- Aligned with Big Idea 4 and Learning Objective 4.2
- Emphasizes Science Practices 2, 3, 4, 5, 6, and 7
Determine orders of reaction, calculate reaction rate constants, and write rate laws for the oxidation of 4 food dyes. Teach this laboratory experience using either the guided activity or inquiry activity. In the guided activity, students mix a food dye with bleach and monitor the solution’s absorbance over time. From their Beer-Lambert graph of absorbance as a function of time, students determine the order of the dye and the sodium hypochlorite and use the slope to calculate a pseudo rate constant. Students then use their data to determine the overall order of the reaction, write an integrated rate law for the reaction, and calculate the reaction’s rate constant. In the inquiry activity, students design an experiment to determine the overall order of reaction, rate law, and rate constant for the oxidation of a food dye by sodium hypochlorite.
Both activities include Big Idea assessment questions that follow the format of the AP® Chemistry Exam free-response questions. In the Big Idea assessment, students must determine the overall order of reaction, rate law, and rate constant for a new reaction with data provided. They must also design an experiment to determine these parameters given only the reaction.
This kit provides the following AP®: Chemistry experiences: design a procedure to collect data, analyze data, plot data, and use instruments to measure absorbance. The use of commercial food dyes and bleach gives this experiment visual appeal and a connection to the real world. Required but not included: spectrophotometer or colorimeter. Materials are sufficient for 30 students working in pairs. Digital teacher’s manual, included FREE with kit purchase or sold separately, is a 12-month eBook license to the Chemical Kinetics teacher’s manual. You can also access the digital student guide for this kit for free at
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