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?
Lv 7
? asked in Science & MathematicsPhysics · 9 years ago

Is it OK and is there a formula relating the kinetic energy of a single molecule to its absolute temperature?

The temperature of a gas is related to its mean kinetic energy - I forget how - I wonder how few the number of molecules can be for this to hold up. This subject is thermodynamics but physicists might have a view.

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  • ?
    Lv 7
    9 years ago
    Favorite Answer

    A single molecule doesn't have a temperature in the normal thermodynamic sense, as I undertsand it. Temperature is a characteristic of a large number of particles.

    For an ideal gas:

    Average kinetic energy = (3/2)k x absolute temperature

    where k is the Boltzmann constant.

    The essence of statistical thermodynamics is that it considers macroscopic properties (temperature, pressure, entropy etc) arising from he statistical behaviour of a very large number of entities.

    'How many' you ask? I don't know but it will it depends on what level of fluctuations you will accept in quantities like temperature; more than a few million particles is probably OK for most purposes.

  • Irv S
    Lv 7
    9 years ago

    "Kinetic energy", so you need the mass of the molecule right?

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