Description
Identify 3 food dyes in powdered drink mixes using paper chromatography and identify the components in plant pigment using thin-layer chromatography. Teach this laboratory experience using either the guided activity or inquiry activity. In the guided activity, students separate the components of 3 drink mixes using paper chromatography and identify each food dye by comparison with paper chromatography separations of pure food dyes they prepare. Using thin-layer chromatography, students separate the components of a plant pigment and identify the components by color and Rf value.
In the inquiry activity, students design an experiment to separate food dyes in drink mixes and must select the proper mobile and stationary phases to effect an efficient separation. The inquiry activity provides an opportunity for students to present their experiment design and results, reinforcing the practice of communicating findings. Detailed preparation and procedure notes guide the teacher through leading a successful inquiry exercise, including a suggested rubric for assessing student performance.
Both activities include assessment questions that follow the format of the AP® Chemistry Exam free-response questions. In the assessment, students consider how interactions between components of a mixture with a mobile phase and stationary phase effect a separation, describe the use of methods other than chromatography to separate mixtures, and design an experiment to separate the components of a water-soluble pen.
Provides the following AP® Chemistry experiences: design a procedure to collect data, analyze data, tabulate data, perform error analysis, and perform multiple trials. The use of food dyes and commercial drink mixes connects the concepts of separation science to the real world and captures students’ interest. Materials are sufficient for 30 students working in teams of 3. Digital teacher’s manual, included FREE with kit purchase, is a 12-month eBook license to the Principles of Chromatography teacher’s manual. You can also access the digital student guide for this kit for free at
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