25 Jun 2011

Macroscopic, particle and symbolic representations of aqueous reactions

In-Class Activity

Submitted by Kristen Murphy, University of Wisconsin-Milwaukee
Categories
Prerequisites: 
Corequisites: 
Course Level: 
Description: 

Students in the courses I teach (primarily general chemistry) have struggled with understanding the three representations of matter: macroscopic, particle, and symbolic. This is particularly evident when these representations extend into reactions. Additionally, students struggle with understanding basic concepts of aqueous solutions and, by extension, reactions in aqueous solution. This activity is designed to help the students recognize different types of representations and then generate these for simple systems. This learning object is designed to follow (or coincide with) the introduction of reactions and stoichiometry and can be extended to include acid/base and redox reactions.

 

Learning Goals: 

Learning Goal

  • Understand the difference between macroscopic, particle and symbolic representations of simple aqueous reactions (precipitation reactions).

Learning Outcomes
After the completion of this activity, it is expected that students should be able to

  • identify the difference between macroscopic, particle and symbolic representations draw macroscopic, particle and symbolic representations for simple systems (such as liquid water, salt solution, etc.)
  • translate a particle representation into a symbolic representation for a simple reaction
  • read a basic solubility table and translate this into macroscopic, particle and symbolic representations
  • use different types of representations to determine products, spectator ions, or reactants
Equipment needs: 

None unless you plan to explode a hydrogen balloon (integrated into #4 on the worksheet). Then you will need a candle on a stick, lighter, hydrogen balloon (or hydrogen and oxygen mix) and goggles.

Implementation Notes: 

I use the hydrogen balloon during the first part of the activity. It helps keep them on task or at least awake. It also helps them answer number 4 on the activity.

I have the students work in small groups (no more than 4 per group, 3 is good) on this activity. I use clicker questions following each part of the activity to help check their understanding (and help me to know if I should continue or go back). It is also great to help monitor their success on the learning outcomes. I have each student respond to the clicker questions, but they are encouraged to discuss the question in their group before responding.

Time Required: 
50 minutes
Evaluation
Evaluation Methods: 

I split this activity up into three parts and usually use clicker questions after each part. These are all multiple choice and are uploaded in a linked problem set.

Evaluation Results: 

I have used some of these as exam questions in general chemistry I with approximately 400 students. The results of this are given following the question.

Creative Commons License: 
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