Equilibriumby: Grace & Mitchell

Equilibrium is a state in which the forward and reverse paths of a change

take place at the same rate.

Forward changes and reverse changes are considered to be part of a Physical Equilibrium.

An example of a physical equilibrium is: H2O(l) H2O(g)

The L stands for liquid and the G stands for gas. The forward change would be evaporation and the reverse change would be condensation.

A Reversible Reaction is a reaction in which the conversion of reactants into products and the conversion of products into reactants happens simultaneously.

An example of a reversible reaction is:2SO2 (g) + O2 2SO3(g)

When the forward reaction (synthesis) equals the reverse reaction (decomposition) then an equilibrium will be reached.

A Chemical Equilibrium is when a chemical reaction does not go to

completion.

An equilibrium will shift if a reaction rate either increases or decreases.

The rule stating, “equilibrium shifts in the direction that relieves the change” was discovered by Henri Le Chatelier. Today the rule is known as le Chatelier’s principle.

By using Le Chatelier’s principle, you can predict changes in temperature, pressure, and concentration.

If you add heat to the equilibrium, it shifts towards the area that will remove heat from the system.

If you increase pressure, the equilibrium will move towards the decreasing pressure of the system.

If you decrease the concentration of the equilibrium, the position will move right to increase the concentration again.

Works Cited• Frank, David. Physical Science Concepts in Action. Boston,

Massachusetts: Pearson, 2009. 957. Print. • Clark , Jim. (2002): n. page. Print.

<http://www.chemguide.co.uk/physical/equilibria/change.html>.

• Sullivan, Dan M.. "Equilibrium." Chemistry: Foundations and Applications. 2004. Encyclopedia.com. 15 Nov. 2012 <http://www.encyclopedia.com>.

• "Chemical Equilibrium." Science of Everyday Things. 2002. Encyclopedia.com. 15 Nov. 2012 <http://www.encyclopedia.com>.

Quizzzzzz1. Equilibrium is a state in which the_______and ________paths of a change take

place at the same rate.2. What are 2 types of equilibriums? A) Physical B) Rate C) Chemical D) Both A&C

3. A Forward change and reverse change are considered to be part of a….. A) Physical Change B) Silly Change C) Mental Change D) None of the above

4. A _________Reaction is a reaction in which the conversion of reactants into products and the conversion of products into reactants happens simultaneously

5. A ________Equilibrium is when a chemical reaction does not go to completion.A) Physical B) Chemical C) Equal D) None of the above

6. An equilibrium will shift if a reaction rate either…. A) Increases B) Decreases C) Both7. The rule stating, “equilibrium shifts in the direction that relieves the change” was discovered by Henri Le Chatelier. True or False8. By using Le Chatelier’s principle, you can predict changes in….

A) Temperature B) Pressure C) Concentration D) All the above9. If you add pressure to the equilibrium, it shifts towards the area that will remove

heat from the system. True or False10. If you increase pressure, the equilibrium will move towards the decreasing

pressure of the system. True or False

Quiz Answer Key1. Forward and Reverse2. D 3. A4. Reversible5. Chemical 6. C7. True8. D9. False10. True