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2005
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In the Laboratory
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Synthesis and Physical Properties of Liquid Crystals: An Interdisciplinary Experiment
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Gerald R. Van Hecke, Kerry K. Karukstis, Hanhan Li, Hansford C. Hendargo, Andrew C. Cosand, and Marja M. Fox
Department of Chemistry, Harvey Mudd College, Claremont, CA 91711
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September 2005
Vol. 82 No. 9
p. 1349
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| Abstract |
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This experiment features an investigative approach designed for the introductory science or engineering major and integrates concepts in the fields of chemistry, biology, and physics. Derived from faculty research interests, this novel experiment gives students the opportunity to draw conclusions from tests performed to illustrate the connection between molecular structure and macroscopic properties. The chemical synthesis of the compounds studied further enhances the connection between molecular structure and macroscopic physical properties. The results of two separate physical measurements, refractometry and absorption spectroscopy, are combined to calculate a microscopic, but very practical, property of chiral nematic liquidsÑthe pitch of the helix formed in the liquid crystalline phase. This pitch depends on temperature and composition of the sample exhibiting the liquid crystalline phase, specifically the chiral nematic (or cholesteric) phase. An additional simple measurement using polarized light and a quarter wave-plate can determine the handedness of the helix.
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| Supplement |
The complete student experimental procedures, prelaboratory assignments with solutions, a MathCad worksheet for the pitch calculations, a sample grading sheet, and extra instructorÕs notes are available.
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 Contents |
Folder JCE2005p1349W containing 6 files
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| More Information |
Citation |
Van Hecke, Gerald R.; Karukstis, Kerry K.; Li, Hanhan; Hendargo, Hansford C.; Cosand, Andrew C.; Fox, Marja M. J. Chem. Educ. 2005 82 1349.
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Keywords |
Acids / Bases; Chirality / Optical Activity; Crystals / Crystallography; Curriculum; Esters; First-Year Undergraduate / General; Hands-On Learning / Manipulatives; Inquiry-Based / Discovery Learning; Interdisciplinary / Multidisciplinary; Laboratory Instruction; Molecular Properties / Structure; Organic Chemistry; Physical Chemistry; Physical Properties; UV-Vis Spectroscopy
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History |
Created:
Last Updated: |
August 2, 2005
August 10, 2005
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| Home > JCE Print > Journal of Chemical Education > Issues >
2005
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September
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1349
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