Graham's law states that the rates of effusion of two gases areinversely proportional to the square roots of their molar masses at thesame temperature and pressure:
Effusion is the term used to describethe passage of a gas through a tiny orifice into an evacuated chamber,as shown in the figure below.
The
rate of effusion measures the
speed at which the gas travels through the tiny hole into a vacuum. Another term to remember for the test is diffusion.
Diffusion is the term used to describe the spread of a gas throughout a space or throughout a second substance.
