Gibbs function diagram

Figure 6.3 The Gibbs function diagram for a monotropic liquid crystal. represents the equilibrium crystal, and Gy a possible metastable crystalline form. The equilibrium pathway on heating (marked by arrows) leads to direct isotropization at Ty. Heating along pathway Gy gives a metastable enantiotropic behavior, with a mesophase at Ty and isotropization at T,ci. (Redrawn from data in [4])...

A further complication arises from the AG term in Equation (4.49). The diagram above is clearer than the derivation in reality, the differential quantity 3G/3 only corresponds to the change in Gibbs function AG under certain, well defined, and precisely controlled experimental conditions. 

Rhombic sulfur is the stable form at room temperature, and monoclinic sulfur is the metastable form. The transition temperature is 95.5°C. The melting point of monoclinic sulfur is 120°C. How would you evaluate a report that 77°C is the melting point of rhombic sulfur Answer in terms of a diagram of Gibbs function versus temperature for this system. 

Figure 13.7. Equilibrium diagram for transformations in Equation (13.16). Gibbs function data from K. K. Kelley, J. Southard, and C. T. Anderson, Bureau of Mines Technical Paper 625, 1941.

Fig. 4 Schematic free energy diagram for the crystallization of polyethylene from the melt showing the specific Gibbs function (chemical potential) for melt (m), hexagonal (h), and orthorhombic (o), phases as function of temperature...

Figure 4.2.1 Stability diagram standard Gibbs functions of formation AFG°for selected species (for hydrocarbons, ApG° is related here to one carbon atom).

The thermodynamics of nitric acid production based on ammonia can be represented well by the stability diagram shown in Eigure 6.4.3. If we recall Eq. (4.2.13), we know that the standard reaction Gibbs function ArG corresponds to the... 

Figure 6.8.2 Stability diagram of hydrodesulfurization of dibenzothiophene (for principle aspects of a stability diagram based on the standard Gibbs functions of formation ApC° see Section 4.2.1).

Figure C2.1.10. (a) Gibbs energy of mixing as a function of the volume fraction of polymer A for a symmetric binary polymer mixture = Ag = N. The curves are obtained from equation (C2.1.9 ). (b) Phase diagram of a symmetric polymer mixture = Ag = A. The full curve is the binodal and delimits the homogeneous region from that of the two-phase stmcture. The broken curve is the spinodal.

Each reactant and product appears in the Nemst equation raised to its stoichiometric power. Thermodynamic data for cell potentials have been compiled and graphed (3) as a function of pH. Such graphs are known as Pourbaix diagrams, and are valuable for the study of corrosion, electro deposition, and other phenomena in aqueous solutions.Erom the above thermodynamic analysis, the cell potential can be related to the Gibbs energy change... 

In order to examine the possible relationship between the bulk thermodynamics of binary transition metal-aluminum alloys and their tendency to form at underpotentials, the room-temperature free energies of several such alloys were calculated as a function of composition using the CALPHAD (CALculation of PHAse Diagrams) method [85]. The Gibbs energy of a particular phase, G, was calculated by using Eq. (14),... 

When a reversible transition from one monolayer phase to another can be observed in the 11/A isotherm (usually evidenced by a sharp discontinuity or plateau in the phase diagram), a two-dimensional version of the Gibbs phase rule (Gibbs, 1948) may be applied. The transition pressure for a phase change in one or both of the film components can be monitored as a function of film composition, with an ideally miscible system following the relation (12). A completely immiscible system will not follow this ideal law, but will... 

Figure 3.4. Ellingham diagram showing standard Gibbs energy of formation of various oxides as a function of temperature.

Figure 9.9. Schematic diagram of the first derivative of the G/At curve in Fig. 9.8 showing the calculation of the minimum in the Gibbs energy as a function of N. ...

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