A STUDY OF HOW PRECURSOR KEY CONCEPTS FOR ORGANIC CHEMISTRY SUCCESS ARE UNDERSTOOOD BY GENERAL CHEMI


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A STUDY OF HOW PRECURSOR KEY CONCEPTS FOR ORGANIC
CHEMISTRY SUCCESS ARE UNDERSTOOOD BY GENERAL
CHEMISTRY STUDENTS

• By Pat Meyer Western Michigan University

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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.
  

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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 students
  first organic chemistry course the belief in
  this strategys 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).

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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.

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Instrumentation

• Covalent Bonding and Structure diagnostic
  instrument (Peterson Treagust Garnett 1989).
  The instrument consists of multiple-choice
  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.

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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.

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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

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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.

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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.

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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.

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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
  theres always exceptions and the exception
  doesnt follow the trend so you have to memorize
  these thousands of exceptions. Like the Periodic
  Table boron doesnt follow its bonding thing
  the octet rule even the Periodic Table isnt
  solid (4A110).
• 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 doesnt.
  They give us a rule and they come up with 20
  exceptions and heres why (8A230).

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Generalized Commentary

• Some subjects referred to the abstract quality of
  the discipline.
• Subject 4A explained how she felt the subject was
  difficult because I cant see molecules
  (4A157).
• Subject 8A spoke of the weirdness of chemistry
  its out there like science fiction (8A123).
• Subject 6B a second-year biology major
  contrasted his major field with chemistry in
  explaining that biology is more hands-on and
  doesnt involve things that are too small to
  directly observe (6B112). He was apparently
  unaware that molecular biology does focus on
  things too small to directly observe.

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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

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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.

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Works Cited

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