Chemical and physical properties, application and production of oxygen

The four elements of the "chalcogen" (i.e., "bearers of copper") lead the main subgroup of the VI group (according to the new classification - the 16th group) of the periodic system. In addition to sulfur, tellurium and selenium, oxygen also belongs to them. 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.

Prevalence of an element

The oxygen content in the earth's crust is almost 50%. It is found in various minerals in the form of oxides and salts.

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

In 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 does not have color, taste and odor. It dissolves weakly in water. The boiling point is 183 degrees below zero Celsius. In liquid form, oxygen has a blue color, and in the 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 thus the so-called oxides - compounds of elements with oxygen. The chemical reaction into which the elements enter with oxygen is called oxidation.

For example,

4Na + O2 = 2Na2O

S + O2 = SO2

Some of the complex substances also react with oxygen, also forming oxides:

CH4 + 2O2 = CO2 + 2H2O

2CO + O2 = 2CO2

If a substance reacts slowly with oxygen, then this oxidation is called slow. For example, these are processes of decomposition of food products, decay.

Obtaining oxygen

This chemical element can be obtained both in the laboratory and in the industrial enterprise.

Oxygen production in the laboratory is carried out in several ways:

1. By the decomposition reaction of the bertoletate salt (potassium chlorate).

2. Through the decomposition of hydrogen peroxide by heating it in the presence of manganese oxide acting as a catalyst.

3. Through the decomposition of potassium permanganate.

Oxygen production in industry is carried out in such ways:

1. For technical purposes, oxygen is obtained from air, in which its usual content is about 20%, i.e. The fifth part. For this purpose, air is first burned to obtain 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 earlier than oxygen.

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

2. Electrolysis of water also gives oxygen a very clean degree. This method has become widespread in countries with abundant resources and cheap electricity.

Application of oxygen

Oxygen is the most important element in the life of the whole of our planet. This gas, which is contained in the atmosphere, is consumed in the process of breathing by plants, animals and humans.

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

In the process of human economic activity, oxygen is consumed in large quantities - for example, by burning various types of fuel: natural gas, methane, coal, wood. In all these processes, carbon monoxide is formed. At the same time nature has provided for the process of natural binding of this compound by 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.