How long will it take?

Question

It took 6.3 minutes for 25 mL of argon to reach the end of an effusion tube with a porous barrier. How long will it take for 25 mL of CHCl3 to effuse throuh the tube under the same conditions?

Answer 1

Grahams Law of Effusion:

rate gas 1/rate gas 2 = √MW gas 2/√MW gas 1

MW Argon = 39.95 g/mol

MW CHCl3 = 119.4 g/mol

Rate gas 1 (Ar) = 25 ml/6.3 min = 3.97 ml/min

Rate gas 2 (CHCl3) = x

3.97/x = √119.4/39.95 = 1.73

x = 2.30 ml/min

So, for 25 ml it will take 2.30 ml/min x 25 min = 57.5 minutes