Effective solution chemistry instruction by integrating live pC–pH diagrams into PowerPoint

Abstract

AbstractpC–pH diagrams provide a graphical illustration of chemical speciation as a function of pH and are hence a very effective tool for understanding the chemical system being studied. This understanding can lead to assumptions that simplify problem solving. However, manual construction of pC–pH diagrams for multiprotic systems is cumbersome and is further complicated by non‐standard temperature and ionic strength conditions. As a result, construction of pC–pH diagrams can become the focus of classroom teaching rather than their application to solving real‐world problems. Students tend to get lost in the complexities of pC–pH diagram construction and often fail to appreciate their value in problem solving. To address this limitation, we have developed interactive pC–pH diagrams for mono, di, and triprotic systems that are all bundled into a single PowerPoint file. The governing equilibrium equations are presented adjacent to the pC–pH diagram which makes the entire process transparent. The diagrams update in real‐time when the total concentration and pKa are changed by the user making them universally applicable to any mono, di, or triprotic system. Temperature impact on pKa and the pC–pH diagram can also be examined for some commonly encountered systems. Because of PowerPoint integration, there is no learning curve and specification of pKa is typically all that is required to use these diagrams. A real‐world application of these interactive pC–pH diagrams is presented by examining the solution chemistry in therapeutic protein‐producing mammalian cell bioreactors. The cause of high bioreactor CO2 concentration and strategies to overcome it were determined just by using the interactive pC–pH diagrams without resorting to numerical calculations. We believe these easy to use and interactive pC–pH diagrams could be more extensively used for problem solving in the classroom simultaneously enhancing student understanding of the chemical system being studied. The PowerPoint file with the pC–pH diagrams is available free of charge for academic use. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 20: 741–749, 2012