Ozone is a molecule made up of 3 oxygen atoms and is in the gaseous state.
In high concentrations this gas has a bluish color and is toxic.
Ozone and the periodic table
If you are looking for ozone as an element of the Periodic table you will not find it, since it only contains the elements made up of a single atom, ordered within it based on their characteristics, giving it the atomic number.
Ozone is the union of 3 oxygen atoms which if you find in this table with the atomic number 8.
Where is it located?
This type of molecule can be found naturally in the earth at the level of the stratosphere in a layer also known as the ozonosphere because it contains the highest density of ozone and ranges from 15km to 50km.
90% of all the ozone on earth is found between 15km and 40km, with a density of 2 to 8 molecules per million.
In fact, if we subjected that amount of ozone to the pressure of 1 atmosphere, that is, at sea level, its thickness would only be 3 millimeters.
The remaining 10% is found in the troposphere, the lowest layer of the atmosphere, being a threat to life because it is a highly oxidizing gas.
Ozone reaches the troposphere either dragged from the stratosphere or is formed in storms through ionization of the air, creating the conditions for the reactions that generate O3 to occur.
Ozone is known to be a good conductive gas since you can often see several consecutive lightning strikes making the same path.
What function does it have in the atmosphere?
This layer protects us from radiation that comes from the sun, such as short-wave ultraviolet rays between 150 and 300 nanometers.
Ozone absorbs between 97% and 99% of ultraviolet rays that are harmful and only lets through a part of these long-wave, greater than 300 nanometers.
These ultraviolet rays are necessary for life processes such as photosynthesis, producing the release of oxygen from water molecules.
It is believed that 70% of all the oxygen on earth has been generated and continues to be generated thanks to the biochemical processes of bacteria and algae found in the oceans, while the remaining 30% is generated in terrestrial vegetation.
The hole in the ozone layer
Ozone is a gas that would have been overlooked by all of us had it not been for so much talk about the hole in the ozone layer and how important it was to reduce it.
The ozone layer is the best shield we have as it protects us from most of the sun’s rays, especially ultraviolet rays, which are harmful and incompatible with life as we know it.
The decrease in the thickness of this layer and the increase of the hole over the Arctic has caused an increase in skin cancer. cataracts and other conditions.
It is believed that this hole was generated due to the chlorofluorocarbon gases CFCs that contain many of the aerosols, refrigeration circuits of refrigerators and freezers and other types of gases expelled into the atmosphere for years and that were banned from 1996 .
At its worst, the ozone hole had an area of about 29,000,000 km2, over the Arctic, equivalent to twice the surface of Australia.
Since 2000, a progressive decrease of 1% to 3% per decade has been detected, calculating that it may close completely, if it continues in the same progression, around 2075.
There is also harmful ozone
We have already seen that there is part of the ozone in the stratosphere that is carried to lower layers and can reach the troposphere where it is harmful in high concentrations.
Ozone is also formed in lower layers due to smog produced by vehicle exhausts.
This accumulation of nitrogen oxides together with volatile organic compounds reacts with the sun’s rays giving rise to the generation of ozone.
In fact, it is produced by a process similar to that which occurs at higher altitudes, but at ground level ozone is harmful to life.
Oxygen, the origin of ozone
Oxygen is the 3rd most abundant element in the universe, only behind hydrogen (H) and helium (He).
Oxygen atoms are element number 8 in the periodic table as they have 8 protons and 8 electrons.
There are 3 different isotypes (configurations) of oxygen existing with 8, 9 and 10 neutrons in its nucleus.
As we know, electrons are distributed in orbits that are at different distances from the nucleus.
In the one closest to this, 2 electrons orbit while 6 in the second one, which is the outer one.
Every atom needs to have 8 electrons in the outermost shell to be stable.
A lack or excess of electrons to reach 8 is known as valence and in the case of oxygen, its valence is -2 two as it lacks 2 electrons to reach 8 in its outer orbit.
Oxygen is also known for being one of the most electro-reactive elements of the periodic table.
This means that it can trap electrons from almost any other chemical element, forming different molecules, which is why it is found in all acids that add oxygen to their molecules.
Thus, oxygen with valence -2 is a highly electro-reactive element that needs to bond with another oxygen atom through a double or covalent bond.
Double bonds are strong bonds and therefore stable, that is why oxygen is found in nature as molecules with two O2 atoms and not as O.
As we said, ozone is a molecule with 3 oxygen atoms, but this type of molecule is only stable at a certain pressure and temperature, such as the conditions of the stratosphere.
How is ozone formed?
This ozone layer is formed by striking photons in the form of ultraviolet rays on the O2 molecules and breaking the bond, releasing oxygen atoms.
These oxygen atoms, being highly electro-reactive, seek to share electrons, joining with molecules of O2 not yet broken, forming ozone O3.
As we have commented, ozone molecules only remain in equilibrium under certain conditions of temperature and pressure, their existence or formation in lower layers of the atmosphere being difficult.
Generating ozone artificially
To obtain ozone, generators are used that, by means of a great difference in power between two electrodes with a dielectric between them, cause the O2 molecules to break down so that the released oxygen atoms end up joining with other O2 molecules that did not break their bond, forming ozone O3.
This gas at pressures and temperatures at sea level is not in stable conditions, so its duration is short and therefore it must be generated when it wants to be applied in the same place as it is not suitable for storage or transport.
Uses of ozone
As it is a very unstable and very reactive gas, it ends up releasing the excess oxygen atom to immediately combine with other surrounding molecules, hence its high oxidative level, ending with all kinds of bacteria, viruses and fungi. < / p>
For this reason, it is used for intensive disinfection in the food industry either in ozonized chambers for the destruction of viruses and bacteria in meat, dairy, fruit and vegetables.
Ozone is also capable of neutralizing Ethylene, used for force the fruit to ripen, stopping said ripening once the optimum level of ripening has been obtained to go on to preserve said fruit in chambers.
It is also used in agriculture to eliminate bacteria underground by not leaving chemical residues when it is decomposed into oxygenate once its function has been performed.
Lately it has also been shown to be effective in disinfecting surfaces in the fight against COVID-19 either with ozone-treated water or directly as a gas.
Different devices have been designed for its use, whether for domestic use as well as for professional or industrial use.
If you are interested in purchasing any of these devices, you can visit the following sections:
Home and professional ozone generators to keep your spaces free of pathogens.
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