This activity demonstrates the fact that carbon dioxide can support combustion of some elements, such as magnesium.

You will need:

- Magnesium ribbon
- Dry ice
- Bunsen burner
- Tongs

Ignite the ribbon and lower it into the beaker full of carbon dioxide gas. The reaction proceeds rapidly despite the low temperature. Click to see a 400 Kb video.

Cabon and magnesium oxide are formed according to the equation below.

2Mg_(s) + CO_2(g) => C_(s) + 2MgO_(s)

The products of the reaction are shown on the right.

1) What observation can you make that supports the formation of carbon.

2) Where did the carbon come from.

3) Explain why water or a CO₂ fire extinquisher should not be used to put out fires involving magnesium.

4) Design a poster informing people of the hazard and how to treat a magnesium fire.

5) The Green House Effect is predominantly as a result of a build up of carbon dioxide in the atmosphere. Is this a feasible way of removing carbon dioxide from the air? Explain.

These questions are for senior chemistry or fo rthoise that really wish to challenge themselves.

1) Is the reaction below a redox reaction? If so identify the oxidant and reductant.

2Mg_(s) + CO_2(g) => C_(s) + 2MgO_(s)

a) What is the oxidation state of :
- Mg: 0 +2 -2 +4 -4
- C in CO₂ 0 +2 -2 +4 -4
- C 0 +2 -2 +4 -4
- Mg in MgO 0 +2 -2 +4 -4