Heterogeneous or heterogeneous systems

In chemistry and physics, as well as a number of other sciences, various terms are used to denote a particular system. This is necessary for making necessary classifications and simplifying the study of specific processes. Heterogeneous systems in the literal sense of the system are heterogeneous, although they consist of homogeneous parts. In this issue, there are a number of features that can make it difficult to understand these processes.

As we know, matter can exist in different states. And between these states is a very significant difference, which ultimately even affects the properties.

The most common heterogeneous systems are a liquid that can pass into a saturated solution or vapor, many alloys, etc. Two basic states of matter are distinguished: crystalline and amorphous. They largely determine certain physical, thermodynamic and other properties.

In heterogeneous systems, all kinds of discontinuities in the continuity of physical properties are observed. Scientists call them interface surfaces, which, as a rule, are fairly easy to determine. When the external conditions change, these sections can also shift to one side or the other, which eventually leads to changes in all properties. Equilibrium in heterogeneous systems is very important if it is necessary to maintain one state throughout the entire reaction or experiment.

Heterogeneous reactions

Speaking of such systems, we can not fail to mention those areas of work where they are applied. Heterogeneous reactions are reactions occurring in heterogeneous systems, i.e. It involves substances that are in different phases. This is a complete heterogeneous system.

Examples of reactions can be the dissolution of metals in acids, the decomposition of salts with the formation of solid and gaseous products and some others. Also included here are some catalytic reactions that occur on the surface of the catalyst. The main feature of such heterogeneous catalytic reactions is that the reagent and the released products can be in different states.

The phase difference as a whole makes it difficult to work with these reactions, because transport of substances, mixing and diffusion is complicated, and the activation of molecules can begin even at the stage of entry to the interface.

For the reaction to take place, it is necessary to continuously replenish the reagents and remove from the zone the products formed as a result of the chemical process. In this case, the kinetics of the reaction or the rate of percolation is determined by the specific substances, the rate of the chemical transformation itself, and the properties possessed by heterogeneous systems. If no difficulties arise, and the diffusion of substances is maintained in the normal state, then the reaction rate is proportional to the size of the zone. This is the so-called specific reaction rate. In this case, the concentration, reaction conditions, partial pressures, and so on are taken into account. The ratio of thermodynamic activities, produced products and starting materials determines the equilibrium constant of the heterogeneous system.

This constant is necessary for the calculation of practically any reactions in heterogeneous systems. With its help it will be possible to accurately determine the amount of initial substances necessary for a full-fledged chemical reaction, and it will also be possible to calculate the exact yield of the products. When operating with such data, the reaction is easily controlled, in addition, the direction of the reaction can always be controlled. In this connection, we can say that the equilibrium constant is extremely important for carrying out reactions in heterogeneous systems.