PlanetPhysics/Ideal Gas Law

The equation that characterizes any amount of a gas is

where is the pressure, the volume, the number of the gas moles and the absolute temperature of the gas; the universal gas constant (approximately 8.314472 ).

The gas law is accurately valid for an ideal gas, but a good approximation for real gases.

The law contains the following gas laws:

  • Boyle--Mariotte law (\, constant when and are constants)
  • Gay--Lussac law (\, constant when and are constants)
  • Avogadro's law (in equal conditions, equal volumes of different gases contain the same number of molecules)

Alternative definition edit

The ideal gas law can also be defined using Boltzmann's constant:


The symbols are those defined above, with the difference that   is the number of gas molecules, and   is the Boltzmann constant,  . This form is often preferred by physicists who consider the number of molecules to be more fundamental than the number of moles.