Oxidation and Reduction
Most metals cannot be found in pure form in nature. In most cases, the element is part of a compound called a mineral. The process by which a mineral is converted to a pure element is called a reduction:
EX: Cu+2 + 2 e- ---> Cu
In the process above, the copper ions (which are apart of a mineral) acquires electrons from another element. When this happens, the ion becomes neutral and stable.
The process by which the metal is changed back into a cation (or becomes part of a mineral again) is called an oxidation:
The process by which the metal is changed back into a cation (or becomes part of a mineral again) is called an oxidation:
EX: Cu ---> Cu+2 + 2 e-
In an oxidation, the copper donates or loses electrons. Because of the loss of electrons, the copper must then become part of a compound.
Redox Reactions
Redox reactions are chemical reactions in which a reduction of one metal occurs at the same time as an oxidation of another metal occurs.
When both happen at the same time, it is called a redox reaction. In these redox reactions, one atom will lose electrons, and those electrons will be absorbed by another atom. The oxidation will occur in conjunction with the reduction. An example is below:
Redox Reactions
Redox reactions are chemical reactions in which a reduction of one metal occurs at the same time as an oxidation of another metal occurs.
When both happen at the same time, it is called a redox reaction. In these redox reactions, one atom will lose electrons, and those electrons will be absorbed by another atom. The oxidation will occur in conjunction with the reduction. An example is below:
EX: Cu+2 (aq) + Mg(s) ---> Cu (s) + Mg+2 (aq)
In the reaction above, the magnesium loses 2 electrons, as it goes from Mg neutral to Mg+2. At the same time, the Cu+2 is gaining the lost electrons from the Mg to become Cu neutral. The magnesium is undergoing oxidation (loss of electrons) and the copper is undergoing reduction (gaining of electrons).
Which of the reactants listed above is the reducing agent (source of electrons)? Answer: Mg provides the electrons in the reaction. The electrons travel from the Mg to the Cu.
Which of the reactants listed above is the oxidizing agent (species removing electrons)? Answer: Cu takes the electrons away from the Mg.
More examples of redox reactions:
Which of the reactants listed above is the oxidizing agent (species removing electrons)? Answer: Cu takes the electrons away from the Mg.
More examples of redox reactions:
MnCl3 (aq) + 3 Li (s) ---> Mn (s) + 3 LiCl (aq)
Mn is reduced, Li is oxidized (becomes part of a compound).
3 Mg (s) + Cr2O3 (aq) ---> 3 MgO (s) + 2 Cr (s)
Mn is reduced, Li is oxidized (becomes part of a compound).
3 Mg (s) + Cr2O3 (aq) ---> 3 MgO (s) + 2 Cr (s)
What is oxidized? What is reduced? What is the oxidizing agent? What is the reducing agent?