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In this reaction we will investigate the reaction between ethanoic acid and calcium carbonate. All acids produce carbon dioxide gas when reacted with a metal carbonate.

Apparatus and chemicals

• Measuring cylinder (25 cm³)
• Boiling tube
• Test-tube
• Disposable pipette/dropper
• Test-tube rack
• Ethanoic acid 0.5 mol/dm³
• Calcium carbonate (3 g)
• Universal Indicator
• Limewater (5 cm³)

Method

1. Using a measuring cylinder, measuring 15 cm³ of ethanoic acid and place into the boiling tube
2. Add 5 drops of universal indicator to the acid
3. Using a clean measuring cylinder, measure 5 cm³ of limewater and place into a test-tube. Place the test-tube and boiling tube side by side in a test-tube rack.
4. Carefully add the calcium carbonate to the acid – record your observations, especially any colour changes to the indicator.
5. Using the disposable pipette/dropper, collect the gas produced by opening and closing the dropper above the reaction in the boiling tube.
6. Once the gas has been collected in the disposable pipette/dropper, bubble the gas through the limewater and record your observations.