Methods for separating mixtures

Most of the substances on our planet are not in pure form, and in compounds and mixtures, together with other substances.

Thus, granite contains three substances that are visible to the naked eye.

But milk seems homogeneous to us until it sours. Sour

the milk separates into clear whey and a white, dense precipitate - protein

casein. Man long ago uses these substances , included in milk, secreting them

from the mixture. Cottage cheese is prepared from insoluble protein - casein, and soluble

Whey proteins are used for therapeutic nutrition.

In what ways can mixtures be separated?

1. If the substance is insoluble in water, for example cereals (rice, buckwheat, semolina, etc.), river sand, chalk, clay, then you can use the filtering method.

Filtration-filtering liquids (gases) through a filter to clean them from solid impurities.

1. Fold the filter. Place it in a funnel, lightly moistening it with water.

2. Insert the funnel with the filter into the flask.

3. Pass the mixture of undissolved substance and water through a filter.

Conclusion. The filtered water passed freely through the filter; There is a substance insoluble in water left on the filter.

2. If solid soluble in water (table salt, sugar, lemon acid), then to separatethe mixture can be used by evaporation method.

Evaporation- the separation of solids dissolved in a liquid by converting it into vapor.

In a glass of water, the salt did not disappear, although it became invisible - the solution is transparent. Evaporation made it possible to isolate a substance dissolved in water from a mixture of substances (water and salt). Table salt crystals are visible on the glass. This confirms the conclusion that that each substance (both water and salt) of the mixture retains its properties.

Conclusion. Soluble substances can be isolated from a solution.

3 .To separate liquids that are soluble in each other, to obtain pure (without impurities) water, the distillation method is used

(or distillation)

Distillation-distillation, separation of substances contained in liquid mixtures according to boiling points, followed by cooling of the steam.

In nature, water does not occur in its pure form (without salts). Ocean, sea, river, well and spring water are types of solutions of salts in water. However, people often need clean water that does not contain salts (used in car engines; in chemical production to obtain various solutions and substances; in making photographs). Such water is called distilled, and the method of obtaining it is called distillation.

Heat over the flame of an alcohol lamp tap water in a test tube closed with a stopper and a gas outlet tube. Place the end of the tube into a clean, dry test tube placed in a glass with ice. Drops of distilled (purified from salts and impurities) water will appear on the bottom and walls of the test tube in a glass with ice.

Exercise

1. Look into empty kettle in which water is boiled. Are there any on the walls and bottom? white coating(scale) substances that were dissolved in water?

2. Droplets of water flow from the lid of the kettle in which water has been boiled. Which water - on the lid or in the kettle itself - contains more salts? Explain your answer.

3. What is the name of the process shown in the figure?

4. If the mixture contains iron, then you can use a magnet to isolate it, because iron and its alloys are attracted by a magnet.

5. To separate two immiscible liquids (oil and water, sunflower oil and water), you need to use a separating funnel.

The liquid with higher density will flow into the glass, and the lighter liquid will remain in the separating funnel.

heterogeneous (heterogeneous)	homogeneous (homogeneous)
Heterogeneous mixtures are those in which the interface between the original components can be identified either with the naked eye or under a magnifying glass or microscope:	Substances in such mixtures are mixed with each other as much as possible, one might say, at the molecular level. In such mixtures, it is impossible to detect the interface between the original components even under a microscope:
Examples
Suspension (solid + liquid) Emulsion (liquid + liquid) Smoke (solid + gas) Solid powder mixture (solid+solid)	True solutions (for example, a solution of table salt in water, a solution of alcohol in water) Solid solutions (metal alloys, crystalline salt hydrates) Gas solutions (a mixture of gases that do not react with each other)

Methods for separating mixtures

Heterogeneous mixtures of the gas-liquid, liquid-solid, gas-solid types are unstable in time under the influence of gravity. In such mixtures, components with a lower density gradually rise upward (float), and with a higher density, they sink down (settle). This process of spontaneous separation of mixtures over time is called defending. For example, a mixture of fine sand and water quite quickly spontaneously divides into two parts:

To speed up the process of deposition of substances with a higher density from a liquid in laboratory conditions, they often resort to a more advanced version of the settling method - centrifugation. The role of gravity in centrifuges is played by centrifugal force, which always occurs during rotation. Since centrifugal force directly depends on the speed of rotation, it can be made many times greater than the force of gravity simply by increasing the number of revolutions of the centrifuge per unit time. Thanks to this, a much faster separation of the mixture is achieved compared to settling.

After settling or centrifugation, the supernatant can be separated from the sediment using the method decanting— by carefully draining the liquid from the sediment.

You can separate a mixture of two liquids that are insoluble in each other (after settling) using a separating funnel, the principle of operation of which is clear from the following illustration:

To separate mixtures of substances in different states of aggregation, in addition to sedimentation and centrifugation, filtration is also widely used. The method consists in the fact that the filter has a different throughput in relation to the components of the mixture. Most often this is due to different sizes particles, but may also be due to the fact that individual components of the mixture interact more strongly with the filter surface ( are adsorbed them).

For example, a suspension of solid insoluble powder with water can be separated using a porous paper filter. The solid remains on the filter, and the water passes through it and is collected in a container located underneath it:

In some cases, heterogeneous mixtures can be separated due to the different magnetic properties of the components. For example, a mixture of sulfur and metallic iron powders can be separated using a magnet. Iron particles, unlike sulfur particles, are attracted and held by a magnet:

Separation of mixture components using magnetic field called magnetic separation.

If the mixture is a solution of a refractory solid in a liquid, this substance can be separated from the liquid by evaporating the solution:

To separate liquid homogeneous mixtures, a method called distillation, or distillation. This method has a principle of operation similar to evaporation, but allows you to separate not only volatile components from non-volatile ones, but also substances with relatively close boiling points. One of the simplest options for distillation apparatus is shown in the figure below:

The meaning of the distillation process is that when a mixture of liquids boils, the vapors of the lighter-boiling component evaporate first. The vapors of this substance, after passing through the refrigerator, condense and flow into the receiver. The distillation method is widely used in oil industry during primary oil refining to separate oil into fractions (gasoline, kerosene, diesel, etc.).

The distillation method also produces water purified from impurities (primarily salts). Water that has been purified by distillation is called distilled water.

Do you know what methods there are to separate mixtures? Don't be too quick to give a negative answer. You use many of them in your daily activities.

Pure substance: what is it?

Atoms, molecules, substances and mixtures are basic chemical concepts. What do they mean? In the table of D.I. Mendeleev 118 chemical elements. This Various types elementary particles - atoms. They differ from each other in mass.

By connecting with each other, atoms form molecules, or substances. The latter, connecting with each other, form mixtures. Pure substances have constant composition and properties. These are homogeneous structures. But they can be separated into components through chemical reactions.

Scientists claim that pure substances practically do not exist in nature. There is a small amount of impurities in each of them. This happens because most substances are different in activity. Even metals immersed in water dissolve in it at the ion level.

The composition of pure substances is always constant. It is simply impossible to change it. So, if you increase the amount of carbon or oxygen in a carbon dioxide molecule, it will be a completely different substance. And in the mixture you can increase or decrease the number of components. This will change its composition, but not the fact of its existence.

What is a mixture

A combination of several substances is called a mixture. They can be of two types. If the individual components in a mixture are indistinguishable, it is called uniform, or homogeneous. There is another name that is most often used in everyday life - solution. The components of such a mixture cannot be separated by physical methods. For example, it is not possible to mechanically extract crystals that are dissolved in it from a saline solution. Not only liquid solutions are found in nature. So, air is a gaseous homogeneous mixture, and a metal alloy is solid.

In inhomogeneous or heterogeneous mixtures, individual particles are visible to the naked eye. They differ from each other in composition and properties. This means that they can be separated from each other purely mechanically. Cinderella, who was forced by her evil stepmother to separate the beans from the peas, coped with this task perfectly.

Chemistry: methods for separating mixtures

There are a huge number of mixtures found in everyday life and nature. How to choose the right way to separate them? It must be based on physical properties ah individual components. If substances have different boiling points, then evaporation followed by crystallization, as well as distillation, will be effective. Such methods are used to separate homogeneous solutions. To separate heterogeneous mixtures, differences in other properties of their components are used: density, wettability, solubility, size, magnetism, etc.

Physical methods for separating mixtures

When separating the components of the mixture, the composition of the substances themselves does not change. Therefore, it is impossible to name methods for separating mixtures chemical process. Thus, by settling, filtering and exposure to a magnet, the individual components can be separated mechanically. In the laboratory they use various devices: separating funnel, filter paper, magnetic strips. These are methods for separating heterogeneous mixtures.

Screening

This method is perhaps the simplest. Every housewife is familiar with it. It is based on the difference in size of the solid components of the mixture. Sifting is used in everyday life to separate flour from impurities, insect larvae and various contaminants. In agricultural production, cereal grains are cleaned of foreign debris in this way. Construction workers sift through a mixture of sand and gravel.

Advocacy

This method of separating mixtures is used for components with different densities. If sand gets into the water, the resulting solution must be mixed well and left for a while. The same can be done with a mixture of water and vegetable oil or petroleum. The sand will settle to the bottom. But the oil, on the contrary, will collect from above. This method is observed in everyday life and nature. For example, soot settles from smoke, and individual dew drops from fog. And if you leave homemade milk overnight, you can collect the cream by morning.

Filtration

Brewed tea lovers use this method daily. It's about about filtration - a method of separating mixtures based on the different solubilities of the components. Imagine that iron filings and salt got into the water. Large insoluble particles will remain on the filter. And the dissolved salt will pass through it. The principle of this method underlies the operation of vacuum cleaners, the action of respiratory masks and gauze bandages.

Action by magnet

Suggest a method for separating mixtures of sulfur and iron powders. Naturally, this is the action of a magnet. Are all metals capable of this? Not at all. Based on the degree of susceptibility, three groups of substances are distinguished. For example, gold, copper and zinc will not attach to a magnet. They belong to the group of diamagnetic materials. Magnesium, platinum and aluminum have weak perception. But if the mixture contains ferromagnets, then this method will be the most effective. These include, for example, iron, cobalt, nickel, terbium, holmium, thulium.

Evaporation

Which method of separating mixtures is suitable for an aqueous homogeneous solution? This is evaporation. If you only have salt water, but need clean water, don’t get upset right away. You need to heat the mixture to boiling point. As a result, the water will evaporate. And crystals of the dissolved substance will be visible at the bottom of the dish. To collect water, it must be condensed - transferred from a gaseous state to a liquid. To do this, the vapors are cooled, touching a surface with a lower temperature, and flow into the prepared container.

Crystallization

In science this term viewed in a broader sense. This is not just a method for obtaining pure substances. Crystals in nature include icebergs, minerals, bones and tooth enamel.

Their growth occurs under the same conditions. Crystals form as a result of cooling liquids or supersaturation of steam, and then the temperature should no longer change. Thus, some limiting conditions are first reached. As a result, a crystallization center appears, around which atoms of liquid, melt, gas or glass gather.

Distillation

Surely you have heard about water, which is called distilled. This purified liquid is necessary for the manufacture of medicines, laboratory research, and cooling systems. And they get it in special devices. They are called distillers.

Distillation is a method of separating mixtures of substances with different boiling points. Translated from Latin, the term means “dripping down”. Using this method, for example, you can separate alcohol and water from a solution. The first substance will begin to boil at a temperature of +78 o C. The alcohol vapor will subsequently condense. The water will remain in liquid form.

In a similar way, refined products are obtained from oil: gasoline, kerosene, gas oil. This process is not a chemical reaction. Oil is divided into separate fractions, each of which has its own boiling point. This happens in several stages. First, primary oil separation is carried out. It is purified from associated gas, mechanical impurities and water vapor. On next stage the resulting product is placed in distillation columns and begin to heat up. This is atmospheric distillation of oil. At temperatures below 62 degrees, the remaining associated gas evaporates. By heating the mixture to 180 degrees, gasoline fractions are obtained, up to 240 - kerosene, up to 350 - diesel fuel. The residue from thermal oil refining is fuel oil, which is used as a lubricant.

Chromatography

This method was named after the scientist who first used it. His name was Mikhail Semenovich Tsvet. Initially, the method was used to separate plant pigments. And literally chromatography is translated from Greek language like “I write in color.” Dip the filter paper into the water and ink mixture. The first one will immediately begin to be absorbed. This is due to different degrees of adsorbing properties. This also takes into account diffusion and the degree of solubility.

Adsorption

Some substances have the ability to attract molecules of other types. For example, we take activated carbon when poisoning to get rid of toxins. This process requires an interface that lies between the two phases.

This method is used in the chemical industry for separating benzene from gaseous mixtures, purifying liquid products of oil refining, and purifying them from impurities.

So, in our article we looked at the main ways to separate mixtures. People use them both at home and on an industrial scale. The choice of method depends on the type of mixture. An important factor is the specific physical properties of its components. To separate solutions in which the individual parts are visually indistinguishable, methods of evaporation, crystallization, chromatography and distillation are used. If the individual components can be identified, such mixtures are called heterogeneous. To separate them, methods of settling, filtering and magnetic action are used.

The lesson material contains information about in various ways separation of mixtures and purification of substances. You will learn to use knowledge of the differences in the properties of mixture components to select optimal method separation of this mixture.

Topic: Initial chemical ideas

Lesson: Methods for separating mixtures and purifying substances

Let us define the difference between “methods for separating mixtures” and “methods for purifying substances.” In the first case, it is important to obtain all the components that make up the mixture in pure form. When purifying a substance, obtaining impurities in pure form is usually neglected.

SETTLEMENT

How to separate a mixture of sand and clay? This is one of the stages in ceramic production(for example, in the production of bricks). To separate such a mixture, the settling method is used. The mixture is placed in water and stirred. Clay and sand with at different speeds settle in the water. Therefore, sand will settle much faster than clay (Fig. 1).

Rice. 1. Separation of a mixture of clay and sand by settling

The settling method is also used to separate mixtures of water-insoluble solids of different densities. For example, this is how you can separate a mixture of iron and wood filings ( sawdust they will float in the water, and the iron ones will settle).

A mixture of vegetable oil and water can also be separated by settling, since oil does not dissolve in water and has a lower density (Fig. 2). Thus, by settling it is possible to separate mixtures of liquids that are insoluble in each other and have different densities.

Rice. 2. Separation of a mixture of vegetable oil and water by settling

To separate a mixture of table salt and river sand, you can use the settling method (when mixed with water, the salt will dissolve and the sand will settle), but it will be more reliable to separate the sand from the salt solution using another method - the filtration method.

Filtering this mixture can be done using a paper filter and a funnel lowered into a glass. Grains of sand remain on the filter paper, and a clear solution of table salt passes through the filter. In this case, the river sand is the sediment, and the salt solution is the filtrate (Fig. 3).

Rice. 3. Using the filtration method to separate river sand from the salt solution

Filtration can be carried out not only using filter paper, but also using other porous or bulk materials. For example, to bulk materials includes quartz sand, and porous ones include glass wool and baked clay.

Some mixtures can be separated using the "hot filtration" method. For example, a mixture of sulfur and iron powders. Iron melts at temperatures above 1500 C, and sulfur at about 120 C. Molten sulfur can be separated from iron powder using heated glass wool.

The salt can be isolated from the filtrate by evaporation, i.e. heat the mixture and the water will evaporate, leaving the salt on the porcelain cup. Sometimes evaporation, partial evaporation of water, is used. As a result, a more concentrated solution is formed, upon cooling of which the dissolved substance is released in the form of crystals.

If a substance capable of magnetization is present in the mixture, it can be easily isolated in its pure form using a magnet. For example, this is how you can separate a mixture of sulfur and iron powders.

The same mixture can be separated by another method, using knowledge of the wettability of the mixture components with water. Iron is wetted by water, i.e. water spreads over the surface of the iron. Sulfur is not wetted by water. If you place a piece of sulfur in water, it will drown because... The density of sulfur is greater than the density of water. But the sulfur powder will float, because... Air bubbles adhere to grains of sulfur that are not wetted by water and push them to the surface. To separate the mixture, you need to place it in water. The sulfur powder will float and the iron will sink (Fig. 4).

Rice. 4. Separation of a mixture of sulfur and iron powders by flotation

The method of separating mixtures based on the difference in wettability of the components is called flotation (French flotter - to float). Let's consider several more methods for separating and purifying substances.

One of the oldest methods of separating mixtures is distillation (or distillation). Using this method, it is possible to separate components that are soluble in each other and have different boiling points. This is how distilled water is obtained. Water with impurities is boiled in one vessel. The resulting water vapor condenses when cooled in another vessel in the form of already distilled (pure) water.

Rice. 5. Obtaining distilled water

Components with similar properties can be separated using chromatography. This method is based on different absorption of the separated substances by the surface of another substance.

For example, red ink can be separated into its components (water and colorant) through chromatography.

Rice. 6. Separation of red ink by paper chromatography

In chemical laboratories, chromatography is carried out using special instruments - chromatographs, the main parts of which are a chromatographic column and a detector.

Adsorption is widely used in chemistry to purify certain substances. This is the accumulation of one substance on the surface of another substance. Adsorbents include, for example, activated carbon.

Try to drop the pill activated carbon into a vessel with colored water, stir, filter and see that the filtrate has become colorless. Coal atoms attract molecules, in this case, dye.

Currently, adsorption is widely used for water and air purification. For example, water purification filters contain activated carbon as an adsorbent.

1. Collection of problems and exercises in chemistry: 8th grade: to the textbook by P.A. Orzhekovsky and others. “Chemistry, 8th grade” / P.A. Orzhekovsky, N.A. Titov, F.F. Hegel. – M.: AST: Astrel, 2006.

2. Ushakova O.V. Chemistry workbook: 8th grade: to the textbook by P.A. Orzhekovsky and others. “Chemistry. 8th grade” / O.V. Ushakova, P.I. Bespalov, P.A. Orzhekovsky; under. ed. prof. P.A. Orzhekovsky - M.: AST: Astrel: Profizdat, 2006. (p. 10-11)

3. Chemistry: 8th grade: textbook. for general education institutions / P.A. Orzhekovsky, L.M. Meshcheryakova, L.S. Pontak. M.: AST: Astrel, 2005.(§4)

4. Chemistry: inorg. chemistry: textbook. for 8th grade. general education institutions / G.E. Rudzitis, Fyu Feldman. – M.: Education, OJSC “Moscow Textbooks”, 2009. (§2)

5. Encyclopedia for children. Volume 17. Chemistry / Chapter. ed.V.A. Volodin, Ved. scientific ed. I. Leenson. – M.: Avanta+, 2003.

Additional web resources

1. Unified collection of digital educational resources ().

2. Electronic version of the journal “Chemistry and Life” ().

Homework

From the textbook by P.A. Orzhekovsky and others. “Chemistry, 8th grade” With. 33 No. 2,4,6,T.

In our article we will look at what pure substances and mixtures are, and methods for separating mixtures. IN Everyday life Each of us uses them. Are pure substances even found in nature? And how to distinguish them from mixtures?

Pure substances and mixtures: methods for separating mixtures

Substances that contain only certain types of particles are called pure. Scientists believe that they practically do not exist in nature, since they all, albeit in insignificant proportions, contain impurities. Absolutely all substances are also soluble in water. Even if immersed in this liquid, for example, silver ring, the ions of this metal will go into solution.

A sign of pure substances is the constancy of composition and physical properties. During their formation, the amount of energy changes. Moreover, it can both increase and decrease. A pure substance can only be separated into its individual components using chemical reaction. For example, only distilled water has the boiling and freezing point typical for this substance, and lacks taste and smell. And its oxygen and hydrogen can only be decomposed by electrolysis.

How do their aggregates differ from pure substances? Chemistry will help us answer this question. Methods for separating mixtures are physical because they do not lead to a change chemical composition substances. Unlike pure substances, mixtures have variable composition and properties, and they can be separated by physical methods.

What is a mixture

A mixture is a collection of individual substances. An example of this is sea water. Unlike distilled, it has a bitter or salty taste, boils at a higher temperature, and freezes at a lower temperature. Methods for separating mixtures of substances are physical. Yes, from sea ​​water Pure salt can be obtained by evaporation and subsequent crystallization.

Types of mixtures

If you add sugar to water, after a while its particles will dissolve and become invisible. As a result, they will be impossible to distinguish with the naked eye. Such mixtures are called homogeneous or homogeneous. Examples of them are also air, gasoline, broth, perfume, sweet and salt water, an alloy of copper and aluminum. As you can see, they can be in different states of aggregation, but liquids are most common. They are also called solutions.

In inhomogeneous or heterogeneous mixtures, particles of individual substances can be distinguished. Iron and wood filings, sand and table salt are typical examples. Heterogeneous mixtures are also called suspensions. Among them, suspensions and emulsions are distinguished. The former consists of a liquid and a solid. So, an emulsion is a mixture of water and sand. An emulsion is a combination of two liquids with different densities.

There are heterogeneous mixtures with special names. So, an example of foam is polystyrene foam, and aerosols include fog, smoke, deodorants, air fresheners, and antistatic agents.

Methods for separating mixtures

Of course, many mixtures have more valuable properties than the individual substances included in their composition. But even in everyday life, situations arise when they need to be separated. And in industry, entire productions are based on this process. For example, from oil as a result of its processing, gasoline, gas oil, kerosene, fuel oil, diesel fuel and machine oil, rocket fuel, acetylene and benzene. Agree, it is more profitable to use these products than to mindlessly burn oil.

Now let's see if there is such a thing as chemical methods separation of mixtures. Let's say from aqueous solution salt we need to get pure substances. To do this, the mixture must be heated. As a result, the water will turn into steam and the salt will crystallize. But in this case there will be no transformation of some substances into others. This means that the basis this process are physical phenomena.

Methods for separating mixtures depend on the state of aggregation, solubility, difference in boiling point, density and composition of its components. Let's look at each of them in more detail using specific examples.

Filtration

This separation method is suitable for mixtures that contain a liquid and an insoluble solid. For example, water and river sand. This mixture must be passed through a filter. As a result, clean water will pass through it freely, but the sand will remain.

Advocacy

Some methods for separating mixtures rely on gravity. In this way, suspensions and emulsions can be separated. If vegetable oil gets into the water, the mixture must first be shaken. Then leave it for a while. As a result, the water will end up at the bottom of the vessel, and the oil will cover it in the form of a film.

In laboratory conditions, they are used for settling. As a result of its operation, the denser liquid is drained into the vessel, and the lighter liquid remains.

Settlement is characterized by a low speed of the process. It takes a certain amount of time for a precipitate to form. In industrial conditions, this method is carried out in special designs, which are called settling tanks.

Action by magnet

If the mixture contains metal, it can be separated using a magnet. For example, separate iron and wood filings. But do all metals have these properties? Not at all. Only mixtures containing ferromagnets are suitable for this method. In addition to iron, these include nickel, cobalt, gadolinium, terbium, dysprosium, holmium, and erbium.

Distillation

This name translated from Latin means “dripping down”. Distillation is a method of separating mixtures based on differences in boiling points of substances. Thus, even at home you can separate alcohol and water. The first substance begins to evaporate already at a temperature of 78 degrees Celsius. Touching a cold surface, alcohol vapor condenses, turning into a liquid state.

In industry, petroleum products, aromatic substances, and pure metals are obtained in this way.

Evaporation and crystallization

These methods of separating mixtures are suitable for liquid solutions. The substances that make up them differ in their boiling point. In this way, salt or sugar crystals can be obtained from the water in which they are dissolved. To do this, the solutions are heated and evaporated to a saturated state. In this case, crystals are deposited. If you need to get clean water, then the solution is brought to a boil, followed by condensation of vapors on a colder surface.

Methods for separating gas mixtures

Gaseous mixtures are separated by laboratory and industrial methods, since this process requires special equipment. Raw materials of natural origin are air, coke oven, generator, associated and natural gas, which is a collection of hydrocarbons.

Physical methods for separating mixtures in a gaseous state are as follows:

• Condensation is the process of gradual cooling of a mixture, during which condensation of its components occurs. In this case, first of all, high-boiling substances, which are collected in separators, pass into a liquid state. In this way, hydrogen is obtained from and ammonia is also separated from the unreacted part of the mixture.
• Sorbing is the absorption of some substances by others. This process has opposite components, between which equilibrium is established during the reaction. For the forward and reverse process you need various conditions. In the first case, this combination high pressure and low temperature. This process is called sorption. Otherwise, the opposite conditions are used: low pressure at high temperature.
• Membrane separation is a method that uses the property of semi-permeable partitions to selectively allow molecules of various substances to pass through.
• Refluxation is the process of condensation of high-boiling parts of mixtures as a result of their cooling. In this case, the temperature of transition to the liquid state of individual components should differ significantly.

Chromatography

The name of this method can be translated as “I write with color.” Imagine adding ink to water. If you dip the end of a filter paper into this mixture, it will begin to be absorbed. In this case, water will be absorbed faster than ink, which is due to the different degrees of sorption of these substances. Chromatography is not only a method for separating mixtures, but also a method for studying such properties of substances as diffusion and solubility.

So, we got acquainted with such concepts as “pure substances” and “mixtures”. The former are elements or compounds consisting only of particles of a certain type. Examples of these are salt, sugar, distilled water. Mixtures are a collection of individual substances. A number of methods are used to separate them. The method of their separation depends on the physical properties of its components. The main ones include settling, evaporation, crystallization, filtration, distillation, magnetic action and chromatography.