# How does the partial pressure, exerted by a single component in a gaseous mixture, relate to the total pressure?

May 8, 2016

The partial pressure of a gas is the pressure exerted by a gas in a gaseous mixture if it alone occupied the container.

#### Explanation:

The total pressure is always the sum of the partial pressures.

The practical application of this is that the partial pressures in gaseous mixtures are always state functions of temperature.

i.e. ${P}_{T o t a l} = {P}_{1} + {P}_{2} + {P}_{3.} \ldots \text{etc}$, where ${P}_{i}$ are the individual partial pressures. Of course, given ideal gas behaviour:

${P}_{T o t a l} = \frac{{n}_{1} R T}{V} + \frac{{n}_{2} R T}{V} + \ldots . \text{etc}$,

${P}_{T o t a l} = \frac{R T}{V} \left\{{n}_{1} + {n}_{2} + \ldots + {n}_{n}\right\}$, which is Dalton's law of Partial Pressures.