Partial pressure Henry s law

In order to use any of the aforementioned operations, the equilibrium relations between liquids and vapors must be ascertained. In other words, the distribution of a component in the two phases after no further interchange takes place must be known. Although Dalton s law of partial pressures, Henry s law of gas solubility, and Raoult s law of vapor-liquid equilibrium are not exact, they are used extensively because complete data are not available. 

A few gases may be involved in some enzyme reactions, e.g., C02 and 02 as used by carbonic anhydrase and produced by catalase, respectively. If the presence of such dissolved gases affects rates and equilibria at ordinary pressure, their importance will increase at higher pressure. Henry s law says that the partial pressure of a gas above a solution is proportional to its mole fraction in the solution. At high pressure it is more correct to speak of the fugacity / of a gas, instead of partial pressure, in the same sense that one uses activity instead of concentration in solution calculations. In dilute solutions, the fugacity of the dissolved gas is given by... 

Let us approach an equivalent to Eq. 3.24 from the perspective of applying the three great laws of phase equilibrium found in most physical chemistry texts Dalton s Law of partial pressures, Raoult s Law of ideal solutions, and Henry s Law for dissolved gases (28). Applying Dalton s law enables one to state that the concentration of analyte in the HS is proportional to its partial pressure. The partial pressure exerted by TCE in the HS is independent of all other gases in the HS mixture and is related to the total pressure in the HS as follows ... 

Henry s law states that when a liquid and a gas are in contact, the weight of the gas that is dissolved in a given quantity of liquid is proportional to the pressure of the gas above the liquid (partial pressure). The value of the constant of proportionality is called the Henry s law constant (H) and is dependant on the solute-solvent pair, temperature and pressure. Henry s law constant is a measure of a chemical s volatility from a solvent (in this chapter it is water) the larger a compound s H value, the more volatile it is, and it is also easier to be transferred from the aqueous phase into air. 

If tire diffusion coefficient is independent of tire concentration, equation (C2.1.22) reduces to tire usual fonn of Pick s second law. Analytical solutions to diffusion equations for several types of boundary conditions have been derived [M]- In tlie particular situation of a steady state, tire flux is constant. Using Henry s law (c = kp) to relate tire concentration on both sides of tire membrane to tire partial pressure, tire constant flux can be written as... 

Henry s Law. The solubility of a gas is directly proportional to the partial pressure exerted by the gas ... 

The solubihty of a gas in water is affected by temperature, total pressure, the presence of other dissolved materials, and the molecular nature of the gas. Oxygen solubihty is inversely proportional to the water temperature and, at a given temperature, directly proportional to the partial pressure of the oxygen in contact with the water. Under equihbrium conditions, Henry s law apphes... 

Chlorine. The solubiUty of chlorine [7782-50-5] in hydrochloric acid is an important factor in the purification of by-product hydrochloric acid. The concentration of chlorine in solution, S, is proportional to the partial pressure of chlorine, p, in the gas phase and follows Henry s law, S = i/p, in the... 

Titanium tetrachloride is completely miscible with chlorine. The dissolution obeys Henry s law, ie, the mole fraction of chlorine ia a solutioa of titanium tetrachloride is proportional to the chlorine partial pressure ia the vapor phase. The heat of solutioa is 16.7 kJ/mol (3.99 kcal/mol). The appareat maximum solubiUties of chlorine at 15.45 kPa (116 mm Hg) total pressure foUow. 

The equihbrium partitioning of a chemical solute between a Hquid and vapor phase is governed by Henry s law when the Hquid mixture is very dilute in the solute. Henry s law generally is vaHd at concentrations below 0.01 mol/L of solution, although the upper limit can sometimes extend to 0.1 mol/L or higher (10). Over this concentration range, a direct proportionaHty, ie, Henry s constant, is observed between the partial pressure of the chemical in the gas phase and its mole fraction in the Hquid phase. Henry s constant, when expressed in this way, has units of pressure (3). 

The H in solubility tables (2-121 to 2-144) is the proportionahty constant for the expression of Henry s law, p = Hx, mere x = mole fraction of the solute in the liqiiid phase p = partial pressure of the solute in the gas phase, expressed in atmospheres and H = a. proportionality constant expressed in units of atmospheres of solute pressure in the gas phase per unit concentration of the solute in the hquid phase. (The unit of concentration of the solute in the liquid phase is moles solute per mole solution.)... 

For dilute concentrations of manv gases and over a fairly wide range for some gases, the equihbrium relationship is given by Henry s law, which relates the partial pressure developed by a dissolved solute A in a liquid solvent B by one of the following equations ... 

For quite a number of gases, Henry s law holds very well when the partial pressure of the solute is less than about 100 kPa (I atm). For partial pressures of the solute gas greater than 100 kPa, H seldom is independent of the partial pressure of the solute gas, and a given value of H can be used over only a narrow range of partial pressures. There is a strongly nonlinear variation of Heniy s-law constants with temperature as discussed by Schulze and Prausnitz [2nd. Eng. Chem. Fun-dam., 20,175 (1981)]. Consultation of this reference is recommended before considering temperature extrapolations of Henry s-law data. 

Henry s law States that the mass of a gas dissolved in a definite volume of liquid at constant temperature is proportional to the partial pressure of the gas. 

The most important equilibrium pliase relationship is diat between liquid and vapor. Raoult s mid Henry s laws theoretically describe liquid-vapor behavior mid, mider certain conditions, are applicable in practice. Raoult s law, sometimes useful for mi.vtures of components of similar structure, states diat die partial pressure of any component in die vapor is equal to die product of the vapor pressure of the pure component and die mole fracdon of tliat component in die liquid. It may be written in die following maimer... 

Henry s Law. This is an empirical formulation that describes equilibrium solubilities of noncondensable gases in a liquid when Raoult s law fails. It states that the mole fraction of a gas (solute i) dissolved in a liquid (solvent) is proportional to the partial pressure of the gas above the liquid surface at given temperature. That is,... 

Strategy Use Henry s law in any problem involving gas solubility and pressure. Perhaps the simplest approach is to use the data at one atmosphere to calculate k. Then apply Henry s law to calculate Cg at the higher pressure. Note that it is the partial pressure of N2 that is required use the relation PNj = XNj X Ptot to find it... 

Apply Henry s law to relate gas solubility to partial pressure. 

CAL Oxygen concentration in equilibrium with liquid phase at the interface, kmol/m3 CAL Oxygen concentration in the bulk of liquid, kmol/m3 a Interfacial area in surface area of bubbles per unit volume of broth, m2/m3 PQ, Oxygen partial pressure at the interface, atm H Henry s law constant, atm... 

NOTE The operational efficiency of a deaerator is governed by its potential to reduce the partial pressure of oxygen in the FW to a minimum. The equilibrium concentration of any gas (such as Of) dissolved in a liquid (i.e., the gas s solubility) is proportional to the partial pressure of that gas in contact with the liquid. This relationship is expressed by Henry s Law ... 

The extent to which carbon dioxide dissolves is proportional to its partial pressure in the steam phase (Henry s Law). Also, C02 (like most gases) is less soluble in hot condensate than in cool condensate. 

A Nemstian response of 59 mV per decade change in concentration is commonly observed (at 25°C). Relation to the partial pressure carbon dioxide is accomplished by the use of Henry s law. A catheter sensor configuration has been developed for in-vivo monitoring of blood carbon dioxide (61). 

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