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ERIC Number: EJ1048344
Record Type: Journal
Publication Date: 2014-Dec
Pages: 5
Abstractor: As Provided
Reference Count: 9
ISSN: ISSN-0021-9584
From Voltage to Absorbance and Chemical Kinetics Using a Homemade Colorimeter
Delgado, Jorge; Quintero-Ortega, Iraís A.; Vega-Gonzalez, Arturo
Journal of Chemical Education, v91 n12 p2158-2162 Dec 2014
The use of the Beer-Lambert law in spectroscopy is the core of standard methods for determining a chromophore concentration in a solution. Its application requires an understanding about interaction of light with a colored solution and the use of light emission and light detection devices. We build here a simple electronic circuit formed of light-emitting diodes and light-dependent resistors that can be used for measuring chromophore concentrations during experiments focused on chemical kinetics: decolorizing of phenolphthalein in a basic solution, and reduction of methylene blue by ascorbic acid. From the chemical point of view, the goal is to determine experimentally the rate law. In addition, students understand, using inexpensive electronics, the basic design of a spectrophotometer to achieve successful measurements of absorbance.
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: Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A