Like most of the substances you meet in your everyday life Cola is not a pure substance, but a mixture of water, sugar, carbon dioxide or carbonic acid, caffeine and dyes. In the following experiment you will separate the carbon dioxide from the cola. At the same time you measure the carbon dioxide content of the drink. In the second part you will gain water from Cola pure water.
1. Pierce the stopper of a wide ampoule at the bottom with yellow pipette tip. 2. Fill a shallow container with water and put into it a 20-mL measuring cylinder so that it fills completely with water. Stand it upright with the opening downwards. The opening of the cylinder must remain below the water surface. (More see below)
3. Put 3 mL cold Coke from a freshly opened can into the wide ampoule.
4. Cap the ampoule immediately with the stopper. Attach one end of the tubing to the pipette tip. Insert the other end into the measuring cylinder from below.
5. Heat the cola until no further evolution of gas is observed in the wide ampoule.
6. Take the graduated cylinder out of the water, add lime water and shake.
7. Withdraw the tube end from the vessel with the water before you stop heating the coke.
8. Immerse this tube end now in a tall ampoule and heat the coke again with the candle. To prevent the boiling coke entering the tube during boiling,
you have to move the ampoule back and forth gently.
First published: 2008 Last modification: 12.06.2014