According to Dalton's law, how is the partial pressure of O2 determined?

Dalton's law states that in a mixture of gases, the total pressure exerted is equal to the sum of the partial pressures of the individual gases present. To determine the partial pressure of oxygen (O2), you take the specific gas fraction of oxygen in the mixture—this is the ratio of the number of moles of oxygen to the total number of moles of gas—and multiply it by the total pressure of the gas mixture.

This process reflects how much of the total pressure is contributed by the oxygen alone, accounting for its presence relative to other gases. The concept is crucial for understanding how gases behave under various conditions, especially in diving operations where gas mixtures are common. By applying this principle, divers can assess the partial pressures of gases they are breathing and make informed decisions about safe diving practices.