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Thermal Physics Distribution of Molecular Speeds Maxwell and Boltzmann used the kinetic
theory to predict the distribution of speeds of molecules to
be expected at a given temperature. They suggested that the
number of molecules, N, which have speeds in a narrow range
(from v to v +
As the temperature of the gas increases, both the range of speeds and the mean (average) speed increases. Therefore, for the same quantity of gas at a higher temperature the distribution is as shown by the red curve on the diagram below.
These predictions have been verified by experiment, thus giving support to the kinetic theory. Some approximate average speeds (actually "root mean square" speeds) for molecules of different gases at different temperatures are given in the table below. The speeds are in ms-1.
You should be able to use any one of the lines in the table to show that temperature on the Kelvin scale is directly proportional to the average kinetic energy of the molecules. Links to:
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v)
should give the following distribution.