Introductory Chemical Engineering Thermodynamics

Unit IV: Reaction Equilibria

Problems involving reactions are affected by equilibrium limitations as well as their kinetics. Briefly, the Gibbs energy related to the “partitioning” of atoms between species must be minimized in a fashion analogous to the way that it was minimized for phase partitioning. For example, the formation of methanol from carbon monoxide and hydrogen is favorable based on the energy from the bond formation, but limited by the reduction in entropy as the carbon monoxide and hydrogen are squeezed into a single molecule. Thus, even though the heat of reaction may be favorable, a balance is struck between the loss in entropy and the favorable energy as the methanol is formed. At 100 bars and 510 K, this balance occurs at about ...