Use of Viscosity in Qualitative Analysis

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 5 Issue 4 (2000) pp 190 -192

Use of Viscosity in Qualitative Analysis

Michael D. Mosher* and Chris Saw

Department of Chemistry, University of Nebraska at Kearney, Kearney, NE 68849-1150

Published online: 1 August 2000

Abstract. There are many examples of undergraduate laboratory experiments that illustrate physical properties (i.e., melting point, boiling point, refractive index, density). There are relatively few examples of the use of viscometry in the freshman and sophomore laboratories. Moreover, the use of viscometry is usually treated in the same fashion as melting point determinations (comparison of the experimental viscosity to the literature value.)
The experiment reported here describes a laboratory exercise that uses viscosity to illustrate the principles of an analytical method. Students prepare a standard curve comparing viscosity to the length of the carbon chain in a series of alcohols or alkanes. Students then measure the viscosity of an unknown straight-chained compound to determine its identity.
The experiment is suitable for students in high school or in freshman- or sophomore-level college chemistry classes. The experiment gives students a greater understanding of both viscosity and the use of analytical methods to qualitatively explore an unknown compound.

Key Words: Laboratories and Demonstrations; qualitative analysis

(*) Corresponding author. (E-mail: mosherm@unk.edu)

Article in PDF format (126 KB) HTML format