Various types of gases are used in medicine, the most common being nitrogen and oxygen. The scope of oxygen is wide, it includes the enrichment of gas mixtures, filling oxygen cushions, making oxygen cocktails and more.

Medical oxygen is characterized by high concentration and absence of impurities. Its main sources in hospitals are oxygen concentrators, cylinders with liquid oxygen for medicine or gaseous, oxygen enrichment systems, and devices for chemical gas production. Today, oxygen concentrators are most often used - they have proven themselves due to their reliability, operational safety, system mobility and efficiency.

Use of oxygen in medicine associated with emergency situations when it is necessary to provide anesthesia, conduct extensive surgical operations or resuscitation actions. In these cases, artificial ventilation is performed. This gas is also needed in the treatment of a number of diseases - in addition to chronic respiratory failure, oxygen is required for heart attacks and strokes.

Oxygen therapy is indispensable in the treatment of a number of diseases:

• Bronchial asthma.
• Pneumonia.
• Tuberculosis.
• Obstructive bronchitis.
• Allergies.
• Intoxication.

Use of oxygen in medicine

The substance, designated by the symbol O, is involved in the redox reactions of the body. In medicine, oxygen can be used to supply gas to intensive care units, hospitals, clinics, sanatoriums, sports clubs, and children's institutions for the prevention of diseases and strengthening the immune system.

The source of life on the planet - oxygen - is in demand in the treatment of anaerobic infections and improving tissue trophism and reparative processes. In most cases, gas is administered by inhalation during artificial and natural ventilation. Oxygen is supplied to medical institutions in compressed form. Liquid oxygen is more convenient to transport and store; before it is supplied to the gas supply system, it is transferred to a gaseous state.

Oxygen in medicine can be used in pure form or as part of gas mixtures. For non-inhalation administration, subcutaneous, intravascular, intracavitary, enteral and other methods of administration are practiced.

The use of oxygen in medicine to prevent hypoxia is also popular. Particularly popular is the use of oxygen cocktails or the use of oxygen concentrators, cans in major cities. To improve well-being, people often resort to oxygen baths.

The abstract was completed by: 9th grade student “A” Vasilyeva N.

Ministry of Education of the Russian Federation

Secondary school No. 34.

Khabarovsk

I . Introduction.

If you look at the table of the periodic system D.I. Mendeleev and look at group VI, you can see that it contains elements whose atoms have 6 valence electrons and their highest oxidation state in compounds is +6. Group VI is divided into two subgroups – main and secondary. The main one includes elements of small and large periods: O (oxygen), S (sulfur), Se (selenium), Te (tellurium), Po (polonium); in the secondary - elements of only long periods: Cr (chromium), Mo (molybdenum), W (tungsten). Such a distribution indicates that within even one group there are elements that are closer in their properties to each other and less similar.

Indeed, in the main subgroup there are elements that are mainly non-metallic in nature. These properties are most pronounced in oxygen and sulfur. Selenium and tellurium occupy an intermediate position between metals and non-metals. In terms of chemical properties, they are closer to non-metals. In polonium, the heaviest element of the subgroup, radioactive and relatively short-lived, the metallic character is more pronounced, but individual properties it is close to tellurium. In accordance with this, during the transition from oxygen to polonium, a large diversity in structural types is observed crystal lattices, both in simple substances and in their compounds.

Oxygen, sulfur, selenium and tellurium are grouped together as “chalcogens,” which in Greek means “generating ores.” These elements are found in many ores. Thus, most metals in nature are found in bound state in the form of sulfides, oxides, selenides, etc. For example, the most important ores of iron and copper are red iron ore Fe2O3, magnetic iron ore Fe3O4, pyrite FeS2, red magnetic ore Cu2O, copper luster Cu2S. All of the above ores contain elements of group VI.

A side subgroup consists of metals: chromium, molybdenum and tungsten. In most physical and chemical properties, molybdenum and tungsten are similar to each other and slightly different from chromium.

II . Characteristics of elements VI subgroups.

The chemical properties of elements are determined primarily by the structure of their outer electronic layers (energy levels). The diagram shown (Fig. 1) shows the sequential filling of layers of atoms of group VI elements with electrons.

The maximum possible number of electrons in layers (Z) is determined by the formula: Z=2n2, where n is the layer number.

According to this dependence, the number of electrons should be equal: in the first layer - 2, in the second - 8, in the third - 18, in the fourth - 32, etc. However, more than 32 electrons in a layer of atoms of any currently known elements have not been found.

8 2 6 1 13 8 2 +24

16 2 8 6 1 13 18 8 2 +42

34 2 8 18 6 2 12 32 18 8 2 +74

84 2 8 18 32 18 6

Rice. 1. Scheme of the structure of atoms of elements of group VI.

The electronic structure of atoms of group VI elements can be presented as follows (Table 1).

Table 1

Electronic configurations of atoms of group VI elements

16S 1s2 2s2 2p6 3s2 3p4

34Se 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p4

52Te 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p4

84Po 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p4

24Cr 1s2 2s2 2p6 3s2 3p6 3d5 4s1

42Mo 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d5 5s1

74W 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d4 6s2

If you look closely at the structures depicted, you will notice that the sum of the electrons of the last two sublevels in the atoms of all these elements is equal to 6. This is the reason for the common chemical properties. But there is also a big difference in electronic configurations between the atoms of the elements of the main and secondary subgroups.

The atoms of the elements of the main subgroup on the outer electronic layer have the same number of electrons - 6. The latter are located on the s- and p-sublevels (s2 p4) and take part in the formation of chemical bonds.

Elements in the atoms of which the p-sublevel of the outer layer is filled with electrons are called p-elements. These are oxygen, sulfur, tellurium, selenium and polonium: in their atoms the s-sublevel is filled and the p-sublevel of the outer layer is filled with electrons. The atoms of these elements have a specific tendency to attract additional (two) electrons compared to neutral atoms. It manifests itself in their compounds with non-metals (CuS, Na2S, K2Te) and in the existence of negative ions in molten salts of the most active metals (S2-, Se2-, Te2-).

It should be noted that the penultimate layer of tellurium and polonium atoms is not completed, unlike oxygen, sulfur and selenium, where it is completely filled. But despite the common properties of p-elements of group VI, there are some differences between them.

Chromium and molybdenum atoms have 1 electron each in the outer electron layer and 13 electrons each in the penultimate one. For tungsten atoms, the number of electrons in the outer layer increases to 2, and in the penultimate layer decreases to 12. Elements in the atoms of which the d-sublevel of the layer adjacent to the outer layer is filled with electrons are called d-elements. These are chromium, molybdenum and tungsten.

Consequently, the outer layer of elements of the secondary subgroup (d-elements) is represented only by the s-sublevel and in the formation of a chemical bond, in addition to 1-2 electrons from this sublevel, a certain number of electrons from the d-sublevel of the penultimate layer participate. These differences affect the chemical properties of d-elements. First of all, these are metals. Their specific properties are associated with the small number of outer electrons in the atoms. Under certain conditions, for example in aqueous solutions of acids, 2 or 3 electrons are completely transferred to other atoms, and the metal atoms are converted, respectively, into two- or three-charged hydrated cations. The ability of metal atoms to partially or completely displace their electrons to other atoms determines the formation of strong compounds with non-metals, the displacement of hydrogen from acids, the basic nature of oxides and hydroxides, etc.

So, the number and state of electrons at the outer levels of an atom is one of the most important signs of chemical nature. However, the chemical individuality of individual elements - their metallic and non-metallic activity - is determined not only by the outer electronic structures of the atoms, but also by the structure of their atoms as a whole: the charge of the nucleus, the number and state of electrons in individual layers, and the radii of the atoms.

The quantitative characteristics of the chemical properties of elements are determined by the structure of the outer electronic layer, which may include electrons from one layer of different sublevels or sometimes from adjacent sublevels of two adjacent layers (for example, in elements of side subgroups).

The oxygen atom has two unpaired p-electrons out of four, and therefore the formation of two electron pairs when interacting with a particular atom does not require excitation energy (a). Cells correspond to certain states (orbitals) of electrons at each sublevel; sublevels are characterized different shapes electronic clouds. Electrons in the diagram are shown by arrows. In all compounds, oxygen has a typical oxidation state of –2, with the exception of O+2F2 and O+4O2 (ozone).

For analogues of oxygen (sulfur, selenium, tellurium and polonium) the situation is completely different. For example, in the outer electron layer of a sulfur atom there are also 6 electrons, but unlike oxygen there can be 18, i.e. there are vacancies (b). Therefore, in order for sulfur to react and acquire an oxidation state of +4 or +6 in compounds, a slight excitation of the atom is necessary, because electrons are transferred to the d-sublevel of the same energy layer, which undoubtedly requires a certain amount of energy (c and d).

The same explanation can be applied to selenium, tellurium, polonium and the chromium subgroup metals. These elements may show varying degrees oxidation: from -2 to +6.

table 2

Possible oxidation states of atoms of group VI elements

Table 2 shows the oxidation states of atoms of group VI elements.

The elements of the main subgroup have wide limits for changing the oxidation state: from the maximum possible negative -2 to the maximum positive, corresponding to the group number.

When going from oxygen to tellurium and from chromium to tungsten, the melting and boiling points increase. Oxygen has the lowest boiling and melting points, since the polarizability of its molecule is low. This can also explain the poor solubility of oxygen in water: 5 volumes of O2 in 100 volumes of H2O at 0°C.

Tungsten is the most refractory and high-boiling among all metals. Its boiling point is almost 6000°C, as on the surface of the Sun. Tungsten melts at 3380°C. At this temperature, most metals turn to steam.

The high melting temperatures of group VI metals are explained by the fact that they have a high electron density, i.e. big number free electrons per unit volume. As is known, the metallic bond is caused by the interaction of free electrons with ion atoms. In group VI metals, the number of free electrons reaches up to six for each atom ion, which is why they are refractory.

I will talk in more detail about oxygen.

III . History of the discovery of oxygen.

The discovery of oxygen marked the beginning of the modern period in the development of chemistry. It has been known since ancient times that combustion requires air, but for hundreds of years the combustion process remained unclear. Oxygen was discovered almost simultaneously by two outstanding chemists of the second half of the 18th century. - Swede Karl Scheele and Englishman Joseph Priestley. K. Scheele was the first to obtain oxygen, but his work “On Air and Fire,” in which this gas was described, appeared somewhat later than D. Priestley’s message.

K. Scheele and D. Priestley discovered a new element, but did not understand its role in the processes of combustion and respiration. Until the end of their days, they remained defenders of the phlogiston theory: combustion was interpreted as the disintegration of a combustible body with the release of phlogiston, in which each combustible substance turned into non-combustible:

zinc = phlogiston + zinc scale

(flammable) (non-flammable)

Hence, metals, sulfur and other simple substances were considered complex and, conversely, complex substances were considered simple (lime, acids, etc.).

Proponents of the phlogiston theory explained the need for air for combustion by the fact that phlogiston does not simply disappear during combustion, but combines with air or some part of it. If there is no air, then combustion stops because phlogiston has nothing to connect with.

F. Engels wrote about the discovery of K. Scheele and D. Priestley: both “they did not know what was in their hands... The element that was destined to overthrow all phlogistic views and revolutionize chemistry disappeared in their hands completely fruitlessly.” Further, F. Engels wrote that the discovery of oxygen belongs to Lavoisier, since K. Scheele and D. Priestley did not even know what they were describing.

The liberation of chemistry from the phlogiston theory occurred as a result of the introduction of precise research methods into chemistry, which began with the works of M. V. Lomonosov. In 1745-1748. M.V. Lomonosov experimentally proved that combustion is a reaction of substances combining with air particles.

Ten years (1771-1781) were spent by the French chemist Antoine Lavoisier to confirm the validity of the theory of combustion as a chemical interaction of various substances with oxygen. Starting to study the phenomena of combustion and “burning” of metals, he wrote: “I propose to repeat everything done by my predecessors, taking all possible precautions in order to combine what is already known about bound or liberated air with other facts and give a new theory. The works of the mentioned authors, if considered from this point of view, provide me with individual links in the chain... But many experiments must be done in order to obtain a complete sequence.” The corresponding experiments, begun in October 1772, were carried out by A. Lavoisier strictly quantitatively, with careful weighing of the initial and final reaction products. He heated mercury in a sealed retort and observed a decrease in the volume of air in it and the formation of red flakes of “mercury scale.” In another retort, he decomposed the “mercury scale” obtained in the previous experiment, obtained mercury and a small volume of that gas, which D. Priestley called “dephlogisticated air”, and concluded: how much air is consumed to convert mercury into scale, so much is released again during decomposition of scale.

The remaining air in the retort, which did not participate in the reaction, began to be called nitrogen, which meant lifeless (translated from the Greek “a” - negation, “zoe” - life). The gas formed as a result of the decomposition of “mercury scale” exhibited properties opposite to nitrogen - it supported respiration and combustion. Therefore, A. Lavoisier called it “vital”. Later, he replaced this name with the Latin word “oxygenum”, borrowed from the Greek language, where the word “oxys” means sour, and “gennao” - I give birth, produce (giving birth to acid). The name of the element is literally translated into Russian - “oxygen”.

So, in 1777, the essence of combustion was clarified. And the need for phlogiston - “fiery matter” - disappeared. The oxygen theory of combustion replaced the phlogiston theory.

IV . Biological role of oxygen.

Oxygen is the most common element on Earth; its share (in various compounds, mainly silicates) accounts for about 47.4% of the mass of the solid earth's crust. Marine and fresh waters contain a huge amount of bound oxygen - 88.8% (by mass), in the atmosphere the content of free oxygen is 20.95% (by volume). The element oxygen is part of more than 1,500 compounds in the earth's crust.

Oxygen is the main biogenic element that is part of the molecules of all the most important substances that provide the structure and function of cells - proteins, nucleic acids, carbohydrates, lipids, as well as many low-molecular compounds. Every plant or animal contains much more oxygen than any other element (on average about 70%). Human muscle tissue contains 16% oxygen, bone tissue - 28.5%; In total, the body of an average person (body weight 70 kg) contains 43 kg of oxygen. Oxygen enters the body of animals and humans mainly through the respiratory organs (free oxygen) and with water (bound oxygen). The body's need for oxygen is determined by the level (intensity) of metabolism, which depends on the mass and surface of the body, age, gender, nature of nutrition, external conditions, etc. In ecology, the ratio of total respiration (that is, total oxidative processes) of a community is determined as an important energy characteristic organisms to its total biomass.

Small amounts of oxygen are used in medicine: oxygen (from so-called oxygen pillows) is given to patients who have difficulty breathing for some time. However, it must be borne in mind that prolonged inhalation of air enriched with oxygen is dangerous to human health. High concentrations of oxygen cause the formation of free radicals in tissues, disrupting the structure and function of biopolymers. They also have a similar effect on the body. ionizing radiation. Therefore, a decrease in oxygen content (hypoxia) in tissues and cells during irradiation of the body ionizing radiation has a protective effect - the so-called oxygen effect. This effect is used in radiation therapy: increasing the oxygen content in the tumor and decreasing its content in the surrounding tissues increases radiation damage to tumor cells and reduces damage to healthy ones. For some diseases, saturation of the body with oxygen under high pressure is used - hyperbaric oxygenation.

V . Physical and chemical properties of oxygen.

The chemical element oxygen forms two simple substances - oxygen O2 and O3, which have different physical properties.

Oxygen O2 is a colorless and odorless gas. Its molecule is O2. It is paramagnetic (attracted by a magnet) because it contains two unpaired electrons. The structure of the oxygen molecule can be represented in the form of the following structural formulas:

O - O or O - O

Atmospheric oxygen consists of diatomic molecules. The interatomic distance in the O2 molecule is 0.12074 nm. Molecular oxygen (gaseous and liquid) is a paramagnetic substance; each O2 molecule has 2 unpaired electrons. This fact can be explained by the fact that in the molecule there is one unpaired electron in each of the two antibonding orbitals.

The dissociation energy of the O2 molecule into atoms is quite high and amounts to 493.57 kJ/mol.

The oxygen molecule O2 is quite inert. The stability of the oxygen molecule and the high activation energy of most oxidation reactions mean that at low and room temperatures, many reactions involving oxygen proceed at a barely noticeable rate. Only when conditions are created for the appearance of radicals - O - or R-O-O-, which excite the chain process, does oxidation proceed quickly. In this case, for example, catalysts are used that can accelerate oxidative processes.

Under normal conditions, the density of oxygen gas is 1.42897 kg/m3. The boiling point of liquid oxygen (the liquid is blue) is -182.9°C. At temperatures from -218.7°C to -229.4°C there is solid oxygen with a cubic lattice (modification), at temperatures from -229.4°C to -249.3°C - modification with a hexagonal lattice and at temperatures below -249.3°C - cubic modification. Other modifications of solid oxygen have been obtained at elevated pressure and low temperatures.

At 20°C, the solubility of O2 gas is: 3.1 ml per 100 ml of water, 22 ml per 100 ml of ethanol, 23.1 ml per 100 ml of acetone. There are organic fluorine-containing liquids (for example, perfluorobutyltetrahydrofuran), in which the solubility of oxygen is much higher.

The high strength of the chemical bond between the atoms in the O2 molecule leads to the fact that at room temperature oxygen gas is chemically quite inactive. In nature, it slowly undergoes transformation during decay processes. In addition, oxygen at room temperature is able to react with hemoglobin in the blood, which ensures the transfer of oxygen from the respiratory organs to other organs.

Oxygen interacts with many substances without heating, for example, with alkali and alkaline earth metals (the corresponding oxides like Li2O, CaO, etc., peroxides like Na2O2, BaO2, etc., and superoxides like KO2, RbO2, etc. are formed), causing the formation rust on the surface of steel products. Without heating, oxygen reacts with white phosphorus, with some aldehydes and other organic substances.

When heated, even slightly, the chemical activity of oxygen increases sharply. When ignited, it reacts explosively with hydrogen, methane, other flammable gases, and a large number of simple and complex substances.

Ordinary atmospheric oxygen consists of a mixture of three isotopes: 16O (99.7%), 17O (0.01%), 18O (0.2%). Due to the fact that the content of the 17O and 18O isotopes in oxygen is small compared to the 16O isotope, the atomic mass of oxygen is taken to be 15.9994 cu. e.

Depending on natural conditions, the isotopic composition of oxygen can change, sometimes becoming enriched in heavy isotopes, sometimes depleted in them. Thus, water molecules H216O pass into the vapor state relatively more easily than molecules H217O and H218O. Therefore, the composition of water vapor evaporating from the sea includes oxygen with a relatively lower content of heavy isotopes than the oxygen remaining in sea water.

With the help of atoms of the heavy oxygen isotope 18O, it was possible to determine the “origin” of oxygen released by plants during photosynthesis. It was previously thought that this was oxygen released from carbon monoxide molecules, not water. It has now become known that plants bind oxygen from carbon monoxide and return oxygen from water to the atmosphere.

Oxygen forms compounds with all elements except some noble gases (helium, neon, argon). Thus, oxygen reacts with most metals already at room temperature, for example:

2Na° + O2° = Na2+102-2

Na° -1(е) Na+1 2 reducing agent

O2° +2(е) 2 2O-2 oxidizing agent

2Zn° + O2° = 2Zn+2O-2

Zn° -2(е) Zn+2 reducing agent

O2° +2(е) 2 2O-2 oxidizing agent

Oxygen usually reacts with nonmetals when heated. Thus, oxygen reacts actively with phosphorus at a temperature of 60°C:

4Р° + 502° = 2Р2+505-2

P° -5(е) P+5 2 reducing agent

O2° +2(е) 2 2O-2 5 oxidizing agent

with sulfur - at a temperature of about 250°C:

S° + 02° = S+402-2

S° -4(е) S+4 reducing agent

O2° +2(е) 2 2O-2 2 oxidizing agent

with carbon (in the form of graphite) - at 700-800°C:

С° + О2° = С+4О2-2

C° -4(е) C+4 reducing agent

O2° +2(е) 2 2O-2 2 oxidizing agent

The interaction of oxygen with nitrogen begins only at 1200°C or in an electrical discharge:

N2 + O2 2NO - Q.

Oxygen also reacts with many complex compounds, for example, it reacts with nitrogen oxides already at room temperature:

2N+2O + O2° = 2N+4O2-2

N+2 -2(е) N+4 1 reducing agent

O2° +2(е) 2 2O-2 2 oxidizing agent

Hydrogen sulfide, reacting with oxygen when heated, gives sulfur:

2H2S-2 + O2° = 2S° + 2H2O-2

S-2 -2(е) S° reducing agent

O2° +2(е) 2 2O-2 oxidizing agent

or sulfur(IV) oxide

2H2S + 3О2 = 2SO2 + 2Н2О

depending on the ratio between oxygen and hydrogen sulfide.

In the above reactions, oxygen is the oxidizing agent. Most oxidation reactions involving oxygen release heat and light, a process called combustion.

Ozone is an allotropic modification of oxygen. Its molecule is triatomic - O3. Its structure can be represented by the following structural formula:

Any change in the number or arrangement of the same atoms in a molecule entails the appearance of a qualitatively new substance with different properties. Ozone has different properties from oxygen. Under normal conditions it is a gas of blue color, with a strong irritating odor. Its name comes from the Greek word "ozein", which means smell. It's toxic. Unlike oxygen, the ozone molecule is characterized by a large molecular weight, polarizability and polarity. Therefore, ozone has a higher boiling point (-111.9°C) than oxygen (-182.9°C), intense color and better solubility in water.

IN natural conditions ozone is formed from oxygen during lightning discharges, and at an altitude of 10-30 km - under the influence of ultraviolet sun rays. It blocks life-harming ultraviolet radiation from the Sun. In addition, ozone absorbs the Earth's infrared rays, preventing it from cooling. Consequently, the allotropic form of oxygen - ozone - plays a large role in preserving life on Earth.

The formation of ozone is accompanied by the release of atomic oxygen. These are basically chain reactions in which the appearance of an active particle (usually denoted by *) causes a large number (chain) of successive transformations of inactive molecules, for example O2. The chain reaction of ozone formation from oxygen can be expressed by the following diagram:

*O2 + O2 = O3 + O

O + O2 = O3,

or in total:

In technology, ozone is produced by electrical discharges in ozonizers.

The O3 molecule is unstable, and at high concentrations, ozone disintegrates explosively:

The oxidative activity of ozone is much higher than that of oxygen. For example, already under normal conditions, ozone oxidizes such low-active simple substances as silver and mercury with the formation of their oxides and oxygen:

8Ag + 2O3 = 4Ag2O + O2

As a strong oxidizing agent, ozone is used for cleaning drinking water, for air disinfection. The air of coniferous forests is considered healthy because it contains a small amount of ozone, which is formed during the oxidation of the resin of coniferous trees.

An even stronger oxidizing agent than oxygen O2 is ozone O3 (allotropic modification of oxygen). It is formed in the atmosphere during lightning discharges, which explains the specific smell of freshness after a thunderstorm.

In laboratories, ozone is produced by passing a discharge through oxygen (endothermic reaction):

302 203 - 284 kJ.

When ozone reacts with a solution of potassium iodide, iodine is released, whereas this reaction does not occur with oxygen:

2KI + 03 + H20 = I2 + 2KON + 02.

The reaction is often used qualitatively for the detection of I- or ozone ions. To do this, starch is added to the solution, which gives a characteristic blue complex with released iodine. The reaction is also qualitative because ozone does not oxidize Cl- and Br- ions

There is another modification of oxygen - tetraatomic (O4):

This modification is formed by the weak interaction of two oxygen molecules. The content of tetraatomic molecules in gaseous oxygen under normal conditions is only 0.1% of total number molecules, in liquid and solid oxygen - up to 50%. There is a balance:

At low temperatures it is shifted to the right, i.e. towards the formation of O4 molecules. Structural changes in molecules cause differences in the properties of substances. Thus, liquid and solid oxygen, unlike gaseous oxygen, are colored blue.

When heated, oxygen reacts with hydrogen to form water. When a mixture of both gases is ignited in volumetric proportions of 2:1 (explosive gas), the reaction occurs explosively. But it can also proceed calmly if this mixture is brought into contact with a very small amount of finely divided platinum, which plays the role of a catalyst:

2H2 + O8 = 2H20 + 572.6 kJ/mol

Oxygen can directly oxidize all metals. If the metal is highly volatile, the oxidation process usually occurs in the form of combustion. Combustion of low-volatile metals in oxygen can be carried out under the condition of high volatility of the resulting oxide. The efficiency of this process depends on the reducing activity of the metal and is characterized by the heat of formation of the resulting product. The products of interaction of metals with oxygen (oxides) can be basic, acidic or amphoteric.

When some active metals burn in oxygen, sometimes not their oxides are formed, but superoxides and peroxides. Thus, when potassium and rubidium burn, superoxides of these metals are formed:

This is due to the fact that an oxygen molecule can gain or lose electrons to form molecular ions such as O2-2, O2- and O2+. The addition of one electron to oxygen causes the formation of superoxide ion O2:

O - O + e = [ O - O ] -

The presence of an unpaired electron in the O2- ion determines the paramagnetism of superoxides.

By adding two electrons, the oxygen molecule

rotates into the peroxide ion O2-2, in which the bond atoms

We have one two-electron bond, and therefore it is diamagnetic:

O - O + 2е = [ O - O ]-2

For example, the interaction of barium with oxygen leads to the formation of peroxide BaO2:

Ba + O2 = BaO2

VI. Obtaining oxygen.

Manifold chemical compounds containing oxygen and their availability make it possible to obtain oxygen different ways. All methods of producing oxygen can be divided into two groups: physical and chemical. Most of them are chemical, that is, the production of oxygen is based on certain reactions. For example, when especially pure oxygen is needed, it is obtained from water by decomposing it. Let's consider this method.

Electrodes, most often platinum, are lowered into a vessel filled with electrolytes (distilled water acidified with sulfuric acid), and electricity. Positively charged hydrogen ions move to the negatively charged electrode (cathode), and negatively charged hydroxide ions OH- and sulfate ions SO42- move to the positively charged electrode (anode). The ions are discharged at the electrodes. It should be noted that the discharge of H+ and OH- ions occurs much more easily than the sulfate ions SO42- Thus, hydrogen is released at the cathode, and oxygen at the anode:

4Н+ + 4е - 2Н2

4OH- - 4е - 2H2O + O2

The released gases are collected in different vessels or used directly.

In a school laboratory, it is more convenient to use an alkali solution as an electrolyte. Then the electrodes can be made from iron wire or sheet. In an alkaline environment, water molecules are directly subjected to discharge at the cathode:

H2O + e - H° + H-

Н° + Н° - H2

For the experiment, a laboratory electrolyzer is used. This is a U-shaped glass tube into which electrodes are soldered. The electrolytic method produces fairly pure oxygen (0.1% impurities).

Let's consider another chemical method for producing oxygen. If barium oxide BaO is heated to 540°C, it adds atmospheric oxygen to form barium peroxide BaO2. The latter decomposes when heated to 870°C, and oxygen is released:

2BaO + O2 = 2BaO2

2BaO2 = 2BaO + O2

Barium peroxide acts as an oxygen carrier.

In the last century, plants were developed to produce oxygen using this method. They included vertically located containers that had a heating system. A current of air was passed through barium oxide heated to 400 - 500°C. After the formation of barium peroxide, the air supply was stopped, and the containers were heated to 750°C (decomposition temperature of BaO2).

With the development of technology for obtaining low temperatures, it was developed physical method obtaining oxygen from atmospheric air. It is based on deep cooling of air and the use of differences in boiling points of gases that make up the air.

Liquid air produced in refrigeration units is a mixture consisting of 79% nitrogen and 21% oxygen by volume. Liquid nitrogen boils at a temperature of - 195.8°C, and liquid oxygen boils at a temperature of - 182.9°C. Their separation is based on the difference in boiling temperatures of nitrogen and oxygen. To completely separate liquid oxygen and gaseous nitrogen, repeated evaporation of liquid air is used, accompanied by condensation of its vapor. This process is called fractional distillation or rectification. Currently, this method has become the main way to obtain technical oxygen (cheap raw materials and high productivity of installations). Liquid oxygen is stored and transported in tanks and tanks specially adapted for this purpose, equipped with good thermal insulation.

Since the physical method of producing oxygen is widely used in industry, chemical methods of production have practically lost their technical significance and are used to obtain oxygen in the laboratory.

In connection with developing scientific and technological progress, people around the world are beginning to worry about the fate of oxygen and atmospheric pollution. In many cities it is already becoming difficult to breathe. According to world statistics, all cars emit up to 600 thousand tons of toxic carbon monoxide CO into the air in just one hour of operation. When 1 ton of gasoline is burned in a car, 600 kg of carbon monoxide CO is formed. Currently, the global automobile fleet numbers 190 million vehicles. According to experts, in 1980 their number will exceed 200 million. These figures make you think.

Air poisoning from automobile exhaust gases has become alarming in cities such as Tokyo, London, New York, Paris, Rome, and Moscow. In addition, the atmosphere is polluted by other harmful gases (SO2, H2S), ash, smoke emitted by many enterprises. As a result, over the past 100 years, the number of sunny days around industrial centers has decreased by a quarter: where there were 200, there are now 150. In all major cities of the world, as a result of thick dirty fogs, solar illumination has decreased compared to the beginning of the 20th century. by 10-30%. In London in 1952, about 4,000 people died in a few days of dirty and unbreathable fog in the air. Therefore, the fight for clean air has become one of the current problems modern hygiene.

It is known that green plants are unsurpassed purifiers and sanitizers of the earth’s atmosphere. Photosynthesis is the only process that has maintained the oxygen cycle in the Earth's atmosphere for about 2 billion years. Green plants are a gigantic laboratory that produces oxygen and absorbs carbon monoxide CO2. Scientists have calculated that plants globe annually absorb about 86.5 billion tons of CO2 oxide. In this regard, the creation of green parks around large cities, the arrangement of gardens, the layout of squares and flower beds is an integral part of modern urban planning, as necessary as the installation of water supply and street lighting. It is estimated that in the green areas of Moscow, Leningrad, and Kharkov, air dust levels are 2-3 times less than on adjacent streets.

During recent years The problem of forest fires is acute in Russia. Thousands of hectares of forests are dying in the fire. I believe that if emergency measures are not taken to extinguish fires and restore forests, we will face an environmental disaster in the near future. Nature reserves and forests are burning, unique plants and animals are dying. In the warm season, cities, villages... are shrouded in smoke. Harmful substances in large quantities contained in the air we breathe. In connection with which various chronic diseases arise or worsen in people, immunity decreases. Children are born with congenital malformations, immunodeficiency, damage to the central nervous system...

Nature conservation and reserves have existed for a long time. But probably, at this stage of development of our country, this issue remains in last place. It is necessary for all people to come to their senses and take care of our nature. After all, 95% of all forest fires are caused by them.

VII . Use of oxygen.

The use of any substance is associated with their physical and chemical properties, as well as their distribution in nature.

The amount of metal produced per capita is one measure of the level of industrial development in each country. The smelting of ferrous and non-ferrous metals is impossible without oxygen.

Now in our country, only ferrous metallurgy absorbs over 60% of the oxygen produced. But oxygen is also used in non-ferrous metallurgy.

Oxygen intensifies not only pyrometallurgical processes, but also hydrometallurgical ones, where the main process of extracting metals from ores or their concentrates is based on the action of special reagents on aqueous solutions. Thus, currently the main method of extracting gold from ores is cyanidation. It allows you to extract up to 95% of gold from gold ores and is therefore used even when processing ores with low gold content. The process of dissolving gold contained in ores is a very labor-intensive operation. It turned out that the dissolution of this metal can be significantly accelerated if pure oxygen is used instead of air. Gold in cyanide solutions forms a complex compound Na, which is then treated with zinc, and as a result gold is released:

4Аu + 8NaCN + 2H2O + O2 = 4Na + 4NaOH

2Na [Аu(CN)2] + Zn = Na2 + 2Аu

This method of extracting gold from ores was developed by the Russian engineer P.R. Bagration, a relative of the hero Patriotic War 1812

Oxygen is widely used in the chemical industry. About 30% of the oxygen produced in our country is consumed for the needs of this industry. Replacing air with oxygen during the production of sulfuric acid by contact method increases the productivity of the installation by five to six times. But this is not the only benefit of using oxygen instead of air. Pure oxygen makes it possible to obtain 100 percent sulfur oxide without carrying out additional labor-intensive operations that are necessary when using air as an oxidizer.

When producing nitric acid by the catalytic oxidation of ammonia, oxygen is also used as an oxidizing agent. If its content in the air is increased to 25%, then the productivity of the installation doubles.

With the participation of oxygen in the process of thermal oxidative cracking, acetylene is produced on a large scale, which is widely used for cutting and welding metals and for syntheses organic matter:

6CH4 + 4O2 = C2H2 + 8H2 + 3CO + CO2 + 3H2O

Oxygen is used to obtain high temperatures. If you burn hydrogen in a stream of oxygen, then when 1 mole of water is formed, 286.3 kJ is released, and 2 moles - 572.6 kJ. This is colossal energy! The high temperatures reached in the flame of such burners (up to 3000°C) are used for cutting and welding metals.

Oxygen also serves in space. Thus, in the second stage engine of the American Centaurus space rocket, liquid oxygen served as the oxidizer. Oxygen is also widely used in rockets for various high-altitude research.

Liquid oxygen is a component of explosives. Long time Ammonites and other nitrogen-containing explosives were used for various blasting operations. Their use presented certain difficulties, such as the complexity and danger of transportation, and the need to build warehouses. Currently, liquid oxygen explosives can be manufactured at the point of use. Any porous flammable substance (sawdust, peat, hay, straw), when saturated with liquid oxygen, becomes explosive. Such substances are called oxyliquits and, if necessary, can replace dynamite in the development of ore deposits. When an explosion occurs, an oxyliquit cartridge is used - a simple long bag filled with flammable material, into which an electronic fuse is inserted. It is charged immediately before insertion into the hole by immersion in liquid oxygen. A borehole is a round hole that is usually drilled in rocks and filled with explosives. If for some reason an explosion of the oxyliquit cartridge in the hole does not occur, the cartridge discharges itself as a result of the evaporation of liquid oxygen from it. The action of oxyliquits is based on the extremely rapid combustion of organic substances in pure oxygen. The short-term combustion process is accompanied by the intense release of large quantities of heat and gases, which determines the use of oxyliquits as powerful explosives with a blasting (crushing) effect.

Oxygen is used in medicine and aviation. In medical practice for pulmonary and cardiac diseases, when breathing is difficult, patients are given oxygen from oxygen pillows and placed in special rooms in which the required oxygen concentration is maintained. One breath of oxygen by a person is equivalent to five breaths of air. Thus, when inhaled, this gas not only enters the patient’s body in sufficient quantities, but also saves energy for the breathing process itself. In addition, subcutaneous administration of oxygen has proven effective in the treatment of certain diseases, such as gangrene, thrombophlebitis, elephantiasis and tropical ulcers.

The phenomenon of “oxygen starvation” in the body can also occur from a lack of oxygen in environment. For example, at an altitude of 10,000 m, barometric air pressure drops to 217 mm Hg. Art. and the absolute oxygen content in the air decreases fourfold. This amount of gas is too small for normal breathing. Therefore on high altitudes pilots use oxygen cylinders.

VIII. Ozone layer above the Earth.

Ozone - " brother» oxygen. Its molecule is formed by three atoms of this chemical element: O3. Where there is an electric spark, a peculiar smell of freshness appears, because an electric discharge is a condition for the conversion of air oxygen into ozone:

oxygen ozone

We smell ozone in the air after a thunderstorm. Ozone is present in coniferous forests, especially pine forests. When tree resin decomposes, some ozone is produced.

Ozone in the lower layer of air is scattered and its content is low. This gas is short-lived because it turns back into oxygen:

ozone oxygen

Even in large quantities Ozone acts as an oxidizing agent for many substances. Ozone disinfects tap water and purifies the air from pathogenic bacteria. Due to its activity, ozone can become hazardous to human and animal health if its permissible content in the air is exceeded. However, this does not happen in nature.

High above the Earth, in the stratosphere at an altitude of up to 30 km (above sea level), there is a constant thin layer of ozone that protects life on our planet from the harmful effects of short-wave ultraviolet radiation from the Sun. Ozone absorbs solar ultraviolet radiation, and only a part of it penetrates to the Earth, without causing much harm to its inhabitants. Short waves, which are harmful to all living things, are blocked, and long ultraviolet waves, which are harmless, are transmitted to the Earth.

There is more ozone in the stratosphere than in surface air, however, this does not mean that the layer is formed only by ozone. There is only 1 molecule of ozone in the ozone layer for every 100,000 molecules of other gases. But this ozone is enough to protect life on the planet from ultraviolet radiation.

Long-wave ultraviolet rays affect human skin, causing a tan. But skin cells can react painfully to short-wave radiation, and various types of tumors will appear. Ultraviolet radiation is also harmful to vision.

This is why it is so important that there is a protective ozone layer above the Earth!

In the stratosphere, ozone exists for quite a long time; it does not often encounter reducing substances there, but if they penetrate there, the ozone reacts with them and its amount decreases. This phenomenon of a decrease in ozone concentration in some parts of the stratosphere is called the formation of “ ozone holes" IN Lately recorded a decrease in ozone concentration in the stratosphere by almost 40% over Antarctica. This flat continent is surrounded by an ocean, above South Pole a funnel is formed from the winds circulating around the continent and bringing substances with which ozone reacts. What substances are these?

These are artificially obtained and very valuable substances in practical terms - chlorofluorocarbons of various compositions, for example the following:

These substances are obtained by substitution reactions of halogens for hydrogen atoms in hydrocarbons. Chlorofluorocarbons - persistent substances, do not dissolve in water, non-toxic, do not burn, do not cause corrosion, excellent insulators. They are used to make insulation for building walls and disposable tableware for hot drinks. Liquid substances from this group (freons) are good solvents and effective refrigerants in refrigerators and air conditioners. They are used in aerosol cans as harmless solvents of special substances in automatic fire extinguishing systems (CBrF3).

The production of these substances developed at an accelerated pace until it was discovered that when they enter the stratosphere, they destroy ozone (Now they are trying to replace freons with less volatile substances. For example, fluorochloromethane is used as refrigerants, and liquefied gaseous saturated hydrocarbons are used for aerosol cans ).

These substances reach the stratosphere unchanged. After all, they are chemically stable. And in the stratosphere, where there is a lot of ultraviolet radiation, their molecules are destroyed, and active halogen atoms, in particular chlorine, are split off:

Monatomic chlorine radical reacts with ozone:

03 + Cl = O2 + ClO

ozone chlorine oxygen oxide

(radical) chlorine(II)

Under the influence of ultraviolet rays, oxygen is formed from ozone, which at the time of release is also in an active monatomic state:

ozone oxygen atomic

oxygen

Chlorine oxide (II) reacts with atomic oxygen, and then a chlorine radical is again formed, which again destroys ozone; a chain reaction occurs, repeating itself many times:

ClO + O = Cl + O2

oxide atomic chlorine oxygen

chlorine (II) oxygen (radical)

О3 + С1= О2 + СlO

One chlorine atom participates in a series of such reactions and can destroy up to 100,000 ozone molecules. Chlorine can “get out of the game” when it encounters a methane molecule. Then it, adding to itself one hydrogen atom from methane, forms hydrogen chloride, which, when dissolved in water, forms hydrochloric acid. This is how chlorine destroyer returns to Earth in the form of acid rain:

CH4 + 2C1 - CH3C1 + HC1

methane chlorine chlorine hydrogen chloride

(radical) methane (in solution - hydrochloric acid)

Even if the production of chlorofluorocarbons is reduced everywhere, the process of destruction of the ozone layer over the entire planet will continue. The ozone-depleted air gradually dissipates, the gases in the atmosphere mix, and the chlorofluorocarbons contained in the air will continue their work destroying ozone for a very long time, at least 100 years.

In 1990, representatives of the government of 92 countries in London signed an agreement to completely stop the production of chlorofluorocarbons by the year 2000. Compliance with this agreement will be a condition for the gradual restoration of the natural content of ozone in the atmosphere, because the concentration of chlorine already in the atmosphere should decrease over time, but this time - century.

IX . Conclusion.

So, we received various information from the field of chemistry of group VI elements and, to a greater extent, about oxygen, we learned about where and how oxygen is used and obtained, and we also learned about the impact of oxygen on our life, national economy and culture.

If, after reading my essay, you have a desire to take a closer look at the vast area of ​​that science from which information on the elements of group VI of D. I. Mendeleev’s periodic system was obtained, then I have completed my task.

Bibliography

1. Chemistry. For schoolchildren Art. classes and entering universities: Proc. Manual / N. E. Kuzmenkoy, V. V. Eremin, V. A. Popkov - 4th ed., stereotype. - M.: Bustard, 2001. - 544 p.: ill.

2. A book to read on inorganic chemistry. Book for students. At 2 p.m. Part 1 / comp. V. A. Kritsman - 3rd ed. - M.: Education, 1993. - 192 pp., 8 l ill.: ill. - ISBN 5-09-002972-5

3. Chemistry. Textbook for 9th grade. avg. school / F. G. Feldman, G. E. Rudzitis - M.: Education, 1990. - 176 pp.: ill. ISBN 5-09-002624-6

4. Chemistry: Textbook. for 8-9 grades. general education Institutions / R. G. Ivanova. - 3rd ed., M.: Education, 2001. - 270 pp.: ill. - ISBN 5-09-010278-3

5. Traveling through the sixth group. Elements of group VI of the periodic system of D. I. Mendeleev. A manual for students. / G. L. Nemchaninova - M., “Enlightenment”, 1976 - 128 pp.: ill.

The use of oxygen is based on its chemical properties.

Oxygen in the air is extremely important for combustion processes. By burning various types of fuel, heat is obtained, which is used to satisfy a wide variety of needs, including converting it into mechanical and electrical energy. With the participation of atmospheric oxygen, fuel is burned at thermal power plants, fuel in car engines, and metal ores are burned at non-ferrous metallurgy factories.

Welding and cutting of metals

Pure oxygen with acetylene is widely used for the so-called autogenous welding of steel pipes and other metal structures and their cutting. For this purpose, a special burner is used, which consists of two metal tubes inserted into each other. Acetylene is passed into the space between the tubes and ignited, and then oxygen is passed through the inner tube. Both gases are supplied from cylinders under pressure. The temperature in an oxygen-acetylene flame is up to 2000 ° C; most metals melt at this temperature.

In medicine

Oxygen is the most important biogenic chemical element that ensures the respiration of most living organisms on Earth. The physiological effect of oxygen is versatile, but decisive in its therapeutic effect has the ability to compensate for oxygen deficiency in body tissues during hypoxia (insufficient supply of oxygen to tissues or impaired absorption).

Inhalation (inhalation) oxygen is widely used for various diseases accompanied by hypoxia (lack of oxygen): for diseases of the respiratory system (pneumonia, pulmonary edema, etc.), of cardio-vascular system(heart failure, coronary insufficiency, a sharp drop in blood pressure, etc.), poisoning with carbon monoxide, hydrocyanic acid, asphyxiants (chlorine, phosgene, etc.), as well as other diseases with impaired respiratory function and oxidative processes.

In anesthesiological practice oxygen is widely used in a mixture with inhaled narcotic analgesics. Pure oxygen and its mixture with carbon dioxide are used for weakened breathing in the postoperative period, for intoxication, etc.

Oxygen is widely used for the so-called hyperbaric oxygen therapy- use of oxygen under high pressure. The high effectiveness of this method in surgery, intensive care of severe diseases, especially in cardiology, resuscitation, neurology and other areas of medicine has been established.

Also used enteral oxygen therapy (introducing oxygen into the intestines or stomach) by introducing oxygen foam into the stomach, used in the form of a so-called oxygen cocktail. Used for general improvement of metabolic processes in the complex therapy of cardiovascular diseases, metabolic disorders and other pathological conditions associated with oxygen deficiency in the body.

Pure oxygen They are also used for breathing by pilots during high flights, divers, on submarines, etc.

Oxygen pillows are used for some diseases to facilitate breathing.

In metallurgy

Oxygen is widely used to intensify chemical and metallurgical processes. Pure oxygen is used, in particular, in the production of sulfuric and nitric acids, synthetic methyl alcohol CH 3 OH and other chemical products.

When oxygen-enriched air is blown into a blast furnace, the temperature of the furnace increases significantly, the process of smelting iron is accelerated, the productivity of the blast furnaces increases and coke is saved.

The idea of ​​the advisability of enriching the blast with oxygen was expressed back in the 19th century. However, the widespread use of oxygen-enriched air in blast furnace production and in metallurgy in general was delayed for a long time. This was due to the high cost of oxygen, as well as disruptions in the technological process that arose during the smelting of processing cast iron.

After many industrial studies, the theory and technology of blast furnace smelting using oxygen-enriched blast was developed.

IN agriculture

In greenhouse farming, to increase the weight of animals, to enrich the aquatic environment with oxygen in fish farming.

In the food industry acts as a propellant (for spraying other substances), as a packaging gas and even as a food additive (E 948).

Rocket fuel

A mixture of liquid oxygen and liquid ozone is one of the most powerful oxidizers of rocket fuel (the specific impulse of the hydrogen-ozone mixture exceeds the specific impulse for the hydrogen-fluorine and hydrogen-oxygen fluoride pairs).

Explosives

Liquid oxygen is used to make explosive mixtures - the so-called oxyliquits. These are mixtures of sawdust, dry peat, coal powder and other flammable substances, compressed in special cartridges and impregnated with liquid oxygen before use. When such a mixture is ignited by an electric spark, it explodes with great force. Oxyliquits are used in the development of ore deposits by explosive methods, when laying tunnels in the mountains, digging canals, etc.

Currently, in industry, oxygen is obtained from the air.

The main consumers of oxygen are energy, metallurgy, chemical industry and medicine.

Oxygen is a colorless, odorless gas, a typical oxidizing agent; when the concentration of this gas in the air increases to 30% or higher, very intense combustion of almost all substances occurs in such an atmosphere. Various metals, non-metals and complex substances burn in oxygen, for example, carbon, sulfur, iron, magnesium, hydrogen sulfide. These properties determine the widespread use of this gas in various industries.

Oil and gas industry

Oxygen is used to increase the productivity of oil cracking plants, to better process high-octane components, and to reduce sulfur deposits in refineries.

Chemical and petrochemical industry

Oxygen is widely used to oxidize starting reagents to produce nitric acid, ethylene oxide, propylene oxide, vinyl chloride and other important chemical compounds.

Metallurgical industry

Pure oxygen is consumed mainly to produce steel from cast iron and scrap metal. Oxygen is used to increase the combustion temperature in furnaces. In many metallurgical units, for more efficient combustion of fuel, an oxygen-air mixture is used instead of air in the burners.

Energy

Electric and thermal power plants fueled by coal, oil or natural gas use atmospheric oxygen to burn fuel.

Mechanical engineering, construction

In mechanical engineering and construction, oxygen is used for welding, cutting and soldering of metals. Combustible acetylene gas, burning in a stream of oxygen, allows you to get temperatures above 3000 ° C! This is approximately twice the melting point of iron.

Glass industry

Oxygen production equipment is effectively used to increase the productivity of glass melting furnaces by increasing the process temperature.

Medicine

In medicine, oxygen is used to maintain the life of patients with difficulty breathing and to treat certain diseases.

Food industry

In the food industry, oxygen is registered as a food additive E948, as a propellant and packaging gas.

Agriculture

In greenhouse farming, oxygen is used to make oxygen cocktails, to increase weight in animals, to enrich the aquatic environment with oxygen in fish farming and when growing shrimp, crabs and mussels.

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Four “chalcogen” elements (i.e., “giving birth to copper”) lead the main subgroup of group VI (according to the new classification - the 16th group) of the periodic system. In addition to sulfur, tellurium and selenium, these also include oxygen. Let's take a closer look at the properties of this element, the most common on Earth, as well as the use and production of oxygen.

Element prevalence

In bound form, oxygen enters chemical composition water - its percentage is about 89%, as well as in the composition of the cells of all living beings - plants and animals.

In the air, oxygen is in a free state in the form of O2, occupying a fifth of its composition, and in the form of ozone - O3.

Physical properties

Oxygen O2 is a gas that is colorless, tasteless and odorless. Slightly soluble in water. The boiling point is 183 degrees below zero Celsius. In liquid form, oxygen is blue, and in solid form it forms blue crystals. The melting point of oxygen crystals is 218.7 degrees below zero Celsius.

Chemical properties

When heated, this element reacts with many simple substances, both metals and non-metals, forming so-called oxides - compounds of elements with oxygen. in which elements enter with oxygen is called oxidation.

For example,

4Na + O2= 2Na2O

2. Through the decomposition of hydrogen peroxide when it is heated in the presence of manganese oxide, which acts as a catalyst.

3. Through the decomposition of potassium permanganate.

Oxygen is produced in industry in the following ways:

1. For technical purposes, oxygen is obtained from air, in which its usual content is about 20%, i.e. fifth part. To do this, the air is first burned, producing a mixture containing about 54% liquid oxygen, 44% liquid nitrogen and 2% liquid argon. These gases are then separated using a distillation process, using the relatively small range between the boiling points of liquid oxygen and liquid nitrogen - minus 183 and minus 198.5 degrees, respectively. It turns out that nitrogen evaporates earlier than oxygen.

Modern equipment ensures the production of oxygen of any degree of purity. Nitrogen, which is obtained by separating liquid air, is used as a raw material in the synthesis of its derivatives.

2. Also produces very pure oxygen. This method has become widespread in countries with rich resources and cheap electricity.

Application of oxygen

Oxygen is the most important element in the life of our entire planet. This gas, which is contained in the atmosphere, is consumed in the process by animals and people.

Obtaining oxygen is very important for such areas of human activity as medicine, welding and cutting of metals, blasting, aviation (for human breathing and for engine operation), and metallurgy.

In the process of human economic activity, oxygen is consumed in large quantities - for example, during combustion various types fuel: natural gas, methane, coal, wood. In all these processes, it is formed. At the same time, nature has provided for the process of natural binding of this compound using photosynthesis, which takes place in green plants under the influence sunlight. As a result of this process, glucose is formed, which the plant then uses to build its tissues.