Types of solutions. Types of solution concentration

Solutions are a homogeneous mass consisting of two or more substances or a mixture in which one substance acts as a solvent and the other as soluble particles.

There are two theories of the treatment of the origin of solutions: chemical, the founder of which is Mendeleev DI, and the physical, proposed by German and Swiss physicists Ostwald and Arrhenius. According to Mendeleyev's interpretation, the components of the solvent and solute become participants in the chemical reaction with the formation of unstable compounds of these very components or particles.

The physical theory denies the chemical interaction between the molecules of the dissolving and dissolving substances, explaining the process of the formation of solutions as a uniform distribution of the particles (molecules, ions) of the solvent between the particles of the dissolved substance as a result of a physical phenomenon called diffusion.

Classification of solutions according to various criteria

To date, there is no single system for classifying solutions, but conditionally the types of solutions can be grouped according to the most significant criteria, namely:

I) According to the aggregate state, solid, gaseous and liquid solutions are isolated.

II) The particle size of the dissolved substance: colloidal and true.

III) The degree of concentration of particles of the dissolved substance in solution: saturated, unsaturated, concentrated, diluted.

IV) By the ability to conduct electric current: electrolytes and non-electrolytes.

V) By purpose and application: chemical, medical, construction, special solutions, etc.

Kinds of solutions by aggregate state

The classification of solutions according to the aggregate state of the solvent is given in the broad sense of the meaning of this term. It is considered to be a solution of liquid substances (both a liquid and a solid element can act as a soluble substance), but if we take into account the fact that a solution is a homogeneous system of two or more substances, it is also logical to recognize also solid solutions, and Gaseous. Solid solutions are considered to be mixtures of, for example, several metals, more commonly known in everyday life as alloys. Gaseous types of solutions are mixtures of several gases, an example is ambient air, which is represented as a combination of oxygen, nitrogen and carbon dioxide.

Solutions to the size of dissolved particles

The types of solutions according to the size of the dissolved particles include true (conventional) solutions and colloidal systems. In true solutions, the dissolved substance breaks up into small molecules or atoms that are approximately the size of molecules of the solvent. In this case, the true types of solutions retain the original properties of the solvent, only slightly transforming it under the action of the physicochemical properties of the element added to it. For example: when dissolving table salt or sugar in water, water remains in the same state of aggregation and the same consistency, practically of the same color, only its taste changes.

Colloidal solutions differ from the usual ones in that the added component decomposes incompletely, preserving complex molecules and compounds, the dimensions of which considerably exceed the solvent particles, exceeding the value of 1 nanometer.

Types of solution concentration

In the same amount of solvent, a different amount of the dissolving element can be added, at the outlet we will have solutions with different concentrations. We list the main of them:

1. Saturated solutions are characterized by the degree of solubility of the substance at which the dissolved component under the influence of a constant value of temperature and pressure no longer dissolves into atoms and molecules and the solution achieves phase equilibrium. Saturated solutions can also be conditionally divided into concentrated solutions, in which the mass fraction of the dissolved component is comparable with the solvent, and diluted, where the dissolved substance is several times smaller than the solvent.
2. Unsaturated - these are solutions in which the solute can still break down into small particles.
3. Supersaturated solutions are obtained when the parameters of the influencing factors (temperature, pressure) change, as a result of which the process of "crushing" the dissolved substance continues, it becomes larger than it was under normal (usual) conditions.

Electrolytes and non-electrolytes

Some substances in solutions decompose into ions that can conduct an electric current. Such homogeneous systems are called electrolytes. This group includes acids, most salts. And solutions that do not conduct electric current are usually called non-electrolytes (almost all organic compounds).

Groups of solutions by purpose

Solutions are indispensable in all branches of the national economy, the specifics of which created such types of special solutions as medical, construction, chemical and others.

Medical solutions are a combination of preparations in the form of ointments, suspensions, mixtures, solutions for infusions and injections and other medicinal forms used for medical purposes for the treatment and prevention of various diseases.

Types of chemical solutions include a huge number of homogeneous compounds used in chemical reactions: acids, salts. These solutions can be of organic or inorganic origin, water (sea water) or anhydrous (based on benzene, acetone, etc.), liquid (vodka) or solid (brass). They have found their application in various branches of the national economy: the chemical, food, and textile industries.

Types of mortars differ viscous and thick consistency, because of what they are more suitable for the name of the mixture.

Due to their ability to quickly solidify, they are successfully used as a binder for masonry walls, ceilings, load-bearing structures, as well as for finishing works. They are aqueous solutions, most often three-component (solvent, cement of various markings, aggregate), where sand, clay, crushed stone, lime, gypsum and other building materials are used as a filler.