transfer of electrons. You'll probably find more detailed information in your textbook.

http://www.chemguide.co.uk/inorganic/redox/definitions.html +5

Oxidation-Reduction Reactions In general oxidation- reduction reactions involve the exchange of electrons between two species. We find examples of oxidation-reduction or redox reactions almost every time we analyze the reactions used as sources of either heat or work. When natural gas burns, for example, an oxidation-reduction reaction occurs that releases more than 800 kJ/mol of energy. CH4(g) + 2 O2(g) CO2(g) + 2 H2O(g) Within our bodies, a sequence of oxidation-reduction reactions are used to burn sugars, such as glucose (C6H12O6) and the fatty acids in the fats we eat. C6H12O6(aq) + 6 O2(g) 6 CO2(g) + 6 H2O(l) CH3(CH2)16CO2H(aq) + 26 O2(g) 18 CO2(g) + 18 H2O(l) We don't have to restrict ourselves to reactions that can be used as a source of energy, however, to find examples of oxidation-reduction reactions. Silver metal, for example, is oxidized when it comes in contact with trace quantities of H2S or SO2 in the atmosphere or foods, such as eggs, that are rich in sulfur compounds. 4 Ag(s) + 2 H2S(g) + O2(g) 2 Ag2S(s) + 2 H2O(g) Fortunately, the film of Ag2S that collects on the metal surface forms a protective coating that slows down further oxidation of the silver metal. The tarnishing of silver is just one example of a broad class of oxidation-reduction reactions that fall under the general heading of corrosion. Another example is the series of reactions that occur when iron or steel rusts. When heated, iron reacts with oxygen to form a mixture of iron(II) and iron(III) oxides. 2 Fe(s) + O2(g) 2 FeO(s) 2 Fe(s) + 3 O2(g) 2 Fe2O3(s) Molten iron even reacts with water to form an aqueous solution of Fe2+ ions and H2 gas. Fe(l) + 2 H2O(l) Fe2+(aq) + 2 OH-(aq) + H2(g) At room temperature, however, all three of these reactions are so slow they can be ignored. Iron only corrodes at room temperature in the presence of both oxygen and water. In the course of this reaction, the iron is oxidized to give a hydrated form of iron(II) oxide. 2 Fe(s) + O2(aq) + 2 H2O(l) 2 FeO H2O(s) Because this compound has the same empirical formula as Fe(OH)2, it is often mistakenly called iron(II), or ferrous, hydroxide. The FeO H2O formed in this reaction is further oxidized by O2 dissolved in water to give a hydrated form of iron(III), or ferric, oxide. 4 FeO H2O(s) + O2(aq) + 2 H2O(l) 2 Fe2O3 3 H2O(s) To further complicate matters, FeO H2O formed at the metal surface combines with Fe2O3 3 H2O to give a hydrated form of magnetic iron oxide (Fe3O4). FeO H2O(s) + Fe2O3 3 H2O(s) Fe3O4 n H2O(s) Because these reactions only occur in the presence of both water and oxygen, cars tend to rust where water collects. Furthermore, because the simplest way of preventing iron from rusting is to coat the metal so that it doesn't come in contact with water, cars were originally painted for only one reason to slow down the formation of rust

A reaction in which electrons are transferred from one atom to another. • Oxidation: The loss of electrons by an atom • Reduction: The gain of electrons by an atom. EXAMPLE: Take a penny, file of the copper to expose the zinc in the inside. Place it in HCl, and zinc is oxidized. Zn(s) + HCl(aq) Zn2+(aq) + Cl - (aq) + H2(g) Zinc gains a positive charge, and is oxidized This is helpful for you if you are not getting this then find more details from examville.com.