Vapor pressure at saturation

Estimation from Henry s Law Constant In certain cases the water solubility at temperature T can be calculated as the ratio of the liquid vapor pressure at saturation, PSL, and Hc, or as the ratio of the solid vapor pressure at saturation, P, and Hc, if these data are known at T ... 

One of the easy and effective approaches for quantifying the polymer volume fraction within films in situ is to use in situ spectroscopic ellipsometry (SE) [49,118, 119, 144], The measurements should be performed in a thermostated cell (Fig. 7) with full control over the solvent vapor atmosphere p/po, where po is the solvent vapor pressure at saturation and p is the actual pressure, which can be adjusted by a combination of the saturated vapor flow and dry nitrogen flow [118, 119], or by the difference between the temperature 7j of the polymer sample and the temperature 72 of the solvent vapor [49, 114, 144],... 

Equation 3.2.6 gives the concentration of water vapor in the inlet air as function of tjw, yiw, and Ahyw, where the subscript, w, means wet bulb. The equations are in functional notation to indicate that these data may be available in tables, graphs or equations. The wet-bulb temperature, tiw, will be discussed later. Equation 3.2.7 expresses the mole fraction of water vapor in the exit air in terms of the vapor pressure at saturation. The air leaving the tower is assumed to be 90% saturated, a value recommended by Walas [12]. 

Vapor permeation of membrane-supported films of IZn has also been studied [31]. Examined as permeants were benzene, toluene, 4-picoUne, 2-picoline, cyclohexane, and methylcyclohexane. In pair-wise comparisons modest permeation selectivities were observed (i.e., factors of 1.1 to 9, depending on the permeant pairs compared). The competitive transport measurements were made at equal vapor pressures for the component pairs. The selectivities decrease if comparisons are made at equal reduced vapor pressures, P/Po, where Po is the vapor pressure at saturation. Nonspecific sorption of volatile compoimds at a given partial pressure generally inversely correlates with values for the saturated vapor pressure. 

Q A relative humidity of 33% is desirable in heated space on wintry days. What volume of water is left in the vaporizer when the room s relative humidity reaches that level (Relative humidity = 100 X P/P°, where P is the actual pressure of water vapor and P° is the vapor pressure at saturation.) continued... 

The reaction involves two electrons per thionyl chloride [7719-09-7] molecule (40). Also, one of the products, SO2, is a Hquid under the internal pressure of the cell, facihtating a more complete use of the reactant. Finally, no cosolvent is required for the solution, because thionyl chloride is a Hquid having only a modest vapor pressure at room temperature. The electrolyte salt most commonly used is lithium aluminum chloride [14024-11-4] LiAlCl. Initially, the sulfur product is also soluble in the electrolyte, but as the composition changes to a higher SO2 concentration and sulfur [7704-34-9] huA.ds up, a saturation point is reached and the sulfur precipitates. 

Because calcium chloride has a number of hydrates, the one that is in equiUbrium with a saturated solution is a function of the temperature. In this case, the sohd is dissolved as it absorbs water to form the saturated solution, and three phases are present soHd, saturated solution, and vapor. Systems having these three phases, or two soHds and a vapor phase, have a constant vapor pressure at a given temperature. Therefore, Class 2 drying agents can be used to maintain a constant relative humidity. 

An analytical method for the prediction of compressed liquid densities was proposed by Thomson et al. " The method requires the saturated liquid density at the temperature of interest, the critical temperature, the critical pressure, an acentric factor (preferably the one optimized for vapor pressure data), and the vapor pressure at the temperature of interest. All properties not known experimentally maybe estimated. Errors range from about 1 percent for hydrocarbons to 2 percent for nonhydrocarbons. 

I. The wet-bulb or saturation temperature line gives the maximum weight of water vapor that I kg of dry air can cariy at the intersecting dry-bulb temperature shown on the abscissa at saturation humidity. The partial pressure of water in air equals the water-vapor pressure at that temperature. The saturation humidity is defined by... 

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... 

Saturated vapor pressure at existing mixture temperature... 

Relative humidity is usually considered only in connection with atmospheric air, but since it is unconcerned with the nature of any other components or the total mixture pressure, the term is applicable to vapor content in any problem. The saturated water vapor pressure at a given temperature is always known from steam tables or charts. It is the existing partial vapor pressure which is desired and therefore calculable when the relative humidity is stated. 

Saturation vapor pressure at 25 °C (Pa) Adsorption potential (cap moP ) Trapping efficiency (%) ... 

The procedure in this lab is done using an air sample over water, and water vapor will saturate and add to the pressure. So, the water vapor pressure must be subtracted from the barometric pressure. You will consult the CRC Handbook of Chemistry and Physics to determine water vapor pressure at the temperature of the water being used in the activity. 

P = the actual air pressure (mmHg) ps = saturated vapor pressure at temperature T (mmHg)... 

Table III SO2 Vapor Pressure at 25 C Obtained by Dynamic Saturation or the S0 Electrode...

R ardless of the chemistry, there are some physical constraints on aerosol-gas interactions. Particles must be close to or at equilibrium with respect to the surrounding vapor to exist in air for any substantial period. Thus, the partial pressure of condensed species on particles must be less than or equal to the saturation vapor pressure at atmospheric temperature for stability. As shown later in this chapter, the requirement of low vapor pressure is particularly important to the stability of organic aerosols. 

Dissolution is endothermic, solution becomes cold (and hence its apphca-tion in freezing bath) elevates the boiling point of water by 1°, 7.5°, 28.5° and 70°C at 10, 40, 80 and 95% (w/w) concentrations, respectively vapor pressure of saturated solution, 11.2 torr at 20°C. 

The gas ballast facility (see Fig. 2.13) prevents condensation of vapors in the pump chamber of the pump. When pumping vapors these may only be compressed up to their saturation vapor pressure at the temperature of the pump. If pumping water vapor, for example, at a pump temperature of 70 °C, the vapor may only be compressed to 312 mbar (saturation vapor pressure of water at 70 °C (see Table XIII In Section 9)). When compressing further, the water vapor condenses without Increasing the... 

Saturation vapor pressure at any air temperature may be computed by the Magnus-Tetons formula ... 

Equation 6.32 was derived from the requirement that void growth by diffusion at any temperature cannot occur if the pressure within the void is greater than the saturated vapor pressure at that temperature (i.e., if Csat > C ). 

R = the universal gas constant T = the absolute temperature Ps = the saturated vapor pressure at temperature T P = the partial pressure of the adsorbate. 

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