Chemical Equilibrium

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Chemical Equilibrium
A StarLogo Tool for Chemistry
Teachers
Team Members
 Rey Martinez
 Janet Penevolpe
 Deborah Haggerton
 Jason Goldberg
(here in spirit)
The Problem

How to teach equilibrium with less
confusion.
The Problem of Equilibrium


First there must be a reversible reaction
Then the “equal” part is the forward
reaction rate and the reverse reaction
rate
The Problem expanded

Le’ Chatelier’s principle states that a
system in equilibrium that is disturbed will
counteract that disturbance and establish
a new equilibrium.
Literature Research

The concept of equilibrium is well
documented. A plethora of full-text
articles were found in which chemical
equilibrium was of primary focus or in
which Le Chatelier's Principle was an
essential part.
Literature Research

Le Chatelier's Principle states that, if a
closed system at equilibrium is subjected
to change, processes will occur that tend
to counteract that change.
Literature Research

According to Sprague, Trey, Pillay & Khan
(2005), Le Chatelier’s Principle remains to
be the most difficult concept for high
school students to comprehend.
Literature Research

It has been found that students are able
to make observations of chemical
processes at the macroscopic level (e.g.,
color change) but tend not to be able to
explain why these changes occur at the
molecular level.
Literature Research

An elaborate study by Azizoglu, Alkan &
Geban (2006), revealed that high school
students may be confused with the
concepts because their instructors do not
have an adequate understanding.
Literature Research

According to the authors, the two most
misunderstood concepts in chemistry are
Le Chatelier's principle and the ideal gas
law
Literature Research


Hanson, from St. Olaf College, suggests
the use of playing-cards to explore
statistical aspects of equilibrium (2003)
While others have posted Web pages
featuring conventional definitions, digital
images and practical examples using
common household items.
Literature Research


This finding is alarming.
Consequently, the idea to create a
computer simulation that offers students
an opportunity to understand
unobservable phenomena is the focus of
the project.
Literature Research

To our knowledge, there are no other
agent-based models of Le Chatelier’s
principle in existence.
Procedure
Questions for programming



How to model the general reaction ?
A+BC
How do the reactants disappear?
How to get the product to breakdown?
Procedure
Agent - Agent interactions



Reactant A responds to B
Reactant B responds to A
Product C has no response
Procedure
Agent - Environment interactions

There are none
Now here’s our model

eqdeb05.slogo
Experiments to analyze output data
or use as Demonstrations
Can you find equilibrium:
 with only reactants?
 with only products?
 faster with double
reactants or products?
Experiments to analyze output data
or use as Demonstrations
Le Chatelier
What happens to equilibrium when:





Add A or Subtract A?
Add B or Subtract B?
Add C or Subtract C?
Add A & B or Subtract A & B?
Add A & B & C or Subtract all?
Citations
Azizoglu N., Alkan M., & Geban O. (2006).
Undergraduate pre-service teachers'
understandings and misconceptions of phase
equilibrium. Journal of Chemical Education,
vol. 83, issue 6, pp. 947-959.
Erickson, F. (1998). Qualitative methods for
science education. In B.J. Fraser & K.G. Tobin
(ed), International Handbook of Science
Education (pp. 1155-1173). Dordretch: Kluwer
Academic Publishers.
Citations continued
Hanson, R.M. (2003). Playing-card
equilibrium. Journal of Chemical
Education. vol.80, issue 11, pg. 1271.
http://www.chemguide.co.uk/physical/equil
ibria/introduction.html#top
http://www.chm.davidson.edu/java/LeChat
elier/LeChatelier.html
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