ABSTRACT
The equilibrium constant (K) and the Gibbs energy of a reaction (∆r G°) both provide metrics for quantifying a reaction, but neither quantity can explain why a reaction happens. Reactions happen because electrons move to become more stable, lower energy. This movement can be the complete transfer of electrons, which is called reduction–oxidation or redox. Reduction is the gain of electrons by an atom, and oxidation is the loss of electrons by an atom. In this chapter, readers are given a framework and tools for quantifying the electrons an atom has (oxidation number) as a means of tracking electron transfers in redox reactions. From there, attention is turned to electrochemistry as a means of further quantifying the likelihood of reactions, through the use of cell potentials (E°cell) and standard reduction potentials. This study also serves as a contextualizing example of the importance and role electrochemistry plays, and will increasingly play, in society.
