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ERIC Number: EJ939006
Record Type: Journal
Publication Date: 2011-Jul
Pages: 4
Abstractor: As Provided
Reference Count: 17
ISSN: ISSN-0021-9584
A Simple System for Observing Dynamic Phase Equilibrium via an Inquiry-Based Laboratory or Demonstration
Cloonan, Carrie A.; Andrew, Julie A.; Nichol, Carolyn A.; Hutchinson, John S.
Journal of Chemical Education, v88 n7 p975-978 Jul 2011
This article describes an activity that can be used as an inquiry-based laboratory or demonstration for either high school or undergraduate chemistry students to provide a basis for understanding both vapor pressure and the concept of dynamic phase equilibrium. The activity includes a simple setup to create a closed system of only water liquid and vapor where volume can be varied. As volume is varied, the vapor pressure remains constant. However, this challenges common misconceptions and can be contrasted with the same system containing only gaseous air. Through discussion, students are challenged to understand the molecular basis for the difference between the two systems and conclude that the liquid-vapor system maintains constant pressure due to phase equilibrium. Through further reasoning, the idea of dynamic equilibrium is illustrated and students come to see that particles are in constant movement within a system even though it appears stationary from the macroscopic view. (Contains 1 table and 2 figures.)
Division of Chemical Education, Inc and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Elementary Secondary Education; High Schools; Higher Education; Postsecondary Education; Secondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A