A Discovery Chemistry Experiment on Buffers

• Autores: Suzanne E. Kulevich, Richard S. Herrick, Kenneth V. Mills
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 91, Nº 8, 2014, págs. 1207-1211
• Idioma: inglés
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• Resumen

  • The Holy Cross Chemistry Department has designed and implemented an experiment on buffers as part of our Discovery Chemistry curriculum. The pedagogical philosophy of Discovery Chemistry is to make the laboratory the focal point of learning for students in their first two years of undergraduate instruction. We first pose questions in prelaboratory sessions that serve as the focus for discussion and that guide inquiry in the lab.

    We then use the experimental results to guide the lecture-hall discussion and discovery of chemical principles. In this experiment, students first discover the Henderson-Hasselbalch equation using pooled student data for three buffers. Students also discover the qualitative effects of buffers by examining the influence of the addition of a strong acid, a strong base, or water on the pH of a buffered solution versus that of nonbuffered solutions. Using their pooled results and knowledge of titration curves discovered in the previous lab, students gain a qualitative and quantitative understanding of buffers and report increased confidence in making buffered solutions