Question

Two gases in a mixture pass through a filter at rates proportional to the gases' rms speeds. (a) find the ratio of speeds for the two isotopes of chlorine, 35cl and 37cl, as they pass through the air. (b) which isotope moves faster?

Answer 1

Answer: 1.03 ,35CL

The rms speed is given by formula:$v_{rms}=\sqrt{\frac{3RT}{M}}$

RMS speed is inversely proportional to the molecular mass. To find ratio of rms speed we take the square root of ratio of molecular masses as:$\frac{v_{rms 35}}{v_{rms 37}} =\sqrt{\frac{M_{37}}{M_{35}}} =\sqrt{\frac{37}{35}} =1.03$