Linguistic Considerations in Teaching Organic Chemistry

Language acquisition and orthography are two ideas from the field of linguistics and applied linguistics that are relevant to teaching organic chemistry.

Language acquisition in children occurs without conscious effort. By hearing examples of the language, children internally codify the rules of the language and can generate language spontaneously. This ability diminishes with age, shutting down around adolescence, which is why adults learn languages through study of rules, vocabulary, and phonetics.

As experts, our acquisition of the language of organic chemistry is an extension of our first language. Consequently, while we did learn some of the language through conscious effort during our education, there is a good deal of the language that we have absorbed through exposure. You can probably recall a term in organic chemistry that you have had to define for someone, and you found yourself creating the definition on the spot. Or you can identify something as incorrect, without ever having learned a formal rule. For example, OHCH2CH3 probably strikes you as an incorrect representation of ethanol. However, you may not recall ever formally learning that the hydrogens attached to initial heteroatoms should precede the atom and not follow it, as in HOCH2CH3. You simply know what’s “right” and “wrong.”

This last example illustrates the relevance of this topic to teaching. We expose our students to a lot of information but may not always consider whether they are capable of interpreting the information as we do. Consider the area of orthography, the written representation of language. Although orthography is most frequently associated with spelling, it also deals with punctuation and any other representation of language. We offer students a significant challenge because we have so many representations for a single item. For example, ethanol can be depicted in the following ways:

We expect students to equate these multiple representations and, in the case of the last two, correlate two-dimensional representations with a three-dimensional object.

Joel’s consideration of these issues is one of the merits of his forthcoming textbook. In the early chapters of the textbook, he addresses representations of organic molecules and lays out the rules for writing condensed formulas, line structures, and using dashes and daggers. For example, he devotes two and a half pages to this last topic, as compared to the half-page I found in a popular organic text. (The same text neglected to provide all possible representations of a simple halomethane and inserted “etc.” instead.)

He also anticipates misinterpretations. In the section on constitutional isomers, for example, he includes duplicate representations; that is, structures that students may think represent isomers but are actually alternate representations of isomers already shown. He explains why the latter are duplicates and need to be eliminated from the list of possible isomers.

Since students’ exposure to the discipline has been relatively brief, particularly at the beginning of the course, we should not assume they have an expert understanding of the language or of its representations/orthography. Explicit explanations, rules, and examples, such as those in Joel’s text, are invaluable; they help “demystify” what students encounter in the textbook and in class.

— Steve Pruett

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