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UNDERSTANDING, DERIVING, AND COMPUTING BUFFER CAPACITY
Citation:
Urbansky*, E T. AND M R. Schock*. UNDERSTANDING, DERIVING, AND COMPUTING BUFFER CAPACITY. JOURNAL OF CHEMICAL EDUCATION 77(12):1640-1644, (2000).
Description:
Derivation and systematic calculation of buffer capacity is a topic that seems often to be neglected in chemistry courses and given minimal treatment in most texts. However, buffer capacity is very important in the chemistry of natural waters and potable water. It affects corrosion, metal solubility, and disinfectant loss, among other things. We derive the buffer capacity contribution equations and provide sample plots of buffer capacity as a function of pH for buffer systems containing mono-, di-, and triprotic weak acids (and their conjugate bases) and amphoteric species (such as zwitterions or metal-hydroxo complexes). In addition, we discuss the evaluation of these equations as well as the numerical approximation of buffer capacity and its associated error. The use of total alkalinity in computing buffer capacity is also covered as this quantity is commonly measured in raw source waters and finished drinking water supplies.