In a Puff of Smoke:
Something's Burning: Combustion

General Safety Guidelines

What happens when something burns? When someone smokes a cigarette, cigar, or pipe, the tobacco burns. Experts have identified about 4000 substances that are produced in tobacco smoke. What is combustion (the process we commonly call burning) and what are the simple products of tobacco combustion? In this experiment you will look at a simple case of combustion, and in an optional part of the activity you can examine the products of a tobacco combustion.

Procedure

1. Obtain a candle from your teacher. Handle it carefully. Your teacher attached the candle to a can lid for stability.

2. Obtain a 400-ml beaker. You can also use a clean jar as long as it will fit over the candle with room to spare.

3. Light the candle and invert the beaker over the candle.

4. Observe the inside of the beaker as the candle burns.

5. Remove the beaker and immediately wipe a strip of cobalt chloride paper along the inside of it. Observe the paper.

6. Rinse the beaker and wipe it dry.

7. Relight the candle and carefully lower the candle into the beaker.

8. Place a sheet of aluminum foil over the beaker so the candle can burn undisturbed.

9. When the candle goes out, slowly and carefully remove the aluminum foil and the candle from the jar, trying not to disturb the contents of the beaker.

10. Obtain 25 ml of lime water solution. Describe it briefly.

11. Pour the lime water solution down the side of the beaker and swirl the beaker.

12. Observe the lime water.