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An introduction to the definition of redox equations

Oxidation-reduction reaction Photo by: Giorgio Clementi The term oxidation-reduction reaction actually refers to two chemical reactions that always occur at the same time: Oxidation-reduction reactions are also referred to more simply as redox reactions.

Redox and electron exchanges

Oxidation, reduction, and redox reactions can all be defined in two ways. The simpler definitions refer to reactions involving some form of oxygen. As an example, pure iron can be produced from iron oxide in a blast furnace by the following reaction: In chemical terms, the carbon is said to be oxidized because it has gained oxygen. At the same time, the iron oxide is said to be reduced because it has lost oxygen. Because of its ability to give away oxygen, iron oxide is called an oxidizing agent.

Oxidation-Reduction Reactions

Similarly, because of its ability to take on oxygen, carbon is said to be a reducing agent. Oxidation and reduction always occur together. If one substance gives away oxygen oxidationa second substance must be present to take on that oxygen reduction. By looking at the above example, you can see that the following statements must always be true: An oxidizing agent in this case, iron oxide is always reduced.

Words to Know Combustion: An oxidation-reduction reaction that occurs so rapidly that noticeable heat and light are produced.

An oxidation-reduction reaction in which a metal is oxidized and oxygen is reduced, usually in the presence of moisture. A process in which a chemical substance takes on oxygen or loses electrons. A chemical substance that gives up oxygen or takes on electrons from another substance. A chemical substance that takes on oxygen or gives up electrons to another substance.

  • In metal — soluble metal salt displacement reactions, the metal atom always loses electrons oxidation and the metal ion always gains electrons reduction;
  • It is based on the fact that when two elements react with each other, they do so by exchanging electrons;
  • A reducing agent in this case, carbon is always oxidized;
  • That energy is put to use to heat homes and buildings; to drive automobiles, trucks, ships, airplanes, and trains; to operate industrial processes; and for numerous other purposes;
  • Combustion is an example of a redox reaction that occurs so rapidly that noticeable heat and light are produced;
  • An atom is oxidized if its oxidation number increases, the reducing agent, and an atom is reduced if its oxidation number decreases, the oxidizing agent.

A process in which a chemical substance gives off oxygen or takes on electrons. A reducing agent in this case, carbon is always oxidized. Redox and electron exchanges For many years, chemists thought of oxidation and reduction as involving the element oxygen in some way or another.

That's where the name oxidation came from. But they eventually learned that other elements behave chemically in much the same way as oxygen. They decided to revise their definition of oxidation and reduction to make it more general—to apply to elements other than oxygen. The second definition for oxidation and reduction is not as easy to see.

Words to Know

It is based on the fact that when two elements react with each other, they do so by exchanging electrons. In an oxidation-reduction reaction like the one above, the element that is oxidized always loses electrons. The element that is reduced always gains electrons.

The more general definition of redox reactions, then, involves the gain and loss of electrons rather than the gain and loss of oxygen.

  1. What happens when we try to run the reaction in the opposite direction? Summary Remember the 7 rules of oxidation states these are vital to understanding redox reactions Oxidation signifies a loss of electrons and reduction signifies a gain of electrons.
  2. The main group metals are all reducing agents.
  3. They tend to be "strong" reducing agents. The more reactive metal magnesium always displaces the less reactive metal iron.
  4. Corrosion, decay, and various biological processes are examples of oxidation that occurs so slowly that noticeable heat and light are not produced.
  5. A brown precipitate of copper forms on the surface of the iron filings and the blue colour fades as the less reactive copper is displaced by the more reactive iron. The hydrogen ions gain electrons to form hydrogen gas molecules reduction.

In the reaction below, for example, sodium metal Na reacts with chlorine gas Cl 2 in such a way that sodium atoms lose one electron each to chlorine atoms: Because chlorine gains electrons in the reaction, it is said to be reduced.

Types of redox reactions. Redox reactions are among the most common and most important chemical reactions in everyday life.

The great majority of those reactions can be classified on the basis of how rapidly they occur. Combustion is an example of a redox reaction that occurs so rapidly that noticeable heat and light are produced.

  • A process in which a chemical substance gives off oxygen or takes on electrons;
  • Hence, Zn is oxidized and acts as the reducing agent.

Corrosion, decay, and various biological processes are examples of oxidation that occurs so slowly that noticeable heat and light are not produced. Any time a material burns, an oxidation-reduction reaction occurs. The two equations below show what happens when coal which is nearly pure carbon and gasoline C 8 H 18 burn.

You can see that the fuel is oxidized in each case: That energy is put to use to heat homes and buildings; to drive automobiles, trucks, ships, airplanes, and trains; to operate industrial processes; and for numerous other purposes.

Most metals react with oxygen to form compounds known as oxides. Rust is the name given to the oxide of iron and, sometimes, the oxides of other metals.

The process by which rusting occurs is also known as corrosion. Corrosion is very much like combustion, except that it occurs much more slowly.

The equation below shows perhaps the most common form of corrosion, the rusting of iron. The compounds that make up living organisms, such as plants and animals, are very complex. They consist primarily of carbon, oxygen, and hydrogen. A simple way to represent such compounds is to use the letters x, y, and z to show that many atoms of carbon, hydrogen, and oxygen an introduction to the definition of redox equations present in the compounds.

When a plant or animal dies, the organic compounds of which it is composed begin to react with oxygen.

  • Potassium iodide is a colourless salt dissolving in water to form a colourless solution;
  • Balancing redox reactions is an important step that changes in neutral, basic, and acidic solutions;
  • The reduced half gains electrons and the oxidation number decreases, while the oxidized half loses electrons and the oxidation number increases;
  • At the same time, the iron oxide is said to be reduced because it has lost oxygen;
  • Many of the changes that take place within living organisms are also redox reactions.

The reaction is similar to the combustion of gasoline shown above, but it occurs much more slowly. The process is known as decay, and it is another example of a common oxidation-reduction reaction. The equation below represents the decay oxidation of a compound that might be found in a dead plant: Many of the changes that take place within living organisms are also redox reactions.

For example, the digestion of food is an oxidation process. Food molecules react with oxygen in the body to form carbon dioxide and water. Energy is also released in the process. The carbon dioxide and water are eliminated from the body as waste products, but the energy is used to make possible all the chemical reactions that keep an organism alive and help it to grow.