Supersaturated solution A

Ham [508] considered that the growth of a random array of precipitating particles could be approximated to a simple cubic lattice of spherical sinks of radius R to which more material diffused from the supersaturated solution. A model of the type is very similar to those models discussed by Reek and Prager [507] and Lebenhaft and Kapral [492], The analysis which Ham introduced highlights a similarity between the competitive effect and the Wigner—Seitz model of metals. 

Apart from the significance as a novel enantiomeric resolution phenomenon, the investigation on the mechanism of Preferential Enrichment has also shed light on the hitherto unknown mechanism of a polymorphic transition occurring during crystallization from a supersaturated solution. A combination of several techniques employed here would also be useful to elucidate the unknown mechanism of another type of polymorphic transition... 

It is possible, under the right conditions, to produce a supersaturated solution. A supersaturated solution is one that is holding more dissolved solute than it should be able to under the current conditions. For example, if you create a solution that contains 60 g of NaCl/100 g of HzO at 90 °C, it would be holding 20 more grams of NaCl than it should be able to. Creating a supersaturated solution can be a little tricky, and the resultant solution is unstable, but the practical applications of such solutions include producing rock candy. 

Supersaturated solution A metastable solution in which the concentration of solute is higher than that of a saturated solution. 

Supersaturated solution A (metastable) solution that contains a higher-than-saturation concentration of solute slight disturbance or seeding causes crystallization of excess solute. 

Supersaturated solution. A solution that contains more of the solute than is present in a saturated solution. (12.1)... 

Naphthalenesulfonic acid 124 Naphthalene, very finely ground (128 g), is added with stirring to sulfuric acid monohydrate (260 g) at 0°. To avoid sudden separation of the sulfonic acid from a supersaturated solution, a seed of the 1-sulfonic add is added after the naphthalene (the seed is obtained by warming a sample of naphthalene in sulfuric add on the water-bath and cooling the product). If the naphthalene has not all been sulfonated, naphthalene will separate when a sample of the reaction mixture is added to watery if that happens the reaction mixture should be warmed for a short time at 60°. 

The fact that solubility changes with temperature and that some substances become more soluble with increasing temperature is the key to forming supersaturated solutions. A supersaturated solution contains more dissolved solute than a saturated solution at the same temperature. To make a supersaturated solution, a saturated solution is formed at a high temperature and then cooled slowly. The slow cooling allows the excess solute to remain dissolved in solution at the lower temperature, as shown in Figure 14.16. 

SUPERSATURATED SOLUTION - A solution of a salt or mineral with a concentration beyond the normal saturation point. 

Figure 3. Correlation between the concentration of L-SCMC and that of D-SCMC in the solution since L-SCMC seeds were added in the supersaturated solution [ A T=3.6K ]...

Veverka, V., Sohnel, O., Bennema, P. and Garside, J. (1991) Concentration gradients in supersaturated solutions a thermodynamic analysis. AIChEJ, 37, 490-498. 

A supersaturated solution, a rain-bearing cloud or a supercooled liquid provides examples of metastable equilibrium. 

Sometimes it is possible to obtain a supersaturated solution, a solution that contains more dissolved substance than a saturated solution does. For example, the solubility of sodium thiosulfate, Na2S203, in water at 100°C is 231 g/lOOmL. But at room temperature, the solubility is much less—about 50 g/100 mL. Suppose you prepare a solution saturated with sodium thiosulfate at 100°C. You might expect that as the water solution is cooled, sodium thiosulfate would crystallize out. In fact, if the solution is slowly cooled to room temperature, this does not occur. Instead the result is a solution in which 231 g of sodium thiosulfate is dissolved in 100 mL of cold water, compared with the 50 g you would normally expect to find dissolved. 

Supersaturated solution a solution that contains more dissolved substance than does a saturated solution the solution is not in equilibrium with the solid substance. (12.2)... 

Figure 16.3 Supersaturated solution, (a) A supersaturated solution of sodium acetate was prepared by dissolving solid sodium acetate in warm water. The solution was then allowed to cool without physical disturbance. Note that, at the macroscopic level, you cannot tell that the solution is supersaturated, (b) A single grain of sodium acetate is added to the solution to initiate crystallization, (c and d) Crystallization continues as long as the solution exceeds... 

Feenstra TP, De Bmyn PL (1981) The Ostwald rule of stages in precipitation from highly supersaturated solutions a model and its application to the formation of the nonstoichiometric amorphous calcium phosphate precursor phase. J Colloid Interface Sci... 

In the case of a supersaturated vapor a = pjpoo, where p and p are the pres-sures of the supersaturated and saturated vapors. In the case of a supersaturated solution a = cjc, the ratio of the concentrations (or better, activities) of the supersaturated and saturated solutions. In some solid-state transformations the significance of a will be similar—the ratio of the concentrations of a certain species—but in other solid-state reactions it will have a more complex significance. 

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