Question

Under certain conditions neon gases diffuse at a rate of 7.0 cm/s under the same conditions as an on known gas defuses at a rate of 4.9 Per second what is the approximate molar mass of the unknown gas?

Answer 1

Answer : To find the molar mass of unknown gas we need to solve the equation of rate of diffusion and molecular weight of the gases, which is as follows;

$\frac{rate of diffusion of gas A X \sqrt{mol wt of gas B} }{rate of diffusion of gas B X \sqrt{mol wt of gas A} } =1$

here the mol wt of gas B is not known so we take it as 'x'

on solving we get 7 X $\sqrt{x}$ / 4.9 X $\sqrt{41}$

mol. wt of unknown gas = 20.0 g