As the nature for the person is unsurprising: in the winter it shrouds the earth in a snow duvet, in the spring - opens as if popcorn flakes, all live, in the summer - storms violence of paints, sets fire red fire of a plant in the fall... And only if to ponder and look narrowly, it is possible to see that there are behind all these so habitual changes difficult physical processes and CHEMICAL REACTIONS. And to investigate all live, it is necessary to be able to solve the chemical equations. The main requirement when equalizing the chemical equations - knowledge of conservation law of amount of substance: 1) the amount of substance before reaction is equal to amount of substance after reaction; 2) the total amount of substance before reaction is equal to total amount of substance after reaction.

Reaction is called transformation of some chemicals into others. And the formula of their record by means of special symbols is also the equation of this reaction. There are various types of chemical interactions, but the principle of record of their formulas is identical.

Electrons are a part of atoms. And complex substances, in turn, consist of these atoms (atoms form elements) and electrons among themselves divide. Oxidation level shows what atom how many electrons to itself took away and what how many gave. This indicator can be defined.

Chemical reactions are the interaction of substances accompanied with change of their structure. In other words, the substances reacting do not correspond to the substances which are turning out as a result of reaction. Faces similar interactions of people hourly, every minute. The processes proceeding in its organism (breath, synthesis of proteins, digestion, etc.) are chemical reactions too.