# Avogadro's Law

(1) According to this law, “Equal volumes of any two gases at the same temperature and pressure contain the same number of molecules.”

Thus, V∝ n (at constant T and P)

or V = Kn (where K is constant)

(2) One mole of any gas contains the same number of molecules (Avogadro's number =6.02×10^{23}) and by this law must occupy the same volume at a given temperature and pressure. The volume of one mole of a gas is called **molar volume, V _{m}** which is 22.4 L mol

^{-1}at S.T.P. or N.T.P.

(3) This law can also express as, “The molar gas volume at a given temperature and pressure is a specific constant independent of the nature of the gas”.

Thus, V_{m} = specific constant = 22.4 Lmol^{-1} at S.T.P. or N.T.P.