Constructing interactive pC-pH diagrams for open and closed multiprotic systems

CHED 99

Chetan Goudar, chetan.goudar.b@bayer.com, R & D, Process Sciences, Bayer HealthCare, 800 Dwight Way, B55-N, Berkeley, CA 94710 and Mark A. Nanny, nanny@ou.edu, School of Civil Engineering and Environmental Science, University of Oklahoma, 202 west Boyd, Room 334, Norman, OK 73019.
The pC-pH diagram is perhaps the most elegant representation of species concentrations as a function of system pH. It is very useful for solving acid-base chemistry problems as it contains information on the relative species concentrations at a specified pH value. While pC-pH diagrams for monoprotic systems can be easily constructed, they are increasingly difficult to plot for multiprotic systems. Moreover, at high ionic strength and non standard temperatures, corrections must be made to species concentrations and equilibrium constants. Thus construction of pC-pH diagrams for multiprotic systems under non-standard conditions is best done using computer programs. We present a novel computer program design that combines instructional information and pC-pH diagram construction in a single PowerPoint file. Interactive pC-pH diagrams for multiprotic systems can be readily constructed through an intuitive user interface. These diagrams are interactive and dynamically update when parameters such as ionic strength and temperature are changed. The sensitivity of species concentration distribution to changes in pH, temperature and ionic strength can be easily explored simplifying the solution of acid-base chemistry problems. The PowerPoint file with the instructional information and pC-pH diagram construction capability is available free of charge for academic use from the authors.
 

General Posters
7:30 PM-9:30 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster

Division of Chemical Education

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006