An effusion container is filled with 2 l of an unknown gas. it takes 350 s for the gas to effuse into a vacuum. from the same container under the same conditions--same temperature and initial pressure, it takes 229 s for 2.00 l of o2 gas to effuse. calculate the molar mass (in grams/mol) of the unknown gas.

6.85g/mol

Explanation:

According to the Graham's law of diffusion,the rate of diffusion is inversely proportional to  the square root of molecular mass.

k=r√m.m

k=constant

r=rate of diffusion or effusion

m.m=molecular mass

taking ''1'' and '2" to be the two gases 1=oxygen,2=unknown gas

r1√m1=r2√m2,molar mass of oxygen=16

mathematically√m2=229√16/350

√m2=2.617

m2=6.85g/mol

fe 55.85 g/mol and h2o 18.02 g/mol.