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Teaching Methods

teaching stoichiometry

Started almost 2 years ago by Loyola Pasiewicz.


Students often struggle with understanding stoichiometry. I have taught stoichiometry using both dimensional analysis and proportions.  In my experience students who struggle with algebra, also struggle with setting up the dimensional analysis, but can successful do stoichiometry using a series of proportions.  While I try to explain the benefits of dimensional analysis, I also allow students to do their stoichiometry using a series of proportions. I'm wondering if others have had similar experiences in teaching stoichiometry and if one way is better or more preferred than the other?  Or, does anyone have other suggestions for ways to teach stoich? 


5 Comments

  • Sherri Rukes

    Posted over 1 year ago

    I usually try to show students many ways of doing these types of problem.  I show the factor label, ratio, the ICE table method, etc to the students and then they do a class vote on which method I will continue to use in the classroom.  However, I tell the students that any method is good for me.  The important take away is understanding why we are doing what we are doing.  The method is not important.  All methods have their pluses ad minuses, but I do notice doing the ICE table method for Stoich helps when we get to equilibrium and they do the same type of thing.  For many teachers, the only time they do factor label method is during stoich and not any other time in the course of the class.

  • Julie Cox

    Posted almost 2 years ago

     I'd ask your math department as to which they think your students would have more experience using.  Then I'd use the exact language your math teachers do. If they say "cross multiply & divide" then use that. I've found that my students see coversions & stoichiometry as just "applied math". I don't even use the term stoichiometry with students because I've never really seen the point of giving a special name to something that's just conversions. That being said I'll teach any student who is struggling with one technique (say proportions) I'll teach the other (dimensional analysis). (I've usually found in a class of 30, 25 use proportions, 3 use dimensional analysis, & 2 just don't do it).  

  • Mark Maurer

    Posted almost 2 years ago

    I have found the following graphic organizer to be helpful to students. I have a more elaborate version for AP Chem.

  • Kimberly Duncan

    Posted almost 2 years ago

    Hi Loyola - You may want to check out the webinar that Kaleb Underwood presented last week: A Visual and Intuitive Approach to Stoichiometry (https://teachchemistry.org/professional-development/webinars/a-visual-and-intuitive-approach-to-stoichiometry). His presentation explained the table set up method that he uses to teach stoichiometry to his students.

  • Ryan Johnson

    Posted almost 2 years ago

    Hi Loyola!

    Thanks for your awesome question! Ahhh, the "dreaded stoichiometry"...I wonder how and why it got such a bad name as the tough thing in chemistry, when it's really pretty self-explanatory!
    I definitely applaud your use of proportionalities, I think that when students realize that dimensional analysis is really just long conversions based on equalities, it's helpful. I also usually start off my mole/stoichiometry unit with a review of doing conversions using simple units, like converting miles to inches, or seconds to years, or something along those lines. Then we introduce the mole, and then review balancing chemical equations, as a lead-in for stoichiometry.

    Some other GREAT resources out there are the PhET simulations on balancing equations...they use a bread/meat/cheese analogy to introduce stoichiometry and also limiting reactant/excess reactant. This can be found at https://phet.colorado.edu/en/simulation/reactants-products-and-leftovers
    This allows students to start to build their use of "for every" language, which I also have students model. (i.e. "for every 2 moles of hydrogen, we can produce 2 moles of water", etc.) Once students realize that it's just a kind of "recipe", it seems to help them with this concept.

    Speaking of recipes, that's another analogy I use with good effect; point out that a recipe can be multiplied or divided, as long as the ingredients still have the same proportions. This is something accessible to most students, as they've all cooked or helped cook at home!

    I hope these suggestions help, and if you have any other questions, please feel free to ask!

    Ryan Johnson
    Chemistry/AP Chemistry teacher
    Sierra HS, Colorado Springs, CO