Reaction coordinate Gibbs diagram

A graphical depiction (frequently called a reaction coordinate diagram) of the relative Gibbs free energies (or, more commonly, the standard Gibbs free energies) of... 

Figure 9-15 (A) Transition state diagram illustrating Gibbs energy vs reaction coordinate for conversion of reactants to products in a chemical reaction. (B) Contour map of Gibbs energy vs interatomic bond distances for reaction B + X - A —> B-X+A.

From the idea of enzyme kinetics as a binding and a reaction step with the corresponding course of the energy curve in the Gibbs free enthalpy-reaction coordinate (AG - E) diagram, the reaction scheme represented by Eq. (2.1) can be drawn. 

Figure 2.9. Schematic diagram of AG versus reaction coordinate for potassium exchange on a Matapeake soil where AG is the Gibbs free energy. [From Sparks and Jardine (1981), with permission.]...

Thus if a mixture of chemical species is not in chemical equilibrium, any reaction that occurs must be irreversible and, if the system is maintained at constant T and P, the total Gibbs energy of the system must decrease. The significance of this for a single chemical reaction is seen in Fig. 15.1, which shows a schematic diagram of G vs. e, the reaction coordinate. Since e is the single variable that... 

A reaction coordinate diagram for a one-step reaction between H—A and B. The dashed lines in the transition state indicate that the H— A bond is partially broken and the new H—B bond is partially formed. On completion of the reaction, the H—A bond is fuUy broken and the H—B bond is fully formed. The energy of the reactants is higher than that of the products. The energy axis in this diagram is Gibbs free energy (G"). 

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