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A novel code system for revealing sources of students' difficulties with stoichiometry

Gulacar, Ozcan; Overton, Tina L.; Bowman, Charles R.; Fynewever, Herb


Ozcan Gulacar

Tina L. Overton

Charles R. Bowman

Herb Fynewever


A coding scheme is presented and used to evaluate solutions of seventeen students working on twenty five stoichiometry problems in a think-aloud protocol. The stoichiometry problems are evaluated as a series of sub-problems (e.g., empirical formulas, mass percent, or balancing chemical equations), and the coding scheme was used to categorize each sub-problem solution as successful, neutral, or unsuccessful, with more detailed codes comprising the neutral and unsuccessful categories, for a total of eight codes. A relatively high frequency of neutral results was found in which students simply did not realize when or how to approach a sub-problem. A lack of conceptual understanding of the mole concept appears to be closely related to students skipping crucial steps in stoichiometry problems, especially the sub-problems stoichiometric ratio and mole concept. Students' failures were also observed to be due to a lack of basic knowledge, such as the names of chemical compounds. The application of the new code system was shown to reveal difficulties that might have otherwise been missed by an analysis that focused on end results only. © The Royal Society of Chemistry.


Gulacar, O., Overton, T. L., Bowman, C. R., & Fynewever, H. (2013). A novel code system for revealing sources of students' difficulties with stoichiometry. Chemistry Education Research and Practice, 14(4), 507-515.

Journal Article Type Article
Acceptance Date Jun 24, 2013
Online Publication Date Jul 15, 2013
Publication Date Jul 15, 2013
Deposit Date Nov 13, 2014
Journal Chemistry Education Research and Practice
Print ISSN 1756-1108
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Volume 14
Issue 4
Pages 507-515
Keywords Education; Chemistry (miscellaneous)
Public URL
Publisher URL!divAbstract
Contract Date Nov 13, 2014