1. Student learn the properties of carbon dioxide.
2. Student make carbon dioxide.

Three oxides of carbon are known: carbon monoxide, CO; carbon dioxide, CO₂; and carbon suboxide C 0 . The first two are the common oxides form in the ordinary combustion of carbon or carbonaceous matter. The third is prepared in a special way and will not be discussed here.

Carbon monoxide is a colorless, odorless, tasteless gas. It is not a normal constituent of the atmosphere, but found in urban areas as a product of combustion of large quantities of fuels. Carbon monoxide has about 200 times more affinity for blood hemoglobin than does oxygen. In this respect it is a poison because it renders the blood incapable of carrying oxygen, and thereby can cause suffocation and death.

Carbon dioxide is a colorless, odorless gas with a very weak acid taste. It is normally present in the atmosphere. Carbon dioxide is about 1.5 times heavier than air. Carbon dioxide is a widely used fire extinguisher. It is formed during animal respiration, in fermentation of starches, sugars and is used by living plants in photosynthesis.

In this experiment students will collect carbon dioxide from a reaction of vinegar and baking soda and from bubbles in soda pop. To do this, students will make an apparatus similar to the one diagramed below.

plastic tubing
plastic clay
soda pop
washbasin of water
several small jars
small bowl of hot water
vinegar
baking soda
beakers
birthday cake candle in holder (see diagram)

The plastic tubing is used to transfer the gas from the soda pop and reaction of vinegar and baking soda to small jars. To make your system work, pinch off clay and stick one end of the tubing through it. Open the bottle of soda and mold the wad of clay into an airtight stopper by pushing it into the mount of the bottle. Put the other end of the tubing into the large basin of water. Submerge one of the small jars in the basin, completely filling it with water. Turn the jar upside down and rest it on the bottom of the basin until you've ready. There should be no air pocket in the jar.

Drive off the air by standing the soda bottle in the small bowl of hot water. This will help drive off more carbon dioxide. Hold the inverted, water-filled jar in the basin over the delivery tube, the bubble will drive out the water from the jar back int the basin. This method of collecting a gas is called displacement of water. When you have filled the jar with gas, hold the gas-filled jar upside down and under water, remove the delivery tube from the jar leaving the tube in the basin, and slide a plastic disk across the mouth of the jar. Hold the dish in place as you remove Hold the dish in place as you remove the inverted jar from the water. Turn the jar right side up when you have removed it from the basin. Set it aside with the lid on.

Have the students follow the lab sheet to discover properties of carbon dioxide.