The phrase "ozone layer", which became famous in the 70s. the last century, has long been set on edge. At the same time, few people really understand what this concept means and why the destruction of the ozone layer is dangerous. An even bigger mystery for many is the structure of the ozone molecule, and yet it is directly related to the problems of the ozone layer. Let's learn more about ozone, its structure and industrial applications.
What is ozone
Ozone, or, as it is also called, active oxygen, is an azure gas with a pungent metallic odor.
This substance can exist in all three states of aggregation: gaseous, solid and liquid.
At the same time, in nature, ozone occurs only in the form of a gas, forming the so-called ozone layer. It is because of its azure color that the sky appears blue.
What does an ozone molecule look like
Your nickname is activeoxygen” ozone received because of its resemblance to oxygen. So the main active chemical element in these substances is oxygen (O). However, if an oxygen molecule contains 2 of its atoms, then the ozone molecule (formula - O3) consists of 3 atoms of this element.
Due to this structure, the properties of ozone are similar to those of oxygen, but more pronounced. In particular, like O2, O3is the strongest oxidizer.
The most important difference between these "related" substances, which is vital for everyone to remember, is the following: ozone cannot be breathed, it is toxic and, if inhaled, can damage the lungs or even kill a person. At the same time, O3 is perfect for cleaning the air from toxic impurities. By the way, it is because of this that it is so easy to breathe after rain: ozone oxidizes harmful substances contained in the air, and it is purified.
The model of the ozone molecule (consisting of 3 oxygen atoms) looks a bit like an image of an angle, and its size is 117°. This molecule has no unpaired electrons and is therefore diamagnetic. In addition, it has polarity, although it consists of atoms of the same element.
Two atoms of this molecule are firmly bonded to each other. But the connection with the third is less reliable. For this reason, the ozone molecule (photo of the model can be seen below) is very fragile and soon after the formation it breaks down. As a rule, in any decomposition reaction O3 oxygen is released.
Due to the instability of ozone, it cannot be producedharvest and store, as well as transport, like other substances. For this reason, its production is more expensive than other substances.
At the same time, the high activity of molecules O3allows this substance to be the strongest oxidizing agent, more powerful than oxygen, and safer than chlorine.
If an ozone molecule breaks down and releases O2, this reaction is always accompanied by the release of energy. At the same time, in order for the reverse process to take place (the formation of O3 from O2), it is necessary to spend it no less.
In the gaseous state, the ozone molecule decomposes at a temperature of 70°C. If it is increased to 100 degrees or more, the reaction will accelerate significantly. The presence of impurities also accelerates the decay period of ozone molecules.
O3 properties
No matter which of the three states ozone is in, it retains its blue color. The harder the substance, the richer and darker this shade.
Each ozone molecule weighs 48 g/mol. It is heavier than air, which helps separate these substances.
O3 capable of oxidizing almost all metals and non-metals (except gold, iridium and platinum).
Also, this substance can participate in the combustion reaction, but this requires a higher temperature than for O2.
Ozone is able to dissolve in H2O and freons. In liquid state, it can mix with liquid oxygen, nitrogen, methane, argon,carbon tetrachloride and carbon dioxide.
How the ozone molecule is formed
O3 molecules are formed by attaching free oxygen atoms to oxygen molecules. They, in turn, appear due to the splitting of other molecules O2 due to the impact on them of electrical discharges, ultraviolet rays, fast electrons and other high-energy particles. For this reason, the specific smell of ozone can be felt near sparking electrical appliances or lamps that emit ultraviolet light.
On an industrial scale, O3 is isolated using electrical ozone generators or ozonizers. In these devices, a high-voltage electric current is passed through a gas stream containing O2, whose atoms serve as the “building material” for ozone.
Sometimes pure oxygen or ordinary air is injected into these machines. The quality of the resulting ozone depends on the purity of the initial product. So, medical O3, intended for treating wounds, is extracted only from chemically pure O2.
History of the discovery of ozone
Having figured out what the ozone molecule looks like and how it is formed, it is worth getting acquainted with the history of this substance.
It was first synthesized by the Dutch researcher Martin Van Marum in the second half of the 18th century. The scientist noticed that after passing electric sparks through a container with air, the gas in it changed its properties. At the same time, Van Marum did not understand that he had isolated the molecules of a newsubstances.
But his German colleague named Sheinbein, trying to decompose H2O into H and O2 with the help of electricity, noticed to the release of new gas with a pungent odor. After a lot of research, the scientist described the substance he discovered and gave it the name "ozone" in honor of the Greek word for "smell".
The ability to kill fungi and bacteria, as well as reduce the toxicity of harmful compounds, which the open substance possessed, interested many scientists. 17 years after the official discovery of O3, Werner von Siemens designed the first apparatus to synthesize ozone in any quantity. And 39 years later, the brilliant Nikola Tesla invented and patented the world's first ozone generator.
It was this device that was first used in France in drinking water treatment plants after 2 years. Since the beginning of the XX century. Europe is starting to switch to ozonation of drinking water to purify it.
The Russian Empire first used this technique in 1911, and after 5 years, almost 4 dozen installations for drinking water purification using ozone were equipped in the country.
Today, ozonation of water is gradually replacing chlorination. Thus, 95% of all drinking water in Europe is purified using O3. This technique is also very popular in the USA. In the CIS, it is still under study because, although this procedure is safer and more convenient, it is more expensive than chlorination.
Ozone applications
Besides water purification, O3 has a number of other uses.
- Ozone is used as a bleach in the manufacture of paper and textiles.
- Active oxygen is used to disinfect wines, as well as to accelerate the aging process of cognacs.
- Various vegetable oils are refined using O3.
- Very often this substance is used to process perishable products such as meat, eggs, fruits and vegetables. This procedure does not leave chemical traces, as with chlorine or formaldehyde, and products can be stored much longer.
- Ozone sterilizes medical equipment and clothes.
- Also purified O3 is used for various medical and cosmetic procedures. In particular, with its help in dentistry, they disinfect the oral cavity and gums, and also treat various diseases (stomatitis, herpes, oral candidiasis). In European countries O3 is very popular for wound disinfection.
- In recent years, portable home appliances for filtering air and water using ozone have become very popular.
Ozone layer - what is it?
At a distance of 15-35 km above the Earth's surface is the ozone layer, or, as it is also called, the ozonosphere. In this place, concentrated O3 serves as a kind of filter for harmful solar radiation.
Where does such a quantity of a substance come from if its molecules are unstable? It is not difficult to answer this question if we recall the model of the ozone molecule and the method of its formation. So, oxygen, consisting of 2oxygen molecules, getting into the stratosphere, is heated there by the sun's rays. This energy is enough to split O2 into atoms, from which O3 is formed. At the same time, the ozone layer not only uses part of the solar energy, but also filters it, absorbs dangerous ultraviolet radiation.
It was said above that ozone is dissolved by freons. These gaseous substances (used in the manufacture of deodorants, fire extinguishers and refrigerators), once released into the atmosphere, affect ozone and contribute to its decomposition. As a result, holes appear in the ozonosphere through which unfiltered solar rays enter the planet, which have a destructive effect on living organisms.
After considering the features and structure of ozone molecules, we can conclude that this substance, although dangerous, is very useful for humanity if used correctly.
