Is mixing a thermodynamic process?
作者:
A. Ben‐Naim,
期刊:
American Journal of Physics
(AIP Available online 1987)
卷期:
Volume 55,
issue 8
页码: 725-733
ISSN:0002-9505
年代: 1987
DOI:10.1119/1.15064
出版商: American Association of Physics Teachers
关键词: THERMODYNAMICS;MIXING;ENTROPY;FREE ENERGY;IRREVERSIBLE PROCESSES;CHEMICAL POTENTIAL;STATISTICAL MECHANICS;GASES
数据来源: AIP
摘要:
Mixing processes exist with positive entropy change and negative free energy change. However, the idea that theirreversibilityof the mixing processes is responsible for the so‐called free energy and entropy of mixing is faulty. The mixing, as well as the demixing processes may be associated with either reversible or irreversible phenomena, depending on the particular conditions. For ideal gases, the word ‘‘mixing’’ in the terms ‘‘mixing entropy’’ and ‘‘mixing free energy’’ may sometimes be useddescriptivelybut nevercausatively. The quantity −∑NiR ln Xi, usually referred to as ‘‘mixing entropy,’’ has nothing to do with the mixing phenomenon. Therefore the terms ‘‘mixing entropy’’ and ‘‘mixing free energy’’ are essentially misconceptions. In fact, it is shown that the process of mixing of ideal gases has, by itself, no relevance to any thermodynamic quantity. Therefore, in a thermodynamical sense, it is a nonprocess. The concepts of assimilation and deassimilation are introduced. It is shown that the ‘‘deassimilation process is essentially irreversible.’’ This should replace the traditional principle that ‘‘the mixing process is essentially irreversible.’’
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