Avogadro's Law

Avogadro’s Law states that, “Equal volume of all gases at same the pressure and temperature contain the same number of molecules_.”

Mathematically Avogadro’s Law can be written as follows;

V a n

or

\[ \frac{V}{n} = K \]

Where V is the volume of the gas and n is the number of moles of the gas and K is a Constant.

According to Ideal Gas Law,

PV = nRT

\[ V = \frac {nRT}{P} \]

\[ \frac {V}{n} = \frac {RT}{P} \]

\( \frac{RT}{P} \) is the constant where R is the universal gas constant, T is the temperature on Kelvin Scale and P is pressure.

Avogadro’s Law can also be expressed as follows;

\[ \frac{V_1}{n_1} = \frac {V_2}{n_2} \]

The above expression is very useful for comparing the same substance under two different sets of conditions.