How does the rate of effusion of sulfur dioxide, SO2, compare to that of helium?

1 Answer
Apr 14, 2016

Helium gas should effuse four times faster than sulfur dioxide.

Explanation:

Rate of diffusion 1Molecular mass

Thus,

Rate of diffusion of helium Rate of diffusion of sulfur dioxide

Molecular Mass SO2Molecular mass He

64gmol14gmol1

Conveniently, the molecular masses are perfect squares. And thus helium should effuse 4 times faster than sulfur dioxide.

This law is a manifestation of the ideal gas law. In fact, fissile (and volatile) 235UF6 is separated from 238UF6 with precisely this principle.