Equilibrium, chemical, 37-47 pass ideal mixtures

The symmetrical ideal behavior is equivalent to the well-known Raoult law. Suppose that a mixture of A and B is in equilibrium with an ideal-gas phase let PA be the partial pressure of A. The chemical potential of A in the gas phase is... 

Most solutions of practical interest satisfy (9.43) only in certain chemical composition ranges and not in others. Let us focus on a binary solution of A and B. If the solution is ideal for every composition, then the partial pressures of A and B will vary linearly with the mole fraction of B (Figure 9.2). When xj = 0, the mixture consists of pure B and the equilibrium partial pressure of B over the solution is and of A zero. The opposite is true at the other end, where jca = 1 and = Pa-... 

At a total pressure of 1 bar, the equilibrium concentrations of N2O4 in the gas phase were reported to be 0.6349 (30 C), 0.4088 (50 X), 0.2113 (70 X), and 0.09321 (90 C). Calculate the difference between the heat capacity of the mixture and a mixture of ideal gases between 20 ""C and 100 C. Assume that only the chemical reaction contributes to the non-ideal behavior. Calculate the equilibrium of water formation from the elements in their most stable state for a stoichiometric feed of oxygen and hydrogen at P = 0.01 Pa and T = 2000 K using the data from Appendix A and assuming ideal gas phase behavior ... 

Because the system shown in Fig. 9.4 is in an equilibrium state, gas A must have the same chemical potential in both phases. This is true even though the phases have different pressures (see Sec. 9.2.7). Since the chemical potential of the pure ideal gas is given by IX = fx°(g) + RT n(p/p°), and we assume that pa in the mixture is equal to p in the pure gas, the chemical potential of A in the mixture is given by... 

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