What is the term for the portion of the total pressure exerted by a specific gas in a mixture?

The term for the portion of the total pressure exerted by a specific gas in a mixture is known as partial pressure. This concept is fundamental in understanding gas laws and the behavior of gases in mixtures, particularly in diving situations where different gases are used, such as nitrox.

When a gas is part of a mixture, the total pressure is the sum of the partial pressures of each gas component present. For example, in a nitrox mixture, the partial pressure of oxygen is the pressure contributed by the oxygen alone within the overall pressure of the gas mixture. Understanding partial pressure is critical for divers to manage the risks associated with different gas mixes, as it helps determine how much of a gas is available for breathing and affects factors such as narcosis and oxygen toxicity.

Concentration refers to the amount of substance in a given volume but does not directly relate to pressure. Absolute pressure is the total pressure exerted by the atmosphere plus the pressure of any additional gases, whereas vapor pressure specifically relates to the pressure exerted by a vapor in equilibrium with its liquid phase. Therefore, partial pressure is the most accurate term to describe the contribution of a specific gas in a mixture under pressure.