SME
Grade 10 Science
Gases and the gas laws (PV = nRT)
The main lesson, then each kind of problem it solves.
Gases and the gas laws (PV = nRT)
Main lesson
Boyle’s law: squeezing a gas
Use this for a gas squeezed or let out at one temperature: “6 L at 1 atm is pressed into 3 L. What is the pressure?”
Charles’s law: heating a gas
Use this for a gas warmed or cooled at one pressure: “2.00 L at 300 K is heated to 450 K. What is its volume?”
Gay-Lussac’s law: a sealed, rigid container
Use this for a gas heated in a rigid container: “A tire at 2.00 atm and 280 K warms to 308 K. What is the pressure?”
The combined gas law
Use this when pressure, volume and temperature all change: “5.00 L at 1.00 atm and 300 K goes to 2.00 atm and 360 K. What is the volume?”
Effusion: Graham’s law
Use this for “Helium (4.00 g/mol) and argon (39.95 g/mol) leak from one tank. Which escapes faster, and how many times as fast?”
Dalton’s law of partial pressures
Use this for a mixture of gases: the total pressure from each gas’s partial pressure, and one gas’s mole fraction.