Pressure saturation vapor

There are two approaches to explain physical mechanism of the phenomenon. The first model is based on the existence of the difference between the saturated vapor pressures above two menisci in dead-end capillary. It results in the evaporation of a liquid from the meniscus of smaller curvature ( classical capillary imbibition) and the condensation of its vapor upon the meniscus of larger curvature originally existed due to capillary condensation. 

At first we tried to explain the phenomenon on the base of the existence of the difference between the saturated vapor pressures above two menisci in dead-end capillary [12]. It results in the evaporation of a liquid from the meniscus of smaller curvature ( classical capillary imbibition) and the condensation of its vapor upon the meniscus of larger curvature originally existed due to capillary condensation. We worked out the mathematical description of both gas-vapor diffusion and evaporation-condensation processes in cone s channel. Solving the system of differential equations for evaporation-condensation processes, we ve derived the formula for the dependence of top s (or inner) liquid column growth on time. But the calculated curves for the kinetics of inner column s length are 1-2 orders of magnitude smaller than the experimental ones [12]. 

Deijaguin and Zorin report that at 25°C, water at 0.98 of the saturation vapor pressure adsorbs on quartz to give a film 40 A thick. Calculate the value of the disjoining pressure of this film and give its sign. 

A heat of immersion may refer to the immersion of a clean solid surface, qs.imm. or to the immersion of a solid having an adsorbed film on the surface. If the immersion of this last is into liquid adsorbate, we then report qsv.imm if tbe adsorbed film is in equilibrium with the saturated vapor pressure of the adsorbate (i.e., the vapor pressure of the liquid adsorbate P ), we will write It follows from these definitions... 

It is important to keep in mind that the phases are mutually in equilibrium. In particular, the designation is a reminder that the solid surface must be in equilibrium with the saturated vapor pressure and that there must therefore be an adsorbed film of film pressure (see Section X-3B). Thus... 

In the second picture, an interfacial layer or region persists over several molecular diameters due to a more slowly decaying interaction potential with the solid (note Section X-7C). This situation would then be more like the physical adsorption of vapors (see Chapter XVII), which become multilayer near the saturation vapor pressure (e.g.. Fig. X-15). Adsorption from solution, from this point of view, corresponds to a partition between bulk and interfacial phases here the Polanyi potential concept may be used (see Sections X-7C, XI-1 A, and XVII-7). 

Table 4. Saturated Vapor Pressure, of 0- and />Hydroxybenzoic Acids ...

The isothermal vaporization of pure Hquid / represents its transition from saturated Hquid to saturated vapor at temperature T and at saturation vapor pressure The treatment of this transition is faciUtated through use of property changes of vaporization defined by equation 139 ... 

Relative Humidity the ratio of the partial pressure of water to the saturation vapor pressure, also called saturation ratio often expressed as a percentage. 

Where e, is in units of inches of water per day. Up is the wind speed 2 feet above the ground expressed in miles per day, and e and e, are the saturation vapor pressures at mean air and mean dew-point temperatures, respectively (expressed in inches of mercury). For development of the wind function, an adjustment in the psychrometric constant is generally made to account for the sensible heat conducted... 

The partial pressure of water vapor in air cannot be higher than the vapor pressure of saturated water ft (T) corresponding to air temperature T. If it were higher, condensation of water vapor would occur until the equilibrium state corresponding to the saturated vapor pressure was achieved. 

Antoine s equation An equation used for calculating saturation vapor pressure. 

Saturated vapor pressure The pressure exerted by a saturated vapor. This pressure is a function of the temperature. 

Few vacuum systems are completely airtight, although some may have extremely low leakage rates. For the ideal system the only load for the ejector is the non-condens-ables of the process (absorbed gases, air, etc.) plus the saturated vapor pressure equivalent of the process fluid. Practice has proven that allowance must be made for air leakage. Considering the air and non-condensables. For base ejector capacity determine inert gases only by ... 

Pg = actual pressure (psia), suction RH, = standard relative humidity, 36%, fraction RHg = actual relative humidity, %, fraction PV, = saturated vapor pressure of water at standard temperature (psi) ... 

PVg = saturated vapor pressure of water at actual temperature (psi) ... 

This compares the amount of moisture in a sample of air with the amount it would contain if saturated. More accurately, relative humidity is the partial pressure of vapor present divided by saturation vapor pressure x 100 per cent. Saturation =100 per cent relative humidity. 

Saturated vapor pressure at existing mixture temperature... 

The solubility of a solid in a liquid at its saturation vapor pressure is usually represented as a (T, x2) graph, where x2 is the mole... 

The only parts of Fig. 5 which can meaningfully be described as solubility in a compressed gas are WX and XV. However, a very different situation arises if the saturated vapor pressure curve cuts the critical curve (M—N of Fig. 3). Figure 4 shows that this does not happen for the three sodium halides. The complete course of the critical curve is not known, but enough is known in the case of the sodium chloride system51 75 for it to be clear that it rises well above the maximum of the saturated vapor pressure curve. However, it is cut by the vapor pressure curves of less soluble salts such as sodium carbonate and sodium sulphate.40 87 The (p, T) projection of a system of the type water + sodium chloride is... 

Fig. 7. The (pt T) projection of a system in which the saturated vapor pressure curve does not cut the critical line, MN.

The critical line is similarly broken into MO and PN. Between 0 and P there is no critical point and no saturated vapor pressure... 

Ewald22 studied this system at 150° and 155°K. These temperatures are above the critical temperature of pure nitrogen, 126°K, but he found that they are below the lower critical end point of the mixture. The saturated vapor pressure of the system was 50 atm at 150°K and 57 atm at 155°K. The mole fraction of xenon in the saturated gas (X in Figs. 5 and 9) was 0.035 and 0.045 at these temperatures, respectively. 

Braune and Strassman8 measured the concentration of iodine in gaseous carbon dioxide at pressures up to 50 atm from 32° to 98°C. They passed the carbon dioxide over an excess of solid iodine and analyzed the effluent mixtures. Their pressures were too low to find the saturation vapor pressures or to show whether or not critical end points were formed. 

Systems in which the saturated vapor pressure curve cuts a three-phase line of liquid + liquid + gas at a second quaternary point (solid + liquid + liquid + gas). Such systems have the first (or normal) quaternary point (solid + solid + liquid + gas) at lower temperatures and pressures (Fig. 13). Examples, ethane +... 

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