CHEMICAL SYSTEMS & EQUILIBRIUM CHRIS, DAN AND TAMARA

Chemica

l Sys

tem

s

& Equilib

rium

Chris, D

an a

nd Tam

ara

Outline

• Big ideas and Guiding Questions

• Unit Plan

• Minds on Activity : Magic Flask

• Misconceptions

• Activity #1: Gizmo – Equilibrium and Concentration

• Activity #2: Jeopardy Review

• STSE Blog

Big Ideas and Guiding Questions

Big Ideas

1. Chemical systems are dynamic and respond to changing conditions in predictable ways.

2. Applications of chemical systems at equilibrium have significant implications for nature and industry.

Big Ideas and Guiding Questions

Guiding Questions1.How do we use buffer systems to our advantage? Why is having a buffer system advantageous? (E1)

 2. How do industries take advantage of chemical equilibrium when producing chemicals? (E2.2)

 3. Why is the pH of our blood buffered? What would happen if it is not buffered? (E2.4, 2.5)

 4. What is the value of having different factors affect the shift in equilibria of chemical systems? (E3)

Unit Plan

Minds On: Magic FLASK

Misconceptions

1. Mass vs. Concentration• Inability to distinguish between concepts

2. Rate vs. Extent• Inability to distinguish between how fast

and how far

3. Constancy of Equilibrium Constant• Uncertainty as to when equilibrium

constant is constant

Kass, W. & Wheeler, A.; Student Misconceptions in Chemical Equilibrium as Related to Cognitive Level and Achievement; present at Annual Meeting for the Research in Science Teaching; April 1974.

4. Misuse of Le Chatelier’s Principle• Application in inappropriate situations

5. Constant Concentration• Inability to understand that certain

substances display fixed concentration in certain reactions

6. Competing Equilibria• Inability to consider all factors affecting

equilibrium condition of chemical system

Misconceptions

Possible Solutions ? ???

? ?

Possible Approaches

Assess cognitive level prior to formal introduction of concept

Combinatorial task/written test Benefit of laboratory approach for students operating at

early/late concrete operational level

Le Chatelier’s principle Provide numerous examples

Graphical representations E.g. concentration vs. time

Activity #1: Gizmo Equilibrium and Concentration

Activity #2: Jeopardy QUIZ REVIEW

STSE Blog

I Love the Smell of Aspirin in the Morning Case 

You are hired by a new drug company Drugs "R" Us to work on their new project on designing a new generic headache tablet using acetylsalicylic acid as the active ingredients (found in Aspirin). Their recipe for the generic tablet is almost complete and clinical testing has already begun. However, you are convinced from your grade 12 equilibrium chemistry knowledge that including a buffer in the tablet would be more beneficial. However, you need to convince your boss that a buffered tablet is going to increase sales of this headache tablet (This is a business after all). 

STSE Blog

 Task Create a poster, power point, website, video, or another alternative method to present your argument based on one of the following view points. i) You are the employee of this drug company and wants to convince your superiors that a buffered tablet is better than an unbuffered tablet. ii) You are an investor of the pharmaceutical company's and consider a buffer system is not necessary in the tablet. Be sure to include the following: what is different about a buffered tablet compared to an unbuffered tabletwhy is a buffer system in a headache tablet importantwhat are the advantages of having a buffer system in a drug tabletany others consequences of including a buffer system

Chemical Equilibrium Blog

THE END