What is oxygen?
Oxygen is an element that is in the 16th group of the second period of the periodic table. It has atomic number 8. Few matter is just as important as oxygen. Oxygen is the basis of life on Earth, without it the breathing of most living organisms is impossible.
Discovery and origin of the name
The word "oxygen", which is a copy of the term "oxygen", coined by M.V. Lomonosov. In translation, both “oxygen” and “oxygen” mean “generating acid”.
The laurels of the discoverer of this substance are divided among themselves by 3 chemists. The English chemist Joseph Priestley received oxygen on August 1, 1774 in a decomposition reaction of mercury oxide. The Frenchman Antoine Lavoisier established in 1775 that oxygen is part of the air. A Swedish chemist Karl Scheele, who was considered the pioneer of oxygen, synthesized it in 1771 from nitric oxide, obtained by calcining nitrate with sulfuric acid.
The role of oxygen
Oxygen - a substance that is part of the crust, water and air. 47.4% of the mass of the earth's crust, 88.8% of water and 23.12% of air are the share of oxygen. It is also contained in all living cells.Living organisms, called aerobes, breathe oxygen. These include all plants, most animals and many microorganisms. Proteins, carbohydrates, lipids and nucleic acids belonging to the class of organic substances contain oxygen. Organic matter, as is known, is the basis of all life on Earth.
In modern industry, oxygen is mainly obtained from the air by its cryogenic rectification. Also for the synthesis of this substance is used oxygen plants operating through membrane technology.
In the laboratory, oxygen is produced by:
- heating potassium permanganate,
- decomposition of hydrogen peroxide using manganese (IV) oxide as a catalyst,
- catalytic decomposition of potassium salt
- electrolysis of aqueous solutions of various alkalis
- decomposition of mercury oxide
Another method of obtaining oxygen is the reaction of sodium peroxide with carbon dioxide. This method is used in submarines.
Oxygen in chemistry
Consider the chemical properties of oxygen. This substance is a strong oxidizing agent, in the interaction with other elements forms oxides.Oxygen has an oxidation state of - 2. An oxidation reaction is usually accompanied by heat and goes faster with increasing temperature.
Oxygen oxidizes most organic and inorganic compounds. It reacts under normal conditions, heating and in the presence of catalysts with almost all simple substances, excluding gold and inert gases. In two-element compounds, excluding fluorides, oxygen is an oxidizing agent. In the free form, this element exists in two versions: oxygen and ozone. The formula for the substance of oxygen is O2.
Oxygen has reactive forms, for example, hydrogen peroxide, singlet oxygen, superoxide, hydroxyl radical and ozone, which are products with a high degree of toxicity. They are obtained in the process of partial reduction or activation of oxygen. Some of them, for example, superoxide and hydroxyl radicals, as well as hydrogen peroxide, are formed in the tissues of living organisms, causing oxidative stress.
Consider the basic physical properties of oxygen. Under normal conditions, oxygen is a gas without taste, color, and odor, slightly heavier than air. 1 liter of oxygen has a mass of 1,429 gThis gas is poorly soluble in water and alcohol, but well - in the melt of silver. Oxygen is a paramagnet. When heated, the substance is reversibly dissociated into atoms. Oxygen in the liquid state of aggregation is a pale blue liquid, and in the solid state - blue crystals. There are 6 crystalline phases of oxygen that form at different pressures.
Oxygen has been widely used in industry since the mid-20th century, when a turbo-expander was invented, intended to liquefy air and its subsequent separation.
- In metallurgy, the chemical oxygen is used in the converter method of steel production and processing of mattes. Oxygen is also included in the mixture introduced into the burners, in order to organize more efficient fuel combustion.
- Oxygen in cylinders is used for gas-flame welding and cutting of metals.
- Liquid oxygen is used in rocket fuel as an oxidizing agent.
- In medicine, oxygen is used as an integral part of mixtures for anesthesia for the treatment of bronchial asthma and gastrointestinal diseases, elimination of hypoxia and respiratory disorders.
- Oxygen is the food additive E948 used in the food industry, as packaging gas and propellant.
- Oxygen is used in the chemical industry as a reagent-oxidizing agent for the synthesis of alcohols, acids, aldehydes, and also nitric acid.
- Oxygen cocktails are used in agriculture for weight gain in animals.