Properties of Gases

understanding matter at its simplest

chem1 virtual textbook

a reference text for General Chemistry

Stephen Lower

Simon Fraser University

The gaseous state of matter is the only one that is based on a simple model that can be developed from first principles. As such, it serves as the starting point for the study of the other states of matter.

The Chem1 Virtual Textbook is a resource for General Chemistry aimed mainly at the first-year university level. It offers a more comprehensive, organized, and measured approach than is found in most standard textbooks. It should also be accessible to advanced high-school courses, and helpful as review material for students in more advanced courses in chemistry, biology, geology, and engineering.

Needlepoint [link] by B. Schaefer[?]

To access the desired page, click one of the lesson titles immediately below; you can also go directly to any sub-section within a lesson by clicking on a smaller heading.

1- Observable properties of gases

- What's special about gases?
- The pressure of a gas
- atmospheric pressure and the barometer
- Temperature and temperature scales
- Absolute temperature
- The volume occupied by a gas
- What you should be able to do
- Concept map

2- Ideal gas model: the basic gas laws

- The law of Charles and Gay-Lussac: effects of temperature
- Avogadro's Law: number of molecules
- The Ideal Gas Equation of State
- The P-V-T surface of an ideal gas
- What you should be able to do
- Concept map

3- Moles and mixtures of gases, Dalton's law

- Molar volume of a gas: standard temperature and pressure
- Molecular weight and density of a gas
- Mixtures of gases: expressing compositions
- Dalton's Law of partial pressures
- Some applications of Dalton's Law
- Collecting a gas over water
- Scuba diving
- What you should be able to do
- Concept map

4- Molecules in motion ("KMT-lite")

- Introduction
- The kinetic-molecular model
- The gas laws explained
- Some practical applications
- Graham's Law and effusion
- Density fluctuations: why the sky is blue
- Incandescent ight bulbs
- Viscosity of gases
- Distribution of gas molecules in a gravitational field
- What you should be able to do
- Concept map

5- More on kinetic-molecular theory ("KMT-classic")

The material in this section is frequently omitted in more elementary courses.

- Velocities of gas molecules and the Boltzmann distribution
- Retention of planetary atmospheres
- Derivation of the ideal gas equation of state
- RT has the dimensions of energy
- How far does a molecule travel between collisions?
- What you should be able to do
- Concept map

6 - Real gases and critical phenomena

- Effects of intermolecular forces
- The van der Waals equation of state
- Condensation and the critical point
- P-V-T surface of a real gas
- Supercritical fluids
- What you should be able to do
- Concept map

Some useful references

Book chapter: Gas Laws and Kinetic Theory (Chapter 3 of Chemical Principles, 3rd Ed (1979) by Dickerson, Gray, and Haight.) Perfectly good for first-year general chemistry courses. (11 Mb pdf)

Online book chapters from Concept Development Studies in Chemistry by John Hutchinson: The Ideal Gas Law - go ; The Kinetic Molecular Theory - go

Khan Academy videos: Ideal Gas Equation- go ; Partial Pressure - go

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