What is "ideal gas law"

n. (context physics English) the equation of state of an ideal gas

The ideal gas law is the equation of state of a hypothetical ideal gas. It is a good approximation of 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 the empirical Boyle's law, Charles' law and Avogadro's Law. The ideal gas law is often written as:

(PV = nRT) 

where:

• P is the pressure of the gas,
• V is the volume of the gas,
• n is the amount of substance of gas (in moles),
• R is the ideal, or universal, gas constant, equal to the product of the Boltzmann constant and the Avogadro constant,
• T is the absolute temperature of the gas,

It can also be derived microscopically from kinetic theory, as was achieved (apparently independently) by August Krönig in 1856 and Rudolf Clausius in 1857.