What is a correct definition of partial pressure?

The correct definition of partial pressure is the individual gas's contribution to total pressure. In a mixture of gases, each gas has a specific pressure it exerts, and this is referred to as its partial pressure. The total pressure of the mixture is the sum of the partial pressures of each gas present. This concept is critical in diving, especially when considering how different gases behave under pressure and how they affect oxygen and nitrogen uptake in the body.

This understanding is fundamental for divers, particularly when making calculations related to dive planning, the management of gas mixtures, and ensuring safe ascent rates to avoid conditions such as decompression sickness. Each gas's contribution reflects its mole fraction in the mixture and allows divers to predict how different scenarios will impact their physiological responses. Understanding partial pressure helps divers comprehend how gases dissolve in liquids, particularly in relation to the physiological effects of breathing gases under the pressures experienced underwater.