CHEMISTRY

= HERE ARE SOME VIDEOS OF CHEMICAL REACTIONS.. ENJOY THEM :) =

media type="youtube" key="Mx5JJWI2aaw" height="344" width="425" _ Sodium is a highly combustible element and the addition of water can make it explode. In this video we see a drop of water added to a small piece of sodium in a flask filled with chlorine gas. The distinctive yellow color of the light emitted is due to sodium’s ‘D lines’ – this is often used in street lighting. This experiment produces a great deal of heat. When you combine sodium and chlorine, you get sodium chloride – common salt. media type="youtube" key="txkRCIPSsjM" height="344" width="425" Potassium Chlorate is a compound containing potassium, chlorine and oxygen. It is often used as a disinfectant and in fireworks and explosives. When potassium chlorate is heated to melting point, any item added to it will cause a rapid disintegration in the form of an explosion (as we see in the video above). The gas coming off the potassium chlorate is oxygen. Because of this, it is often used in airplanes, space stations, and submarines as a source for oxygen. A fire on the space station Mir was attributed to this substance. media type="youtube" key="nWTSzBWEsms" height="344" width="425" When a superconductor is cooled to below its transitional temperature, it becomes diamagnetic: this is when something is repulsed from a magnetic field rather than drawn in to it. This discovery by Meissner has lead to the concept of frictionless transportation, as an object could be “floated” along a track rather than “attached” to it by wheels. media type="youtube" key="uy6eKm8IRdI" height="344" width="425" Sodium acetate, when heated and cooled, becomes supersaturated in water. When it comes in contact with another object it re-crystalizes. This reaction also causes heat, and so this has a practical use in heat pads. Sodium acetate is also used as a preservative, and also gives salt and vinegar chips their distinctive taste. It is referred to in foods as E262 or sodium diacetate.

Here is the link if you want to see more :D http://listverse.com/2008/03/04/top-10-amazing-chemical-reactions/ _________________________________________________________________________________________________________________- Reviewed by GL: And your sources of information?


 * Types of chemical separations: **
 * Extraction: is a useful technique for separating compounds such as somemones that have different polarities. This technique can also be used to extract a solut from a solid.
 * Distillation: it is used frequently to purify liquids,.
 * Recrystallization: it is the technique that purifies solids, which take advantage of diferences in the solubility of different compiunds of a mixture in different solvents.
 * Chromatography: it is one of the fast-growing methods for separating compounds, it was first used to separate the colored pigments in plants.
 * Examples:**
 * For extraction coffe´s a good example, because coffe is decaffeinated by extraction.
 * [[image:file/view/cafe.jpg]]
 * For distillation all mixtures that have a liquid/liquid mixture are a good example.
 * [[image:file/view/tareaa.jpg]]
 * For recrystallization purifying soilids like crystals are some examples.
 * [[image:file/view/crys.jpg]]
 * For chromatography there are a lot of examples.. but the first that was used were plants.
 * [[image:file/view/plan.jpg]]


 * __PROPERTIES__**

● Pure silver has a brilliant white metallic luster. It is a little bit harder than gold and it is malleable, also pure silver has the highest electrical and thermal conductivity of all metals and have the lowest contact resistance. It is stable in water and oxygen. ● Silver is considered to be non-toxic. However, most silver salts are poisonous and some carcinogenic. ● Symbol: Ag – is an abbreviation of the Latin word for silver, “argentum” ●The name Silver come from the Anglo-Saxon “Seolfor” meaning silver. ● Silver was discover after gold and copper, it has been known since ancient times, it is mentioned in the book of Genesis and was used by the ancient South Americans, Asians, Egyptians, Greeks, Romans and Chinese. ● Silver was found in Canada, Mexico, Peru, and Australia and in the USA. ● Total electron configuration: 1s 2s 2p/ 3s 3p 4s/ 3d /4p 5s /4d ● Atomic Radius: The silver atom has a radius of 144.5 pm ● Ionization energy: The silver Ionization energy needed to remove a group of electrons from an atom that later will serve to the production of positive charge of ion in Silver. Ag -> Ag+ + e - this process can be repeated many times, but the energy increases a lot. The general equation of silver is: AgN+ -> Ag(N+1) + + e- ● Electro negativity: in the Pauling scale is 1. 93 The Pauling scale gives a dimensionless quantity it also gives us a scale that starts from 0.7 to 4.0. **__Uses__**

● It is use like a precious metal, dental alloys, jewelry, coins, and about the half of silver produced in USA is used in photographic films. ● Silver is also use in electrical and electronic equipment, the 20 percent of silver is used for this porpoise. ● In medicine silver is a very important agent because it is use for anti-bacterial and as healing, nowadays silver is also use as a germicide and antibiotic. ● In industry silver is very important because it is use in switches and circuit breakers and this thing people use in all parts. Other things that are made of Silver are: batteries, brazing and soldering, electronics, etc.

**__Economic Impact__**

● In the last 10 years silver has had up and downs, in countries Italy and Thailand the production of silver was not too good. However, in other countries like China, India and Russia the production of silver was better. ● In the last year Peru was the first Country with more silver production followed by Mexico.

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Reviewed by GL: Well done!

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