Multi-Pronged Approach to Learning: Clearing Up Organic Chemistry Confusion

Vol. 4 2025

Ivan A. Shibley Jr.

David J. Aurentz 

Abstract

To support students’ understanding of content and their ability to articulate their understanding, we have developed a teaching system that uses metaphors, interactive diagrams, online open book quizzes, and unannounced quizzes to teach about organic chemistry.

     We both teach undergraduate Organic Chemistry I and Organic Chemistry II, with class sizes of 30-55 students and, in which, most our students are pursuing either a science or an engineering major. We have found that with a variety of activities: metaphors; in class practice; online, open book quizzes; and unannounced quizzes, in combination, the strategies support students overcoming their misconceptualizations and students are able to correctly articulate their knowledge. At the same time students’ content knowledge is strengthened, thinking through and explaining an initially puzzling concept, in a variety of formats, strengthens students’ metacognition.

How do we help learners understand electrons are in motion, rather than atoms – and how can we help students develop a vocabulary to describe electron motion?

     A concept that many students have had difficulty with is electron motion. Therefore, in both Organic Chemistry I and II, we weave learning about electron motion throughout the course. To think like a chemist requires conceptualizing that electrons form bonds. However, learners falsely believe that it is atoms that are in motion, to form bonds. How do we help change the mind of learners so that they understand electrons are in motion, rather than the atoms – and how can we help students develop a vocabulary to describe electron motion?

Metaphors

      We provide metaphors in our classes, to assist students in thinking about organic reactions. For example, we have invited students to think of electrons, as the prongs on a power cord, on a toaster. You would not demonstrate plugging in a cord by ripping the outlet from the wall and bringing it to your toaster. Yet to move an atom toward electrons would be akin to such an absurdity.

     Another metaphor is thinking of electrophiles as a hole in the ground. The nucleophile must fill the hole; the hole does not leave the ground to find the dirt. We have considered using a visual on a slide, such as plugging in a power cord, but, so far, have only used verbal metaphors.

In-Class Practice

     As Freeman et al. (2014) assert, students need to practice. To facilitate practice, we have created worksheets that illustrate electron motion, in a variety of ways. One item provides reactants and products, and students must identify the nucleophile. Another question shows reactants and products, and instructs students to draw arrows, to indicate the flow of electrons in the mechanism. Another item asks students to draw the structures of the products, based on the reactants and arrows provided. In addition, we ask students to draw a mechanism, if we provide a verbal description of the mechanism; and we ask students to write a verbal description for a mechanism that we provide. (See Appendix for sample worksheet items.)
 
     The most cognitively demanding items are ones where students are asked to draw arrows and products, given only a set of reactants. We use the in-class worksheets, unannounced quizzes, and online quizzes to help students develop an understanding of chemistry mechanisms, from a variety of perspectives.

A chemical mechanism describes what takes place, at each stage, of a chemical reaction. It describes how a reaction takes place – the sequence from reactants to products. However, the detailed steps of a reaction are not observable.

Source: Soderberg, T. (n.d.) 6.2: A First Look at Some Organic Reaction Mechanisms. LibreTexts.

     We help students develop skills by doing problems—identifying nucleophiles, drawing arrows, and predicting products—to develop the skills necessary to solve a mechanism problem with only the reactants shown. As students read the questions on the worksheet, students are learning how to communicate the motion of electrons. As they identify nucleophiles, write arrows, write verbal descriptions, and draw products, the students are learning to think carefully and critically about electron motion.

     If the class is small enough, we might circulate around the class and look at each student’s work. As another scaffold, we have undergraduate peer mentors who, already, have completed Organic Chemistry and who attend every class, a design we adopted from our general chemistry course (Amaral & Shank, 2010; Amaral, Shank, Shibley, & Shibley, 2013). The mentors have been trained to patiently explain to students where they have made a mistake. 

Online Quizzes

     Another way we promote students’ learning is with weekly online, open book quizzes. The quizzes are designed to align with the learning objectives for the course and we have created an extensive database of questions, for each topic, so that students can take the quiz multiple times, without seeing the same problem twice. We give students three attempts per quiz, with only the highest score counting toward the grade. The online quizzes cover all the material from the class’s assigned book chapter, in a multiple-choice, multiple-select, or fill in the blank type of question. Gradually, electron motion questions have been added, and reflect the work done in class.
 
     While we have not formally assessed the utility of open book quizzes, we do know that our students perform well on their exams. The importance of the online quizzes seems to be the immediate feedback students receive, and that the quizzes require students to rehearse material from class.The goal of the quizzes is to help students structure their outside of class studying. Rather than telling students to “study the material” the quizzes help guide their studying.

     Online work is cognitively related to, yet distinctly different from, the in-class worksheets. In the online quizzes, students do not draw arrows or write organic structures. Instead, in their online quizzes, students select among possible answers. The deliberate practice of an online quiz allows students to receive immediate feedback, at any time, which cannot be accomplished with the written worksheets. In the online quizzes, we aim to provide students with questions that help them rehearse mechanisms, to foster deeper understanding.
 

Unannounced Quizzes

     Unannounced quizzes are given to students to encourage students to think about a concept, without advanced planning. The unannounced quizzes cover information that is difficult to assess in an online format, such as drawing arrows, writing the structure of a product, or writing a mechanism based on a verbal explanation. Because of the number of online quizzes, we initially resisted the idea of more quizzes, yet we were aware of the literature supporting the idea of frequent quizzing (Duty, 1982).

     While the students know that quizzes are given some days, they do not know which days. Students seem to take the unannounced quizzes more seriously than the online quizzes. The unannounced aspect of the quiz heightens the seriousness of the quiz, perhaps because the quiz is only taken one time, whereas the online quizzes can be taken up to three times, with only the highest score counting toward the course grade. The unannounced quizzes ask similar questions, as the type of questions that we ask on worksheets and on our PowerPoint slides, where students answer with a classroom response system.

     The online quizzes are multiple choice and open book; but like our exams, the unannounced quizzes require short answers, which was another reason for the development of unannounced quizzes. Unannounced quizzes is another way to propel our goal of getting students to study, regularly. We also want to encourage retrieval and effortful retrieval makes for stronger learning and retention, as Brown, Roediger, & McDaniel (2014) assert. The first year we used unannounced quizzes we gave four quizzes, the next year was five, and we now give six or seven, each semester.

Reflections

     For a formal study we are conducting, we interviewed 17 students, at the end of their second semester of Organic Chemistry, in a think-aloud format. Students drew out a mechanism and talked about how they thought through electron motion, while doing the mechanism.
The metacognitive strategies that we identified by doing a qualitative analysis of the transcripts of the interviews, suggest that students have gained a sound understanding of electron motion.

     The interviews also reveal that students use metacognition to monitor their thinking about mechanisms. Our analysis coincides with the feedback we have gotten from instructors in our students’ subsequent classes: our students know how to think about their thinking. The strategies students use to analyze electron motion are transferable skills to other types of challenging problems that do not have clear answers, which demonstrates deeper learning.

          We realize that strong exam performance is not a sign of deeper learning. We do know that students, who go on to take advanced courses like biochemistry, utilize their understanding of mechanisms to help succeed in their subsequent courses. When we talk to the instructors, they tell us that our students have a well founded understanding of chemical mechanisms, and that the students are able to apply it, to biochemical pathways.
 In addition, the think-aloud interviews we have conducted, contribute to our belief in the effectiveness of our methods, in helping students understand and articulate potentially confusing concepts.

     We encourage our students to be persistent; and persistence is not only important for our students, it is important for us. Our PhD training gave us the content knowledge to teach about organic chemistry, but neither of us had the pedagogical content knowledge. Over time, we have developed teaching practices that promote content understanding and strengthen metacognition.

     Many of the activities utilized to help students learn organic chemistry are not as genuine as we would like, but we do try to include a lot of synthesis problems in the course, and organic chemists often have to solve synthesis problems as part of drug discovery. Also, we use chemical mechanisms, as appropriate, to further students’ learning.
 
     In addition, we constantly try to tie new material to older material. Since both authors teach Organic Chemistry I and II, we view the pedagogical process along a continuum. Another reason we hope to convey unified thinking about organic chemistry is because we do not want students to leave Organic Chemistry class, with a fragmented understanding of the subject, the way one of the authors did in his undergraduate coursework.

     We believe the activities we have described: metaphors, in-class practice with interactive diagrams, online open book quizzes, and unannounced quizzes, might be useful as part of any course’s instruction.
 

References

Amaral, K. E., Shank, J. D., Shibley, I. A., & Shibley, L. R. (2013). Web-enhanced general chemistry increases student completion rates, success, and satisfaction. Journal of Chemical Education, 90(3), 296-302. 

Brown, P. C., Roediger, H. L., & McDaniel, M. A. (2014). Make it stick : The science of successful learning. Harvard University Press. 

Duty, R. C. (1982). Weekly or biweekly quizzes in organic chemistry: Does it make a difference? Journal of Chemical Education, 59(3), 218. 

Freeman, S., Eddy, S. L., McDonough, M., Smith, M. K., Okoroafor, N., Jordt, H., & Wenderoth, M. P. (2014). Active learning increases student performance in science, engineering, and mathematics. Proceedings of the National Academy of Sciences,111(23), 8410-8415.

Ivan A. Shibley Jr., PhD, is Associate Professor of Chemistry and Chair, Division of Science. Penn State Berks, The Pennylvania State University. Ivan A. Shibley Jr can be reached at ias1@psu.edu.

David J. Aurentz, PhD, is Associate Professor of Chemistry, Division of Science, Penn State Berks, The Pennsylvania State University. David J. Aurentz can be reached at dja5@psu.edu.