In a material that contains a mixture of gases, the amount of pressure each gas exerts is called its pressure.

In a mixture of gases, the amount of pressure each gas exerts is called its partial pressure. This concept is essential in understanding how gases behave in a mixture, as described by Dalton's Law of Partial Pressures. According to this law, the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the individual gases present in the mixture.

Mathematically, if we have multiple gases (let's say gas A, gas B, and gas C) in a container, the total pressure (P_total) can be expressed as:

$P_{total} = P_A + P_B + P_C$

where $P_A$, $P_B$, and $P_C$ are the partial pressures of gases A, B, and C, respectively. Each gas in a mixture contributes to the total pressure proportional to the number of moles of the gas and its temperature, following the ideal gas law. This principle is fundamental in various applications, including respiratory physiology, industrial gas mixtures, and atmospheric science.