Wiktionary
n. (context physics chemistry English) The pressure one component of a mixture of gases would contribute to the total pressure.
Wikipedia
In a mixture of gases, each gas has a partial pressure which is the hypothetical pressure of that gas if it alone occupied the volume of the mixture at the same temperature. The total pressure of an ideal gas mixture is the sum of the partial pressures of each individual gas in the mixture.
It relies on the following isotherm relation:
$$\frac{V_x}{V_{tot}} = \frac{p_x}{p_{tot}} = \frac{n_x}{n_{tot}}$$
:* V is the partial volume of any individual gas component (X)
:* V is the total volume of the gas mixture
:* p is the partial pressure of gas X
:* p is the total pressure of the gas mixture
:* n is the amount of substance of gas (X)
:* n is the total amount of substance in gas mixture
The partial pressure of a gas is a measure of thermodynamic activity of the gas's molecules. Gases dissolve, diffuse, and react according to their partial pressures, and not according to their concentrations in gas mixtures or liquids.
This general property of gases is also true in chemical reactions of gases in biology. For example, the necessary amount of oxygen for human respiration, and the amount that is toxic, is set by the partial pressure of oxygen alone. This is true across a very wide range of different concentrations of oxygen present in various inhaled breathing gases or dissolved in blood.
Usage examples of "partial pressure".
The higher partial pressure of oxygen on Sparta made it even more deadly than prairie fires on earth.
An assault of strange odors kept me busy stifling sneezes, and the carbon dioxide partial pressure triggered recurrent yawns.
It was the partial pressure of oxygen that counted, and so with the percentage of oxygen in the atmosphere so high.
No, this was to get the partial pressure of oxygen up, so that people and animals could breathe it.
First I took her down some, because 60,000 feet is thin and chilly-too little partial pressure of oxygen for the human lung.
He identified a tinge of ozone in the swamp reeks and thought that an increased partial pressure of oxygen might prove valuable.
The glaciers carry veins of dry ice heatward, so there are sudden jumps in the partial pressure of carbon dioxide.