Introduces environmental chemistry with a focus on using thermodynamics to understand processes governing chemical behaviors in natural and engineered systems. Topics include vaporization, gas-solution partitioning, salt and mineral dissolution/precipitation, acid-base chemistry, metal complexation, adsorption via ion exchange, and absorption within natural organic matter and organism tissues. Process formulations are combined in box models to compare with observations. Covers intermediate topics in environmental chemistry requiring kinetics to understand processes governing biogeochemical behaviors in natural and engineered systems. Topics include atmospheric oxidations, radiochemistry, mass transfers, and catalysis. Combines an introduction to geochemical modeling, using transport and transformation process formulations in chemical fate models, to compare with observations of concentrations as a function of space and time.