### By the end of this unit students will be able to:

- State the kinetic-molecular theory of matter, and describe how it explains certain properties of matter.
- Distinguish between an ideal and a real gas.
- Describe each of the following characteristic problems of gases: expansion, density, compressibility, diffusion, and effusion.
- Define pressure, give units of pressure, and describe how pressure is measured.
- State the standard conditions of STP.
- Use Boyle’s Law to calculate volume-pressure changes at constant temperature.
- Use Charles’ Law to calculate volume-temperature changes at constant pressure.
- Use Gay-Lussac’s Law to calculate pressure-temperature changes at constant volume.
- Use the Combined Gas Law to calculate volume-pressure-temperature changes.
- Use the Ideal Gas Law to calculate pressure, volume, temperature, or amount of gas when the other three quantities are known.
- Use Dalton’s Law of partial pressures to calculate partial pressures and total pressures.
- Calculate the mole fraction of a gas.
- Relate the ideal gas law stoichiometrically using chemical equations and STP values.
- Use Graham’s Law of Effusion to calculate the rate and molar mass of a gas.

Introduction to Gases at PhET

Explore the Properties of Gases at PhET

Explore Difusion at PhET