As the temperature increases, the average kinetic energy of molecules increases. What would be the effect of the increase of temperature on pressure provided the volume is constant?

Gay Lussac gave a general relation between pressure and temperature of the gas. He said that pressure of given mass is directly proportional to the temperature at constant volume.

Gay Lussac law state that at constant volume, temperature is directly proportional to the pressure of a fixed amount of gas.

P α T (at constant volume)

P = kT

K = constant

We can write:

= k

The line showing pressure-temperature behaviour at constant volume are called ISOCHORES.