Acid-base equilibrium is one of the most important and most challenging topics in a typical general chemistry course. This article introduces an alternative to the algebraic approach generally used in textbooks, the graphical log "C" method. Log "C" diagrams provide conceptual insight into the behavior of aqueous acid-base systems and allow students to solve complicated problems using simple geometry and algebra. Examples of the use of log "C" diagrams are given and the advantages and limitations of the technique discussed. (Contains 7 figures.)