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ERIC Number: EJ1062288
Record Type: Journal
Publication Date: 2015-Apr
Pages: 5
Abstractor: As Provided
Reference Count: 16
ISBN: N/A
ISSN: ISSN-0021-9584
Learning Chemistry from Good and (Why Not?) Problematic Results: Kinetics of the pH-Independent Hydrolysis of 4-Nitrophenyl Chloroformate
El Seoud, Omar A.; Galgano, Paula D.; Are^as, Elizabeth P. G.; Moraes, Jamille M.
Journal of Chemical Education, v92 n4 p752-756 Apr 2015
The determination of kinetic data is central to reaction mechanism; science courses usually include experiments on chemical kinetics. Thanks to PC-controlled data acquisition and availability of software, the students calculate rate constants, whether the experiment has been done properly or not. This contrasts with their experience in, e.g., organic synthesis, where a broad melting point indicates an impure product. In order to teach quality kinetics and link theory to experiment, we used a multistep project, based on the (convenient) pH-independent hydrolysis of 4-nitrophenyl chloroformate in aqueous organic solvents. The steps of the project included statement of the experiment's objective; a quiz on reaction mechanism and experimental techniques in chemical kinetics; students' decision on the organic solvent to be employed; extraclass activity to assess their choice of the solvent; carrying out the experiment; and discussion of the results obtained. We have applied the constructivist approach to illustrate that controlling the experimental conditions (solution temperature and homogeneity) is a prerequisite for obtaining quality kinetic data. The students' evaluation was highly positive because they participated in the different steps of the project.
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