Amalgam is typically found in dental offices, as it is ideal for filling cavities in decayed teeth. The earliest recorded use of dental amalgam dates back to AD to the Tang Dynasty in China, where records show that cavities in teeth were filled with a metal alloy consisting of silver and tin. Due to the high percentage of elemental mercury used in dental amalgam, there are of course stringent regulations put in place to ensure its formation, use, and disposal are handled properly.
It releases low levels of mercury in the form of a vapor that can be inhaled and absorbed by the lungs. High levels of mercury vapor exposure are associated with adverse effects in the brain and the kidneys.
In regards to the disposal of dental amalgam waste, the environment is the concern. If not disposed of properly, amalgam waste containing mercury can be exposed to the environment and impact a community.
To combat this risk, dental offices are required to make use of amalgam separators. Amalgam separators are machines that remove amalgam particles from the wastewater generated by dental offices.
The amalgam waste cannot be discarded in the trash once separated from the wastewater. Instead, it must be sent to a facility that specializes in melting the metals and recycling that mercury.
The definition of an amalgam is a mixture of metals and mercury, which can be man-made or can be naturally occurring. An example of an amalgam is a mixture of silver and mercury which is used as a dental filling.
Amalgams are use to make dental fillings, to bind to precious metals so they can be isolated later, and to produce mirror coatings. As with elements in other alloys, a small amount of mercury may be released by contact with an amalgam. Because mercury is toxic, amalgams may present health or environmental risks. In other cases, such as mixing oil with water, salt with gasoline, or sugar with hexane, the enthalpy of solution is large and positive, and the increase in entropy resulting from solution formation is not enough to overcome it.
Thus in these cases a solution does not form. The column on the far right uses the relative magnitudes of the enthalpic contributions to predict whether a solution will form from each of the four. Keep in mind that in each case entropy favors solution formation. In two of the cases the enthalpy of solution is expected to be relatively small and can be either positive or negative. Thus the entropic contribution dominates, and we expect a solution to form readily.
In the other two cases the enthalpy of solution is expected to be large and positive. The entropic contribution, though favorable, is usually too small to overcome the unfavorable enthalpy term. Hence we expect that a solution will not form readily. In contrast to liquid solutions, the intermolecular interactions in gases are weak they are considered to be nonexistent in ideal gases. Consequently, all gases dissolve readily in one another in all proportions to form solutions.
In contrast, naphthalene is a nonpolar compound, with only London dispersion forces holding the molecules together in the solid state. Hence we do not expect naphthalene to be very soluble in water, if at all. Benzoic acid has a polar carboxylic acid group and a nonpolar aromatic ring. The strength of the interaction of benzoic acid with water should also be intermediate between those of LiCl and naphthalene. Solutions are homogeneous mixtures of two or more substances whose components are uniformly distributed on a microscopic scale.
The component present in the greatest amount is the solvent, and the components present in lesser amounts are the solute s. Substances that are miscible, such as gases, form a single phase in all proportions when mixed. Substances that form separate phases are immiscible. Solvation is the process in which solute particles are surrounded by solvent molecules.
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