5. Partial pressure of a gas is the pressure it exerts in a mixture of gases and is equal to the total pressure of the mixture divided by the percentage that gas in the mixture. The partial pressure of a gas is directly proportional to its concentration in the mixture.
6. The partial pressure of oxygen is expressed as Paz, while that of carbon dioxide.
7. Gas diffuses across a membrane from a region with higher partial pressure to the region with lower partial pressure.