Problem :
Samples of H_{2} and He are at the same temperature. What is the ratio of their average velocities?

The molar mass of H_{2} is half that of He. The temperatures of the two samples are the same, so their kinetic energies are the same. This leads to the following equation:

M_{H2}(V_{H2})^{2} = M_{He}(V_{He})^{2}

Rearranging and solving this equation, we find that = .

Problem :
A volume of H_{2} and an identical volume of O_{2} are at the same temperature. Plot the Maxwell-Boltzmann speed distributions for the two gases on the same graph.

Problem :
Calculate $v_{\mbox{rms}}$ for a sample of O_{2} at 300 K.

v_{rms}

=

=

=

480m/s

Remember that M must be in !

Problem :
Rank v_{rms}, , and v_{p} in order of increasing speed.

v_{p} < < v_{rms}

Problem :
Calculate the ratio of the rates of effusion of H_{2} over He.

=

=

Note that this exactly mirrors the ratio of the average velocities of the two gases.