Boltzmann constant and Ek

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Boltzmann constant and Ek

Remember:.

pV = nRT

Where:.

n = number of moles of gas

and

R = universal molar gas constant.

Boltzmann decided it would be useful if we know what the gas constant was per molecule, not per mole. He came up with a new constant - named the Boltzmann constant, of course - which was:

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Where:.

k = the Boltzmann constant

R = the universal molar gas constant

NA = Avogadro's number, the number of particles in one mole.

Then it was possible to rewrite

pV = nRT

as

pV = NkT

Where:.

N = no of atoms or molecules involved.

If you combine

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and

pV = NkT

to give

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or, in words

The average Ek of the particles = a constant x temperature (in kelvin).

This confirms what we've mentioned a number of times in this section, that the temperature of a gas depends only on the Ek of the molecules that make it up.

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