7. Dalton's law

In experiments, it's more often not using a pure gas like oxygen, hydrogen, etc., but a mixture of gases. Atmospheric air, in particular, is a mixture of nitrogen, oxygen and many other gases. Each of the gases in the mixture makes its own "contribution" to the total pressure on the walls of the container. The pressure, that each of the gases in the mixture would have if the remaining gases were removed from the container, were called partial (i.e. private) pressure.

The simplest assumption that can be made is that the pressure of the gas mixture \(p\) equals the sum of the partial pressures of all gases \(~ p_1, p_2, p_3, \dots \)

\( p \,= \,p_1 \,+ \,p_2 \,+ \,p_3 \dots \) (1-3)

English chemist Dalton experimentally found that for fairly rarefied gases, it is true. The law (1-3) is called the Dalton law.