Solubility of sugars

Just as the saturated solubility of sugar in water is limited, so the solid solubility of element B in metal A may also be limited, or may even be so low as to be negligible, as for example with lead in iron or carbon in aluminium. There is extensive interstitial solid solubility only when the solvent metal is a transition element and when the diameter of the solute atoms is < 0 6 of the diameter of the solvent atom. The Hume-Rothery rules state that there is extensive substitutional solid solubility of B in >1 only if ... 

Figure 1.12 shows the solubility of sugar in water as a function of temperature. Alternatively, we can say that it gives the concentration of sugar in a saturated solution at various temperatures. For example, at 20°C, we could say that the solubility of sugar is 204 g/100 g water or that a saturated solution of sugar contains 204 g/100 g water. ... 

From 0.1 to 8% water in the first solvent aids this extraction. More water improves the efficiency of the solvent but decreases its selectivity— i.e., the solubility of many impurities is increased considerably, but so is the solubility of sugar. Thus, the water reduces the yield of refined sugar but increases its purity. 

An ordinary solution is homogeneous it is not a substance, however, because its composition is variable—a sugar solution may contain any amount of sugar per unit amount of water, from a trace to the ampunt determined by the solubility of sugar (or even more, if the solution is supersaturated). 

The synthesis of di- or trisaccharides by condensation of mono- or disaccharides by reversal of the hydrolytic reaction is difficult due to unfavorable equilibrium, and yields of products are usually low. Reaction conditions must be tuned to shift the equilibrium, normally by increasing substrate concentrations. This is feasible, given the high solubility of sugars in buffer solutions. For example, mannose oligosaccharides were synthesised via reversal of the... 

Solubility varies with temperature. The solubilities of solids usually increase as the temperature rises. For example, more sugar dissolves in hot coffee than in cold coffee. Table 3 shows the effect of temperature on the solubility of sugar. 

When all of the water has evaporated, pure sugar remains in the beaker. The separation is possible because of the difference in solubility of sugar and sand. 

As you realized in the fudge example above, the solubility of sugar increases as the temperature increases. More and more solute is able to dissolve at higher and higher temperatures. Temperature has a significant effect on solubility for most solutes. 

Temperature affects the solubility of most substances. You may have noticed, for example, that not only does sugar dissolve more quickly in hot tea than in iced tea, but more sugar dissolves in other words, the solubility of sugar in tea is greater at higher temperatures. Let s examine the effects of temperature on the solubility of solids and of gases. 

LOOK AROUND AT THE GREAT vahoty of coloES, textuEGS, and other properties in the materials that surround you—the colors in a garden, the texture of the fabric in your clothes, the solubility of sugar in a cup of coffee, or the transparency and beauty of a diamond. The materials in our world exhibit a striking and... 

A sugar cube dissolving in water. The properties of a solution are markedly different from those of its solvent. The solubility of sugar molecules in water is mainly due to hydrogen bond formation between the solute and the solvent. The models show glucose and water molecules. 

Sugars are solubility-limited in acetonitrile and so samples are often made up in pure water. This has two important chromatographic ramifications (1) there will be a peak associated with water in the refractive index detector-based chromatogram, and (2) the retention of sugars increases as acetonitrile levels in the mobile phase increase. This is due to the limited solubility of sugars in acetonitrile. Therefore, even though acetonitrile is considered a strong solvent, solubility dominates the retention process at elevated acetonitrile levels. 

Extrusion tripled the water solubility of sugar beet pulp fiber, primarily by reducing the molecular weight of pectin and hemicelluloses molecules (Ralet et ai, 1991). Ferulic acid, a phenolic acid normally associated with plant cell walls, was also recovered from the soluble sugar beet fraction. Smaller fragments may be soluble in aqueous ethanol, and thus discarded during the extraction steps common to enzymatic-gravimetric and enzymatic-chemical methods of fiber analysis. 

The solubility of sugar is greater than 260 g/100 g H2O at all temperatures above 50°C. Therefore, the solution is unsaturated at 70°C and 60°C. At 50°C, the solubility is equal to the amount dissolved, so the solution is saturated. At 40°C, the solution contains more dissolved sugar than it should on the basis of solubility, and the solution is supersaturated. At 30°C, the excess sugar crystallizes from solution, and the resulting solution becomes saturated. From that point, excess sugar continues to crystallize from the solution, and the solution r ains saturated to 20°C. 

Refer to Figure 7.6 and answer the question. How would the solubility of sugar compare in equal amounts of hot and iced tea ... 

Because of the solubility of sugar, poly(vinyl alcohol) and polysugar in DMSO and water, the polysugar product could not be readily purified by crystallization. Polysugar processed in DMSO could retain residual amounts of DMSO. This is objectionable. Therefore, these polysugars were dissolved in water at 70 C, and the water and trace DMSO were removed by flash evaporation to dryness. Complete removal of the solvent was achieved by subsequent drying in a vacuum oven at 80 C for 24 hours. 

The solubility of a substance is the amount of that substance required to form a saturated solution with a specific amount of solvent at a specified temperature. The solubility of sugar, for example, is 204 g per 100. g of water at 20.°C. The temperature must be specified because solubility varies with temperature. For gases, the pressure must also be specified. Solubilities must be determined experimentally and can vary widely, as shown in Figure 2.4. Solubility values are usually given as grams of solute per 100. g of solvent or per 100. mL of solvent at a given temperature. 

More sugar dissolves in hot tea than in iced tea because the aqueous solubility of sugar, like that of most solid substances, increases as the temperature increases. Figure 13.4 shows the solubility of some common solids in water as a function of temperature. Note how the solubility of a solid and the change in solubility over a particular temperature range vary considerably. The relationship between temperature and solubility is complex and often nonUnear. 

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