It is not a revelation to know that matter or chemicals can convert from one species or state of matter to another. Often the general properties that govern this transformation can be described in terms of an equilibrium. That is, a situation whereby the quantity or quality of the sample does not change in time. Such a situation is intimately connected to "thermodynamics" as discussed in Chapter 19. As you will learn in Chem 2C, electrochemistry is the third member of this troika.