Oxidation and reduction together are called redox (reduction and oxidation) and generally characterized by the transfer of electrons between chemical species, like molecules, atoms or ions, where one species undergoes oxidation, a loss of electrons, while another species undergoes reduction, a gain of electrons. This transfer of electrons between reactants entails changes in energy to form new products and will be either endothermicA chemical reaction that is accompanied by or requires the absorption of energy from its environment. A classic endothermic reaction is the melting of ice cubes in a cup of water. Click on Term to Read More or exothermicA chemical or nuclear reaction that liberates heat energy so that heat flows from the system to the surroundings. Exothermic reactions cause an increase in temperature. A classic exothermic reaction is the mixing of a strong acid with water. In order to prevent an explosive and dangerous reaction, the acid Click on Term to Read More.
Oxidation is a chemical reaction in which electrons are lost/donated during a reaction by a chemical species. Specifically, it means the substance that donates electrons is oxidized. For example, within the protoplanetary discFlattened and rotating disk of dense gas and dust/solids orbiting a young star from which planets can eventually form. Click on Term to Read More, OH– molecules and free oxygenElement that makes up 20.95 vol. % of the Earth's atmosphere at ground level, 89 wt. % of seawater and 46.6 wt. % (94 vol. %) of Earth's crust. It appears to be the third most abundant element in the universe (after H and He), but has an abundance only Click on Term to Read More atoms created oxidizing conditions that enabled carbonElement commonly found in meteorites, it occurs in several structural forms (polymorphs). All polymorphs are shown to the left with * indicating that it been found in meteorites and impact structures: a. diamond*; b. graphite*; c. lonsdalite*; d. buckminsterfullerene* (C60); e. C540; f. C70; g. amorphous carbon; h. carbon nanotube*. Click on Term to Read More dust to form simple molecules like CO and more complex molecules such as CH4 and C2H2 depending on their distance from the sunOur parent star. The structure of Sun's interior is the result of the hydrostatic equilibrium between gravity and the pressure of the gas. The interior consists of three shells: the core, radiative region, and convective region. Image source: http://eclipse99.nasa.gov/pages/SunActiv.html. The core is the hot, dense central region in which the1. A much simpler example is when iron rusts, in this process the free iron interacts with oxygen (the oxidizer/oxidant/oxidizing agent) to produce iron oxide (FeO). Though the term used to imply that oxygen was the only oxidizer in the reaction, in modern chemistry, oxygen does not have to be present in a reaction for it to be an oxidizing reaction.
The opposite process is called reduction in which electrons are gained (accepted) during a reaction by a chemical species. When we describe a metalElement that readily forms cations and has metallic bonds; sometimes said to be similar to a cation in a cloud of electrons. The metals are one of the three groups of elements as distinguished by their ionization and bonding properties, along with the metalloids and nonmetals. A diagonal line drawn Click on Term to Read More like Fe (iron) as being reduced, we mean that the reactions used to extract that iron from, for example, its oxides (FeO) is produced by adding another moleculeCollection of atoms held together by chemical bonds into a discrete, finite structure. One way molecules are represented is by a chemical formula where symbols for the elements are used to indicate the types of atoms present and subscripts are used to indicate the relative numbers of atoms. For example, Click on Term to Read More under various systemDefinable part of the universe that can be open, closed, or isolated. An open system exchanges both matter and energy with its surroundings. A closed system can only exchange energy with its surroundings; it has walls through which heat can pass. An isolated system cannot exchange energy or matter with conditions so that the added molecule has greater affinity for the Fe-bound oxygen than the iron itself.
Note, there are many other and more complex ways to oxidize/reduce iron, and the FeO example was simply chosen for simplicity.