We have now approached Exam 3, which means that students have been exposed to material that includes Chapter 19 content. I am quite excited to see that my students are starting to build their “organic chemistry toolbox,” but I’ve also noticed that they are starting to confuse how and when reagents are used. While I am thrilled that they’re learning and applying these synthetic transformations, they’re more likely to use them incorrectly without routine practice, which I’m planning to take care of in class.
Back when I was a student, I remember that I tried to look at reactions according to their named classifications and/or proper transformations. For instance, reactions in chemistry can be classified as addition, substitution, or elimination; they can also be classified by their functional group: alkyl halide, alcohol, aldehyde, ketone, etc. Although I realize that our class text is not arranged according to functional groups, and I agree with Karty about the importance of teaching organic chemistry through a mechanistic organization, I’ve found that reviewing reactions with their functional group transformations can foster the growth of students’ “organic chemistry toolbox.”
To help them do so, I created a 23-page document, available on our online learning system called Cougarview (CV), as an informative study aid. I had personally received this document as a student 16 years ago, and it has continued to developed by a number of tutors, including myself, since then. The reason that I love this study guide so much is because it organizes the reactions for each functional group.
Below is an example of the isolation of alkanes and alkenes:
When taking a closer look at alkanes, we can see that there are a number of reactions included this section, such as reductions of ketones, protonation carbanion, and alkylation with organometallic reagents. When navigating through all these different reactions, I emphasize to my students that it is important to know what reagents they have and what substrates they are reacting with. Likewise, I mention that it can help to predict the product and think through retrosynthesis to figure out how to start if they ever find themselves stuck.
When brainstorming on the best ways to write exams for second-semester content, I realized that the primary struggle with assessing students on this material arises from the fact that students have learned a ton of information about mechanisms rather than single theories or rules of thumb (ROTs). In order to properly assess them on these concepts, then, the multiple-choice questions that we use would need to be rich with information. Unfortunately, though, most multiple-choice questions tend to be surface-level.
Even though I had used multiple-choice exams for our previous two exams in the first half of the semester, I wasn’t sure if they would truly do justice to assessing students’ grasp of the material presented in the second half of the semester, especially given that each lesson in class so far has been spent reviewing electron movements and other mechanistic discussions. In this case, students’ true understanding of the material at hand is directed towards explaining why nucleophiles move and attack in different positions, which can be incredibly hard to assess simply through multiple-choice questions.
Because of this roadblock, I decided to write Exams 3 and 4, as well as our Final Exam, in short-response and free-style formats. I’ve designed them so that, out of all the test questions, students will be able to pick five that they’d like to answer and be graded on, which should boost their confidence by allowing for greater flexibility. As a sneak preview of the kinds of questions that will show up on Exam 3, I divided the assessment into key sections like “provide the reagents” and “devise an appropriate synthesis.” Needless to say, I’m aware of the fact that I have created extra grading for myself by setting up our last few exams this way, but, to me, being an impactful teacher means writing exams that fairly assess the depth and breadth of students’ skill levels and knowledge.
As a disclaimer, my students won’t take Exam 3 until next week, so I haven’t seen their results just yet, but I’m hoping to read more unique and individualized responses, which should also translate into greater overall exam success. My ultimate goal with these new-and-improved assessments, though, is to nurture my students’ critical-thinking and analytical skills, which will not only help them further build their “organic chemistry toolbox,” but will also help them in all their future career paths and endeavors.
-Kerri Taylor, Columbus State University
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