Equation of state of perfect gases

Equation of state

As for any gas, the state of balance Thermodynamique of a Perfect gas is fixed for N mole S of molecules, by two macroscopic parameters, with the choice. The other parameters can be calculated starting from the two parameters chosen by a formula called “equation of state”.

The equation most usually used is the equation of perfect gases , which is a thermoelastic equation

$pV = nRT = Nk_BT~$

where

p is the Pression (in Pascal);
V is the Volume occupied by gas (in Cubic meter);
N is the Quantité of matter, in mole
NR is the number of particle
R is the constant perfect gases
R = 8,314 472 J·K^-1·mol^-1
on has in fact R = N_A · k_B where N_A is the Nombre of Avogadro (6,022) and k_B is the Boltzmann constant (1,38);
T is the absolute Température (in Kelvin).

This equation derives in fact from other laws found before: the Law of Charles, the Law of Boyle-Mariotte and the Law of Gay-Lussac.

Numerical application:

for a pressure of an atmosphere ( p = p ₀ = 1,013 25 Pa)
and a temperature of 0°C ( T = T ₀ = 273,15 K, temperature of the melting ice under p ₀),

molar volume is thus

V ₀ = 22,413 996 (39) L/mol

one retains the approximate value 22,4 in general L/mol.

Internal bonds

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