Grahams Law Diffusion and Effusion Diffusion the gradual

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 = ½mv 2

• Kinetic energy is dependent on temperature, meaning two different gases will have the same kinetic energy at the same temperature ½m 1 v 12 = ½m 2 v 22

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 = distance/time Units = m/s

• Compare the rates of diffusion of hydrogen and oxygen at the same temperature and pressure. • rate. H 2 rate. O 2 √MH 2 √ 32. 00 g/mol √ 2. 02 g/mol 3. 98 Hydrogen diffuses 3. 98 times faster than oxygen

• 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