A STUDY OF HOW PRECURSOR KEY
CONCEPTS FOR ORGANIC CHEMISTRY
SUCCESS ARE UNDERSTOOOD BY
GENERAL CHEMISTRY STUDENTS
By Pat Meyer, Western Michigan University
Purpose of the study
• To determine how general chemistry students
understand the key concepts most likely to
enhance student performance in organic
chemistry
• Necessary preliminary step: survey organic chemistry instructors to
find out what general chemistry key concepts are most important for
their students to understand in order to do well.
Literature Review
• A common error students make when they study organic chemistry
is sensing the difficulty of the task before them and trying to
memorize results and algorithms. Students wrongly believe that
doing so gives them a sufficient grasp of the field. (Nahkleh, Lowry,
& Mitchell, 1996).
• Although the flashcard strategy will sometimes work for a while at
the beginning of a student’s first organic chemistry course, the belief
in this strategy’s appropriateness seems to stymie student
performance in the long run (Bradley, Ulrich, Jones, & Jones, 2002).
• The weaknesses of rote learning have been clearly demonstrated in
the literature (Bodner 1986), (Pendely, Bretz, & Novak, 1994),
(Pungente & Badger, 2003).
The Setting and the Research population
• Volunteers were solicited from one Fall section and one Winter
section of CHEM 110 (a traditional first-year general chemistry
course) and information was collected regarding their time
availability during the week. Random selection was performed on
the list of subjects who both expressed interest and had a
class/work schedule complementary to that of the interviewer.
• The majority of the potential participants in this study were
Caucasian, Midwestern USA students, and approximately 18-24
years of age.
• They varied in the amount of previous college-level science
experience, but the majority of them had only a fairly small amount
or none at all.
Instrumentation
• Covalent Bonding and Structure diagnostic instrument (Peterson,
Treagust, & Garnett, 1989). The instrument consists of multiplechoice two-tiered items. The first part of each item asks about
chemistry subject matter content, while the second part asks the
subject to choose from a list of reasons why he or she picked a
certain answer to the first part.
• The second instrument, the Geometry and Polarity of Molecules
diagnostic (Furió & Calatayud, 1996) deals with many of the same
topics. It is not a two-tiered instrument, but rather a set of 16 single
tier (traditional) multiple-choice questions, with three or four possible
answers given.
Interview Protocol
• Subjects were videotaped while attempting to work certain items and
questions from the diagnostic instruments during individual sessions
ranging from 45 minutes to an hour.
• The subjects were encouraged to “think out loud” during their efforts.
They were required to use a marker and large whiteboard for any
scratch work they did during the interview.
• Probes were used when no commentary was given, and secondary
probes were sometimes used if a subject gave an interesting
response to a certain item or question.
• Subjects were compensated by a $15 cash payment and were
encouraged by a bonus payment at the end of the series (an
additional $15) if they participated in all four interviews.
Data Collection and Methodology
• Out of 19 subjects, 16 completed all four interviews, eight in Fall and
eight in Winter.
• Subjects were asked 16 two-tiered items and up to 16 single-tiered
questions during the four hours of interviewing. Questions were
grouped by key concept during the interview sequence.
• Transcription and coding procedures were preformed on the raw
data from the videotapes.
• Lectures and the textbook were carefully studied as a check.
• When the correct and incorrect responses were studied, certain
commonalities were found across several subjects. These
responses needed to be grouped in some way to make the data
more manageable for analysis because there were hundreds of
responses and justifications collected from the subjects
Assertions 1-3
•
Many students misunderstand the location and nature
of intermolecular forces.
•
Some think electronegativity differences among atoms
in a molecule are sufficient to make the molecule polar,
regardless of spatial arrangement.
•
Most know that higher phase change temperatures
imply stronger intermolecular attractions, but many do
not understand the difference between covalent
molecular and covalent network substances.
Assertions 4-6
•
Many have difficulty deciding whether a molecule is
polar or non-polar, often confusing bilateral symmetry
with spatial symmetry in all three dimensions.
•
Many cannot reliably draw correct Lewis structures
due to carelessness and overuse of flawed algorithms.
•
Many are confused by how electrons can both repel
one other and facilitate bonding between atoms via
orbitals – this seems oxymoronic to them.
Assertions 7-9
•
Many cannot explain why the atoms of certain
elements do not follow the octet rule and some believe
the octet rule alone can determine the shape of a
molecule.
•
Most do know that electronegativity and polarity are
not adequate to determine the shape of a molecule –
but some apply the VSEPR theory in incorrect ways.
•
Students do not reason significantly differently when
working with various representations of molecules
such as ball-and-stick models, molecular formulas, and
Lewis structures.
Generalized Commentary
• Subjects 4A, 5A, 8A, 9A, and 2B mentioned the problem of
exceptions in chemistry. It seems to them that every time a rule is
given, it will soon be broken, making them question the value of the
rule in the first place.
• Subject 4A noted that “Every time you get a rule, there’s always
exceptions, and … the exception doesn’t follow the trend so you
have to memorize these thousands of exceptions. Like the Periodic
Table, boron doesn’t follow its bonding thing [the octet rule]… even
the Periodic Table isn’t solid” (4A1:10).
• Subject 8A (a fifth-year senior) in expressing frustration that this
course was going to be the first C grade she ever earned: “I want it
to click like everything else … but it doesn’t. They give us a rule and
they come up with 20 exceptions and here’s why …” (8A2:30).
Generalized Commentary
• Some subjects referred to the abstract quality of the discipline.
• Subject 4A explained how she felt the subject was difficult because
“I can’t see molecules” (4A1:57).
• Subject 8A spoke of the “weirdness of chemistry … it’s out there…
like science fiction (8A1:23).
• Subject 6B, a second-year biology major, contrasted his major field
with chemistry in explaining that biology is more hands-on and
doesn’t involve things that are too small to directly observe (6B1:12).
He was apparently unaware that molecular biology does focus on
things too small to directly observe.
Further Research
• A worthwhile investigation would be to expand and change the
recruiting of subjects to focus on current organic chemistry students.
The conceptual understanding of these students could be
statistically compared with their organic chemistry exam scores to
check the assumption that high performance on the items of the
diagnostics really does correlate to high performance in the organic
chemistry examination room.
• Assuming there is a significant difference between the performance
of these two samples, is the difference between the conceptions of
pre-organic and current organic chemistry students merely a matter
of degree (i.e. refinements of ideas) or does it reflect dramatic
“paradigm-shifts” (Kuhn, 1970) in the subjects’ thinking?
• Another expansion of the research sample, to include organic
chemistry researchers in academia and industry. How would their
performance and conceptions of the key ideas compare with that of
students? The possibility exists that the key ideas revealed in the
survey are not necessarily essential for high organic chemistry
performance in career situations …
Acknowledgements
• My family: James, Barbara, and Frank Meyer for their caring
expressed in so many ways.
• William Cobern, Marcia Fetters, Heather Petcovic, and Elke
Schoffers for sharpening my writing and thinking.
• Debra Stoyanoff and William Merrow for administrative and technical
support, respectively.
• My close friends Brian Nolan and Kimberly Jack, for listening and
giving solid advice during my data collection and writing
• My wife and best friend Cindy Meyer, for her patience, helpfulness,
and confidence in me. Mere words can neither explain nor quantify
how grateful I am for her role in my endeavors.
Works Cited
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Bradley, Alexander Z., Ulrich, Scott M., Jones, Maitland Jr., & Jones, Stephanie M. (2002). Teaching
the Sophomore Organic Course without a Lecture. Are You Crazy? Journal of Chemical
Education, 79 (4) 514-519.
Furió, C., & Calatayud, M. L. (1996). Difficulties with the Geometry and Polarity of Molecules: Beyond
Misconceptions. Journal of Chemical Education, 73 (1), 36– 41.
Kuhn, Thomas S. (1970). The Structure of Scientific Revolutions, 2nd edition. The University of
Chicago Press: Chicago, p. 10-11.
Nahkleh, Mary B.; Lowry, Kirsten A; & Mitchell, Richard C. (1996). Narrowing the Gap between
Concepts and Algorithms in Freshman Chemistry. Journal of Chemical Education, 73 (8), 758 –
762.
Pendley, Bradford D., Bretz, Richard L., & Novak, Joseph D. (1994). Concept Maps as a Tool To
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Peterson, Raymond F., Treagust, David F., & Garnett, Patrick (1989). Development and Application of
a Diagnostic Instrument to Evaluate Grade-11 and -12 Students’ Concepts of Covalent Bonding
and Structure Following a Course of Instruction. Journal of Research In Science Teaching, 26 (4),
301-314.
Pungente, Michael D., & Badger, Rodney A. (2003). Teaching Introductory Organic Chemistry:
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