- Aligned with Big Idea 6 and Learning Objective 6.18
- Emphasizes Science Practices 2, 3, 4, 5, 6, and 7
Prepare buffer solutions of assigned pH values and determine the buffer capacity of these solutions. Teach this laboratory experience using either the guided activity or inquiry activity. In the guided activity, students calculate the amounts of acid and base they need to prepare their stock acid and base solutions. Then using the Henderson-Hasselbalch equation they determine the volumes of stock acid and base solutions needed to prepare their buffers. Students then test the buffering capacity of these buffer solutions. In the inquiry activity, students choose the best conjugate acid-base pair to attain a buffer solution of desired pH and determine the concentration of the conjugate acid-base solutions needed to attain the required buffer capacity of the final solution.
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 choose the best conjugate acid-base pair for the assigned pH, calculate the pH of the concentrated acid solution, and then calculate the required mass of conjugate base to mix with the acid to achieve the assigned pH value. These questions require setting up equilibrium equations and using the Henderson-Hasselbalch equation.
This kit provides the following AP® Chemistry experiences: design a procedure to collect data, analyze data, prepare solutions, and use volumetric glassware. This experiment provides a thorough experience in both buffer preparation and buffer capacity. Materials are sufficient for 30 students in teams of 3. Digital teacher’s manual, included FREE with kit purchase or sold separately, is a 12-month eBook license to the Preparation of a Buffered Solution teacher’s manual. You can also access the digital student guide for this kit for free at
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