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ERIC Number: EJ820275
Record Type: Journal
Publication Date: 2006-Jul
Pages: 3
Abstractor: As Provided
Reference Count: 16
ISSN: ISSN-0021-9584
A Demonstration of the Continuous Phase (Second-Order) Transition of a Binary Liquid System in the Region around Its Critical Point
Johnson, Michael R.
Journal of Chemical Education, v83 n7 p1014-1016 Jul 2006
In most general chemistry and introductory physical chemistry classes, critical point is defined as that temperature-pressure point on a phase diagram where the liquid-gas interface disappears, a phenomenon that generally occurs at relatively high temperatures or high pressures. Two examples are: water, with a critical point at 647 K (critical temperature: T[subscript c]) and 215 bar (critical pressure: P[subscript c]); and carbon dioxide, with a critical point of 304 K (T [subscript c]) and 73 bar (P[subscript c]). In colloid chemistry, there is another critical point, which occurs at a specific temperature and mole fraction in a specific binary liquid system where immiscible or partially miscible species become completely miscible. These phenomena of colloidal systems occur at atmospheric pressure and over a temperature range which, for some systems, includes room temperature ([similar to]300 K). The purpose of this demonstration is to show this critical-temperature phase-transition phenomenon for a specific binary liquid system, where T[subscript c] is approximately 300 K. (Contains 2 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: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A