Lesson Plan
(A) Major Concepts

Chemistry II

III. Chemical Reaction

2. Reaction Rate and Chemical Equilibrium

(1) Chemical Equilibrium
(B) Performance Objective / Content Standards

Students can explain what the state of chemical equilibrium is.

Students can write and calculate the equilibrium constant of a system.

Students can use the LeChatelier’s principle to predict the effect of changes in
concentration, temperature, and pressure.

California Content Standard
9. Chemical equilibrium is a dynamic process at the molecular level. As a basis for
understanding this concept:
Students know how to use Le Chatelier's principle to predict the effect of
a.
changes in concentration, temperature, and pressure.
Students know equilibrium is established when forward and reverse
b.
reaction rates are equal.
c. *
Students know how to write and calculate an equilibrium constant
expression for a reaction.
(C) Materials and Equipment

Computer labs with the Internet Access

Calculator program in the computers.
(D) Independent Practice/Assignments (handouts, readings, problems)
(E) Outline of Lesson
(1) Warm-up/Dispatch Activity (5min): Students review about the
equilibrium constant using the following site.
http://www.avogadro.co.uk/definitions/kc.htm
(2) Introduction.(10min) : Teacher gives a lecture with the following site
to teach about the shift of chemical equilibrium.
http://www.chem.uncc.edu/faculty/murphy/1252/Chapter15/sld001.htm
(3) Laboratory Experiments Activity (20min): Students do experiments
with virtual labs in the following sites.

The effect of changes in concentration
http://www.chm.davidson.edu/ChemistryApplets/equilibria/LeChatelier.html

The effect of changes in volume
http://www.chm.davidson.edu/ChemistryApplets/equilibria/Volume.html

The effect of changes in temperature.
http://www.chm.davidson.edu/ChemistryApplets/equilibria/Temperature.html
(4) Discussion (10min): Teacher and students talk about the
experiments analyzing the results and drawing the conclusions.
http://www.ausetute.com.au/lechatsp.html
http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch16/lechat.html
(5) Summary (5min): Teacher announces the next instruction
and homework.
(F) Homework (textbooks, readings, problems, projects, etc.)

Find 10 examples of Chemical equilibrium shifts in our daily life.
(G) Lab paper for students
Le Chatelier's Principle
1. The objects of the experiments

Students can explain what the state of chemical equilibrium is.

Students can write and calculate the equilibrium constant of a system.

Students can use the Le Chatelier’s principle to predict the effect of changes in
concentration, temperature, and pressure.
2. Concepts
The first step in the conversion of coal into gasoline is the steam reforming reaction.
C (s) + H2O (g)
CO (g) + H2 (g)
Suppose that 0.0500 mole (the analytical amount) each of carbon, water, carbon
monoxide, and hydrogen are placed in a 10.0 L glass bulb, which is then heated to 1000
K and the steam reforming reaction is allowed to reach equilibrium. When the system
reaches equilbrium, the amounts of four materials have been changed to the
equilibrium amount: the equilibrium amounts of carbon and water are 0.0093 mole and
the equilibrium amounts of carbon monoxide and hydrogen are 0.0907 mole. However,
if we change the conditions of the system, the system will reach a new equilibrium by a
reaction occurring. We are going to find the direction of the reaction and new
equilibrium constants when the concentrations, volumes and temperature are changed.
Question) Write the formula of the chemical equilibrium constant of this reaction. And
calculate the constant using the equilibrium amounts of the materials at 1000K. Beware
of the fact that the volume of the container is 10.0L.
3. Method & Data
(1) The effect of changes in concentration
Using the following site, do experiments and fill out the table of data.
http://www.chm.davidson.edu/ChemistryApplets/equilibria/LeChatelier.html
The distinction between analytical amount and equilibrium amount is especially
important in this experiment. The analytical amount of material, such as carbon, is the
amount physically added to the system. The equilibrium amount is the amount of
material that actually exists in the system at equilibrium. The two amounts are generally
not the same, because the reaction will consume or produce the material in order to
reach equilibrium.
The question to be answered in this experiment is:
How does a change in the analytical amount of a reactant or product affect the
equilibrium amounts of reactants and products in the system?
1. Change the analytical amount of hydrogen gas in the reaction, and find the
equilibrium amounts of the four materials and calculate the equilibrium constants.
Number of experiment
1
2
3
4
The increase or decrease of the
analytical amount of hydrogen gas
The equilibrium amount of C
The equilibrium amount of H2O
The equilibrium amount of CO
The equilibrium amount of H2
The equilibrium constant
2. Change the analytical amount of carbon in the reaction, and find the equilibrium
amounts of the four materials. What do find out from these changes? Explain why.
3. Change the analytical amount of water in the reaction, and find the equilibrium
amounts of the four materials and calculate the equilibrium constants.
Number of experiment
1
2
3
4
The increase or decrease of the
analytical amount of water
The equilibrium amount of C
The equilibrium amount of H2O
The equilibrium amount of CO
The equilibrium amount of H2
The equilibrium constant
(2) The effect of changes in volume.
Using the following site, do experiments and fill out the table of data.
http://www.chm.davidson.edu/ChemistryApplets/equilibria/Volume.html
In this experiment the stress brought upon the system is a change in volume.
What is the consequence of changing the volume of a gas?
Change the volume of the system and find the equilibrium amounts of the four materials
and calculate the equilibrium constants.
Number of experiment
The changed volume (L)
The equilibrium amount of C
The equilibrium amount of H2O
The equilibrium amount of CO
The equilibrium amount of H2
The equilibrium constant
1
2
3
4
(3) The effect of changes in Temperature.
Using the following site, do experiments and fill out the table of data.
http://www.chm.davidson.edu/ChemistryApplets/equilibria/Temperature.html
Change the temperature of the system and find the equilibrium amounts of the four
materials and calculate the equilibrium constants.
Number of experiment
1
2
3
The changed temperature(K)
The equilibrium amount of C
The equilibrium amount of H2O
The equilibrium amount of CO
The equilibrium amount of H2
The equilibrium constant
4. Findings
(1) The effect of changes in concentration
1. When a reactant is increased, which direction of reaction occurs? Why?
2. When a reactant is decreased, which direction of reaction occurs? Why?
3. When a product is increased, which direction of reaction occurs? Why?
4. When a product is decreased, which direction of reaction occurs? Why?
4
5. How does a change in the analytical amount of a reactant or product affect the
equilibrium constant in the system?
(2) The effect of changes in volume.
1. When the volume is increased, which direction of reaction occurs? Why?
2. When the volume is decreased, which direction of reaction occurs? Why?
3. What is the consequence of changing the volume of a gas?
(3) The effect of changes in Temperature
1. When the temperature is increased, which direction of reaction occurs? Why?
2. When the tempertaure is decreased, which direction of reaction occurs? Why?
3. What is the consequence of changing the volume of a gas?
4. Is this reaction endothermic or exothermic? Why?
5. Conclusion
6. Home work
Find 10 examples of the chemical equilibrium shift in our daily life.
A satellite photograph of a recent storm in North America.
인공위성 사진 : http://www.weather.gov/sat_tab.php?image=ir