splint
- Limewater 5 cm3
- Universal indicator solution
- Carefully place the calcium carbonate into the conical flask.
- Collect 50 cm3 of hydrochloric acid in a small beaker.
- Connect the delivery tube and thistle funnel to the conical flask with the delivery tube in a basin of water.
- Have three gas jars/test tubes filled with water also inverted in the basin of water.
- Carefully pour the hydrochloric acid into the thistle funnel, wait 5 s then carefully place the first water filled gas jar/test tube over the end of the delivery tube. Allow the gas jar/test tube to fill with gas (when all of the water has been displaced).
- Leave the gas jar/test tube inverted in the water to retain the gas.
- Repeat step 5 until three gas jars/test tubes of gas have been collected.
- Remove each gas jars/test tube from the water as required for the following tests.
Testing the gas
- To the first gas jar/test tube insert a lit splint – record your observations.
- To the second gas jar/test tube add 1 cm3 of limewater, stopper and shake – record your observations.
- To the third gas jar/test tube add 5 drops of universal indicator, stopper and shake – record your observations. Add a little deionised water if no change observed and shake again.