Avogadro's Hypothesis

Amedeo Avogadro proposed that equal volumes of any gas, measured under the same temperature and pressure, contain equal numbers of molecules -- regardless of the gas's chemical identity. Put another way, volume is directly proportional to the amount (number of moles) of gas present:

$V\propto n,\qquad \frac{V_1}{n_1}=\frac{V_2}{n_2}=\text{constant}\qquad(6.10)$ …