The noble gases neon (atomic mass 20.1797 u) and krypton (atomic mass 83.798 u) are accidentally mixed in a vessel that has a temperature of 79.2°c. what are the average kinetic energies and rms speeds of neon and krypton molecules in the vessel?

(a) average kinetic energies kav, ne = j kav, kr = j

(b) rms speeds vrms, ne = m/s vrms, kr = m/s

(a) Kav Ne = Kav Kr = 7.29x10⁻²¹J

(b) v(rms) Ne= 659.6m/s and v(rms) Kr= 323.7m/s

Explanation:

(a) According to the kinetic theory of gases the average kinetic energy of the gases can be calculated by:

(1)        

where : is the kinetic energy, k: Boltzmann constant = 1.38x10⁻²³J/K, and T: is the temperature

From equation (1), we can calculate the average kinetic energies for the krypton and the neon:

(b) The rms speeds of the gases can be calculated by:

where m: is the mass of the gases and : is the root mean square speed of the gases

For the neon:

For the krypton:

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