Sodium and its compounds have been known to people since ancient times. Probably the most popular and well-known compound is sodium chloride, better known as table salt. Table salt is an essential component of almost any dish. According to scientists, people began to eat table salt several thousand years ago.
Another popular compound is sodium carbonate. Sodium carbonate is regular soda that is sold in any store. The substance has also been used by people since ancient times as a detergent. Thus, people have been exposed to sodium and its compounds every day for many tens and hundreds of years. Sodium easily reacts with both metallic and non-metallic elements, forming alloys and compounds widely used in industry. Let's take a closer look at the properties and characteristics of this metal.
Characteristics of sodium
Physical properties
Sodium is a soft, ductile metal that can be cut very easily with a knife. It has a silvery-white color and a characteristic metallic sheen. Metal conducts heat and electricity well. Sodium atoms are connected by a metal bond.
Chemical properties
When reacting with other chemical elements, sodium atoms easily give up valence electrons. In this case, sodium atoms transform into ions with a positive charge.
- Sodium oxidizes very quickly in open air. This is why metal is usually stored in kerosene.
- When burned in oxygen, it forms the compound sodium peroxide (Na 2 O 2)
- When heated, Sodium reacts with hydrogen to form a hydride (2NaH)
- Sodium reacts quite easily with non-metals such as sulfur, porcelain and others.
- Sodium is also capable of reacting with metals. This produces various alloys that are widely used in manufacturing and industry.
- Sodium reacts violently with water.
Finding sodium in nature
Sodium is in seventh place on the list of the most abundant elements on Earth. Sodium is also the fifth most common metal. Among the metals, the only metals found more often than sodium are aluminum, iron, calcium and magnesium.
Sodium does not occur in nature in its pure form. The reason for this is the high chemical activity of sodium. The element occurs in nature as chloride, carbonate, nitrate, sulfate and other salts.
Where is sodium found in nature?
Firstly, a fairly high sodium content is recorded in the earth's crust. The proportion of the substance is approximately 2.6%.
Secondly, sodium and its compounds are found in large quantities in places where ancient seas evaporated.
Another place where sodium and its compounds accumulate is ocean waters. Scientists have calculated that all the salt that is in the World Ocean is about 19 million cubic kilometers.
Sodium is also found in small quantities in living things. At the same time, the sodium content in animals is slightly higher than in plants. Sodium ions in living organisms perform a critical function: they facilitate the transmission of nerve impulses.
Application of sodium in industry
Sodium is widely used in many industries: chemical, metallurgical, nuclear, food, light and other industries.
In the chemical industry, sodium is used to produce various detergents and cleaning products, fertilizers and antiseptics.
In metallurgy, sodium is used in the process of producing other substances such as thorium, uranium, titanium, zirconium and other compounds. Sodium acts as a reducing agent in such reactions.
Sodium is also widely used in nuclear energy. Sodium and its alloys are used as a coolant.
In light industry, sodium is widely used for leather processing.
Sodium is an essential element in the food industry. Sodium chloride, better known as table salt, is perhaps the most common food additive, without which any dish cannot be prepared.
-element the main subgroup of the first group, the third period of the periodic system of chemical elements of D.I. Mendeleev, with atomic number 11. Denoted by the symbol Na (lat. Natrium). The simple substance sodium (CAS number: 7440-23-5) is a soft alkali metal of silvery-white color.
In water, sodium behaves almost the same as lithium: the reaction proceeds with the rapid release of hydrogen, and sodium hydroxide is formed in the solution.
History and origin of the name
Sodium atom diagram
Sodium (or rather, its compounds) has been used since ancient times. For example, soda (natron), found naturally in the waters of soda lakes in Egypt. The ancient Egyptians used natural soda for embalming, bleaching canvas, cooking food, and making paints and glazes. Pliny the Elder writes that in the Nile Delta, soda (it contained a sufficient proportion of impurities) was isolated from river water. It went on sale in the form of large pieces, colored gray or even black due to the admixture of coal.
Sodium was first obtained by the English chemist Humphry Davy in 1807 by electrolysis of solid NaOH.
The name "sodium" comes from the Arabic natrun in Greek - nitron and originally it referred to natural soda. The element itself was previously called Sodium.
Receipt
The first way to produce sodium was the reduction reaction sodium carbonate coal when heating a close mixture of these substances in an iron container to 1000°C:
Na 2 CO 3 +2C=2Na+3CO
Then another method of producing sodium appeared - electrolysis of molten sodium hydroxide or sodium chloride.
Physical properties
Metallic sodium stored in kerosene
Qualitative determination of sodium using a flame - bright yellow color of the emission spectrum of the “sodium D-line”, doublet 588.9950 and 589.5924 nm.
Sodium is a silvery-white metal, in thin layers with a purple tint, plastic, even soft (easily cut with a knife), a fresh cut of sodium is shiny. The electrical and thermal conductivity values of sodium are quite high, the density is 0.96842 g/cm³ (at 19.7° C), the melting point is 97.86° C, and the boiling point is 883.15° C.
Chemical properties
An alkali metal that oxidizes easily in air. To protect against atmospheric oxygen, metallic sodium is stored under a layer kerosene. Sodium is less active than lithium, therefore with nitrogen reacts only when heated:
2Na + 3N 2 = 2NaN 3
When there is a large excess of oxygen, sodium peroxide is formed
2Na + O 2 = Na 2 O 2
Application
Sodium metal is widely used in preparative chemistry and industry as a strong reducing agent, including in metallurgy. Sodium is used in the production of highly energy-intensive sodium-sulfur batteries. It is also used in truck exhaust valves as a heat sink. Occasionally, sodium metal is used as a material for electrical wires intended to carry very high currents.
In an alloy with potassium, as well as with rubidium and cesium used as a highly efficient coolant. In particular, the alloy composition is sodium 12%, potassium 47 %, cesium 41% has a record low melting point of −78 °C and has been proposed as a working fluid for ion rocket engines and a coolant for nuclear power plants.
Sodium is also used in high and low pressure discharge lamps (HPLD and LPLD). NLVD lamps of the DNaT (Arc Sodium Tubular) type are very widely used in street lighting. They give off a bright yellow light. The service life of HPS lamps is 12-24 thousand hours. Therefore, gas-discharge lamps of the HPS type are indispensable for urban, architectural and industrial lighting. There are also lamps DNaS, DNaMT (Arc Sodium Matte), DNaZ (Arc Sodium Mirror) and DNaTBR (Arc Sodium Tubular Without Mercury).
Sodium metal is used in the qualitative analysis of organic matter. The alloy of sodium and the test substance is neutralized ethanol, add a few milliliters of distilled water and divide into 3 parts, J. Lassaigne's test (1843), aimed at determining nitrogen, sulfur and halogens (Beilstein test)
Sodium chloride (table salt) is the oldest used flavoring and preservative.
- Sodium azide (Na 3 N) is used as a nitriding agent in metallurgy and in the production of lead azide.
- Sodium cyanide (NaCN) is used in the hydrometallurgical method of leaching gold from rocks, as well as in the nitrocarburization of steel and in electroplating (silvering, gilding).
- Sodium chlorate (NaClO 3) is used to destroy unwanted vegetation on railway tracks.
Biological role
In the body, sodium is found mostly outside the cells (about 15 times more than in the cytoplasm). This difference is maintained by the sodium-potassium pump, which pumps out sodium trapped inside the cell.
Together withpotassiumsodium performs the following functions:
Creating conditions for the occurrence of membrane potential and muscle contractions.
Maintaining blood osmotic concentration.
Maintaining acid-base balance.
Normalization of water balance.
Ensuring membrane transport.
Activation of many enzymes.
Sodium is found in almost all foods, although the body gets most of it from table salt. Absorption mainly occurs in the stomach and small intestine. Vitamin D improves the absorption of sodium, however, excessively salty foods and foods rich in protein interfere with normal absorption. The amount of sodium taken in from food shows the sodium content in the urine. Sodium-rich foods are characterized by accelerated excretion.
Sodium deficiency in the dieter balanced food does not occur in humans, however, some problems can arise with vegetarian diets. Temporary deficiency may be caused by diuretic use, diarrhea, excessive sweating, or excess water intake. Symptoms of sodium deficiency include weight loss, vomiting, gas in the gastrointestinal tract, and impaired absorption amino acids and monosaccharides. Long-term deficiency causes muscle cramps and neuralgia.
Excess sodium causes swelling of the legs and face, as well as increased excretion of potassium in the urine. The maximum amount of salt that can be processed by the kidneys is approximately 20-30 grams; any larger amount is life-threatening.
Sodium in its pure form was obtained in 1807 by Humphry Davy, an English chemist who discovered sodium shortly before. Davy carried out the process of electrolysis of one of the sodium compounds - hydroxide, by melting which he obtained sodium. Humanity has been using sodium compounds since ancient times; soda of natural origin was used back in Ancient Egypt (calorizator). Named the element sodium (sodium) , sometimes this very name can be found even now. The usual name is sodium (from the Latin sodium- soda) was proposed by the Swede Jens Berzelius.
Sodium is an element of group I of III of the third period of the periodic table of chemical elements D.I. Mendeleev, has an atomic number of 11 and an atomic mass of 22.99. The accepted designation is Na(from Latin sodium).
Being in nature
Sodium compounds are found in the earth's crust and sea water as an impurity that tends to color rock salt blue due to the action of radiation.
Sodium is a soft, malleable alkali metal that is silvery-white in color and shiny when cut fresh (it is quite possible to cut sodium with a knife). When pressure is applied, it turns into a transparent red substance; at normal temperatures it crystallizes. When interacting with air, it quickly oxidizes, so sodium must be stored under a layer of kerosene.
Daily sodium requirement
Sodium is an important microelement for the human body; the daily requirement for adults is 550 mg, for children and adolescents - 500-1300 mg. During pregnancy, the sodium norm per day is 500 mg, and in some cases (excessive sweating, dehydration, taking diuretics) should be increased.
Sodium is found in almost all seafood (crayfish, crabs, octopus, squid, mussels, seaweed), fish (anchovies, sardines, flounder, smelt, etc.), chicken eggs, cereals (buckwheat, rice, pearl barley, oatmeal, millet), legumes (peas, beans), vegetables (tomatoes, celery, carrots, cabbage, beets), dairy products and meat by-products.
Beneficial properties of sodium and its effect on the body
The beneficial properties of sodium for the body are:
- Normalization of water-salt metabolism;
- Activation of enzymes of the salivary and pancreas;
- Participation in the production of gastric juice;
- Maintaining normal acid-base balance;
- Generating functions of the nervous and muscular system;
- Vasodilator effect;
- Maintaining blood osmotic concentration.
Sodium digestibility
Sodium is found in almost all foods, although the body receives most of it (about 80%) from. Absorption mainly occurs in the stomach and small intestine. improves the absorption of sodium, however, excessively salty foods and foods rich in proteins interfere with normal absorption.
Interaction with others
The use of sodium metal is in the chemical and metallurgical industries, where it acts as a powerful reducing agent. Sodium chloride (table salt) is used by all inhabitants of our planet without exception; it is the most famous flavoring agent and the oldest preservative.
Signs of sodium deficiency
Sodium deficiency usually occurs due to excessive sweating - in hot climates or during physical activity. A lack of sodium in the body is characterized by memory impairment and loss of appetite, dizziness, fatigue, dehydration, muscle weakness, and sometimes cramps, skin rashes, stomach cramps, nausea, and vomiting.
Signs of excess sodium
An excessive amount of sodium in the body makes itself felt by constant thirst, swelling and allergic reactions.
Sodium
SODIUM-I; m. Chemical element (Na), a soft, silvery-white metal that oxidizes quickly in air.
◁ Sodium, oh, oh. N-th connections. Nth saltpeter.
sodium(lat. Natrium), chemical element of group I of the periodic table; refers to alkali metals. The name (from the Arabic natrun) originally referred to natural soda. Silver-white metal, soft, light (density 0.968 g/cm3), fusible ( t mp 97.86°C). In air it oxidizes quickly. Interaction with water may result in an explosion. It ranks 6th in abundance in the earth's crust (minerals halite, mirabilite, etc.) and 1st among metallic elements in the World Ocean. They are used to produce pure metals (K, Zr, Ta, etc.), as a coolant in nuclear reactors (an alloy with potassium) and as a source of luminescence in sodium lamps. Sodium is involved in the mineral metabolism of all living organisms.
SODIUMSODIUM (Latin Natrium, from Arabic natrun, Greek nitron - natural soda), Na (read “sodium”), a chemical element with atomic number 11, atomic mass 22.98977. One stable isotope, 23 Na, occurs in nature. Belongs to the alkali metals. Located in the third period in group IA in the periodic table of elements. Outer electron layer 3 configuration s 1 . Oxidation state +1 (valence I).
The radius of the atom is 0.192 nm, the radius of the Na + ion is 0.116 nm (coordination number 6). The sequential ionization energies are 5.139 and 47.304 eV. Electronegativity according to Pauling (cm. PAULING Linus) 1,00.
Historical reference
Table salt (sodium chloride NaCl), caustic alkali (sodium hydroxide NaOH) and soda (sodium carbonate Na 2 CO 3) were used in ancient Greece.
Na metal was first obtained in 1807 by G. Davy (cm. DAVY Humphrey) using electrolysis of molten caustic soda.
Being in nature
Content in the earth's crust is 2.64% by weight. Main minerals: halite (cm. HALITE) NaCl, mirabilite (cm. MIRABILIT) Na 2 SO 4 10H 2 O, thenardite (cm. THENARDITIS) Na 2 SO 4, Chilean saltpeter NaNO 3 ,
throne (cm. TRON) NaHCO 3 Na 2 CO 3 2H 2 O, borax (cm. BORA) Na 2 B 4 O 7 10H 2 O and natural silicates, for example, nepheline (cm. NEPHELIN) Na.
The water of the World Ocean contains 1.5 10 16 tons of sodium salts.
Receipt
Na is obtained by electrolysis of molten sodium chloride NaCl, with the addition of NaCl 2, KCl and NaF to reduce the melting point of the electrolyte to 600°C. Anodes are made of graphite, cathodes are made of copper or iron. Electrolysis of the melt is carried out in a steel electrolyzer with a diaphragm. In parallel with Na electrolysis, Cl 2 is obtained:
2NaCl=2Na+Cl2
The resulting Na is purified by vacuum distillation or treatment with titanium or a titanium-zirconium alloy.
Physical and chemical properties
Sodium is a soft, silvery-white metal that quickly tarnishes when exposed to air.
Na is soft, easy to cut with a knife, and can be pressed and rolled. Above -222°C the cubic modification is stable, A= 0.4291 nm. Below is the hexagonal modification. Density 0.96842 kg/dm3. Melting point 97.86°C, boiling point 883.15°C. Sodium vapor consists of Na and Na 2 .
Na is chemically very active. At room temperature it interacts with O 2
air, water vapor and CO 2 with the formation of a loose crust. When Na burns in oxygen, Na 2 O 2 peroxide and Na 2 O oxide are formed:
4Na+O 2 =2Na 2 O and 2Na+O 2 =Na 2 O 2
When heated in air, Na burns with a yellow flame; many sodium salts also turn the flame yellow. Sodium reacts violently with water and dilute acids:
2Na+H 2 O=2NaOH+H 2
When Na and alcohol interact, H2 is released and sodium alkoxide is formed. For example, interacting with ethanol C 2 H 5 OH, Na forms sodium ethanolate C 2 H 5 OHa:
C 2 H 5 OH + 2Na = 2 C 2 H 5 ONa + H 2
Oxygen-containing acids, interacting with Na, are reduced:
2Na+2H 2 SO 4 =SO 2 +Na 2 SO 4 +2H 2 O
When heated to 200°C, Na reacts with H2 to form NaH hydride:
2Na+H 2 =2NaH
Sodium spontaneously ignites in a fluorine atmosphere (cm. FLUORINE) or chlorine (cm. CHLORINE), with iodine (cm. IOD) reacts when heated. When ground in a mortar, Na reacts with S to form sulfides of variable composition. With N 2 the reaction occurs in an electric discharge, sodium nitride Na 3 N or azide NaN 3 are formed. Na reacts with liquid ammonia to form blue solutions, where Na is present as Na+ ions.
Sodium oxide Na 2 O exhibits pronounced basic properties, easily reacts with water to form a strong base - sodium hydroxide NaOH:
Na 2 O+H 2 O=2NaOH
Sodium peroxide Na 2 O 2 reacts with water to release oxygen:
2Na 2 O 2 +2H 2 O=4NaOH+O 2
Sodium hydroxide is a very strong base, an alkali, ( cm. ALKALI) are highly soluble in water (108 g of NaOH dissolves in 100 g of water at 20 °C). NaOH interacts with acidic and amphoteric (cm. AMPHOTERIC) oxides:
CO 2 +2NaOH=Na 2 CO 3 +H 2 O,
Al 2 O 3 +2NaOH+3H 2 O=2Na (in solution),
Al 2 O 3 +2NaOH=2NaAlO 2 +H 2 O (when fused)
In industry, sodium hydroxide NaOH is produced by electrolysis of aqueous solutions of NaCl or Na 2 CO 3 using ion exchange membranes and diaphragms:
2NaCl+2H 2 O=2NaOH+Cl 2 +H 2
Contact of solid NaOH or drops of its solution on the skin causes severe burns. Aqueous solutions of NaOH during storage destroy glass, and melts destroy porcelain.
Sodium carbonate Na 2 CO 3 is obtained by saturating an aqueous solution of NaCl with ammonia and CO 2. The solubility of the resulting sodium bicarbonate NaHCO 3 is less than 10 g in 100 g of water at 20°C, the main part of NaHCO 3 precipitates:
NaCl+NH 3 +CO 2 =NaHCO 3,
which is separated by filtration. When NaHCO 3 is calcined, soda ash is formed:
2NaHCO 3 =Na 2 CO 3 +CO 2 +H 2 O
For most Na salts, the solubility does not increase as much with increasing temperature; for potassium salts (cm. POTASSIUM).
Na is a strong reducing agent:
TiCl 4 +4Na=4NaCl+Ti
Application
Sodium is used as a reducing agent for active metals; its melt mixed with potassium is a coolant in nuclear reactors, since it does not absorb neutrons well. Na vapor is used in incandescent lamps.
NaCl is used in the food industry, sodium hydroxide NaOH - in the production of paper, soap, artificial fibers, and as an electrolyte. Sodium carbonate Na 2 CO 3 and bicarbonate NaHCO 3 - used in the food industry, is a component of fire extinguishing agents, and a medicine. Sodium phosphate Na 3 PO 4 is a component of detergents, used in the production of glass and paints, in the food industry, and in photography. Silicates m Na 2 O n SiO 2 - charge components in glass production, for the production of aluminosilicate catalysts, heat-resistant, acid-resistant concrete.
Physiological role
Sodium ions Na + are necessary for the normal functioning of the body; they are involved in metabolic processes. In human blood plasma the content of Na + ions is 0.32% by weight, in bones - 0.6%, in muscle tissue - 1.5%. To replenish natural loss, a person must consume 4-5 g of Na with food daily.
Features of handling sodium metal
Store sodium in hermetically sealed iron containers under a layer of dehydrated kerosene or mineral oil. The ignited Na is poured with mineral oil or covered with a mixture of talc and NaCl. The resulting Na metal waste is destroyed in containers with ethyl or propyl alcohol.
encyclopedic Dictionary. 2009 .
Synonyms:See what “sodium” is in other dictionaries:
SODIUM- SODIUM. Natrium, chemical element, symbol Na, a silvery-white, shiny, monatomic metal with a waxy density at ordinary temperatures, becoming brittle in the cold and distilling in bright red-hot heat; discovered by De.wi (1807) by electrolysis... ... Great Medical Encyclopedia
- (Greek nitron, Latin natrum). A white metal that is part of table salt, soda, saltpeter, etc. A dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. SODIUM is a white shiny soft metal that quickly oxidizes into... ... Dictionary of foreign words of the Russian language
Sodium breakdown diagram 22 ... Wikipedia
- (Natrium), Na, chemical element of group I of the periodic table, atomic number 11, atomic mass 22.98977; soft alkali metal, melting point 97.86°C. Sodium and its alloys with potassium are coolants in nuclear reactors. Sodium component of alloys for... ... Modern encyclopedia
- (symbol Na), a common silvery-white metallic element, one of the ALKALI METALS, first isolated by Humphry Davy (1807). It is found in salts in seawater and in many minerals. Its main source is CHLORIDE... ... Scientific and technical encyclopedic dictionary
Sodium- (Natrium), Na, chemical element of group I of the periodic table, atomic number 11, atomic mass 22.98977; soft alkali metal, melting point 97.86°C. Sodium and its alloys with potassium are coolants in nuclear reactors. Sodium is a component of alloys for... ... Illustrated Encyclopedic Dictionary
- (lat. Natrium) Na, chemical element of group I of the periodic system of Mendeleev, atomic number 11, atomic mass 22.98977; refers to alkali metals. The name (from Arabic natrun) originally referred to natural soda. Silvery white... ... Big Encyclopedic Dictionary
Na (Latin Natrium, from Arabic natrun, Greek nitron, originally natural soda * a. sodium, natrium; n. Natrium; f. sodium; i. sodio), chemical. element of group I periodic. Mendeleev's system; at.s. 11, at. m. 22.98977; belongs to alkaline... ... Geological encyclopedia
Na is a chemical element of group I of the periodic system, atomic number 11, atomic mass 22.99; alkali metal; Due to its high thermal conductivity and relatively small cross section for capturing slow neutrons, metallic sodium (sometimes alloyed with... ... Nuclear energy terms
SODIUM- chem. element, symbol Na (lat. Natrium), at. n. 11, at. m. 22.98; belongs to alkali metals, silvery-white color, density 968 kg/m3, t = 97.83°C, very soft, has high thermal and electrical conductivity. N. easily interacts with... ... Big Polytechnic Encyclopedia
SODIUM, sodium, pl. no, husband (lat. natrium) (chemical). A soft and white lightweight alkali metal. Table salt is a chemical compound of chlorine and sodium. Ushakov's explanatory dictionary. D.N. Ushakov. 1935 1940 … Ushakov's Explanatory Dictionary
Books
- Thermodynamics and electrochemistry of lithium-chalcogen and sodium-chalcogen systems, Morachevsky Andrey Georgievich, Demidov Alexander Ivanovich. Currently, there is great interest in creating rechargeable chemical power sources (batteries) with high energy performance for vehicles,…
In 1890, an electrolytic method for obtaining element No. 11 was developed. Essentially, this was the transfer to industry of the experience of 80 years ago - Davy's experience. A melt of caustic soda was subjected to electrolysis, only the energy sources were different - more advanced than the voltaic column. 34 years later, the American engineer G. Down fundamentally changed the process of electrolytic production of sodium, replacing alkali with much cheaper table salt. Today, global sodium production is measured in hundreds of thousands of tons. What is it spent on?
First of all, for the production of some compounds of element No. 11 - after all, not all of them exist in nature. Rock salt (or) NaCI, Chilean saltpeter NaN03, Na3AlF6, Glauber's salt Na2SO4 10NaO, Ma2B407 10H2O and some are the main natural ones. And important sodium salts, such as soda or hyposulfite, have to be obtained artificially. Fortunately, the production of these substances does not require sodium metal. But sodium cyanide, used in electrochemistry and in the extraction of non-ferrous metals, is most advantageously obtained using element No. 11 itself as a raw material.
Or another example. An ammonia derivative, sodium amide NaNH2, is obtained by reacting liquid NH3 with sodium metal. This substance is unstable, it reacts violently with water, and in general, when working with it, you need to be no less careful than when working with sodium metal. Sodium amide is needed to obtain two very important substances for us - synthetic indigo and vitamin A. Therefore, to obtain both the dye and the vitamin, it is needed. It is also needed for the production of another important organic product, which does not contain sodium. An intermetallic compound of sodium with lead (10% sodium by weight) is used in the production of the well-known anti-knock agent - tetraethyl lead. Obviously, sodium here is assigned the role of initiator of the reaction, as in the well-known experiments of S.V. Lebedev and his colleagues.
In 1928, a group of Leningrad chemists led by Professor S.V. Lebedev synthesized the world's first synthetic rubber, which was called sodium butadiene rubber. “Butadiene” - because this SA is a product of the polymerization of butadiene-1,3, and “sodium-” - because it was the elemental one that served as a catalyst for the polymerization process.
The starting materials in the production of synthetic detergents are most often higher alcohols (i.e., alcohols whose molecules contain long chains of carbon atoms). These alcohols are obtained by reducing the corresponding acids, and the best reducing agent in these reactions is the same...
Many will probably find it strange to say that element No. 11 is needed for transport. Nevertheless, this is true. In the production of tetraethyl lead - still the most common anti-knock agent in motor fuels - an alloy of lead and sodium is used as a raw material (in a ratio of 9: 1). Another lead-based alloy, containing 0.58% sodium, is needed for railway transport. This alloy is used to make axle bearings for railway cars.
Sodium metal - both solid and liquid - conducts and transfers heat very well. This is the basis for its use as a coolant. Sodium plays this role in quite a few chemical industries (when uniform heating with a temperature of 450-650°C is needed), in injection molding machines, in aircraft engine valves, and in nuclear reactors. It is also important for nuclear technology that sodium almost does not capture thermal neutrons and does not affect the course of the nuclear chain reaction.
We must not forget about another important use of sodium. As one of the most active reducing agents, element No. 11 is used to obtain some rare metals, such as zirconium.
After all this, is it any wonder that sodium production continues to increase?
We end our story about element No. 11 with the words of Dmitry Ivanovich Mendeleev, written many years ago, but doubly true for our days: “The production of metallic sodium is one of the most important discoveries in chemistry, not only because the concept of simple bodies has expanded and become more correct, but especially because sodium exhibits chemical properties that are only weakly expressed in other well-known metals.”
A detailed account of the chemical properties of sodium is omitted for the reason that this is one of the few sections of chemistry that are presented quite fully in school textbooks.
SODIUM IN SUBMARINES
Sodium melts at 98, and boils only at 883 ° C. Consequently, the temperature range of the liquid state of this element is quite large. That is why (and also due to the small neutron capture cross section) sodium began to be used in nuclear energy as a coolant. In particular, American nuclear submarines are equipped with power plants with sodium circuits. The heat generated in the reactor heats the liquid sodium, which circulates between the reactor and the steam generator. In the steam generator, the patium, when cooled, evaporates water, and the resulting high-pressure steam rotates the steam turbine. For the same purposes, an alloy of sodium and potassium is used.
INORGANIC PHOTOSYNTHESIS. Typically, the oxidation of sodium produces an oxide with the composition Na20. However, if sodium is burned in dry air at elevated temperatures, Na-202 peroxide is formed instead of oxide. This substance easily gives up its “sticky” oxygen atom and therefore has strong oxidizing properties. At one time, sodium peroxide was widely used to bleach straw hats. Now the proportion of straw hats in the use of sodium peroxide is negligible; its main quantities are used for bleaching paper and for air regeneration in submarines. When sodium peroxide reacts with carbon dioxide, a process occurs that is the opposite of respiration; 2Na2O2+2C02-2Na2C03+02, i.e. carbon dioxide is bound and released. Just like a green leaf!
SODIUM AND . By the time sodium was discovered, alchemy was no longer in favor, and the idea of transforming sodium into did not excite the minds of natural scientists. However, now a lot of sodium is consumed to obtain gold. “Gold ore” is treated with a solution of sodium cyanide (and it is obtained from elemental sodium). At the same time, it turns into a soluble complex compound, from which it is isolated with the help of zinc. Gold miners are among the main consumers of element No. 11. On an industrial scale, sodium cyanide is produced by the interaction of sodium, ammonia and coke at a temperature of about 800 ° C.
SODIUM WIRE. The electrical conductivity of sodium is three times lower than the electrical conductivity of copper. But sodium is 9 times lighter! It turns out that sodium wires are more profitable than copper wires. Of course, thin wires are not made from sodium, but it is advisable to make busbars for high currents from sodium. These tires are steel pipes welded into the ends and filled with sodium inside. Such tires are cheaper than copper ones.
SODIUM IN WATER
Every schoolchild knows what happens if you throw a piece of sodium into water. More precisely, not into water, but onto water, because sodium is lighter than water. The heat that is released when sodium reacts with water is enough to melt the sodium. And now a sodium ball runs through the water, driven by the released hydrogen. However, the reaction of sodium with water is not only dangerous fun; on the contrary, it is often useful. Sodium is used to reliably remove traces of water from transformer oils, alcohols, ethers and other organic compounds, and with the help of sodium amalgam (i.e., an alloy of sodium with mercury), the moisture content in many compounds can be quickly determined. reacts with water much more calmly than sodium itself. To determine moisture content, a certain amount of sodium amalgam is added to an organic sample and the moisture content is determined by the volume of hydrogen released.
SODIUM BELT OF THE EARTH. It is quite natural that sodium is never found in a free state on Earth - this metal is too active. But in the upper layers of the atmosphere - at an altitude of about 80 km - a layer of atomic sodium was discovered. At this altitude there is virtually no oxygen, water vapor, or anything at all for sodium to react with. Sodium was also discovered in interstellar space using spectral methods.
ISOTOPES OF SODIUM
Natural sodium consists of only one isotope with a mass number of 23. There are 13 known radioactive isotopes of this element, two of which are of significant scientific interest. Sodium-22, when decaying, emits positrons - positively charged particles whose mass is equal to the mass of electrons. This isotope with a half-life of 2.58 years is used as a positron source. And the isotope sodium-24 (its half-life is about 15 hours) is used in medicine for the diagnosis and treatment of some forms of leukemia - a serious blood disease.
HOW DO YOU OBTAIN SODIUM? A modern electrolyzer for producing sodium is a rather impressive structure that looks like a furnace. This “stove” is made of refractory brick and is surrounded on the outside by a steel casing. A graphite anode is inserted from below through the bottom of the electrolyzer, surrounded by a ring-shaped mesh - a diaphragm. This mesh does not allow sodium to penetrate into the anode space, where it is released.
Otherwise, the sodium would burn in the chlorine. The anode, by the way, is also ring-shaped. It is made of steel. A mandatory accessory for the electrolyzer is two caps. One is installed above the anode to collect chlorine, the other above the cathode to remove sodium.
A mixture of thoroughly dried sodium chloride and calcium chloride is loaded into the electrolyzer. This mixture melts at a lower temperature than pure sodium chloride. Usually carried out at a temperature of about 600° C.
The electrodes are supplied with a direct current of about 6 V; At the cathode, Na+ ions are discharged and sodium metal is released. The sodium floats up and is taken into a special collection (of course, without air access). Chlorine ions Cl- are discharged at the anode and gaseous
