According the kinetic theory the average kinetic energy of gas molecules depends on the temperature. If we want to count the thermal velocity we will need the kinetic energy, and the molecular mass, but as far as I understand for more complicated molecules the shape of the molecule matters too. This is because the kinetic energy is stored not just as translational movement, but as rotational and vibrational movement too. Is it true, that for different molecular shapes with the same numbers and types of atoms (structural isomers) we get different thermal velocities, because different proportions of the kinetic energy are used for translation, rotation and vibration?

  • 3
    $\begingroup$ Those extra degrees of freedom play into the heat capacity, not the center-of-mass thermal velocities. $\endgroup$
    – Jon Custer
    Nov 22, 2019 at 20:00


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