An Inexpensive and Versatile Cryoscope for Measuring Freezing-Point Depression

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

Abstract Volume 11 Issue 6 (2006) pp 410-412

An Inexpensive and Versatile Cryoscope for Measuring Freezing-Point Depression

Domingo González-Arjona* and Cayetano Yanes Durán

Department of Physical Chemistry, Faculty of Chemistry, University of Seville, E-41012, Seville, Spain, dgonza@us.es.
Received June 2, 2006. Accepted November 4, 2006.

Published online: 1 December 2006

Abstract. An inexpensive and versatile cryoscope (the cost of the whole instrument is under $150) was designed and built. It is suitable for learning and teaching the concepts associated with colligative properties. The portability and user-friendliness make it very suitable for classroom demonstrations. Two kinds of thermometric sensors are described, a commercial one and one home made from a NTC electronic component. The data can be recorded manually or by a common RS-232 multimeter. The instrument provides an easy way of determining molecular weights, association/dissociation constants, and is even useful for near-quantitative treatment of nonideal behavior when used by undergraduate students at a more advanced level. The instrument can be easily modified for use with solvents that possess freezing points above room temperature.

Key Words: Laboratories and Demonstrations; physical chemistry; laboratory equipment; solutions/solvents; thermodynamics

(*) Corresponding author. (E-mail: dgonza@us.es)

Article in PDF format (86 KB) HTML format