Question

How Charles law lead to the concept of absolute zero

Answer 1

Charles law states that at constant pressure, a given quantity of gas will have a volume proportional to the absolute temperature.

Answer 2

According to Charles' Law, At constant pressure, the volume of a definite mass of any gas increases with an increase in temperature (in Celsius scale) but not in equal proportion.

• When the Volume (V) of a definite mass of gas is plotted against temperature at different sets of pressure, different straight lines will be obtained for each set of pressure.

• Among these straight lines, no one will exceed the origin.

• If the straight lines are extrapolated backwards, then all these lines meet the temperature axis at -273°C.

• Therefore, at constant pressure and -273°C temperature, the volume of all gases becomes zero. Below this temperature, the volume of the gas becomes negative, which is absurd. Thus -273°C is the lowest possible temperature and this temperature is called absolute zero.