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Oxidation: Compendium of definitions and concepts
Definition of oxidationThe oxidation is the chemical reaction from which an atom, ion or molecule gives electrons; then it is said that it increases its oxidation state. While this explanation is sufficient in practical terms, it is not entirely correct since while the transfer of electrons will always cause a change in oxidation state, also this change can occur without occurring a transfer of electrons. As we shall see there are various forms of the same, as that occurs in a piece of Apple with time, or other less household, best known in the field of science.
The name of the reaction chemistry, "oxidation", derives from the fact that in the majority of cases, the transfer of electrons is conducted acquiring oxygen atoms, but it is important to emphasize that also the oxidation occurs without involving the exchange of oxygen. In simple terms, during the reaction a substance gives electrons and another the gana (reduction), so the term "redox" is more convenient to refer to the process - Redox is an abbreviation for "reduction/oxidation", and refers to all those chemical reactions in which atoms change their oxidation state.
Provided that an oxidation occurs there is release of energy. This energy can be released slowly, as it is the case of oxidation or corrosion of metals, or you can be released very quickly and explosive as in the case of combustion.
Oxidation is present everywhere and occurs in places that we cannot imagine. There are several types of oxidation, such as combustion, and some, as we shall see, occur within our organism.
Breathing, one of the types of oxidation, is the physiological process by means of which plants exchanging carbon dioxide (CO2) with oxygen (O2). Through this important process plant is capable of photosynthesis.
On the other hand, within types of oxidation, we find the fermentation. Fermentation is a catabolic oxidation process that obtains, as a final product, an organic compound. This final compound is that dictate what type of fermentation is about. This may be, lactic acid, alcohol, butterfat, acetic or Glycerin.
In living beings the fermentation is a fairly common process, since it gives in microorganisms such as bacteria and yeast, as well as the muscle tissue of animals and humans when the supply of oxygen in the cells is not enough to generate a muscle contraction or carry out metabolic processes.
Concept of oxidationOxidation is the process and the result of rust. This verb refers to generaroxido from a chemical reaction. On the other hand, is what occurs when oxygen combines a metal oxide, or with the elements known as Metalloids.
When the oxidation of an ion or unatomo, the element in question loses a certain amount of electrons. Considered a system, oxidation implies that one of the elements come off electrons and another to assimilate them. Thus, what occurs is unatransferencia of electrons.
The element that gives the electrons is known as reducing agent and is which is oxidized. The oxidizing agent, on the other hand, stays with electrons that the gearbox releases. While the first oxidation state increases, the second oxidation state is reduced.
It should be noted that the chemical elements have an oxidation number. All the elements have an apparent charge within compounds, which tends to obey laregla byte (a trend that indicates how often behave ions). According to this rule, the atoms usually have 8 electrons in the energy level more external. If an atom X 5 electrons required to fulfill the octet, its oxidation number of sera5 rule. On the other hand, if an atom and boasts 5 electrons that must contribute to achieve that Atom X complies with the aforementioned law, the oxidation of this number will be 5 +.
Definition of oxidationExpressed in a very general way, will say that the oxidation occurs when an unstable Atom loses an electron, thus allowing the atom to form a new compound with another element.
There are basically two types of chemical reactions:
1) Those in which react ions or molecules without apparent change of the electronic structure of the particles, and
(2) Reactions in which atoms or ions undergo changes of electronic structure.
In the second type of reaction may be actual transfer of electrons from one particle to another or can modify the way in which the electrons are shared. The latter type of reaction that involves electronic changes is called oxidation-reduction reaction.
Originally, the term oxidation was assigned to the combination of oxygen with other elements. There are many known examples of this. Mildew iron and coal burning. Mildew, oxygen is slowly combines with the iron forming ferrous oxide (Fe2 O3); in combustion, combined quickly with carbon to form CO2. The observation of these reactions originated the terms oxidation 'slow' and 'fast'.
However, the chemicals noted that other non-metallic elements combined with substances in the same manner as the towards the oxygen with these substances. Oxygen, antimony and sodium burn in chlorine and iron in the presence of fluorine atmosphere. Because these reactions were similar, the chemicals gave a definition of more general oxidation. O2 or Cl2, reagents and eliminated every element electrons. Therefore, the oxidation was defined as the process whereby there is apparent loss of electrons in an atom or ion.
Originally a reduction reaction was limited to the type of reaction in which oxides were "reduced" (it gave off) their oxides. Iron oxide is "reduced" to iron with carbon monoxide. Copper oxide (II) could be "reduced" to copper with hydrogen. These reactions removed oxygen and getting the free element. The free element can be obtained in other ways. The immersion of a nail of iron in a solution of copper sulfate (II) causes a reaction which occurs free copper.
The similarity between the oxidation-reduction reactions led to chemists to formulate a more general definition of reduction: the reduction is a process whereby atoms or ions gain electrons.
Concept of oxidationOxidation is a chemical reaction where a metal or a Nonmetal gives electrons, and therefore increases its oxidation state. The opposite to oxidation chemical reaction is known as reduction, i.e. when a chemical species accepts electrons. These two reactions always together, occur i.e., when a substance is oxidized, always is by the action of another will be reduced. One transfers electrons and the other accepts. For this reason, the general term of redox reactions is preferred. Life itself is a redox phenomenon. Oxygen is better oxidizer that exists since the molecule is poorly reactive (by its double bond) and however is very electronegative, almost like fluorine.
The more oxidizing substance that exists is the cation KrF + because it is easily Kr and F +. Among several substances with the same oxidation state; oxidizing capacity differs greatly according to the ligand as well the - CF3 has an electronegativity (C) similar to chlorine (3,1) much greater than for example - CBr3, although both have the same number of oxidation. The HBrO3 properties are very different to the BrF5, the latter being much more oxidizing although both have the same valencia.
If the element is for State cationic or neutral group: KrF2 has one less than the KrF + although formally have the same number of oxidation. Thus MnF3 MnF4 (- 1) and the MnF2 (+ 1) all with the same number of oxidation have in different.
The most common oxidizing substances are potassium permanganate (KMnO4), (K2Cr2O7) potassium dichromate, the hydrogen peroxide (H2O2), nitric acid (HNO3), the hipohalitos and the halatos (e.g. sodium hypochlorite (NaClO) strongly oxidizing in alkaline medium and potassium bromate (KBrO3)). Ozone (O3) is a very strong oxidant:
BR (- 1) + O3 = BrO3 (- 1)
The name of "oxidation" comes from that in the majority of these reactions, the electron transfer occurs through the acquisition of atoms of oxygen (electron transfer) or vice versa. However, the oxidation and reduction can occur without having oxygen exchange of by means, for example, the oxidation of sodium iodide to iodine through the reduction of chlorine to sodium chloride:
Way + Cl2 → I2 + 2NaCl
This can be broken down into its two corresponding hemireacciones:
2 I-1 ←→ I2 + 2 e -
Cl2 + 2 e-←→ 2 Cl-1
The transfer of electrons is made explicit in these two equations. If the two above equations are added, you get the first.