Showing Substitution and Elimination With Real-Life Examples

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Showing Substitution and Elimination With Real-Life Examples Bob Hanson St. Olaf College, Northfield, MN http://www.stolaf.edu/individuals/hansonr 20 th Biennial Conference on Chemical Education Indiana University July 29, 2008

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Road Map for This Presentation Background: Data-Driven Chemistry The Course: 1 st Semester Organic The Data: 39 responses The Exam: 25 questions Conclusions

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Background: "Information Driven" Chemistry produce information break down information extrapolate speculations produce theories

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Background: "Information Driven Chemistry" Start with crude information Transform the information into significant data Create a working model R. M. Hanson, S. A. Bergman, "Data-Driven Chemistry: Making Molecular Models (Literally) from Electron Diffraction Data", J. Chem. Educ. 1994, 150

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Background: concentrate on investigation break down information (distinguish patterns) create information (trial) produce speculation (clarify shapes and patterns) extrapolate theory (anticipate shapes)

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Application: natural science examine information (recognize patterns) create information (trial) create theory (clarify responses) extrapolate theory (foresee responses)

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The Course 1 st semester of a standard two-semester course 55 understudies in my area (approx. 120 understudies add up to): 39 sophomores 13 youngsters 3 seniors Textbook: Paula Bruice, Organic Chemistry , 5 th ed.

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Focus: substitution and end investigate information (recognize patterns) produce information (test) create theory (clarify responses) extrapolate speculation (anticipate responses)

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Data Sources Ingold, Structure and Mechanism in Organic Chemistry, second Ed. , 1969 Compendium of Organic Synthetic Methods , 1971 M: March, Advanced Organic Chemistry, third Ed ., 1985 V: Vogel, Textbook of Practical Organic Chemistry, fifth Ed. , 1989

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The Data

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The Data

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The Data

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The Data

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The Data

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The Data

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The Data

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The Data

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The Data

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The Data

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The Exam 55 minutes 25 various decision questions Instructions: For every situation, read every conceivable reply, utilize a procedure of disposal, and circle the BEST reply. In the event that you are experiencing difficulty settling on two answers, quickly clarify your last decision. In the event that you do as such, utilize only a couple words, just to enlighten me to what you are considering. Try not to harp on a specific issue for an augmented timeframe. Every question is worth 2 focuses.

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The Exam

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The Exam

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The Exam

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The Exam

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The Exam

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The Exam

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The Exam

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The Exam

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The Exam normal score: 75% (normal exam score for the semester: 73%) three extra inquiries

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The Exam This test was: (an) Easier than I suspected it would be. (b) Somewhat harder than I suspected it would be. (c) WAY harder than I suspected it would be.

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The Exam This test was: (an) Easier than I suspected it would be. 15 (b) Somewhat harder than I suspected it would be. 14 (c) WAY harder than I suspected it would be. 1 (d) Maybe a bit harder. 1 (e) About as hard as expected. 16 (f) Not too bad. 1

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The Exam I think taking a gander at the information along these lines… "… is GREAT, I took in a considerable measure!" "… appears to apply to this present reality more so than the book." "… makes for a fascinating method for finding out about these responses." "… truly works with the way I think. I enjoyed it a considerable measure!"

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The Exam I think taking a gander at the information along these lines… "… is GREAT, I took in a ton!" "… appears to apply to this present reality more so than the book." "… makes for an intriguing method for finding out about these responses." "… truly works with the way I think. I preferred it a considerable measure!" "… you can see and thoroughly consider all parts of the response, doesn't feel as much like retention and spewing forth of information… you can thoroughly consider why an answer is correct or wrong in examination with others."

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Conclusions 1/3 For the most part, understudies "got it." Generally, understudies did not experience difficulty with the meanings of S N 1, S N 2, E1, and E2. A critical number of the understudies were all the while experiencing difficulty distinguishing solid and powerless bases.

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Conclusions 2/3 Stereochemical ideas and documentation were incorporated into 6 of the 25 questions (24%). For these inquiries, 77% of the reactions were right. In any case, appropriate pivotal/central examination was basic for 4 of those 6 questions, and for those, the normal was to some degree bring down – 68%.

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Conclusions 3/3 Using an information driven approach can work in natural science. Understudies meet people's high expectations of guided request. Substitution and Elimination are still troublesome ideas!

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Thank you! This presentation is accessible at http://www.stolaf.edu/depts/science/bh/bcce20

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