|
|
Department of Chemistry and Biochemistry | |
| DEMONSTRATIONS |
Faculty & Research |
| |
Academic Programs |
| |
Industrial Relations |
| |
Research Facilities |
| |
Department Administration |
Charles' Law
Procedure
One balloon is inflated with helium, another with air. The helium balloon is attached to a weight so it doesn't float away. Both balloons inserted into containers filled with liquid nitrogen. The helium balloon will shrink to a fraction of its original size, the oxygen balloon will shrink to a smaller size.
Discussion
Charles' Law predicts a fourfold decrease in the volume of a gas as it is chilled from room temperature, 20 degrees Celsius, to liquid nitrogen temperature, -196 degrees Celsius. If the gas in the balloon condenses, as oxygen gas does at -183 C, the volume change is much greater. The density of liquid oxygen at -183 C is 1.149g/ml, and that of the gas at 0 C is 1.429g/liter. Therefore, the volume of the balloon can shrink by a factor of more than 700.
