Physically dissolved

According to Eq. (8.7), the total concentration of H2S in the aqueous caustic soda (physically dissolved and chemically reacted) can be expressed as follows... 

In this system, the physically dissolved H2S is much less than the chemically combined, i.e.,... 

Now that a procedure for establishing the corresponding composition scales for the rich lean pairs of stream has been outlined, it is possible to develop the CID. The CID is ccHistructed in a manner similar to that described in Chapter Five. However, it should be noted that the conversion among the corresponding composition scales may be more laborious due to the nonlinearity of equilibrium relations. Furthermore, a lean scale, xj, represents all forms (physically dissolved and chemically combined) of the pollutant. First, a composition scale, y, for component A in... 

Iodine is enriched to a greater extent in chromatogram zones coated with lipophilic substances than it is in a hydrophilic environment. Hence, iodine is only physically dissolved or adsorbed. Occasionally a chemical reaction also takes place, such as, for example, with estrone [19] (cf. Iodine Reagents ). In general it may be said that the longer the iodine effect lasts the more oxidations, additions or electrophilic substitutions are to be expected. 

As with oxygen, the amount of carbon dioxide physically dissolved in the plasma is proportional to its partial pressure. However, carbon dioxide is 20 times more soluble in plasma than is oxygen. Therefore, approximately 10% of carbon dioxide in blood is transported in the dissolved form. 

The anhydride of sulfurous acid is sulfur dioxide, which is very soluble in water. Although most of the gas is physically dissolved, the ionization takes place slightly as indicated by the equations... 

A brief reading of the literature would indicate that the liquid-phase reaction is what is technically known as an absorption with fast reaction and that gaseous CO2 physically dissolves in the liquid phase and reacts in a region close to the gas—liquid interface with dissolved NH3, according to second order in ammonia, first order in CO2 homogeneous liquid-phase kinetics... 

Inherent in Henry s law is the concept that when a liquid is exposed to a gas, a partial pressure equilibrium will be achieved between the gas and liquid phases. Thus, molecules of the gas that are physically dissolved in the liquid will exert tension that is equal to the partial pressure of the gas above the liquid. It is not neces-... 

Carbon dioxide in aqueous solutions exist in three forms (i) physically dissolved CO2 (ii) bicarbonate ion HCOg and (iii) carbonate ion COj"-. In the physiological range of pH the latter form can be neglected. The bicarbonate ion HCOg is produced by the following hydration reaction ... 

The values of k a for CO, desorption in a stirred-tank fermentor, calculated from the experimental data on physically dissolved CO, concentration (obtained by the above-mentioned method) and the CO2 partial pressure in the gas phase, agreed well with the k a values estimated from the k a for O, absorption in the same fermentor, but corrected for any differences in the liquid-phase diffusivities [11]. Perfect mixing in the liquid phase can be assumed when calculating the mean driving potential. In the case of large industrial fermentors, it can practically be assumed that the CO, partial pressure in the exit gas is in equilibrium with the concentration of CO, that is physically dissolved in the broth. The assumption of either a plug flow or perfect mixing in the gas phase does not have any major effect... 

As mentioned in Section 15.3.3, most CO2 in blood exists as HCO3". In evaluating the CO2 desorption performance of blood oxygenators, we must always consider the simultaneous diffusion of HCOg", the rate of which is greater than that of physically dissolved COg. Experimental data on the rates of CO2 desorption... 

The nucleophilic nature of the alkanes is also shown by the influence of the acidity level on their solubility. Torek and co-workers90 have investigated the composition of the catalytic phase obtained when w-pentane or w-hexane is thoroughly mixed with HF-SbF5 in an autoclave under hydrogen pressure [Eq. (5.41)]. The total amount of hydrocarbon in the catalytic phase (dissolved ions and neutrals) was obtained by extraction with excess of methylcyclopentane. The amount of physically dissolved... 

The calculation methods for the gas solubility are largely based on the Henry constant, which gives a relationship between the liquid-phase concentration of a physically dissolved gas and its partial pressure. The determination of such coefficients in presence of chemical reactions becomes complicated and, therefore, different estimations based on chemically inert systems are often applied. One of these methods uses the Henry coefficients of similar, but chemically inert, species in order to estimate the solubility of a reactive component An example is represented by the N2O analogy for the determination of CO2 solubility in amine solutions [47]. 

The formula NH4OH is sometimes used for convenience, but such a molecule apparently does not exist. Ammonia is extremely soluble in water, however. Most of the NH3 is physically dissolved in water, with a small amount undergoing the reaction shown in Eq. (12.12). Ammonia can also act as an acid toward extremely strong Brpnsted bases ... 

Phthalate esters are widely used in the production of plastics, particularly vinyl plastics, to add flexibility to products made with these materials. DEHP is commonly used in medical devices, including cardiac catheters, endotracheal tubes, and certain implanted devices, while DINP is more often found in wires and cables, hoses, and plastic toys. DEHP is also used in plastic containers, such as those used for food. These phthalates are not bound chemically to the plastic but are physically dissolved in it. 

Bicarbonate is the second largest fraction (behind Ci ) of plasma anions ( 25 mmol/L). Conventionally, it is defined to include (1) plasma bicarbonate ion, (2) carbonate, and (3) CO2 bound in plasma carbamino compounds (Figure 46-7). At the pH of blood, the plasma carbonate concentration is 25 pmol/L, which is -1/700 to 1/1000 of the total bicarbonate concentration. C02-bound carbamino compounds (RCNHCOOH) are 0.2 mmol/L in plasma and 1.5 mmol/L in erythrocytes. Actual bicarbonate ion concentration is not measured, but rather calculated from the Henderson-Hasselbalch equation as described below (and discussed in detail in Chapter 27). Also, as described in Chapter 27, the analyte usually measured in plasma is total COa, which includes bicarbonate and dissolved CO (dC02). The dC02 fraction is defined to include both the undissociated carbonic acid and physically dissolved, free CO2. At the pH of the blood, the amount of dissolved CO2 is 700 to 1000 times greater than the amount of carbonic acid and therefore... 

When the reaction is rapid, most of the reaction takes place in a thin film near the interface, and the bulk concentration of the physically dissolved gas remains low. In that case the rate of gas absorption and reaction will then be proportional to the interfacial surface area and is given by an expression of the type shown in (14), provided all other parameters are held constant. 

Henry s Law states that the amount of gas dissolved by a given liquid, with which, it does not combine chemically, is directly proportional to the partial pressure of the gas if the pressure of a gas is doubled then the amount of gas physically dissolved in the solution is doubled. The constant which converts the proportionality to an equality in the Henry s Law equation is called the Henry s Law constant this constant is the solubility coefficient of the gas in the particular solution. The solubility coefficient varies with the nature of the gas and liquid, the presence of solutes in the liquid, and inversely with the temperature. Thus at a constant pressure, but under hypothermic conditions, more gas can be dissolved in a given amount of fluid (tissue). 

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