Problem: We separate U-235 from U-238 by fluorinating a sample of uranium to form UF6 (which is a gas) and then taking advantage of the different rates of effusion and diffusion for compounds containing the two isotopes.Calculate the ratio of effusion rates for 238 UF6 and 235 UF6. The atomic mass of U-235 is 235.054 amu and that of U-238 is 238.051 amu.

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FREE Expert Solution

Recall that Graham's Law of Effusion allows us to compare the rate of effusion of two gases. Graham's Law states that the rate of effusion of a gas is inversely proportional to its molar mass.

$\mathbf{rate}\mathbf{=}\frac{\mathbf{1}}{\sqrt{\mathbf{MM}}}$

This means that when comparing two gases:

$\boxed{\frac{\mathbf{rate}\mathbf{ }\mathbf{1}}{\mathbf{rate}\mathbf{ }\mathbf{2}}\mathbf{=}\sqrt{\frac{{\mathbf{MM}}_{\mathbf{2}}}{{\mathbf{MM}}_{\mathbf{1}}}}}$