A century after the work of Boyle, the French scientist Charles made measurements to show how the volume of a gas at constant pressure changes when the temperature of the gas is changed.
Furthermore, irrespective of the gas used, extrapolation of the V against T line predicted that the volume would be zero at -273.15°C.
This lowest temperature attainable (absolute zero) is 0 on the Kelvin temperature x scale. Kelvins have the same size as degrees in Celsius.
T/K = °C + 273.15
0 K = -273.15°C
Thus V/T is constant. Change of volume or temperature of a gas produces a corresponding change in the other. If either the new temperature in K or volume is known, the other can be calculated.
The particle view of Charles' observations
Increasing the temperature of the sample increases the kinetic energy (energy of motion) of particles in the sample.
The cartoon shows that faster moving particles result in a higher pressure on the walls of the container.
Pressure has also been shown experimentally to be directly proportional In temperature in Kelvin. Thus if the pressure is to remain constant when a gas sample is heated, the volume must increase.
He found that for every 1°C temperature change, the percentage change in volume is the same (1/273 of its volume at 0°C). The graph shows that volume is a linear function of the temperature in Celsius.
Furthermore, irrespective of the gas used, extrapolation of the V against T line predicted that the volume would be zero at -273.15°C.
graph
graph
This lowest temperature attainable (absolute zero) is 0 on the Kelvin temperature x scale. Kelvins have the same size as degrees in Celsius.
T/K = °C + 273.15
0 K = -273.15°C
Thus V/T is constant. Change of volume or temperature of a gas produces a corresponding change in the other. If either the new temperature in K or volume is known, the other can be calculated.
V = constant × T/K
Increasing the temperature of the sample increases the kinetic energy (energy of motion) of particles in the sample.
The cartoon shows that faster moving particles result in a higher pressure on the walls of the container.
Pressure has also been shown experimentally to be directly proportional In temperature in Kelvin. Thus if the pressure is to remain constant when a gas sample is heated, the volume must increase.