The vapor pressures are calculated using these pressures plus the mole fractions in the liquid phase [Pg.623]

In vapor-liquid equilibria, if one phase composition is given, there are basically four types of problems, characterized by those variables which are specified and those which are to be calculated. Let T stand for temperature, P for total pressure, for the mole fraction of component i in the liquid phase, and y for the mole fraction of component i in the vapor phase. For a mixture containing m components, the four types can be organized in this way [Pg.3]

Calculate the mole fraction in the vapor phase. When the components of the system are soluble in each other in the liquid state (as is the case for benzene and toluene), so that there is only one liquid phase, then the moles of vapor V per total moles can be calculated from the equation [Pg.122]

The vapor pressures of pure liquids A and B at 300 K are 200 and 500 mm Hg, respectively. Calculate the mole fractions in the vapor and the liquid phases of a solution of A and B when the equilibrium total vapor pressure of the binary liquid solution is 350 mm Hg at the same temperature. Assume that the liquid and vapor phases are ideal. [Pg.230]

These are both pressure fractions, as calculated, and also are the mole fractions in the vapor phase. [Pg.298]

Since the partial pressure is the mole fraction in the vapor phase multiplied by the total pressure, (i.e., Pi = Yi P), the equilibrium [Pg.481]

Since the partial pressure is the mole fraction in the vapor phase multiplied by the total pressure, (i.e., p, = y, P), the equilibrium constant Keq is expressed as Keq = Ky PAn, where An = (2 - 1 - 3), the difference between the gaseous moles of the products and the reactants in the ammonia synthesis reaction. [Pg.481]

The vapor pressure of pure chloroform at 40°C is 366 torr, and that of pure carbon tetrachloride is 143 torr. If a solution with mole fraction 0.180 in chloroform is allowed to evaporate, the vapor phase is separated from the solution and condensed, and the resulting solution is allowed to evaporate, what would be the mole fraction of the vapor phase after the second evaporation [Pg.442]

The empirical description of dilute solutions that we take as the starting point of our discussion is Henry s law. Recognizing that when the vapor phase is in equUibrium with the solution, p,2 in the condensed phase is equal to p,2 g, we can state this law as follows For dilute solutions of a nondissociating solute at constant temperature, the fugacity of the solute in the gas phase is proportional to its mole fraction in the condensed phase That is. [Pg.337]

The fundamental idea of this procedure is as follows For a system of two fluid phases containing N components, we are concerned with N — 1 independent mole fractions in each phase, as well as with two other intensive variables, temperature T and total pressure P. Let us suppose that the two phases (vapor and liquid) are at equilibrium, and that we are given the total pressure P and the mole fractions of the liquid phase x, x2,. .., xN. We wish to find the equilibrium temperature T and the mole fractions of the vapor phase yu y2,. .., yN-i- The total number of unknowns is N + 2 there are N — 1 unknown mole fractions, one unknown temperature, and two unknown densities corresponding to the two limits of integration in Eq. (6), one for the liquid phase and the other for the vapor phase. To solve for these N +2 unknowns, we require N + 2 equations of equilibrium. For each component i we have an equation of the form [Pg.171]

Binary (vapor + liquid) equilibria studies involve the determination of / as a function of composition. the mole fraction in the liquid phase. Of special interest is the dependence of/ on composition in the limit of infinite dilution. In the examples which follow, equilibrium vapor pressures, p,. are measured and described. These vapor pressures can be corrected to vapor fugacities using the techniques described in the previous section. As stated earlier, at the low pressures involved in most experiments, the difference between p, and / is very small, and we will ignore it unless a specific application requires a differentiation between the two. [Pg.268]

The inclusion in the model of the mass and energy transport equations introduces the mole fractions and temperature at the interface. It is common in almost all treatments of mass transfer across a phase boundary to assume that the mole fractions in the vapor and liquid phases at the interface are in equilibrium with each other. We may, therefore, use the very famihar equations from phase equilibrium thermodynamics to relate the interface mole fractions [Pg.49]

P7.1 Vapor pressure data for ethanol (1) + 1,4-dioxane (2) at T = 323.15 K is given in the following table, where. vq is the mole fraction in the liquid phase and y is the mole fraction in the vapor phase. [Pg.378]

Because C-C6H12 has a higher vapor pressure than c-CsHuCHj, the vapor phase above the liquid mixture is richer in C-C6H12 than is the liquid phase. Thus, if 2 is the mole fraction of c-C6H 2 in the liquid phase and >2 is the corresponding mole fraction in the vapor phase, then yz > 2. [Pg.406]

The limits of the Lewis fugacity rule are not determined by pressure but by composition the Lewis rule becomes exact at any pressure in the limit as y( - 1, and therefore it always provides a good approximation for any component i which is present in excess. However, for a component with small mole fraction in the vapor phase, the Lewis rule can sometimes lead to very large errors (P5, R3, RIO). [Pg.145]

Estimated relative errors are 0.2% for temperature, 5% for pressure, 4% for carbon dioxide mole fraction in the liquid phase, and 10% for lemon oil mole fraction in the vapor phase. Relative error is defined as experimental error divided by sample average val ue. [Pg.204]

Table II presents some consequences of these analogies for a vapor phase and a condensed phase together with the thermal analogs. Here rti is the concentration of the vapor in molecules per unit volume, Nt is the mole fraction in the condensed phase, Vc is the molar volume of the substrate, p< is the partial pressure, and y< is the rational activity coefficient. |

Three streams enter the volume, including air, water, and the chemical substance whose hazard we are trying to control. When n is defined as the number of moles, y is defined as the mole fraction in the vapor phase, and x is defined as the mole fraction in the liquid phase. The subscripts C, a, and w correspond to the chemical in question, air, and water, respectively. The individual molar flow rates of these three species are [Pg.63]

Hydrate inhibition occurs in the aqueous liquid, rather than in the vapor or hydrocarbon liquid phases. While a significant portion of the methanol partitions into the water phase, a significant amount of methanol either remains with the vapor or partitions into any liquid hydrocarbon phase. Although the methanol mole fraction in the vapor or liquid hydrocarbon may be low relative to the water phase, the large amounts (phase fractions) of vapor and liquid phases will cause a substantial amount of inhibitor loss. [Pg.646]

If two pure liquids A and B with different boiling temperatures TA and TB (and therefore different vapor pressures PA and PB at any given common temperature T) are mixed, then since TA TB, we must consider mole fractions in the liquid phase X and XB = 1—X that will be different from [Pg.265]

Figure 11.6 shows a vessel in which a vapor mixture and a liquid solution coexi in equilibrium. The temperature T and pressure P are uniform throughout vessel, and can be measured with appropriate instruments. Samples of the vap and liquid phases may be withdrawn for analysis, and this provides experiment values for the mole fractions in the vapor y, and the mole fractions in the liqui Xj. For species i in the vapor mixtures, Eq. (11.33) is written [Pg.185]

Equation (1) is of little practical use unless the fuga-cities can be related to the experimentally accessible quantities X, y, T, and P, where x stands for the composition (expressed in mole fraction) of the liquid phase, y for the composition (also expressed in mole fraction) of the vapor phase, T for the absolute temperature, and P for the total pressure, assumed to be the same for both phases. The desired relationship between fugacities and experimentally accessible quantities is facilitated by two auxiliary functions which are given the symbols (f [Pg.14]

See also in sourсe #XX -- [ Pg.481 ]

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