Question

Please help?
Graham's gas law of diffusion:of the three gases H2 , CH4, C3H8 which would you expect to diffuse faster?

(how do you figure this out/ do you just take a educated guess?)

Answer 1

Grahams says Rate of diffusion is proportional to (1/sqrt(density)).... so what property of the gases would you compare?

Answer 2

Would it be the atomic mass?

Answer 3

@chemENGINEER

Answer 4

Not quite. Grahams law relates rate to densities. So i would go to my handbook and look up the accepted average density values for these gases, and plug them into the proportionality statement Grahams law. You will see which rate is highest, middle, lowest...

Answer 5

Also, another cool side note that is extra info in case you are interested: if we were given a reaction rate of some general reaction of these gases, and a Damkohler number, (a dimensionless number) we could say that Damkohler=reaction rate/ rate of diffusion.

Answer 6

Thanks for you help :)

Answer 7

No probs