ABSTRACT
Quantitative understanding of the chemistry of natural waters involves the two cornerstones of physical chemistry: thermodynamics and kinetics. Equilibrium approaches are useful in relating the inorganic composition of lakes, rivers, groundwater, and the oceans to weathering reactions of minerals in watersheds, but the ability of thermodynamics to describe aquatic systems is limited. Kinetics often is considered an empirical science in which reaction rates are measured rather than predicted. Aquatic chemists have placed increasing emphasis on kinetic and process-oriented models of natural waters. Biological processes affect chemical conditions that control equilibrium and thus indirectly induce chemical reactions. The length scale over which environmental processes occur also is of interest, and a crude correlation exists over many orders of magnitude between the characteristic time and length scales for many processes. The chapter also presents an overview of the key concepts discussed in this book.
