Countertop Chemistry Experiment 9
Production of Carbon Dioxide

Some common chemicals will produce carbon dioxide. Some of the properties of carbon dioxide are easily observed.

Materials	Substitutions
sodium hydrogencarbonate (3 g)	baking soda
acetic acid 0.80 M	vinegar
125 mL Erlenmeyer flask	small jar
beral pipet	dropper
wood splints	toothpicks
matches and a candle

Procedure

1. Measure approximately 3 grams (1/2 teaspoon) of baking soda and place it in the flask.
2. Using the pipet, add a few drops of vinegar to the sodium hydrogencarbonate. Gas bubbles will form.
3. Light a wooden splint or toothpick with the candle.
4. Carefully tip the flask, insert the burning splint into the neck of the flask, and observe the effect the gas (carbon dioxide) has on the flame.
5. Using the candle, re-light the splint and test the gas again.

Questions

1. Write the equation for the reaction occurring in the above experiment.
2. Describe the effect of carbon dioxide on the burning splint.
3. What property of carbon dioxide allowed us not to use a stopper or lid?
4. Since carbon dioxide is often used in fire extinguishers, describe how you could use this experiment to create your own extinguisher.
5. Other chemicals can react to produce carbon dioxide. Compare this reaction with the one used in experiment # 5 of this book.

Teacher's Notes

1. The equation for this reaction is
   NaHCO₃ (s) + HC₂H₃O₂ (aq) --> NaC₂H₃O₂ (aq) + CO₂ (g) + H₂O(l)
2. Carbon dioxide does not support combustion. Oxygen is the substance that is necessary for any burning to take place. The splint should be extinguished.
3. The density of carbon dioxide is 1.56 g/mL while that of air is 1.0 g/mL. Since the carbon dioxide is denser than air, it will remain below the air in the container.
4. For the extinguisher, use a plastic drink bottle. Drill a small hole into the screw top and insert a drinking straw. Place a small amount of baking soda in the bottom of a plastic drink bottle. Add a small amount of vinegar to the container. To initiate the extinguisher, tip the bottle to start the reaction, and the carbon dioxide will form.

Safety Precautions

1. Proper ventilation is required due to the odors of vinegar.
2. The reaction containers should be wrapped with tape. Pressure will increase if the containers are sealed.

Disposal

The solutions can be poured into the sink and followed with water. Unreacted sodium hydrogen carbonate may be dissolved in water and poured down the sink. Solid residues may be placed in the trash can.

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