Basic Properties of Gases

1. Dalton's Law of Partial Pressures
1. partial pressure - the "part" of the total air pressure caused by one component of a gas
• Gas Percent Partial Pressure (P)
• ALL AIR 100.0% 760 mm Hg
• Nitrogen 78.6% 597 mm Hg (0.79 X 760)
• Oxygen 20.9% 159 mm Hg (0.21 X 760)
• Carbon Dioxide 0.04% 0.3 mm Hg (0.0004 X 760)
2. altitude - air pressure @ 10,000 ft = 563 mm Hg
3. scuba diving - air pressure @ 100 ft = 3000 mm Hg
2. Henry's Law of Gas Diffusion into Liquid
1. Henry's Law - a certain gas will diffuse INTO or OUT OF a liquid down its concentration gradient in proportion to its partial pressure
2. solubility - the ease with which a certain gas will "dissolve" into a liquid (like blood plasma)
• HIGHest solubility in plasma Carbon Dioxide
• Oxygen
• LOWest solubility in plasma Nitrogen
3. Hyperbaric (Above normal pressure) Conditions
1. Creates HIGH gradient for gas entry into the body
2. therapeutic - oxygen forced into blood during: carbon monoxide poisoning, circulatory shock, asphyxiation, gangrene, tetanus, etc.
3. harmful - SCUBA divers may suffer the "bends" when they rise too quickly and Nitrogen gas "comes out of solution" and forms bubbles in the blood

Category: Physiology Notes