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ERIC Number: EJ820292
Record Type: Journal
Publication Date: 2006-Jul
Pages: 11
Abstractor: As Provided
Reference Count: 14
ISSN: ISSN-0021-9584
The Heat Capacity of Ideal Gases
Scott, Robert L.
Journal of Chemical Education, v83 n7 p1071-1081 Jul 2006
The heat capacity of an ideal gas has been shown to be calculable directly by statistical mechanics if the energies of the quantum states are known. However, unless one makes careful calculations, it is not easy for a student to understand the qualitative results. Why there are maxima (and occasionally minima) in heat capacity-temperature curves and where they occur are questions that are sometimes hard to answer. Fortunately, the statistical mechanical equation can be transformed to an exact variant that expresses the heat capacity as the sum of jumps from one quantum state to a higher one, and, with this, explanations become more transparent. In particular, figures show how the low-temperature rotational heat capacity arises from the sum of a very few jumps. Moreover, it is shown that the heat capacity reaches a virtually classical value long before the energy spacings become small in comparison with k[subscript B]T. (Contains 14 figures.)
Division of Chemical Education of the American Chemical Society. Subscription Department, P.O. Box 1267, Bellmawr, NJ 08099-1267. Tel: 800-691-9846; Tel: 856-931-5825; Fax: 856-931-4115; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education; Postsecondary Education
Audience: Teachers
Language: English
Sponsor: N/A
Authoring Institution: N/A