Concentration, of saturated solution

For description of the amount of ammonium sulfate used for precipitation mostly the term % saturation is used, because at a given temperature the concentration of a saturated ammonium sulfate solution is constant. But because the concentration of saturated solution is temperature dependent, the description should also contain data for temperature of saturated ammonium sulfate solution used for precipitation as well as for sample solution. 

Fig. 17 Simulation of two dilution waves initiated by a small, localized perturbation. There is a fixed time period between each of the curves. The parameter is the scaled difference between concentrations of saturated solutions cE and cp2 in equilibrium with, respectively, extended and folded-chain crystals at temperature Tc, such that c = cE + (cp2 - cE) (from [46] by permission of American Institute of Physics)...

In some publications only equilibrium concentrations (concentration in solution equilibrated with the solid for certain time) are reported, and these concentrations are shown in Tables 4.1-4.6. They are somewhat lower than the initial (total) concentrations, but the difference between initial and equilibrium concentration usually does not exceed one order of magnitude. In some publications the amount of adsorbate per gram of per of adsorbent is reported. Such concentrations cannot be converted into mol dm unless the solid to liquid ratio is known. The mass or molar ratio between an element - constituent of the adsorbate and another element - constituent of the adsorbent has been reported in some publications. There are a few other examples of concentration reported in original paper that cannot be easily converted into mol dm without additional information, e.g. solutions were prepared by dilution of saturated solution of a salt by known factor, but the concentration of saturated solution is not reported, and the temperature is unknown. 

A substance that has lower surface tension is usually a surface active one. If component A is surface active with respect to component B, then the component B is inactive with respect to A, i.e. the surface tension, a(c), isotherms usually exhibit a monotonous behavior. The isotherms with a minimum are rarely encountered. They may be observed in systems consisting of substances whose surface tension values are close, such as, e.g., a carbon disulfide - dichloroethane system. When the components have limited solubility in each other, the surface tension isotherms consist of two separate sections separated by a gap, the borders of which correspond to the concentrations of saturated solutions. It is essential to point out that when the mutual solubility of components is limited, an interface with a very low interfacial tension may form between two saturated solutions (see Chapter III, 2). 

Some conditions, however, are known which allow mineral crystallization from solution. The main agents of crystallization are the crystallization power and the crystallization rate crystallization is possible in systems out of equilibrium. The measure of a system s deviation from equilibrium is called the driving force of crystallization, and its actual expression is supersaturation and supercooling. The most important parameter allowing the growth of crystals from solution is solubility. The concentration of saturated solution quantitatively determines the solubility of the substance under particular conditions. Crystals do not grow from unsaturated solutions, crystals mainly dissolve in them. 

Dissociation constants and corresponding pK values of the drugs were obtained from measured free-base solubilities (determined at high pH s) and the concentrations of saturated solutions at intermediate pH s. Morphine, fentanyl, and sufentanil exhibited pJCa values of 8.08,8.99, and 8.51, respectively. Over the pH range of 5 to 12.5 the apparent solubilities are determined by the intrinsic solubility of the free base plus the concentration of ionized drug necessary to satisfy the dissociation equilibrium at a given pH."... 

Nature of n-alkanes Molar concentration of saturated solution... 

Transition metals are nearly insoluble in alkali metals compared to the metals of the groups just described. The concentrations of saturated solutions at 500 °C are on the level of a few wppm. Among these metals, nickel has a relatively high solubility in liquid metals, whereas molybdenum has an extremely low miscibility in the liquid state. 

This method is more frequently used than the previously described one. It may be employed for oxide solubility studies in a wide range of concentrations of saturated solutions. This method allows to determine solubility products of oxides and in some cases (the existence of the non-saturated solution region) dissociation constants may be calculated. 

McGowan [36] considered the process of solution in water as the formation of a cavity in the solvent followed by occupation by the solute. He symbolised the energy changes involved as and respectively. E —Ej therefore represents the free energy of solution, and since by definition a saturated solution is one in equilibrium with the pure solute, Equation (4) can be rewritten as Equation (31), where and represent molar concentrations of saturated solution and pure liquid respectively. 

Since saturated NaCl brine has a vapor pressure approximately 75% of that of water, a relative humidity greater than 75% will cause condensation onto the salt. This is known as the critical humidity. KCl solutions have higher vapor pressures and therefore higher critical humidity. Because KCl also has a higher temperature coefficient of solubility, the concentration of saturated solutions increases more rapidly with temperature. The critical humidity therefore is not so nearly constant as is the case with NaCl, and it decreases with increasing temperature. At most ambient temperatures, the critical humidity of KCl is 85% or higher. 

There are two other ways to express a substance s solubility molar solubility, which is the number of moles of solute in 1 L of a saturated solution (mol L ), and solubility, which is the number of grams of solute in 1 L of a saturated solution (g L ). Note that both these expressions refer to the concentration of saturated solutions at some given temperature (usually 25°C). 

Where R is the ideal gas constant, T is the absolute temperature, v is the molar volume, C is the concentration of solution, and Cs is the concentration of saturated solution. QCs is the supersaturation. 

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