To simplify the chemical processes and better their perception used reaction equation.It is a conventional recording materials interact with each other and, as a consequence, the formation of new products.In this schematic "image" in the law of conservation of mass, using numerical coefficients.This description of chemical reactions using numbers and symbols proposed in 1615 by Jean Runner.Later, after the discovery of the laws of stoichiometry began to use quantitative values.
chemical reaction equation is written so:
- On the left side of the schematic "image" are substances, between which there is an interaction between them put a "+".On the left side - reaction products, i.e.new compounds that are formed.Between the left and right sides put an arrow indicating the direction of reaction.For example, C + E → CE.
- then coefficients are arranged, whose task "equalize", ieto make the number of each type of atoms before the reaction was equal to the number of atoms after.Thus the "working" the law of conservation of mass.For example, 2HCl - H2 + Cl2.
There kinetic reaction equation, which expresses the dependence of the rate of the chemical process of the concentration of substances unreacted.Simple such reactions in a single step, schematically written as: V = k [A1] n1 * [A2] n2, where
V - the speed of the reaction;
[A1], [A2] - concentration of substances;
K - constant of the reaction rate, which depends on the nature of the unreacted substances and temperature;
n1, n2 - order reaction.
If the reaction proceeds in several stages, that make up the system of kinetic equations, each of which will be described separately.
also a separate species is the ionic equation that, when drawing up its has features asrecorded therein a substance are in the form of ions.Such recording schematic typical chemical interaction only substitution and exchange reactions in aqueous solution, or alloy in which a precipitate is formed, poorly dissociable substance (water) or gas is released.For example, entering into a chemical reaction, hydrochloric acid and potassium hydroxide, and the salt formed and water.
HCl + KOH- KCl + H2O
Write these substances in the form of ions, with the exception of water, becauseit does not dissociate.Such a reaction equation is called the full ion.
H + + Cl- + K ++ OH- --K ++ Cl- + H2O
Now, in this scheme, on the basis of similarity to the right and left sides of "reducing" repetitive ions and obtain:
H ++ OH - H2O.
more and redox reactions, characterized by a change in the oxidation states of the atoms, will be particularly in the preparation of schematic entry.It is necessary to define the atoms change the degree of oxidation, and make an electronic balance, on the basis of which the then arrange factors.
Thus, the chemical reaction equation is a schematic account all complex process of the formation of new substances by decomposition of the compounds, the substitution and exchange.It also provides qualitative and quantitative information on the reactants and reaction products.
