30 Jul 2012

Stoichiometry Roadmap

In-Class Activity

Submitted by Craig J. Donahue, U. of MIchigan-Dearborn
Categories
Prerequisites: 
Corequisites: 
Course Level: 
Description: 

 

I use this Stoichiometry Roadmap in my first semester General Chemistry course.  The students are given an In-Class Exercise involving a stoichiometry problem and given 10-12 minutes to complete the assignment and turn it in.  When I go over this problem in class with the students I use this roadmap to help solve the problem.  I encourage the students to use this roadmap when they work stoichiometry homework problems.  This roadmap incorporates most of the concepts or relationships one typically encounters in stoichiometry - atomic or molar mass, density, Avogadro’s number, molarity, and mole ratios.  The roadmap illustrates that we are restricted in how we can successfully go from one quantity to other.  That is, the double-headed arrows represent allowed pathways and the call-out box associated with a double-headed arrow identifies the concept we use to go from one quantity to other.  I also emphasize that moles are located in the middle of this roadmap because moles are the bridge from one type of atom/molecule to another. 

AttachmentSize
File Stoichiometry Roadmap - Final.pptx90.55 KB
Learning Goals: 

The student  should be able to apply the stoichiometry roadmap to solve a one-step problem (e.g. grams to moles), a two-step problem (e.g. milliters A to grams A to moles A), a three-step problem (e.g. grams A to moles A to moles B to grams B),  a four-step problem (e.g. milliliter A to gram A to moles A to moles B)., etc.

 

 

Equipment needs: 

Calculator or slide rule.

Implementation Notes: 

I would suggest you use this roadmap with your students first so you can illustrate how to use it.  After that I just encourage the students to refer to the roadmap whenever they are working/practicing stoichiometry problems.

Evaluation
Evaluation Methods: 

In-Class Exercises, Problem Sets, and Exams.

Evaluation Results: 

I sent this roadmap to my daughter who was taking General Chemistry at another university.  She commented that she found it to be very useful.  A few days later she contacted me to ask if she could make copies of the roadmap for her friends.  They had seen her using the roadmap and wanted one of their own.

Creative Commons License: 
Creative Commons Licence

Comments

This looks interesting.  I am teaching gen chem this fall, so may give it a try.  We do extra practice with stoichiometry problems as part of our labs, too, so I'm going to give our lab coordinator a heads up about this to see if she wants to use it.

I just gave this to my prep chem class to help them get used to stoichiometry problems.  I think they'll find it very helpful.

 

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