Difference between ozone and air. Allotropic modifications of oxygen: comparative characteristics and significance How a different combination of atoms affects the properties of a substance

Atoms of the same type can be part of different substances. For the element denoted by the symbol "O" (from the Latin name Oxygenium), two common in nature are known simple substances A. The formula of one of them is O 2, the second is O 3. These are oxygen (allotropes). There are other compounds that are less stable (O 4 and O 8). To understand the difference between these forms, a comparison of molecules and

modifications?

Many chemical elements can exist in two, three or more forms. Each of these modifications is formed by atoms of the same type. The scientist J. Berzellius in 1841 was the first to call such a phenomenon allotropy. The open regularity was originally used only to characterize substances of a molecular structure. For example, two allotropic modifications of oxygen are known, the atoms of which form molecules. Later, the researchers found that modifications can be among the crystals. According to modern concepts, allotropy is one of the cases of polymorphism. Differences between forms are caused by the formation mechanisms chemical bond in molecules and crystals. This feature is manifested mainly by elements of groups 13-16 of the periodic table.

How do different combinations of atoms affect the properties of matter?

Allotropic modifications of oxygen and ozone are formed by atoms of the element with the atomic number 8 and the same number of electrons. But they differ in structure, which led to a significant discrepancy in properties.

Conclusions based on the comparison results: allotropic modifications of oxygen do not differ in their qualitative composition. The structure of a molecule is reflected in the physical and chemical properties of substances.

Are the amounts of oxygen and ozone the same in nature?

A substance whose formula is O 2 is found in the atmosphere, hydrosphere, earth's crust and living organisms. About 20% of the atmosphere is formed by diatomic oxygen molecules. In the stratosphere at an altitude of about 12-50 km from earth's surface There is a layer called the ozone layer. Its composition reflects the formula O 3 . Ozone protects our planet by intensely absorbing the dangerous rays of the red and ultraviolet spectrum of the sun. The concentration of a substance is constantly changing, and its low concentration is 0.001%. Thus, O 2 and O 3 are allotropic modifications of oxygen, which have significant differences in distribution in nature.

How

Molecular oxygen is the most important simple substance on Earth. It is formed in the green parts of plants in the light in electric discharges of natural or artificial origin, the diatomic oxygen molecule decomposes. The temperature at which the process starts is about 2000 °C. Some of the resulting radicals combine again, forming oxygen. Some active particles react with diatomic oxygen molecules. This reaction produces ozone, which also reacts with oxygen free radicals. This creates diatomic molecules. The reversibility of reactions leads to the fact that the concentration of atmospheric ozone is constantly changing. In the stratosphere, the formation of a layer consisting of O 3 molecules is associated with ultraviolet radiation Sun. Without it protective screen dangerous rays could reach the surface of the Earth and destroy all forms of life.

Allotropic modifications of oxygen and sulfur

The chemical elements O (Oxygenium) and S (Sulfur) are located in the same group of the periodic table, they are characterized by the formation of allotropic forms. Of the molecules with different numbers of sulfur atoms (2, 4, 6, 8), under normal conditions, the most stable is S8, resembling a crown in shape. Rhombic and monoclinic sulfur are built from such 8-atomic molecules.

At a temperature of 119 °C, the monoclinic form yellow color forms a brown viscous mass - a plastic modification. The study of allotropic modifications of sulfur and oxygen is of great importance in theoretical chemistry and practical activities.

Oxidizing properties are used on an industrial scale different forms. Ozone is used to disinfect air and water. But at concentrations above 0.16 mg/m3, this gas is dangerous for humans and animals. Molecular oxygen is essential for breathing and is used in industry and medicine. An important role in economic activity is played by allotropes of carbon (diamond, graphite, red) and other chemical elements.

characterize and compare the allotropic modifications of oxygen, physical and Chemical properties, methods of obtaining oxygen and ozone, their practical significance; the importance of the ozone layer for life on Earth;

explain the essence of allotropy;

draw up equations and schemes of the electronic balance of the corresponding chemical reactions.

oxygen and ozone. Oxygen forms two simple substances: oxygen O2 and ozone O3. Mr(O2) = 32, Mr(O3) = 48.

In nature, ozone is formed in the atmosphere from oxygen during lightning electrical discharges. The characteristic smell of freshness that we feel after a thunderstorm is the smell of ozone. The phenomenon of the existence of a chemical element in the form of two or more simple substances, different in properties and structure, is called allotropy, and the simplest substances are called allotropic modifications (forms, modifications) of a chemical element.

Oxygen O2 and ozone O3 are allotropic modifications of the chemical element oxygen.

What is the reason various properties allotropic modifications, namely oxygen and ozone? You already know that the properties of a substance are determined by its composition and structure.

Oxygen and ozone have the same qualitative composition, but different quantitative; the same molecular structure, but different spatial structure of molecules: linear - in non-polar oxygen molecules and angular - in polar ozone molecules. So, in addition to similar substances, these substances have different properties.

- Make an electronic balance diagram for each equation. Explain how the presence of manganese (IV) oxide floats away in the course of the decomposition reactions of H2O2 and KClO3.

In the laboratory, ozone is produced in special devices- ozonizers from oxygen under the action of an electric discharge (Fig. 36).

Chemical properties of allotropic modifications of oxygen. The high electronegativity of oxygen results in strong oxidizing properties of its allotropic modifications.

You know that oxygen is highly reactive. It reacts with most simple substances to form oxides.

The use of oxygen on an industrial scale began in the middle of the 20th century. - After the invention of a device for liquefying and separating air. As an oxidizing agent, it is used in metallurgy to obtain steel by the converter method, to cut metals, in a mixture with other oxygen-rich compounds - for oxidation. rocket fuel, V gas mixtures for breathing during underwater work, in medicine in case of respiratory failure.

The use of ozone is due to its very high reactivity. It is used for disinfection drinking water, flue gas cleaning, industrial and domestic Wastewater, fabric bleaching, and as a propellant oxidizer.

Physiological action of O3. It should be remembered that the extreme oxidizing power of ozone leads to its toxic effects on humans, animals and plants. Even small concentrations of ozone, exceeding natural ones, cause irritation of the respiratory tract, coughing, vomiting, dizziness, and fatigue. These symptoms can be seen in major cities where increased vehicle emissions containing oxides of nitrogen cause oxygen to be converted to ozone.

Ozone reaches its maximum concentration in the atmosphere at a distance of 23-25 ​​km from the Earth's surface, forming the so-called ozone layer.

The ozone layer plays an important role in maintaining life on our planet. It delays the part of the harmful ultraviolet solar radiation that is harmful to humans, animals and plants, which can cause skin diseases (including cancer), and adversely affect biological processes. In addition, together with carbon dioxide, the ozone layer absorbs the thermal, infrared radiation of the Earth and prevents it from cooling.

However, under the influence anthropogenic factors The ozone layer is undergoing destruction, and "ozone holes" are formed in it. Dozens of substances are known - atmospheric pollutants that destroy the ozone layer. Scientists have studied that nitrogen oxides, which are formed during the operation of aircraft engines, are especially dangerous. According to the degree of influence of other substances, it has not been finally determined in natural conditions.

Preservation and restoration of the ozone layer, establishing the causes of its destruction is one of the most pressing problems of mankind that needs to be addressed.

Briefly about the main

Oxygen forms two allotropic modifications - oxygen O2 and ozone O3, which differ in the composition and structure of the molecule and, accordingly, in properties. The existence of a chemical element in the form of two or more simple substances, different in properties and structure, is called allotropy, and the simplest substances are called allotropic modifications (forms) of a chemical element. The allotropic modifications of oxygen - oxygen O2 and ozone O3 - are strong oxidizing agents, which manifests itself in reactions with most simple substances and many complex ones. The products of oxidation reactions with oxygen are usually oxides. The oxidizing power of O3 ozone is higher than that of O2 oxygen, which is due to the formation of exclusively active oxygen atoms.

The effect of ozone on human health is controversial. Already for many years goes by a deep study of the effects of ozone, because the concept of ozone is air is not entirely correct. Learn more about it, and then you will say with confidence whether ozone is your friend or not.

Ozone is practically oxygen, it does not even have a separate cell in the periodic table. By chance, the oxygen atoms connected in threes, and not in twos, as usual. At one time, a Dutch physicist, conducting experiments, discovered this discrepancy. In order to understand what is ozone, and what oxygen is, it is worth saying in more detail. Oxygen is the air that we breathe every minute, but ozone is the smell of air after a thunderstorm. The storm acts in this way, by the power of its magnetism, forcing oxygen to combine in three atoms, and as a result, what happens is what happens. Rarely, but still such a connection occurs under the influence of some chemical compounds. And although ozone is considered and is an integral component of the air, the official date of the appearance of ozone is considered to be 1840, which means that ozone is a fairly young component of the air. In translation, ozone means smelling, the fact that it smells is a proven fact, but it’s difficult to talk about everything else, since scientists have not come to a consensus, and unfortunately no one can say what is more harm or benefit in it.

For information, in the United States of America, the ozone therapy method is in high demand, and as statistics show, such treatment copes with a huge number of diseases, at the moment, ozone treatment is also included in Russia. But here infectious disease specialists intervene, they say that a very large number of viruses can enter the human body by this method, which, as a result, can mutate, and this is already serious. But they cannot back up their words with facts. Then it is too early to think and talk about it. Of the treatment with ozone, the following should be noted, the first is the vessels. Blood enriched with ozone improves microcirculation in the capillaries of the skin, thereby removing swelling and inflammation, both external and internal. Ozone also has a divine positive effect on the whole nervous system of a person, it is no coincidence that after a noisy metropolis, getting into the forest, for example, it becomes incredibly good both physically and mentally.

Probably, the time is not far off when scientists will finally tell us whether ozone is useful or harmful, but the first is likely to be proven, since there can be no harm from ozone, in any case, many, many, both scientists and ordinary people, are convinced of this. planets that want to breathe clean and healthy air.