It took 4.5 minutes for 1.0L helium to effuse through a porous barrier. How long will it take for 1.0 L Cl2 gas to effuse under identical conditions

Answer 1

Graham's Law of Effusion

rate gas 1 / rate gas 2 = sqrt MW gas 2 / sqrt MW gas 1

gas 1 = He, MW = 4

gas 2 = Cl₂, MW = 70.9

rate He = 1 L / 4.5 min = 0.222 L / min

rate Cl₂ = ?

0.222 / rate Cl₂ = √ (70.9/4)

0.222 / rate Cl₂ = 4.21

rate Cl₂ = 0.0528 L / min

Thus rate for 1 L is ...

0.0528 L / min = 1 L / x min

x = 18.9 minutes

So, it will take 18.9 minutes for 1 L of Cl₂ to diffuse under the same conditions