Materials:
- Two clear glass bottles with caps
- Cold tap water
- Carbon dioxide gas cylinder or a carbonated beverage (e.g., soda or sparkling water)
- Pressure gauge (optional)
Procedure:
1. Fill both glass bottles with an equal amount of cold tap water.
2. Seal one of the bottles tightly with its cap. This will serve as the control bottle.
3. Connect the carbon dioxide gas cylinder or use a carbonated beverage to introduce carbon dioxide gas into the other bottle. Add gas until the bottle is pressurized. If available, monitor the pressure inside the bottle using the pressure gauge.
4. Seal the bottle containing carbon dioxide gas tightly with its cap.
5. Set aside both bottles at room temperature for a few minutes to allow the gas to dissolve in the water.
Observations:
Open both bottles and observe the following:
1. In the control bottle, there should be little to no carbon dioxide gas present, as it is in equilibrium with the atmosphere.
2. In the bottle that was pressurized with carbon dioxide gas, you should observe the presence of bubbles or fizzing, indicating the dissolved carbon dioxide gas.
Explanation:
Henry's law states that the solubility of a gas in a liquid is directly proportional to the partial pressure of that gas above the liquid. In other words, as the pressure of carbon dioxide gas increases, so does its solubility in water.
When you pressurize the bottle with carbon dioxide gas, you increase the partial pressure of carbon dioxide above the water. This drives more carbon dioxide molecules into the water, leading to an increase in the solubility of carbon dioxide in the water.
By comparing the control bottle (without added pressure) to the pressurized bottle, you can clearly observe the effect of pressure on the solubility of carbon dioxide gas in water.
