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# All about chemical equilibrium

Welcome to the Chem1 Chemical Equilibrium home page

This site contains a set of textbook-like tutorials covering this important subject, but doing so in a manner that I hope will be both more understandable and more complete than will be found in most current General Chemistry textbooks. Although the emphasis is on the development of the major ideas and concepts relating to equilibrium, there are many problem examples that will help you relate these principles to the practical applications you are likely to encounter in a typical first-year college chemistry course, and in further courses in analytical chemistry, biochemistry, and physical chemistry.

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#### How is this set organized and how do I find my way around?

There are five main sections to this tutorial; you can access them by clicking on the appropriate title at the top or bottom of this page. The topics are listed in the order that you would probably want to follow if you were using this tutorial as the primary source of instruction on equilibrium. Please note that some specialized types of equilibrium, notably acid-base, oxidation-reduction, and solubility equilibria, are not covered in this tutorial.

#### How can I use these tutorials?

In two very general ways:

As a supplement or substitute for a textbook. It's always nice to have a complex topic explained to you in more than one way, so if you already have a textbook, you will find alternative, and possibly more understandable, discussions of the same material. One problem with textbooks is that the amount of detail they can provide is limited by the space available, as well as by editorial and marketing considerations (they often use up pages with lots of pictures and other glitzy stuff to entice teachers to adopt the book— this is big business!). That's fine as far as it goes, but often a bit more is needed.

As a supplement to the Chem1 Concept Builder lessons. These computer-based materials provide guided, interactive, and in-depth instruction, but they leave no permanent record (except, we hope, in your head!) of what was covered. These Chemical Equilibrium tutorials parallel the Chem1 CB - Equilibrium lessons in their organization and coverage. They also contain many of the same graphics, so you can easily obtain a copy of a particular graph or illustration for your own reference.

Detailed list of topics

The left column of the following table contains links to each separately-addressable section of the equilibrium tutorial pages. The corresponding URLs in the right column are for the convenience of instructors who wish to reference an individual section within a course-management system such as Web-CT. Note that the base part of the link is not given, since this is subject to change.

Topic | link
Part 1: Introduction to chemical equilibrium | Eq-01.html
Chemical change | Eq-01.html#CHANGE
What is equilibrium? | Eq-01.html#WHATIS
Chemical equilibrium | Eq-01.html#CHEMEQ
What is a reversible reaction? | Eq-01.html#REV
How did Napoleon help discover reversible reactions? | Eq-01.html#NAP
What is the Law of Mass Action? | Eq-01.html#MASS
How do we know when a reaction is at equilibrium? | Eq-01.html#ATEQ
Part 2: The LeChâtelier principle | Eq-02.html
What is the LeChâtalier Principle and why is it important? | Eq-02.html#LECHAT
How do changes in temperature affect equilibria? | Eq-02.html#TEMP
How do changes in pressure affect equilibria? | Eq-02.html#PRESS
The LeChâtalier Principle and physiology | Eq-02.html#PHYSIO
The Haber process for the synthesis of ammonia | Eq-02.html#HABER
Part 3: Q and K: what's the difference? | Eq-03.html
What is the equilibrium quotient? | Eq-03.html#WHATSQ
A visual way of thinking abo ut Q and K | Eq-03.html#VISUAL
Does everything stop when equilibrium is reached? | Eq-03.html#STOP
Part 4: More on equilibrium expressions | Eq-04.html
Concentrations and pressures in eq. expressions | Eq-04.html#OTHER
Don't show unchanging concentrations! | Eq-04.html#UNCHANGING
What does the magnitude of K tell you? | Eq-04.html#VALUE
Do equilibrium constants have units? | Eq-04.html#UNITS
How writing the equation affects K | Eq-04.html#EQN
Vapor pressures of hydrates | Eq-04.html#HYD
Consecutive reactions | Eq-04.html#CONSEC
Part 5: Equilibrium calculations | Eq-05.html
Measuring and calculating equilibrium constants | Eq-05.html #MEAS
Calculating equilibrium compositions from equilibrium constants | Eq-05.html #COMP
Effects of dilution on equilibrium | Eq-05.html#DIL
Phase distribution equilibria | Eq-05.html#DIST