Stoichiometry: An inquiry-based general chemistry activity

This page authored by Paul Frazey, Whatcom Community College
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Initial Publication Date: December 31, 2016

Summary

In this inquiry-based classroom activity, students build an understanding of stoichiometry through the analogy of building bicycles. Students are presented with a model in which bicycles are built from packages of parts of particular masses. Students are then asked to apply the model to the calculation of the number and masses of bikes that can be built from certain masses of packages of parts. Finally, students extend the application of the model to the calculation of the number and masses of molecules that can be produced from certain masses of reactant molecules.

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Learning Goals

The goal of this activity is for students to perform calculations involving

chemical symbolism
chemical equations
the mole
counting by weighing
stoichiometry
limiting reactant
theoretical yield

If implemented using the POGIL approach, students will practice

model investigation
critical thinking
application
collaboration

Context for Use

This activity was designed to be used in the early stages of the development of stoichiometry in college-level general chemistry. The activity was designed to be used with the POGIL(Process-Oriented Guided Inquiry Learning) approach.

Description and Teaching Materials

This activity is designed to be implemented using the POGIL (Process-Oriented Guided Inquiry Learning) approach. For more information on this approach, see the POGIL website at https://pogil.org/

All that is needed to implement this activity are printed copies of the activity and a periodic table. The activity takes approximately 2 hours of class time to complete. Alternatively, the first half of the activity could be assigned for completion prior to class. Students could then discuss their answers prior to working on the second half of the activity as a group in class. Student handout for stoichiometry acitvity (Microsoft Word 41kB Nov26 16)

Teaching Notes and Tips

Stoichiometry is often a difficult concept for general chemistry students. This is due at least in part to the high degree of symbolism involved and misconceptions about what the balanced chemical equation represents. This activity was designed for students to discover then concepts of stoichiometry using an inquiry-based approach in which students work in groups to construct their understanding. Using the POGIL approach, students have assigned roles in the group which should facilitate constructive group work. The instructors role is only to make sure that groups are working effectively and efficiently through the activity. Groups generally achieve consensus and come to the appropriate conclusions. The POGIL approach allows for various approaches for larger discussions. Some examples included sharing spokespersons between groups, reporting out, and simultaneous reporting.

Assessment

Formative assessment can be conducted through reporting out and class discussion. The instructor should also circulate through the classroom to monitor the progress that students are making. If summative assessment is desired, the instructor can collect and grade the assignment, although this is generally not part of the POGIL approach. Alternatively, the instructor could have a quiz on the content of the activity during the following class period.

References and Resources

For information on the POGIL approach and descriptions of how to set up groups, see the POGIL website at the following URL
https://pogil.org/