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The Chemical Educator

ISSN: 1430-4171 (electronic version)

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Abstract Volume 10 Issue 1 (2005) pp 24-25

"Order-to-Disorder" for Entropy Change? Consider the Numbers!

Evguenii I. Kozliak*,† and Frank L. Lambert

Department of Chemistry, University of North Dakota, Grand Forks, ND 58202-9024, and Professor Emeritus, Occidental College, Department of Chemistry, Los Angeles, CA 90041,
Received June 8, 2004. Accepted November 16, 2004.

Published online: 21 January 2005

Abstract. Defining entropy increase as a change from order to disorder is misleading at best and incorrect at worst. Although Boltzmann described it this way in 1898, he did so innocently in the sense that he had never calculated the numerical values of W using ΔS = kBln (W/W0) (because this equation was not stated, kB was not known, and W0 was indeterminable before 1900–1912). Prior publications have demonstrated that the word “disorder” is misleading in describing entropy change. In this paper, convincing evidence is provided that no starting system above ca. 1 K can be said to be orderly so far as the distribution of its energy (the fundamental determinant of entropy) is concerned. This is supported by a simple calculation showing that any system with “a practical state of zero entropy” has an incomprehensibly large number of microstates.

Key Words: In the Classroom; physical chemistry; general chemistry; thermodynamics; statistical mechanics; entropy

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Issue date: February 1, 2005

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