Chemical Equilibrium

1
Chemical Equilibrium

• A StarLogo Tool for Chemistry Teachers

2
Team Members

• Rey Martinez
• Janet Penevolpe
• Deborah Haggerton
• Jason Goldberg
• (here in spirit)

3
The Problem

• How to teach equilibrium with less confusion.

4
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

5
The Problem expanded

• Le Chateliers principle states that a system in
  equilibrium that is disturbed will counteract
  that disturbance and establish a new equilibrium.
  

6
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.

7
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.

8
Literature Research

• According to Sprague, Trey, Pillay Khan (2005),
  Le Chateliers Principle remains to be the most
  difficult concept for high school students to
  comprehend.

9
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.

10
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.

11
Literature Research

• According to the authors, the two most
  misunderstood concepts in chemistry are Le
  Chatelier's principle and the ideal gas law

12
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.

13
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.

14
Literature Research

• To our knowledge, there are no other agent-based
  models of Le Chateliers principle in existence.

15
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?

16
Procedure

• Agent - Agent interactions
• Reactant A responds to B
• Reactant B responds to A
• Product C has no response

17
Procedure

• Agent - Environment interactions
• There are none

18
Now heres our model

• eqdeb05.slogo

19
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?

20
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?

21
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.

22
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/equilibria/int
  roduction.htmltop
• http//www.chm.davidson.edu/java/LeChatelier/LeCha
  telier.html