WHAT IS ALUMINUM

Lightweight, durable, corrosion-resistant and functional - it is this combination of qualities that has made aluminum the main structural material of our time. Aluminum is in the houses we live in, the cars, trains and planes we travel on, in mobile phones and computers, on refrigerator shelves and in modern interiors. But 200 years ago little was known about this metal.

“What seemed impossible for centuries, what yesterday was just a daring dream, today becomes a real task, and tomorrow - an accomplishment.”

Sergei Pavlovich Korolev
scientist, designer, founder of practical astronautics

Aluminum – silvery-white metal, the 13th element of the periodic table. Incredible but true: aluminum is the most abundant metal on Earth, accounting for more than 8% of the total mass of the earth's crust, and it is the third most abundant chemical element on our planet after oxygen and silicon.

However, aluminum is not found in nature in its pure form due to its high chemical reactivity. That's why we learned about it relatively recently. Aluminum was formally produced only in 1824, and another half a century passed before its industrial production began.

Most often in nature, aluminum is found in the composition alum. These are minerals that combine two salts of sulfuric acid: one based on an alkali metal (lithium, sodium, potassium, rubidium or cesium), and the other based on a metal of the third group of the periodic table, mainly aluminum.

Alum is still used today in water purification, cooking, medicine, cosmetology, chemical and other industries. By the way, aluminum got its name thanks to alum, which in Latin was called alumen.

Corundum

Rubies, sapphires, emeralds and aquamarine are aluminum minerals.
The first two belong to corundum - this is aluminum oxide (Al 2 O 3) in crystalline form. It has natural transparency and is second only to diamonds in strength. Bulletproof glass, airplane windows, and smartphone screens are made using sapphire.
And one of the less valuable corundum minerals, emery, is used as an abrasive material, including to create sandpaper.

Today, almost 300 different aluminum compounds and minerals are known - from feldspar, which is the main rock-forming mineral on Earth, to ruby, sapphire or emerald, which are no longer so common.

Hans Christian Oersted(1777–1851) – Danish physicist, honorary member of the St. Petersburg Academy of Sciences (1830). Born in the city of Rudkörbing in the family of a pharmacist. In 1797 he graduated from the University of Copenhagen, in 1806 he became a professor.

But no matter how common aluminum was, its discovery became possible only when scientists had a new tool at their disposal that made it possible to break down complex substances into simpler ones - electricity.

And in 1824, using the process of electrolysis, the Danish physicist Hans Christian Oersted obtained aluminum. It was contaminated with impurities of potassium and mercury involved in chemical reactions, but this was the first time aluminum was produced.

Using electrolysis, aluminum is still produced today.

The raw material for aluminum production today is another aluminum ore common in nature - bauxite. This is a clayey rock consisting of various modifications of aluminum hydroxide with an admixture of oxides of iron, silicon, titanium, sulfur, gallium, chromium, vanadium, carbonate salts of calcium, iron and magnesium - almost half of the periodic table. On average, 1 ton of aluminum is produced from 4-5 tons of bauxite.

Bauxite

Bauxite was discovered by geologist Pierre Berthier in the south of France in 1821. The breed got its name after the area of ​​Les Baux where it was found. About 90% of the world's bauxite reserves are concentrated in countries of the tropical and subtropical zones - Guinea, Australia, Vietnam, Brazil, India and Jamaica.

It is obtained from bauxite alumina. This is aluminum oxide Al 2 O 3, which has the form of a white powder and from which metal is produced by electrolysis in aluminum smelters.

Aluminum production requires huge amounts of electricity. To produce one ton of metal, about 15 MWh of energy is required - this is how much a 100-apartment building consumes for a whole month. Therefore, it makes the most sense to build aluminum smelters close to powerful and renewable energy sources. The most optimal solution is hydroelectric power stations, representing the most powerful of all types of “green energy”.

Properties of aluminum

Aluminum has a rare combination of valuable properties. This is one of the lightest metals in nature: it is almost three times lighter than iron, but at the same time it is strong, extremely ductile and not subject to corrosion, since its surface is always covered with a thin, but very durable oxide film. It is not magnetic, conducts electricity well, and forms alloys with almost all metals.

Easy

Three times lighter than iron

Lasting

Comparable in strength to steel

Plastic

Suitable for all types of mechanical processing

No corrosion

Thin oxide film protects against corrosion

Aluminum is easily processed by pressure, both hot and cold. It can be rolled, drawn, stamped. Aluminum does not burn, does not require special painting and is non-toxic, unlike plastic.

The malleability of aluminum is very high: sheets with a thickness of only 4 microns and the thinnest wire can be made from it. And ultra-thin aluminum foil is three times thinner than a human hair. In addition, compared to other metals and materials, it is more economical.

The high ability to form compounds with various chemical elements has given rise to many aluminum alloys. Even a small proportion of impurities significantly changes the characteristics of the metal and opens up new areas for its application. For example, the combination of aluminum with silicon and magnesium can be found literally on the road in everyday life - in the form of alloy wheels, engines, chassis elements and other parts of a modern car. And if you add zinc to the aluminum alloy, then perhaps you are holding it in your hands now, because this alloy is used in the production of cases for mobile phones and tablets. Meanwhile, scientists continue to invent new aluminum alloys.
Aluminum reserves
About 75% of the aluminum produced throughout the industry's existence is still in use today.

Photo materials used in this article are © Shutterstock and © Rusal.

Metals are one of the most convenient materials to process. They also have their own leaders. For example, the basic properties of aluminum have been known to people for a long time. They are so suitable for everyday use that this metal has become very popular. What are both a simple substance and an atom, we will consider in this article.

History of the discovery of aluminum

For a long time, man has known the compound of the metal in question - it was used as a means that could swell and bind together the components of the mixture; this was also necessary in the manufacture of leather products. The existence of aluminum oxide in its pure form became known in the 18th century, in its second half. However, it was not received.

The scientist H. K. Ørsted was the first to isolate the metal from its chloride. It was he who treated the salt with potassium amalgam and isolated gray powder from the mixture, which was aluminum in its pure form.

Then it became clear that the chemical properties of aluminum are manifested in its high activity and strong reducing ability. Therefore, no one else worked with him for a long time.

However, in 1854, the Frenchman Deville was able to obtain metal ingots by electrolysis of the melt. This method is still relevant today. Especially mass production of valuable material began in the 20th century, when the problems of generating large amounts of electricity in enterprises were solved.

Today, this metal is one of the most popular and used in construction and the household industry.

General characteristics of the aluminum atom

If we characterize the element in question by its position in the periodic table, then several points can be distinguished.

1. Serial number - 13.
2. Located in the third small period, third group, main subgroup.
3. Atomic mass - 26.98.
4. The number of valence electrons is 3.
5. The configuration of the outer layer is expressed by the formula 3s 2 3p 1.
6. The element name is aluminum.
7. strongly expressed.
8. It has no isotopes in nature; it exists only in one form, with a mass number of 27.
9. The chemical symbol is AL, read as “aluminum” in formulas.
10. The oxidation state is one, equal to +3.

The chemical properties of aluminum are fully confirmed by the electronic structure of its atom, because having a large atomic radius and low electron affinity, it is capable of acting as a strong reducing agent, like all active metals.

Aluminum as a simple substance: physical properties

If we talk about aluminum as a simple substance, then it is a silvery-white shiny metal. In air it quickly oxidizes and becomes covered with a dense oxide film. The same thing happens when exposed to concentrated acids.

The presence of such a feature makes products made of this metal resistant to corrosion, which, naturally, is very convenient for people. That is why aluminum is so widely used in construction. They are also interesting because this metal is very light, yet durable and soft. The combination of such characteristics is not available to every substance.

There are several basic physical properties that are characteristic of aluminum.

1. High degree of malleability and ductility. Light, strong and very thin foil is made from this metal, and it is also rolled into wire.
2. Melting point - 660 0 C.
3. Boiling point - 2450 0 C.
4. Density - 2.7 g/cm3.
5. The crystal lattice is volumetric face-centered, metal.
6. Type of connection - metal.

The physical and chemical properties of aluminum determine the areas of its application and use. If we talk about everyday aspects, then the characteristics we have already discussed above play a big role. As a lightweight, durable and anti-corrosion metal, aluminum is used in aircraft and shipbuilding. Therefore, these properties are very important to know.

Chemical properties of aluminum

From a chemical point of view, the metal in question is a strong reducing agent that is capable of exhibiting high chemical activity while being a pure substance. The main thing is to remove the oxide film. In this case, activity increases sharply.

The chemical properties of aluminum as a simple substance are determined by its ability to react with:

• acids;
• alkalis;
• halogens;
• sulfur.

It does not interact with water under normal conditions. In this case, of the halogens, without heating, it reacts only with iodine. Other reactions require temperature.

Examples can be given to illustrate the chemical properties of aluminum. Equations of reactions of interaction with:

• acids- AL + HCL = AlCL 3 + H 2;
• alkalis- 2Al + 6H 2 O + 2NaOH = Na + 3H 2;
• halogens- AL + Hal = ALHal 3 ;
• gray- 2AL + 3S = AL 2 S 3.

In general, the most important property of the substance in question is its high ability to restore other elements from their compounds.

Regenerative capacity

The reducing properties of aluminum are clearly visible in the reactions of interaction with oxides of other metals. It easily extracts them from the composition of the substance and allows them to exist in a simple form. For example: Cr 2 O 3 + AL = AL 2 O 3 + Cr.

In metallurgy, there is a whole method for producing substances based on similar reactions. It is called aluminothermy. Therefore, in the chemical industry this element is used specifically for the production of other metals.

Distribution in nature

In terms of prevalence among other metal elements, aluminum ranks first. It is contained in the earth's crust 8.8%. If we compare it with non-metals, then its place will be third, after oxygen and silicon.

Due to its high chemical activity, it is not found in pure form, but only as part of various compounds. For example, there are many known ores, minerals, and rocks that contain aluminum. However, it is extracted only from bauxite, the content of which in nature is not very high.

The most common substances containing the metal in question:

• feldspars;
• bauxite;
• granites;
• silica;
• aluminosilicates;
• basalts and others.

In small quantities, aluminum is necessarily found in the cells of living organisms. Some species of club mosses and marine inhabitants are capable of accumulating this element inside their bodies throughout their lives.

Receipt

The physical and chemical properties of aluminum make it possible to obtain it only in one way: by electrolysis of a melt of the corresponding oxide. However, this process is technologically complex. The melting point of AL 2 O 3 exceeds 2000 0 C. Because of this, it cannot be subjected to electrolysis directly. Therefore, proceed as follows.

The product yield is 99.7%. However, it is possible to obtain even purer metal, which is used for technical purposes.

Application

The mechanical properties of aluminum are not so good that it can be used in its pure form. Therefore, alloys based on this substance are most often used. There are many of these, you can name the most basic ones.

1. Duralumin.
2. Aluminum-manganese.
3. Aluminum-magnesium.
4. Aluminum-copper.
5. Silumins.
6. Avial.

Their main difference is, naturally, third-party additives. All of them are based on aluminum. Other metals make the material more durable, corrosion-resistant, wear-resistant and easy to process.

There are several main areas of application of aluminum, both in pure form and in the form of its compounds (alloys).

Together with iron and its alloys, aluminum is the most important metal. It was these two representatives of the periodic table that found the most extensive industrial application in human hands.

Properties of aluminum hydroxide

Hydroxide is the most common compound that aluminum forms. Its chemical properties are the same as those of the metal itself - it is amphoteric. This means that it is capable of exhibiting a dual nature, reacting with both acids and alkalis.

Aluminum hydroxide itself is a white gelatinous precipitate. It is easily obtained by reacting an aluminum salt with an alkali or by reacting with acids, this hydroxide gives the usual corresponding salt and water. If the reaction occurs with an alkali, then hydroxo complexes of aluminum are formed, in which its coordination number is 4. Example: Na - sodium tetrahydroxoaluminate.

Aluminum was first isolated in its pure form by Friedrich Wöhler. A German chemist heated anhydrous chloride of the element with potassium metal. This happened in the 2nd half of the 19th century. Until the 20th century kg aluminum cost more.

Only the rich and state-owned could afford the new metal. The reason for the high cost is the difficulty of separating aluminum from other substances. A method for extracting the element on an industrial scale was proposed by Charles Hall.

In 1886, he dissolved the oxide in molten cryolite. The German enclosed the mixture in a granite vessel and connected an electric current to it. Plaques of pure metal settled to the bottom of the container.

Chemical and physical properties of aluminum

What aluminum? Silvery white, shiny. Therefore, Friedrich Wöhler compared the metal granules he obtained with. But there was a caveat: aluminum is much lighter.

Plasticity is close to precious and. Aluminum is a substance, easily drawn into thin wire and sheets. Just remember the foil. It is made on the basis of the 13th element.

Aluminum is lightweight due to its low density. It is three times less than that of iron. At the same time, the 13th element is almost as strong as it is.

This combination has made silver metal indispensable in industry, for example, in the production of car parts. We are also talking about handicraft production, because aluminum welding possible even at home.

Aluminum formula allows you to actively reflect light, but also heat rays. The electrical conductivity of the element is also high. The main thing is not to heat it up too much. It will melt at 660 degrees. If the temperature rises a little higher, it will burn.

The metal will disappear, only aluminium oxide. It is also formed under standard conditions, but only in the form of a surface film. It protects the metal. Therefore, it resists corrosion well, because oxygen access is blocked.

The oxide film also protects the metal from water. If you remove plaque from the surface of aluminum, a reaction with H 2 O will start. The release of hydrogen gases will occur even at room temperature. So, aluminum boat does not turn into smoke only due to the oxide film and protective paint applied to the ship’s hull.

Most active aluminum interaction with non-metals. Reactions with bromine and chlorine take place even under normal conditions. As a result, they are formed aluminum salts. Hydrogen salts are obtained by combining the 13th element with acid solutions. The reaction will also take place with alkalis, but only after removing the oxide film. Pure hydrogen will be released.

Application of aluminum

Metal is sprayed onto mirrors. High light reflectance values ​​come in handy. The process takes place under vacuum conditions. They make not only standard mirrors, but also objects with mirror surfaces. These include: ceramic tiles, household appliances, lamps.

Duet aluminum-copper– the base is duralumin. Simply called duralumin. Add as quality. The composition is 7 times stronger than pure aluminum, therefore, it is suitable for mechanical engineering and aircraft construction.

Copper gives the 13th element strength, but not heaviness. Dural remains 3 times lighter than iron. Small mass of aluminum– a guarantee of lightness of cars, planes, ships. This simplifies transportation and operation, and reduces the price of products.

Buy aluminum automakers are also keen because its alloys can easily be coated with protective and decorative compounds. The paint applies faster and more evenly than on steel and plastic.

At the same time, the alloys are malleable and easy to process. This is valuable, given the mass of bends and design transitions on modern car models.

The 13th element is not only easy to dye, but can also act as a dye itself. Purchased in the textile industry aluminum sulfate. It is also useful in printing, where insoluble pigments are required.

I wonder what solution sulfate aluminum They are also used for water purification. In the presence of the “agent,” harmful impurities precipitate and are neutralized.

Neutralizes the 13th element and acids. Particularly good at this role aluminum hydroxide. It is valued in pharmacology and medicine, adding it to heartburn medications.

Hydroxide is also prescribed for ulcers and inflammatory processes of the intestinal tract. So the drug is also available in pharmacies aluminum. Acid in the stomach - a reason to learn more about such medications.

In the USSR, bronze with an 11% addition of aluminum was also minted. The denominations of the signs are 1, 2 and 5 kopecks. They started producing it in 1926 and finished it in 1957. But the production of aluminum cans for canned food has not stopped.

Stewed meat, saury and other tourist breakfasts are still packaged in containers based on the 13th element. Such jars do not react with food; at the same time, they are light and cheap.

Aluminum powder is part of many explosive mixtures, including pyrotechnics. The industry uses blasting mechanisms based on trinitrotoluene and crushed element 13. A powerful explosive is also obtained by adding ammonium nitrate to aluminum.

In the oil industry it is necessary aluminum chloride. It plays the role of a catalyst in the decomposition of organic matter into fractions. Oil has the property of releasing gaseous, light hydrocarbons of the gasoline type, interacting with the chloride of the 13th metal. The reagent must be anhydrous. After adding chloride, the mixture is heated to 280 degrees Celsius.

In construction I often mix sodium And aluminum. It turns out to be an additive to concrete. Sodium aluminate accelerates its hardening by accelerating hydration.

The rate of microcrystallization increases, which means the strength and hardness of concrete increases. In addition, sodium aluminate saves the reinforcement laid in the solution from corrosion.

Aluminum mining

Metal closes the top three most common on earth. This explains its availability and widespread use. However, nature does not give the element to humans in its pure form. Aluminum has to be separated from various compounds. The 13th element is most abundant in bauxite. These are clay-like rocks, concentrated mainly in the tropical zone.

Bauxite is crushed, then dried, crushed again and ground in the presence of a small volume of water. It turns out to be a thick mass. It is heated with steam. At the same time, most of it, of which bauxite is also not poor, evaporates. What remains is the oxide of the 13th metal.

It is placed in industrial baths. They already contain molten cryolite. The temperature is kept at around 950 degrees Celsius. An electric current of at least 400 kA is also required. That is, electrolysis is used, just like 200 years ago, when the element was isolated by Charles Hall.

Passing through a hot solution, the current breaks the bonds between the metal and oxygen. As a result, the bottom of the bath remains clean aluminum. Reactions finished. The process is completed by casting from the sediment and sending it to the consumer, or using it to form various alloys.

The main aluminum production is located in the same place as the bauxite deposits. In the forefront - Guinea. Almost 8,000,000 tons of the 13th element are hidden in its depths. Australia is in 2nd place with an indicator of 6,000,000. In Brazil, aluminum is already 2 times less. Global reserves are estimated at 29,000,000 tons.

Aluminum price

For a ton of aluminum they ask for almost $1,500. These are the data from non-ferrous metals exchanges as of January 20, 2016. The cost is set mainly by industrialists. More precisely, the price of aluminum is influenced by their demand for raw materials. It also affects the demands of suppliers and the cost of electricity, because the production of the 13th element is energy-intensive.

Different prices are set for aluminum. He goes to the smelter. The cost is announced per kilogram, and the nature of the material being delivered matters.

So, for electrical metal they give about 70 rubles. For food-grade aluminum you can get 5-10 rubles less. They pay the same for motor metal. If you rent out a mixed variety, its price is 50-55 rubles per kilogram.

The cheapest type of scrap is aluminum shavings. You can get only 15-20 rubles for it. They will give a little more for the 13th element. This refers to containers for drinks and canned food.

Aluminum radiators are also not highly valued. The price per kilogram of scrap is about 30 rubles. These are averages. In different regions and at different points, aluminum is accepted more expensive or cheaper. Often the cost of materials depends on the volumes delivered.

Aluminum is a silvery-white metal that has high electrical and thermal conductivity. (The thermal conductivity of aluminum is 1.8 times greater than that of copper and 9 times greater than that of stainless steel.) It has a low density - approximately three times less than that of iron, copper and zinc. And yet it is a very durable metal.

Three electrons from the outer shell of an aluminum atom are delocalized throughout the crystal lattice of aluminum metal. This lattice has a face-centered cubic structure, similar to the lattice of tin and gold (see Section 3.2). Therefore, aluminum has good malleability.

Chemical properties

Aluminum forms ionic and covalent compounds. It is characterized by high ionization energy (Table 15.1). The charge density (ratio of charge to radius) for the ion is very high compared to cations of other metals of the same period (see Table 15.2).

Rice. 15.2. Hydrated aluminum ion.

Table 15.2. Ratio of charge to radius of cations

Because the ion has a high charge density, it has great polarizing power. This explains why the isolated ion is found in only a very few compounds, such as anhydrous aluminum fluoride and aluminum oxide, and even these compounds show a noticeable covalent character. In an aqueous solution, the ion polarizes water molecules, which consequently hydrate the cation (see Fig. 15.2). This hydration is characterized by great exothermicity:

The standard redox potential of aluminum is - 1.66 V:

Therefore, aluminum is located quite high in the electrochemical series of elements (see Section 10.5). This suggests that aluminum should react easily with oxygen and dilute mineral acids. However, when aluminum reacts with oxygen, a thin, non-porous layer of oxide forms on its surface. This layer protects aluminum from further interaction with the environment. The oxide layer can be removed from the surface of aluminum by rubbing it with mercury. Aluminum is then able to combine directly with oxygen and other non-metals such as sulfur and nitrogen. Interaction with oxygen leads to a reaction

Anodizing. Aluminum and light aluminum alloys can be further protected by thickening the natural oxide layer through a process called anodizing. In this process, an aluminum object is placed as an anode in an electrolytic cell, where chromic acid or sulfuric acid is used as the electrolyte.

Aluminum reacts with hot dilute hydrochloric and sulfuric acids to form hydrogen:

This reaction is slow at first due to the presence of an oxide layer. However, as it is removed, the reaction becomes more intense.

Concentrated and dilute nitric acid, as well as concentrated sulfuric acid, make aluminum passive. This means that it does not react with said acids. This passivity is explained by the formation of a thin oxide layer on the surface of aluminum.

Solutions of sodium hydroxide and other alkalis react with aluminum, forming tetrahydroxoaluminate(III) ions and hydrogen:

If the oxide layer is removed from the surface, aluminum can act as a reducing agent in redox reactions (see Section 10.2). It displaces metals located below it in the electrochemical series from their solutions. For example

A clear example of the reducing ability of aluminum is the aluminothermic reaction. This is the name of the reaction between powdered aluminum and

oxide In laboratory conditions, it is usually initiated using a magnesium strip as an igniter. This reaction proceeds very violently, and it releases an amount of energy that is sufficient to melt the resulting iron:

The aluminothermic reaction is used to carry out aluminothermic welding; for example, rails are connected in this way.

Aluminum Oxide Aluminum oxide, or alumina as it is often called, is a compound that has both ionic and covalent properties. It has a melting point and, when molten, is an electrolyte. For this reason, it is often considered an ionic compound. However, in the solid state, aluminum oxide has a framework crystalline structure.

Corundum. Anhydrous forms of aluminum oxide are formed under natural conditions by minerals of the corundum group. Corundum is a very hard crystalline form of aluminum oxide. It is used as an abrasive material, as its hardness is second only to diamond. Large and transparent, often colored, corundum crystals are valued as precious stones. Pure corundum is colorless, but the presence of small amounts of metal oxide impurities gives precious corundum its characteristic color. For example, the color of ruby ​​is due to the presence of ions in corundum, and the color of sapphires is due to the presence of cobalt ions. The purple color of amethyst is due to the presence of manganese impurities in it. By fusing alumina with oxides of various -metals, artificial gemstones can be obtained (see also Tables 14.6 and 14.7).

Aluminum oxide is insoluble in water and has amphoteric properties, reacting with both dilute acids and dilute alkalis. The reaction with acids is described by the general equation:

Reaction with alkalis leads to the formation of -ion:

Aluminum halides. The structure and chemical bonding in aluminum halides are described in Section. 16.2.

Aluminum chloride can be produced by passing dry chlorine or dry hydrogen chloride over heated aluminum. For example

With the exception of aluminum fluoride, all other aluminum halides are hydrolyzed by water:

For this reason, aluminum halides “smoke” in contact with moist air.

Aluminum ions. We have already indicated above that the ion is hydrated in water. When aluminum salts are dissolved in water, the following equilibrium is established:

In this reaction, water acts as a base because it accepts a proton, and the hydrated aluminum ion acts as an acid because it donates a proton. For this reason, aluminum salts have acidic properties. If in

One of the most common elements on the planet is aluminum. The physical and chemical properties of aluminum are used in industry. You will find everything you need to know about this metal in our article.

Atomic structure

Aluminum is the 13th element of the periodic table. It is in the third period, group III, the main subgroup.

The properties and uses of aluminum are related to its electronic structure. The aluminum atom has a positively charged nucleus (+13) and 13 negatively charged electrons, located at three energy levels. The electronic configuration of the atom is 1s 2 2s 2 2p 6 3s 2 3p 1.

The outer energy level contains three electrons, which determine the constant valence of III. In reactions with substances, aluminum goes into an excited state and is able to give up all three electrons, forming covalent bonds. Like other active metals, aluminum is a powerful reducing agent.

Rice. 1. Structure of the aluminum atom.

Aluminum is an amphoteric metal that forms amphoteric oxides and hydroxides. Depending on the conditions, the compounds exhibit acidic or basic properties.

Physical Description

Aluminum has:

• lightness (density 2.7 g/cm 3);
• silver-gray color;
• high electrical conductivity;
• malleability;
• plasticity;
• melting point - 658°C;
• boiling point - 2518.8°C.

Tin containers, foil, wire, and alloys are made from metal. Aluminum is used in the manufacture of microcircuits, mirrors, and composite materials.

Rice. 2. Tin containers.

Aluminum is paramagnetic. Metal is attracted to a magnet only in the presence of a magnetic field.

Chemical properties

In air, aluminum quickly oxidizes, becoming covered with an oxide film. It protects the metal from corrosion and also prevents interaction with concentrated acids (nitric, sulfuric). Therefore, acids are stored and transported in aluminum containers.

Under normal conditions, reactions with aluminum are possible only after removing the oxide film. Most reactions occur at high temperatures.

The main chemical properties of the element are described in the table.

Reaction	Description	The equation
With oxygen	Burns at high temperatures releasing heat	4Al + 3O 2 → 2Al 2 O 3
With non-metal	Reacts with sulfur at temperatures above 200°C, with phosphorus - at 500°C, with nitrogen - at 800°C, with carbon - at 2000°C	2Al + 3S → Al 2 S 3 ; Al + P → AlP; 2Al + N 2 → 2AlN; 4Al + 3C → Al 4 C 3
With halogens	Reacts under normal conditions, with iodine - when heated in the presence of a catalyst (water)	2Al + 3Cl 2 → 2AlCl 3 ; 2Al + 3I 2 → 2AlI 3 ; 2Al + 3Br 2 → 2AlBr 3
With acids	Reacts with dilute acids under normal conditions, with concentrated acids when heated	2Al + 3H 2 SO 4 (diluted) → Al 2 (SO 4) 3 + 3H 2; Al + 6HNO 3 (conc.) → Al(NO 3) 3 + 3NO 2 + 3H 2 O
With alkalis	Reacts with aqueous solutions of alkalis and upon fusion	2Al + 2NaOH + 10H 2 O → 2Na + 3H 2; 2Al + 6KOH → 2KAlO 2 + 2K 2 O + 3H 2
With oxides	Displaces less active metals	2Al + Fe 2 O 3 → 2Fe + Al 2 O 3

Aluminum does not react directly with hydrogen. Reaction with water is possible after removing the oxide film.

Rice. 3. Reaction of aluminum with water.

What have we learned?

Aluminum is an amphoteric active metal with constant valency. It has low density, high electrical conductivity, and plasticity. Attracted by a magnet only in the presence of a magnetic field. Aluminum reacts with oxygen, forming a protective film that prevents reactions with water, concentrated nitric and sulfuric acids. When heated, it interacts with non-metals and concentrated acids, and under normal conditions - with halogens and dilute acids. In oxides it displaces less active metals. Does not react with hydrogen.

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