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ERIC Number: EJ1452118
Record Type: Journal
Publication Date: 2023-Dec
Pages: 7
Abstractor: As Provided
ISBN: N/A
ISSN: ISSN-0021-9584
EISSN: EISSN-1938-1328
Using Indicators as Impurities to Monitor the Washing Process in the Organic Chemistry Laboratory
Sigurdur Gudni Gunnarsson; So´lru´n Eli´n Freygardsdo´ttir; O´skar Rudolf Kettler; Benjami´n Ragnar Sveinbjo¨rnsson
Journal of Chemical Education, v100 n12 p4796-4802 2023
Laboratory experiments provide training to students in experimental techniques and strengthen the understanding of the theory. Herein, a new introductory experiment for organic chemistry laboratory courses is described where students are trained in washing an unknown neutral organic compound using liquid/liquid extraction, isolating it via distillation, and identifying it using its boiling point. The use of indicators as impurities allowed for a fun visualization of the impurities appearing suddenly and students being able to see them disappear through the washing procedure. The success of the experiment was evaluated via in-lab observations, analysis of postlab reports/worksheets, and a postlab survey that included a test question. All of the students were able to wash their compounds to the point where no color from the indicators remained in the aqueous phases. Furthermore, 93% of the students were able correctly identify their unknown compound after distillation based on its boiling point, and 84% of the students explained what is happening chemically in the liquid/liquid extraction process to receive 75-100% of the points allocated for that explanation. A postlab worksheet with two general questions about how to separate organic compounds from one another using extraction, one of which was an extraction flowchart, was found to be better at helping students identify what solvent to use to wash an organic base from a neutral organic compound in the postlab survey. This shows the importance of designing well how the students work through the experiment and the experimental topic after the laboratory experiment.
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: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Grant or Contract Numbers: N/A