ERIC Number: EJ1253813
Record Type: Journal
Publication Date: 2020-May
Pages: 5
Abstractor: As Provided
ISBN: N/A
ISSN: ISSN-0021-9584
EISSN: N/A
Relating [delta]"H"[subscript vap] of Organic Liquids to Intermolecular Forces: Simple Modifications of a Classic General Chemistry Experiment
Fitzgerald, Jeffrey P.; Ferrante, Robert F.; Brown, Michael; Cabarrus, Jonathan
Journal of Chemical Education, v97 n5 p1406-1410 May 2020
The concept of equilibrium vapor pressure plays a key role in the general chemistry curriculum; it is among the first and most easily demonstrated examples of equilibrium and frequently caps off the first semester of general chemistry where it illustrates the properties of liquids and intermolecular forces. We report here simple modifications of Levinson's classic experiment that allow measurement of vapor pressures for organic samples at a variety of temperatures. Data analysis gives heats of vaporization which may be interpreted in terms of intermolecular attractive forces. Equipment needs are simple and readily available: a 10 mL graduated cylinder, a tall 1 L beaker, disposable graduated syringes, and a 10 in. needle or cannula bent into a "J" shape. The method uses 1 mL or less of organic sample per trial and works well for organic liquids that are immiscible with and are less dense than water. Student results are presented for the experiment conducted over three semesters as well as the impact on student learning as assessed by common exam results and end-of-semester student surveys.
Descriptors: Science Instruction, Chemistry, Science Experiments, Science Laboratories, Laboratory Experiments, College Science, Undergraduate Study, Molecular Structure, Scientific Concepts, Water, Heat
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: eic@jce.acs.org; Web site: http://pubs.acs.org/jchemeduc
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education; Postsecondary Education
Audience: Teachers
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A