Homogeneous reactions.

As is known, the chemical reaction isthe transformation of one substance, which is usually called the source material, into another, which will already differ from it by its chemical composition, and also by its structure. In the first case, they talk about reagents, and in the second case they talk about reaction products. This is known to everyone else from the school chemistry course. It is also known from the course of school chemistry that during such a reaction the composition of chemical elements does not change, in this case only the distribution of nuclei and electrons occurs, as a result of which new chemicals are formed.

All chemical reactions can be divided into classes. It is worth first to note homogeneous reactions. These are reactions that occur in one phase. Homogeneous reactions, examples of which are also easily found in any textbook on chemistry, imply the occurrence of a variety of homolytic reactions characterized by the breakdown of molecules into radicals, substitutions and cleavages, rearrangements, and so on. And this happens, as a rule, in the liquid phase. The rate of homogeneous reaction, if the volume of substances remains constant, will depend on the law of the acting masses. Homogeneous reactions occurring between reagents, which initially are in different phases, become possible only if diffusion occurs between them. Then the reaction rate will also increase significantly. If the diffusion of the initial substances is slow, the homogeneous reaction itself will occur at the interface between the diffusion phases. All the features of such reactions, as well as their mechanisms, will depend on the conditions in which the reagents will act.

The reaction rate will depend on somefactors, such as the nature of the substances reacting, their concentration, the temperature at which the reaction takes place, and the presence of a certain catalyst in it. It helps the reaction to proceed at a higher rate and with less activation energy. With regard to the concentration of substances, it is clear that the more substances will react, the more they will collide and, as a result, the reaction rate will increase.

A vivid example of a homogeneous system can beany mixture of gases. All gases at elevated temperature will dissolve in large quantities in each other. This also applies to a mixture of nitrogen and oxygen. One more example can be given, showing what a homogeneous reaction is. This is nothing more than an aqueous solution containing sodium chloride, magnesium sulfate, nitrogen and oxygen. The system passes in this case only one phase. If the reaction proceeds in a homogeneous system, then it proceeds throughout the volume. If, say, when the solutions of sulfuric acid and sodium thiosulfate are blended and mixed with stirring, turbidity will occur. It will occur due to sulfur, which will appear throughout the volume of the solution.

During the course of this or that homogeneousa certain amount of heat is released. The thermal effect of the reaction will depend on the amount of reagents taken in the reaction, as well as on what products are obtained as a result of the reaction. The question of how fast a homogeneous reaction will proceed will depend on the time interval in which it takes place. An entire science is engaged in elucidating these issues. It is called "Kinetics". Its most important postulate is the fact that for the reaction to proceed, the molecules that participate in it must constantly touch each other. However, not every such contact can lead to a chemical reaction. Homogeneous reactions are only those in the course of which the contiguous particles will have such a supply of energy that will exceed the threshold value.