Solubility of argon in water

This small volume of air, ignored for a hundred years by later experimenters, was presumably argon and its related gases. That Cavendish s estimate of 1/120 of the volume of the nitrogen used, or. 65 volume per cent of the atmosphere, is smaller than the actual content (about. 93 volume percent as at present determined) is doubtless due to the fact of the solubility of argon in water. 

Extrapolate The solubility of argon in water at various pressures is shown in Figure 14.28. Extrapolate the data to 15 atm. Use Henry s law to verify the solubility determined by your extrapolation. 

The atmosphere is a well-mixed reservoir with known concentrations of noble gases (Table 13.1). These atmospheric noble gases have characteristic isotopic abundances that are given in Table 13.2. The solubility of the noble gases is given in Fig. 13.1, expressed in cc STP noble gas/cc water. STP stands for standard temperature (0°C) and pressure (760mmHg=l atmosphere). What is the solubility of argon in distilled water at sea level at 15 °C The answer, from Fig. 13.1, is 3.5 x 10 4cc STP Ar/cc water. 

The solubility of air in water has been made the subject of considerable research, and possesses several points of interest. The independence of the tw-o main constituents (argon being included with the nitrogen) is clearly observable from the table given below- further, owing to the fact that the coefficients of solubility of the individual gases are affected differently with rise of temperature the composition of the dissolved mixture is not constant. 

The most extensive series of studies in this area are those of Ben-Naim and co-workers.They have measured the solubilities of argon in various mixed solvents as a function of temperature, and calculated free energies, enthalpies, and entropies of solution. All data are presented in graphical form, and include the solvent systems, water-ethanol, water-p-dioxan, and water-methanol. The last two of these systems were studied over the entire concentration range, and while the primary interest was in aqueous and highly aqueous mixed solution, useful information is given on organic systems. 

Table 3.1 shows some values of the Ostwald absorption coefficient y of argon in water and in some liquids. It should be noted that the solubility as measured by y is about an order of magnitude smaller in water compared with other solvents. Note, however, that the solubility of argon in ethylene glycol at 25°C is about 0.035, almost the same as in water Isee Ben-Naim (1968)]. 

The second striking difference between the solubility of gases in water and in other solvents is the temperature dependence of the solubility. Figure 7.2 illustrates that difference for argon in water and in methanol. The steep decrease in the solubility (in terms of y) as a function of temperature is very characteristic of water. In other solvents, the solubility may either increase or decrease with temperature in both cases, it occurs with a relatively small slope. Figure 7.3 includes some further information on the temperature dependence of the solubility of methane (intermsofzl// ) in water and in a few other solvents. The difference in the temperature dependence of the solubility is also discernible from Table 7.1. 

The poor solubility of coelenterazine in neutral aqueous buffer solutions often hampers the use of this compound in biological applications. The simplest way to make an aqueous solution is the dilution of a methanolic 3 mM coelenterazine with a large volume of a desired aqueous buffer solution. If the use of alcoholic solvents is not permitted, dissolve coelenterazine in a small amount of water with the help of a trace amount of 1 M NaOH or NH4OH, and then immediately dilute this solution with a desired aqueous buffer solution. However, because of the rapid oxidation of coelenterazine in alkaline solutions, it is recommended that the procedure be carried out under argon gas and as quickly as possible. 

Weiss, R. F. (1970a) The solubility of nitrogen, oxygen and argon in water and seawater. Deep Sea Res., 17, 721-35. 

The solubility of noble gases in various solutions (often aqueous-nonaqueous mixtures) gives indications of both hydrophobic and hydrophilic effects (Fig. 2.68). When substances exhibiting both effects are present, there is a maximum in the solubility of argon. Thus (Fig. 2.68, curve 1) in the system water-acetone, no hydrophilic effects are caused by the added solvent component, and the solubility increases. On the other hand, for systems in which urea is added, there are no hydrophobic effects and the solubility or the gas therefore deaeases. In curve 2 of Fig. 2.68, hydrophilic and hydrophobic effects compete (due to the properties of acetamide in water) and there is a maximum on the curve. 

The aqueous mixtures of polymers (PEG and PPG) were selected for comparison with the theory, because accurate data [4,5] regarding the solubility of argon (Ar), methane (CH4), ethane (C2H6) and propane (CsHg) in the individual constituents and the polymer + water mixtures are available. In addition, the above polymers and water are miscible in all proportions and solubility data [4,5] are available for the entire composition range. The theoretical approach regarding the solubility of gases in polymer + water mixed solvents can be extended to the correlation of their solubility in mixed solvents formed of water and pharmaceuticals, proteins, biomolecules, etc. 

A. Lannung, The solubilities of helium, neon and argon in water and some organic solvents, /ACS, 1930,52,67-80. 

Wang SL, Chen CT, Hong GH, Chung CS (2000) Carbon dioxide and related parameters in the East China Sea. Cont Shelf Res 20(4-5) 525-544 Weiss RF (1970) Solubility of nitrogen, oxygen and argon in water and seawater. Deep Sea Res 17(4) 721-731... 

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