This edition: Equilibrium and Advanced Thermodynamics: Balance in Chemical Reactions
Some chemical reactions, like metal rusting, happen spontaneously. Others require external energy in order to occur. Expanding upon the basic thermodynamics of enthalpy from Unit 7, disorder (entropy) and Gibbs free energy are key to understanding what makes chemical reactions proceed thermodynamically. When the thermodynamics of a reaction prevent it from reaching completion, (both products and reactants are always present) it is called equilibrium. When equilibrium reactions are disrupted, such as the binding of oxygen by hemoglobin, as in carbon monoxide poisoning, it can be life threatening. Conversely, controlling an equilibrium reaction is important in chemical manufacturing, like in the synthesis of ammonia.