A sample of br2(g) takes 48.0 min to effuse through a membrane. how long would it take the same number of moles of ar(g) to effuse through the same membrane?
From the periodic table: mass of Br = 79.9 grams mass of Ar = 39.9 grams Therefore, molar mass of Ar = 39.9 grams molar mass of Br2 = 2(79.9) = 159.8 grams
Now, time for Ar / time for Br2 = sqrt(molar mass of Ar / molar mass of Br2) time for Ar = 48 * sqrt(39.9 / 158.9) time for Ar = 24.0528 minutes
