Fugacity diagrams

Fig. 17 Left Fugacity diagram of some iron compounds as a function of P(02) and P(COj) at 25°C (modified after Garrels u. Christ 1965), Right Fugacity diagram of some iron and sulfide compounds as a function of P(02) and P(S2) at 25°C (modified after Garrels u. Christ 1965)...

Fig. 18 3-D illustration of a fugacity diagram of some iron compounds as a function...

Calculate the fugacity correction (i) by using the generalized fugacity diagram, (ii) by means of the van der Waals constants (cf. 29c) hence, determine the true equilibrium constant at 500 C. (Cf. Pease, ref. 2.)... 

Utilizing heat content, heat capacity and entropy data, together with the generalized fugacity diagram, make a thermodynamic study of the reaction... 

In order to find out rapidly whether real behaviour of gas phase must be taken into account when calculating a chemical equilibrium, the fugacity coefficients of pure constituents may be estimated directly from the generalized Gamson-Watson fugacity diagram . When the calculation shows that the assumption of real behaviour is justified, values obtained in this way can be included in the input data at the start of the calculation. 

Diagrams of Binary Systems With Picric Acid , GlasnikKhemDrushtva, BeogradBullSocChim, Belgrade 12, Iui-8 (1947) CA 43, 6066 (1949) 62) M.A. Cook, "Fugacity Determina-... 

Case I. At sufficiently low pressures, the solubility curve does not intersect the coexistence curve. In this case, the gas solubility is too low for liquid-liquid immiscibility, since the coexistence curve describes only liquid-phase behavior. Stated in another way, the points on the coexistence curve are not allowed because the fugacity f2L on this curve exceeds the prescribed vapor-phase value f2v. The ternary phase diagram therefore consists of only the solubility curve, as shown in Fig. 28a where V stands for vapor phase. 

L termination, 62-63 Lewis fugacity rule, 144-145 Liquid-liquid equilibria in binary systems, 184-190 in ternary systems, 194-203 phase diagram, 196-202... 

Fig. 1.15. Diagram showing the homogenization temperature of fluid inclusions vs. the iron content of the host sphalerite growth zone for sample locality NJP-X on the OH vein. The line shows the predicted iron content of the sphalerite if the sulfur fugacity of the system had been buffered by the triple point — Fe-chlorite (daphnite), pyrite, hematite (Hayba et al., 1985).

Oxygen fugacity (fot)- The /oj-pH diagrams (Figs. 1.90 and 1.91) were constructed at 200°C and 250°C based on the homogenization temperatures and electrum-sphalerite temperatures (Shikazono, 1985d). 

Figure 2A. Diagram of processes included in the QWASI fugacity model showing D values for a trichlorobiphenyl in a lake similar to Lake Michigan.

Fig. 3. Simulations calculated with the PHREEQC geochemical code (Parkhust Appelo 1999) (a) time-dependent diagram for the pH evolution of the Aspo ground water/bentonite interaction (b) time-dependent diagram for the pe evolution of the Aspo groundwater/bentonite interaction. Curves correspond to different initial partial oxygen pressures. Initial calcite and pyrite contents are 0.3 wt% and 0.01 wt% respectively, except for the curve of log/02 = —0.22 where calcite and pyrite contents are 1.4 wt% and 0.3 wt%, respectively, pe calculated stands for the cases where the oxygen fugacity is obtained from the groundwater redox potential (Bruno et at. 1999).

The liquid composition is known for a bubblepoint determination, but the temperature is not at the start, so that starting estimates must be made for both activity and fugacity coefficients. In the flow diagram, the starting values are proposed to be unity for all the variables. After a trial value of the temperature is chosen, subsequent calculations on the diagram can be made directly. The correct value of T has been chosen when E X = 1-... 

Fig. 2. Logarithmic activity diagram depicting equilibrium phase relations among aluminosilicates and sea water in an idealized nine-component model of tire ocean system at the noted temperatures, one atmosphere total pressure, and unit activity of H20. The shaded area represents (lie composition range of sea water at the specified temperature, and the dot-dash lines indicate the composition of sea water saturated with quartz, amotphous silica, and sepiolite, respectively. The scale to the left of the diagram refers to calcite saturation foi different fugacities of CO2. The dashed contours designate the composition (in % illite) of a mixed-layer illitcmontmorillonitc solid solution phase in equilibrium with sea water (from Helgesun, H, C. and Mackenzie, F T.. 1970. Silicate-sea water equilibria in the ocean system Deep Sea Res.).

Pyrite-Pyrrhotite Stability Field. The first graphical representation (Figure l) is of a pyrite-pyrrhotite stability field, in the form log fugacity of sulfur (log fc ) vs. temperature, T. This diagram derives... 

Figure 1.7 Pourbaix diagram for the system water-hydrogen-oxygen-hydrogen ion-hydroxyl ion. Activity of water is unity fugacities of hydrogen and oxygen are unity. Temperature 25° C...

Therefore for an analysis of mineral equihbria it is necessary to plot sections of the diagrams along the line of graphite stability (see Figs. 79, 80). If the fugacities of COj and H2O are used as independent variables such a... 

Fig. 82. Diagrams of mineral equilibria in silicate-carbonate iron-formations (isothermal sections in coordinates of log /coj /h o graphite buffer). Fields of actual pressures in metamorphism are hatched I = phase boundaries 2 = isobars of fluid pressure, in kbar isobars of partial fugacity (log/j, in bar) 3 = O2 4 - H2 5 - CO 6 = CH4.

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