Connected Chemistry Curriculum: Equilibrium
Time
The CCC Equilibrium unit can be broken into the following lessons:
Phase 1 (42 minutes): Physical and chemical changes with demos, explaining
concepts of equilibrium, predicting the submicroscopic view of molecules in
equilibrium. CCC student manual pages 1-8.
Phase 2 (42 minutes): Discussion of student answers from the previous day, Keq
explanation, Simulations of four reactions. CCC student manual pages 9-15.
Phase 3 (42 minutes): Completion of student responses and simulations. CCC
manual pages 16-18.
Phase 4 (42 minutes): Final teacher led discussion of results. Practice worksheet
of Keq calculations.
Extension Activity (42 minutes): Students investigate everyday example of
dynamic equilibrium. CCC manual page 23.
Lab experiments and activities would extend the unit further.
Level
High School level Chemistry (regular and honors)
Purpose
The purpose of this lesson is to introduce students to the
concept of chemical equilibrium. Students will use the
University of Illinois at Chicago Connected Chemistry
Curriculum, CCC, to understand the chemical
representations and chemical symbols of reversible
reactions. The CCC Equilibrium unit will be used to
model the behavior of molecules in a reversible and
irreversible reaction. In addition, students will be able to
distinguish reversible and irreversible reactions based on observations of plots of
concentration versus time. They will also know that equilibrium position, Keq, of a
reversible reaction is defined as the ratio of concentrations of products to reactants.
Overview
The teacher will begin the unit by reviewing physical and chemical changes. Students
will need this background information to understand reversible reactions. The teacher
will provide guidance on the predictions of identifying reversible reactions and the
meaning of Keq. Students will work with four different simulations. Lastly, the teacher
will lead a discussion of the results of identifying irreversible and reversible reactions. If
time permits students will research and present a dynamic equilibrium topic
(rechargeable batteries, cellular diffusion, role of potassium in body, or pH buffers in the
blood).
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Student Outcomes
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Learner Objectives
I can describe the quantitative relationship between the concentrations of the
reactants and products in a system that exists in a state of equilibrium.
I can define Keq and write expressions for Keq for both homogeneous and
heterogeneous reactions.
I can relate the magnitude if Keq to relative amounts of product and reactant.
I can predict the direction of a reaction, using the reaction quotient, Q, and the
equilibrium constant, Keq.
o Q<K the reaction moves to produce more product
o Q=K dynamic equilibrium
o Q>K the reaction moves to produce more reactant
I can calculate the equilibrium constant when given the equilibrium concentration.
I can calculate equilibrium concentrations using the value of the equilibrium
constant, Keq.
Next Generation Science Standards
PS1.B Chemical Reactions
Computational Thinking (CT) STEM taxonomy chart:
1e. Analyzing Data. See appendix C
1f Visualizing Data: See appendix D
3a Using Computational Modeling to Understand a Concept: See Appendix E
3c Assessing Computational Models: See Appendix F
Teaching Notes
Phase 1 (42 minutes):
1. Activity 1 (CCC manual page 4-5) Teacher will ask students to identify the
differences between physical and chemical changes. Use demonstrations to assess
student understanding. Demos could include burning paper, boiling water,
combusting vapors, etc.
2. Students should read page 4-5 from the CCC Equilibrium manual and highlight
bold face vocabulary words. For the first time students will be introduced to
reversible reactions and the meaning of dynamic equilibrium. You may ask
students to create a chart comparing irreversible and reversible reactions. Discuss
the differences between irreversible and reversible reactions with the class. There
are various demonstrations you could use to enhance student understanding of
irreversible. Examples of demonstrations include color changing toys or clothing
items, N2O4 to NO2 tubes, two-faced thionin demo, cobalt chloride pink to blue,
etc.
3. Activity 2 (CCC manual page 6-8). Ask students to make predictions of how
submicroscopic molecules will react during a reversible reaction. Students should
complete the CCC manual before returning to class the next day.
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Phase 2 (42 minutes):
1. Ask students to share answers in class from pages 6-8. Check for understanding of a
reversible reaction. If you have a document camera you may wish to present a student’s
drawing of their prediction. The teacher will then explain the mathematical calculations
of Keq. Page 9 in the CCC manual will provide additional references. If time permits the
teacher should ask students to identify the reversible and irreversible reactions found
online. The teacher will demonstrate how to open the CCC Equilibrium Simulation 1
program. Go to the website www.connchem.org and download the simulation file.
“Java Program File The Connected Chemistry Curriculum Simulation
(ConnectedChemistry.jar) version 1.7.2 (15 December 2012) You only need to
download this program to your computer once. It is not necessary to download
the program each time you would like to use it.”
2. Once you have downloaded the program open the Equilibrium program by clicking on
the “Choose Simulation” link found on the upper left corner. Scroll to Unit 7 Equilibrium
Sim 1. Complete the first reaction as a class. The instructions can be found on page 11 of
the CCC student manual. Model the way you would like students to complete the
remaining three reactions. Allow time for students to complete and draw their
observations. Be careful of the time, some students may want to spend too much time
perfecting their drawings.
Phase 3 (42 minutes): Students may need the full
period to complete the reactions and finish the
questions that follow on pages 16-18. If time is short
you can skip the questions and move into a class
discussion about the results of the simulation. This
would also be a good time to use the simulations to
verify the Keq values with each reaction.
Phase 4 (42 minutes): Final teacher led discussion of
results (if students answers questions in manual).
Practice worksheet of Keq calculations.
Pre-class Preparation
Teacher should decide on which physical and chemical change demonstrations to use.
Labs accompanying this unit will vary. Examples of labs are listed in the “Additional
Information” section.
Materials and Tools
CCC student manual pages 1-23 are online at www.connchem.org. This unit is:
Unit 7: Equilibrium.
Students will need Java installed on the computers they will be using in order to run the
simulations and have access to Molecular workbench. Students will be able to save and
print reports.
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Assessment
Formative and Summative assessments can be used to measure student understanding. It
is suggested teachers account for completion of student manuals by using stamps or a
checklist. Students will write predictions and draw submicroscopic molecules. The
accuracy and artistic expression should not be assessed since it is their interpretation of
what they observe. Checking for student understanding of learning objectives could be
assessed with quizzes and a summative exam.
Additional Information
1. Extension Activity (42 minutes): CCC manual page 23. Students investigate everyday
example of dynamic equilibrium. Students will spend one period researching the topic
and gathering information about how equilibrium applies to the topic. Students would
work in groups of four.
2. Online demonstrations of equilibrium
The Chromate – Dichromate Equilibrium
http://www.digipac.ca/chemical/equilibrium/dichromate/dichromate.htm
3. Lab experiments and activities would extend the unit further. See following
attachments for instructions.
a. Transfer Tube Activity
b. Chemical Equilibrium Finding a Constant Kc
c. Chemical Equilibrium and Application of LeChatelier’s Principle
4. Worksheet Examples
a. Intro. to Equilibrium ChemQuest 45 (www.ChemistryInquiry.com)
b. Equilibrium and LeChatelier’s Principle (http://www.pogil.org)
Acknowledgements
These materials are taken from the University of Illinois at Chicago Connected Chemistry
Curriculum (CCC), http://www.connchem.org/.
Handouts are at www.connchem.org.
The assessment is on the following page.
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