Question

The ratio of the rate of diffusion of a given element to that of helium is 1.4.
The molecular weight of the element is?

Answer 1

Answer:

The molecular weight of the element is 64.048 g/mol

Explanation:

Let,

the rate of diffusion of an element be “r1”  

the rate of diffusion of Helium gas be “r2”

the molecular weight of the element be “M1”

We know that, the molecular weight of helium be “M2” = 4.003 g/mol

And,

r1 / r2 = 1 : 4

Now, by using Graham’s law,  

r1 / r2 = √[M2/M1]

or, [ 1 / 4 ]^2 = [(4.003)/M1]

or, 1 / 16 = 4.003 / M1

or, M1 = 16 * 4.003 = 64.048 g/mol

Answer 2

Answer:

answer is in the attachment... it may be helpful..