Question

The molecular weight of an unknown gas is found by measuring the time required for a known volume of the gas to effuse through a small hole, under constant pressure. The apparatus is calibrated by measuring the time needed for the same volume of O2 (Molecular weight =32g/mol) to effuse through the same pinhole, under the same conditions. The time found for O2 is 60s and that for the unknown gas is 120s compute the molecular weight of the unknown gas.

Answer 1

rate = volume/time and mm stands for molar mass.
(rateO2/rate unk) = sqrt[(mm unk)/mm O2)]