Lindlar Catalyst: Its Discovery, Magic and Mystery

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 25 (2020) pp 25-30

Deriving the Relationship Between Absorbance and Transmittance: An Inquiry-based Activity

Sarah E.C. Gray*^,†,‡, Lea W. Padgett^‡, Ruthanne H. Paradise^§_,Joshua Williams**

^†Chemistry Program, School of Natural Science and Mathematics, Stockton University, 101 Vera King Farris Dr., Galloway, NJ, 08205, sarah.gray@stockton.edu;^‡Department of Chemistry and Biochemistry, Georgia Southern University, Savannah, GA, 31419; ^§Department of Chemistry, University of Massachusetts, Amherst, MA, 01003; **Department of Psychology, Georgia Southern University, Savannah, GA, 31419 Received September 5, 2017. Accepted January 14, 2020.

Published: 19 February 2020

Abstract. Understanding the relationship between absorbance and transmittance is critical to understanding how spectroscopic measurements work, yet many students struggle with grasping the logarithmic nature of the relationship. Students often also have difficulty analyzing laboratory data in spreadsheet programs, due to a lack of experience. Here, an inquiry-based activity conducted in the laboratory component of an undergraduate analytical chemistry course is described. In the activity, students derive the relationship between absorbance and transmittance using wooden blocks and a grid as a model. The model is converted into mathematical values that are used to teach graphing and statistical analyses in a spreadsheet program. Students completed a pre- and post-test to survey their content knowledge and technical skills related to the activity. Results show a statistically significant increase in the overall percent of correct answers from the pre- to the post-test, as well as a significant increase on individual questions related to technical skills and to content knowledge about trendline fits of data.

Key Words: Laboratories and Demonstrations; analytical chemistry; quantitative analysis; statistical analysis inquiry-based/discovery learning modeling of absorbance data

(*) Corresponding author. (E-mail: sarah.gray@stockton.edu )

Article in PDF format (192 KB) HTML format

Supporting Materials:

The Absorbance vs. Transmittance student handout, the Absorbance vs. Transmittance Instructor’s notes, the pre/post-test, and a sample data set are available in a Zip file. (341 KB)