Ideal gas law
The ideal gas law is the equation of state of a hypothetical ideal gas. It is a good approximation to the behavior of many gases under many conditions, although it has several limitations. It was first stated by Émile Clapeyron in 1834 as a combination of Boyle's law, Charles's law and Avogadro's Law. The ideal gas law is often written as:
where the letters denote pressure, volume, amount (in moles), ideal gas constant, and temperature of the gas, respectively.
It can also be derived microscopically from kinetic theory, as was achieved (apparently independently) by August Krönig in 1856 and Rudolf Clausius in 1857.
Equation
The state of an amount of gas is determined by its pressure, volume, and temperature. The modern form of the equation relates these simply in two main forms. The temperature used in the equation of state is an absolute temperature: in the SI system of units, Kelvin.
Common form
The most frequently introduced form is
where:
P is the pressure of the gas
V is the volume of the gas