Information AboutSolution |
| CATEGORIES ABOUT SOLUTION | |
| solutions | |
| homogeneous mixtures | |
| alchemical processes | |
| physical chemistry | |
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Examples of solid solutions are Alloys , certain Mineral s and polymers containing Plasticizer s. The ability of one Compound to dissolve in another compound is called Solubility . The physical properties of compounds such as Melting Point and Boiling Point change when other compounds are added. Together they are called Colligative Properties . There are several ways to quantify the amount of one compound dissolved in the other compounds collectively called Concentration . Examples include ''molarity'', ''molality'', and ''parts per million'' (ppm). Solutions should be distinguished from non-homogeneous mixtures such as Colloid s and Suspensions . TYPES OF SOLUTIONS Many types of solutions exist, as Solid s, Liquid s and Gas es can be both solvent and solute, in any combination:
SOLVENTS Solvents can be broadly classified into Polar and non-polar solvents. A common measure of the polarity of a solvent is the Dielectric Constant . The most widely used polar solvent is water, with a dielectric constant of 78.5. Ethanol, with a dielectric constant of 24.3, has intermediate polarity. An example of a non-polar solvent is Hexane , which has a dielectric constant of 1.9. Generally polar or ionic compounds will only dissolve in polar solvents. A simple test for the polarity of a liquid solvent is to rub a Plastic rod, to induce Static Electricity . Then hold this charged rod close to a running stream of the solvent. If the path of the solvent deviates when the rod is held close to it, it is a polar solvent. Certain molecules have polar and non-polar regions, for example Sodium Dodecyl Sulfate . This class of molecules (called Amphipathic molecules) includes Surfactant s like Soap s and Emulsifier s, as they have the ability to stabilize emulsions by aligning themselves on the interface between the non-polar and polar liquids, with their polar ends in the polar liquid and their non-polar ends in the non-polar liquid. SOLVATION During Solvation , especially when the solvent is polar, a structure forms around it, which allows the solute-solvent interaction to remain stable. When no more of a solute can be dissolved into a solvent, the solution is said to be Saturated . However, the point at which a solution can become saturated changes significantly with different environmental factors, such as Temperature , Pressure , and contamination. Raising the Solubility (for example by increasing the temperature) to dissolve more Solute , and then lowering the solubility causes a Solution to become Supersaturated . In general the greater the temperature of a solvent, the more of a given solid solute it can dissolve. However, some compounds exhibit reverse solubility, which means that as a solvent gets warmer, less solute can be dissolved. Some Surfactant s exhibit this behaviour. The solubility of liquids in liquids is generally less temperature-sensitive than that of solids or gases, while gases usually become less soluble with increasing temperature. IDEAL SOLUTIONS The properties of an ideal solution can be calculated by the Linear Combination of the properties of its components. If both solute and solvent exist in equal quantities (such as in a 50% Ethanol , 50% water solution), the concepts of "solute" and "solvent" become less relevant, but the substance that is more often used as a solvent is normally designated as the solvent (in this example, water). SEE ALSO
REFERENCES IUPAC Gold Book Definition |
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