Gay-Lussac's Law (Amonton's Law)

(1) In 1802, French chemist Joseph Gay-Lussac studied the variation of pressure with temperature and extende the Charle’s law so, this law is also called Charle’s-Gay Lussac’s law.

(2) It states that, “The pressure of a given mass of a gas is directly proportional to the absolute temperature (= °C+273) at constant volume.”

Thus, P ∞ T at constant volume and mass

or P = KT=K(t(°C)+272.15)   (where K is constant)

Thus, for every 1° change in temperature, the pressure of a gas changes by 1/273.15(=1/273) of the pressure at 0°C.

(4) This law fails at low temperatures, because the volume of the gas molecules be come significant.

(5) Graphical representation of Gay-Lussac's law : A graph between P and T at constant V is called isochore.