Partial pressure

<p>In a mixture of <a href="/facts/Gas/hVVAoodV">gases</a>, each constituent gas has a partial pressure which is the notional <a href="/facts/Pressure/eyc37GRG">pressure</a> of that constituent gas as  if it alone occupied the entire <a href="/facts/Volume/aeAXCBUd">volume</a> of the original mixture at the same <a href="/facts/Temperature/QyGe4gmj">temperature</a>. The total pressure of an <a href="/facts/Ideal_gas/80EfYGFj">ideal gas</a> mixture is the sum of the partial pressures of the gases in the mixture (<a href="/facts/Dalton%27s_Law/kWQDom5X">Dalton's Law</a>).
</p><p>In <a href="/facts/Respiratory_physiology/KKWAJIbd">respiratory physiology</a>, the partial pressure of a dissolved gas in liquid (such as oxygen in arterial blood) is also defined as the partial pressure of that gas as it would be undissolved in gas phase yet in equilibrium with the liquid. This concept is also known as <a href="/facts/Blood_gas_tension/8SIHAoI6">blood gas tension</a>. In this sense, the diffusion of a gas liquid is said to be driven by differences in partial pressure (not concentration). In <a href="/facts/Chemistry/SrNqkGVm">chemistry</a> and <a href="/facts/Thermodynamics/q4hIx3yP">thermodynamics</a>, this concept is generalized to non-ideal gases and instead called <a href="/facts/Fugacity/C2gdkThT">fugacity</a>.
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Partial pressure open-in-new

Partial pressure