GRAHAM'S LAW OF
EFFUSION (p. 387 in text book)
* compares the rates of effusion
of different gases
* lighter gases (lower molar
masses) effuse faster than heavier gases (higher molar masses)
rate A
= MM B
rate
B MM
A
the rate of gas A compared to the rate
of gas B is equal to the square root of the inverse of the molar masses of the
gases
EXAMPLE 1: Compare
the rates of effusion for oxygen gas and hydrogen gas.
EXAMPLE 2: An
unknown gas effuses 1.18 times faster than SO2. What is the
molar mass of the unknown gas?