Volume Nonadditivity of Liquid Mixtures: Modifications to Classical Demonstrations

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 6 Issue 3 (2001) pp 161-163

Volume Nonadditivity of Liquid Mixtures: Modifications to Classical Demonstrations

Vladimir M. Petruševski* and Metodija Z. Najdoski

Institut za hemija, PMF, Univerzitet “Sv. Kiril i Metodij”, Arhimedova 5, PO Box 162, 1001 Skopje, Macedonia
Received September 12, 2000. Accepted March 1, 2001

Published online: 13 April 2001

Abstract. Departures from Raoult’s law are often found in liquid mixtures resulting in volume nonadditivity. Modifications are proposed for experiments demonstrating volume contraction of water/ethanol and volume expansion of ethyl acetate/carbon disulfide liquid mixtures. A layer of paraffin oil or water is used to prevent mixing of the liquids at an earlier stage then desired. A demonstration of volume expansion in a CS₂/ethyl acetate system is proposed as well. The modifications significantly improve the ease of the demonstrations, which can be made even more impressive by coloring the liquids. A reaction vessel of simple construction is offered for a more vivid demonstration of the phenomenon.

Key Words: Laboratories and Demonstrations; physical chemistry; general chemistry; Raoult; volume contraction; volume expansion; intermolecular forces

(*) Corresponding author. (E-mail: vladop@iunona.pmf.ukim.edu.mk)

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Supporting Materials:

Movies and Photographs of demo (7.54 MB ZIP file) 10.1007/s00897000477b

Photo 1 (239 KB) JPEG file
Photo 2 (201 KB) JPEG file
Movie 1 (4.59 MB) AVI file
Movie 2 (2.95 MB) AVI file