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The Chemical Educator
ISSN: 1430-4171 (electronic version)
Abstract Volume 16
(2011) pp 116-118
Determination of Ethylene Glycol in Engine Coolants using Refractive Index
Bettie Obi Johnson*, Fernanda M. Burke, and Samantha Burdette
University of South Carolina Lancaster, 476 Hubbard
Drive,
Lancaster, SC 29720, obijohns@mailbox.sc.edu
Received August 6, 2010. Accepted
March 1, 2011.
Published: 25 March 2011
Abstract. A simple experiment to determine the ethylene glycol concentration in engine coolant samples using refractive index is described. This laboratory exercise involves creating an external standard calibration using known mixtures of ethylene glycol and water and using the calibration to correlate measured refractive indices to unknown ethylene glycol concentrations. Students use reference data to predict the freezing point of their engine coolant samples based on the determined ethylene glycol concentration. Refractive index is a relatively simple and fast technique for determining concentration and provides an opportunity to cover the concepts of light refraction, instrumental calibration, and colligative properties of solution. The real-world relevance of this experiment makes it particularly appealing to undergraduate students in general chemistry, quantitative analysis, and analytical chemistry courses.
Key Words: Laboratories and Demonstrations; general chemistry; quantitative analysis; analytical chemistry
(*) Corresponding author. (E-mail: obijohns@mailbox.sc.edu)
Article in PDF format (73 KB) HTML format
Supporting Materials:
Student handouts are available as attachments (137 KB).
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