In chemistry and physics, as well as a number of other sciences, various terms are used to refer to a particular system. This is necessary to make the necessary classification and simplify the study of specific processes. Heterogeneous systems are literally heterogeneous systems, although they consist of homogeneous parts. In this matter, there are a number of features that may make it difficult to understand these processes.
As we know, matter can exist in different states. And between these states lies a very significant difference, which ultimately even affects the properties.
The most common heterogeneous systems are liquids, which can pass into a saturated solution or vapor, many alloys, etc. Two main states of matter are distinguished - crystalline and amorphous. They largely determine certain physical, thermodynamic, and other properties of it.
In heterogeneous systems, all kinds of gaps in the continuity of physical properties are observed. Scientists call them interface surfaces, which are usually fairly easy to identify. When external conditions change, these sections can also shift in one direction or another, which ultimately leads to changes in all properties. Equilibrium in heterogeneous systems is very important if it is necessary to maintain one state throughout the reaction or experiment.
Heterogeneous reactions
Speaking about such systems, one cannot but mention the areas of work where they are applied. Heterogeneous reactions are reactions that occur in heterogeneous systems, i.e. it involves substances in different phases. This is a complete heterogeneous system.
Examples of reactions include dissolution of metals in acids, decomposition of salts to form solid and gaseous products, and some others. Also included 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 isolated products can be in different states.
The phase difference as a whole complicates the work with these reactions, because the transport of substances, mixing and diffusion are complicated, and the activation of molecules can begin even at the stage of contact with the interface.
For the course of the reaction, it is necessary to constantly replenish the reagents and remove products from the zone resulting from the chemical process. In this case, the kinetics of the reaction or the rate of flow is determined by 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 a 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, etc. are taken into account. The ratio of the thermodynamic activities of the products obtained and the starting materials determines the equilibrium constant of the heterogeneous system.
This constant is necessary for calculating almost any reactions in heterogeneous systems. With its help, it will be possible to accurately determine the amount of starting materials necessary for a full-fledged chemical reaction, and it will also be possible to calculate the exact yield of products. When handling such data, the reaction is easily controlled, in addition, you can always control the direction of the reaction. In this regard, we can say that the equilibrium constant is extremely important for carrying out reactions in heterogeneous systems.