For getting oxygen, you will need substances that are rich in them. These are peroxides, nitrates, chlorates. We will use those that can be obtained without much difficulty.

There are several ways to get oxygen at home, we will analyze them in order.

The easiest and most affordable way to obtain oxygen is to use potassium permanganate (or the more correct name is potassium permanganate). Everyone knows that potassium permanganate is an excellent antiseptic, used as a disinfectant. If it is not available, then you can buy it at the pharmacy.

Let's do this. Pour a little potassium permanganate into the test tube, close it with a test tube with a hole, install a gas outlet tube in the hole (oxygen will flow through it). We place the other end of the tube in another test tube (it should be upside down, since the released oxygen is lighter than air and will rise up. Close the second test tube with the same stopper.
As a result, we should get two test tubes connected to each other by a gas outlet tube through plugs. In one (not inverted) test tube - potassium permanganate. We will heat a test tube with potassium permanganate. The dark purple-cherry color of potassium permanganate crystals will disappear and turn into dark green crystals of potassium manganate.

The reaction goes like this:

2KMnO 4 → MnO 2 + K 2 MnO 4 + O 2

So from 10 grams of potassium permanganate you can get almost 1 liter of oxygen. After a couple of minutes, you can remove the flask with potassium permanganate from the flame. We got oxygen in an inverted test tube. We can check it out. To do this, carefully disconnect the second tube (with oxygen) from the gas outlet tube, covering the hole with your finger. Now, if you put a weakly burning match into a flask with oxygen, it will flare up brightly!

Obtaining oxygen it is also possible with the help of sodium or potassium nitrate (corresponding sodium and potassium salts of nitric acid).
(Potassium and sodium nitrates - they are also nitrates, are sold at fertilizer stores).

So, to get oxygen from saltpeter, we take a test tube of refractory glass on a tripod, put saltpeter powder there (5 grams will be enough). You will need to put a ceramic cup with sand under the test tube, because glass can melt from temperature and leak. Therefore, the burner will need to be held a little to the side, and the test tube with nitrate - at an angle.

With strong heating of saltpeter, it begins to melt, while oxygen is released. The reaction goes like this:

2KNO 3 → 2KNO 2 + O 2

The resulting substance is potassium nitrite (or sodium, depending on which saltpeter is used) - a salt of nitrous acid.

Another way getting oxygen- use hydrogen peroxide. Peroxide, hydroperite - all the same substance. Hydrogen peroxide is sold in tablets and in the form of solutions (3%, 5%, 10%), which can be purchased at a pharmacy.

Unlike previous substances, saltpeter or potassium permanganate, hydrogen peroxide is an unstable substance. Already in the presence of light, it begins to decompose into oxygen and water. Therefore, in pharmacies, peroxide is sold in dark glass vials.

In addition, catalysts such as manganese oxide, activated carbon, steel powder (fine chips) and even saliva contribute to the rapid decomposition of hydrogen peroxide into water and oxygen. Therefore, hydrogen peroxide does not need to be heated, a catalyst is enough!

Four elements - "chalcogen" (i.e. "giving birth to copper") head 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, they also include oxygen. Let's take a closer look at the properties of this most common element on Earth, as well as the use and production of oxygen.

Element abundance

In a bound form, oxygen is included in the chemical composition of 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 colorless, tasteless and odorless gas. It is slightly soluble in water. The boiling point is 183 degrees below zero Celsius. In liquid form, oxygen has a blue color, 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, while forming the 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.

The production of oxygen in industry is carried out 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, obtaining a mixture with a liquid oxygen content of about 54%, liquid nitrogen - 44% and liquid argon - 2%. These gases are then separated by a distillation process using a relatively small interval between the boiling points of liquid oxygen and liquid nitrogen - minus 183 and minus 198.5 degrees, respectively. It turns out that nitrogen evaporates before 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 gives oxygen to a very pure degree. 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 humans.

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

In the process of human economic activity, oxygen is consumed in large quantities - for example, when burning various types of 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 through photosynthesis, which takes place in green plants under the influence of sunlight. As a result of this process, glucose is formed, which the plant then uses to build its tissues.

>> Obtaining oxygen

Obtaining oxygen

This paragraph is about:

> about the discovery of oxygen;
> on the production of oxygen in industry and laboratories;
> about decomposition reactions.

Discovery of oxygen.

J. Priestley obtained this gas from a compound whose name is mercury (II) oxide. The scientist used a glass lens to focus sunlight on matter.

In a modern version, this experience is shown in Figure 54. When heated, mercury (||) oxide (yellow powder) turns into mercury and oxygen. Mercury is released in a gaseous state and condenses on the walls of the test tube in the form of silvery droplets. Oxygen is collected over water in the second test tube.

Now the Priestley method is not used because mercury vapor is toxic. Oxygen is produced by other reactions similar to the one discussed. They usually occur when heated.

Reactions in which several other substances are formed from one substance are called decomposition reactions.

To obtain oxygen in the laboratory, the following oxygen-containing compounds are used:

Potassium permanganate KMnO 4 (common name potassium permanganate; substance is a common disinfectant)

Potassium chlorate KClO3

A small amount of catalyst - manganese (IV) oxide MnO 2 - is added to potassium chlorate so that the decomposition of the compound occurs with the release of oxygen 1 .

Laboratory experiment No. 8

Obtaining oxygen by decomposition of hydrogen peroxide H 2 O 2

Pour 2 ml of a hydrogen peroxide solution (the traditional name for this substance is hydrogen peroxide) into a test tube. Light a long splinter and extinguish it (as you do with a match), so that it barely smolders.
Pour a little catalyst - black powder of manganese (IV) oxide into a test tube with a hydrogen oxide solution. Observe vigorous evolution of gas. Use a smoldering splinter to verify that this gas is oxygen.

Write an equation for the decomposition of hydrogen peroxide, the product of which is water.

In the laboratory, oxygen can also be obtained by decomposition of sodium nitrate NaNO 3 or potassium nitrate KNO 3 2 . When heated, compounds first melt and then decompose:

1 When the compound is heated without a catalyst, another reaction occurs

2 These substances are used as fertilizers. Their common name is saltpeter.

Scheme 7. Laboratory methods for obtaining oxygen

Turn reaction schemes into chemical equations.

Information on how oxygen is obtained in the laboratory is collected in Scheme 7.

Oxygen together with hydrogen are products of the decomposition of water under the action of an electric current:

In nature, oxygen is produced by photosynthesis in the green leaves of plants. A simplified diagram of this process is as follows:

conclusions

Oxygen was discovered at the end of the 18th century. several scientists .

Oxygen is obtained in industry from the air, and in the laboratory - with the help of decomposition reactions of certain oxygen-containing compounds. During a decomposition reaction, two or more substances are formed from one substance.

129. How is oxygen obtained in industry? Why is potassium permanganate or hydrogen peroxide not used for this?

130. What reactions are called decomposition reactions?

131. Turn the following reaction schemes into chemical equations:

132. What is a catalyst? How can it affect the course of chemical reactions? (Also refer to § 15 for your answer.)

133. Figure 55 shows the moment of decomposition of a white solid that has the formula Cd(NO3)2. Look at the picture carefully and describe everything that happens during the reaction. Why does a smoldering splinter flare up? Write the appropriate chemical equation.

134. The mass fraction of Oxygen in the residue after heating potassium nitrate KNO 3 was 40%. Has this compound completely decomposed?

Rice. 55. Decomposition of a substance when heated

Popel P. P., Kriklya L. S., Chemistry: Pdruch. for 7 cells. zahalnosvit. navch. zakl. - K .: Exhibition Center "Academy", 2008. - 136 p.: il.

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Oxygen appeared in the earth's atmosphere with the emergence of green plants and photosynthetic bacteria. Thanks to oxygen, aerobic organisms carry out respiration or oxidation. It is important to obtain oxygen in industry - it is used in metallurgy, medicine, aviation, the national economy and other industries.

Properties

Oxygen is the eighth element of Mendeleev's periodic table. It is a gas that supports combustion and oxidizes substances.

Rice. 1. Oxygen in the periodic table.

Oxygen was officially discovered in 1774. The English chemist Joseph Priestley isolated the element from mercury oxide:

2HgO → 2Hg + O 2 .

What Priestley did not know, however, was that oxygen was part of the air. The properties and presence of oxygen in the atmosphere were later pointed out by Priestley's colleague, the French chemist Antoine Lavoisier.

General characteristics of oxygen:

• colorless gas;
• has no smell and taste;
• heavier than air;
• the molecule consists of two oxygen atoms (O 2);
• in the liquid state it has a pale blue color;
• poorly soluble in water;
• is a strong oxidizing agent.

Rice. 2. Liquid oxygen.

The presence of oxygen can be easily checked by lowering a smoldering torch into a vessel with gas. In the presence of oxygen, the torch flares up.

How to receive

There are several ways to obtain oxygen from various compounds in industrial and laboratory conditions. In industry, oxygen is obtained from air by liquefying it under pressure and at a temperature of -183°C. Liquid air is subjected to evaporation, i.e. gradually warm up. At -196°C, nitrogen begins to volatilize, while oxygen retains its liquid state.

In the laboratory, oxygen is formed from salts, hydrogen peroxide, and electrolysis. The decomposition of salts occurs when heated. For example, potassium chlorate or Bertolet salt is heated to 500 ° C, and potassium permanganate or potassium permanganate is heated to 240 ° C:

• 2KClO 3 → 2KCl + 3O 2;
• 2KMnO 4 → K 2 MnO 4 + MnO 2 + O 2.

Rice. 3. Heating Berthollet salt.

You can also get oxygen by heating saltpeter or potassium nitrate:

2KNO 3 → 2KNO 2 + O 2 .

The decomposition of hydrogen peroxide uses manganese (IV) oxide - MnO 2 , carbon or iron powder as a catalyst. The general equation looks like this:

2H 2 O 2 → 2H 2 O + O 2.

The sodium hydroxide solution is subjected to electrolysis. As a result, water and oxygen are formed:

4NaOH → (electrolysis) 4Na + 2H 2 O + O 2.

Oxygen is also isolated from water by electrolysis, decomposing it into hydrogen and oxygen:

2H 2 O → 2H 2 + O 2 .

On nuclear submarines, oxygen was obtained from sodium peroxide - 2Na 2 O 2 + 2CO 2 → 2Na 2 CO 3 + O 2. The method is interesting in that carbon dioxide is absorbed along with the release of oxygen.

How to apply

Collection and recognition is necessary to release pure oxygen, which is used in industry to oxidize substances, as well as to maintain breathing in space, under water, in smoky rooms (oxygen is necessary for firefighters). In medicine, oxygen tanks help patients with breathing difficulties breathe. Oxygen is also used to treat respiratory diseases.

Oxygen is used to burn fuel - coal, oil, natural gas. Oxygen is widely used in metallurgy and engineering, for example, for melting, cutting and welding metal.

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Oxygen is one of the most commonly used gases by mankind; it is widely used in almost all areas of our life. Metallurgy, chemical industry, medicine, national economy, aviation - this is just a short list of areas where this substance is indispensable.

Oxygen production is carried out in accordance with two technologies: laboratory and industrial. The first techniques for the production of colorless gas were based on chemical reactions. Oxygen is obtained as a result of the decomposition of potassium permanganate, bertolet salt or hydrogen peroxide in the presence of a catalyst. However, laboratory techniques cannot fully meet the demand for this unique chemical element.

The second way to produce oxygen is cryogenic distillation or using adsorption or membrane technologies. The first technique provides high purity of the separation products, but has a longer (compared to the second methods) start-up period.

Adsorption oxygen plants have proven to be among the best among high-performance systems for the production of oxygen-enriched air. They make it possible to obtain a colorless gas with a purity of up to 95% (up to 99% with the use of an additional purification stage). Their use is economically justified, especially in situations where there is no need for high-purity oxygen, for which one would have to pay extra.

Main characteristics of cryogenic systems

Interested in producing oxygen up to 99.9% purity? Then pay attention to the installations operating on the basis of cryogenic technology. Advantages of high purity oxygen production systems:

• long service life of the installation;
• high performance;
• the ability to obtain oxygen with a purity of 95 to 99.9%.

But due to the large dimensions of cryogenic systems, the impossibility of a quick start and stop, and other factors, the use of cryogenic equipment is not always appropriate.

The principle of operation of adsorption plants

The scheme of operation of oxygen systems using adsorption technology can be represented as follows:

• compressed air moves into the receiver, into the air preparation system to get rid of mechanical impurities and filtration from condensed moisture;
• purified air is sent to the adsorption air separation unit, which includes adsorbers with an adsorbent;
• during operation, adsorbers are in two states - absorption and regeneration; at the absorption stage, oxygen enters the oxygen receiver, and nitrogen at the generation stage is discharged into the atmosphere; after which oxygen is sent to the consumer;
• if necessary, the gas pressure can be increased using a booster oxygen compressor with subsequent filling into cylinders.

Adsorption complexes are distinguished by a high level of reliability, full automation, ease of maintenance, small dimensions and weight.

Advantages of gas separation systems

Installations and stations using adsorption technology to produce oxygen are widely used in various fields: in welding and cutting metals, in construction, fish farming, growing mussels, shrimp, etc.

Advantages of gas separation systems:

• the possibility of automating the process of obtaining oxygen;
• no special requirements for the premises;
• quick start and stop;
• high reliability;
• low cost of produced oxygen.

Benefits of adsorption plants NPK "Grasys"

Are you interested in the production of oxygen in the way used in industry? Would you like to receive oxygen at minimal financial cost? Scientific and production company "Grasys" will help to solve your problem at the highest level. We offer reliable and efficient systems for obtaining oxygen from the air. Here are the main distinguishing features of our products:

• full automation;
• well-thought-out designs;
• modern control and management systems.

The oxygen produced by our air separation adsorption units is up to 95% pure (with the option of post-treatment up to 99%). Gas with such characteristics is widely used in metallurgy for welding and cutting metals, in the national economy. Our equipment uses modern technologies that provide unique opportunities in the field of gas separation.

Features of our adsorption oxygen plants:

• high reliability;
• low cost of produced oxygen;
• innovative highly intelligent monitoring and control system;
• ease of maintenance;
• the ability to produce oxygen with a purity of up to 95% (with the option of additional purification up to 99%);
• the capacity is up to 6000 m³/h.

Adsorption oxygen plants NPK "Grasys" - a unique combination of world design experience in the production of gas separation equipment and domestic innovative technologies.

The main reasons for cooperation with NPK Grasys

The industrial method of obtaining oxygen using installations based on adsorption technology is one of the most promising today. It allows to obtain a colorless gas with minimal energy costs of the required purity. A substance with these parameters is in demand in metallurgy, mechanical engineering, the chemical industry, and medicine.

The method of cryogenic distillation is the optimal solution if it is necessary to produce oxygen of high purity (up to 99.9%).

Grasys, a leading domestic company, offers highly efficient systems for the production of oxygen using adsorption technology on favorable terms. We have extensive experience in the implementation of various turnkey projects, so we are not afraid of even the most complex tasks.

Benefits of working with a responsible supplier of equipment NPK Grasys:

• our company is a direct manufacturer, so the cost of the installations being sold does not increase the additional commissions of intermediaries;
• high quality products;
• a full range of services for the repair and maintenance of oxygen production plants;
• Individual approach to each client;
• many years of experience in the field of oxygen production.

Call our managers to clarify the nuances of cooperation.

In more detail you can get acquainted with oxygen equipment (oxygen generators, oxygen plants, oxygen stations) on the page