-Diffusion Graham’s Law of Effusion Dalton’s Law of Partial Pressures Chemistry Mrs. Coyle

Diffusion

Diffusion  The process in which particles of matter move from areas of high concentration to areas of low concentration.

Effusion  The passage of gases through a small hole or pores of a membrane.

Note  Gases of lower molar mass diffuse and effuse faster than gases of higher molar mass.

Graham’s Law of Effusion ________ v a = √ v b (MM b ) MM a v = rate of effusion MM= molar mass -The rate of effusion of a gas is inversely proportional to the square root of its molar mass.

Example  Compare the rates of effusion of CO 2 oxygen gas.

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Dalton’s Law of Partial Pressures http://cwx.prenhall.com/bookbind/pubbooks/hillchem3/medialib/media_portfolio/text_images/CH05/FG05_14.JPG

Dalton’s Law of Partial Pressures:  The total pressure in a gas mixture is the sum of the partial pressures of each individual gas.  P total = P gas 1 + P gas 2 + P gas 3 + …

Partial Pressure of a Gas:  The pressure that the gas would exert if it were the only gas present in the container.