Graham’s Law

Diffusion and Effusion Diffusion – the gradual mixing of 2 or more gases due to their spontaneous, random motion Effusion – molecules of gas confined in a container randomly pass through a tiny opening in the container

The rates of diffusion and effusion depend on the velocities of the gas molecules. Velocity is determined by the equation KE = ½mv2

Kinetic energy is dependent on temperature, meaning two different gases will have the same kinetic energy at the same temperature ½m1v12 = ½m2v22

Graham’s Law of Diffusion: Rates of diffusion of gases at the same temp and pressure are inversely proportional to the square roots of their molar masses. Rate means velocity velocity = distance/time Units = m/s

Compare the rates of diffusion of hydrogen and oxygen at the same temperature and pressure. rateH2 √MO2 √32.00g/mol rateO2 √MH2 √2.02g/mol Hydrogen diffuses 3.98 times faster than oxygen 3.98

Lighter gases travel faster Heavier gases travel slower …therefore, lighter gases travel farther in the same amount of time.

Make a kids book about gas laws! For each Gas Law (all 8 now) - Name of law - Formula - Explain what law means (in words) - Way to remember law - Example of law (using real life examples) - Drawing