The base is hydrogen. Hydrogen in nature (0.9% in the earth's crust)

Chemical properties of hydrogen

Under normal conditions, molecular hydrogen is relatively active, directly connecting only with the most active non-metals (with fluorine, and in light and with chlorine). However, when heated, it enters the reaction with many elements.

Hydrogen enters into reactions with simple and complex substances:

- hydrogen interaction with metals it leads to the formation of complex substances - hydrides, in the chemical formulas of which the metal atom always stands in the first place:

At high temperatures, hydrogen reacts directly with some metals (alkaline, alkaline earth and others), forming white crystalline substances - metal hydrides (Li H, Na N, KN, San 2, etc.):

H 2 + 2Li \u003d 2LIH

Metal hydrides are easily decomposed with water with the formation of appropriate alkali and hydrogen:

SA H 2 + 2N 2 O \u003d CA (OH) 2 + 2N 2

- when the interaction of hydrogen with non-metals Falling hydrogen compounds are formed. IN chemical formula A flying hydrogen compound, a hydrogen atom can stand both on the first and in second place, depending on the location in PSHE (see the sign in the slide):

1). With oxygenHydrogen forms water:

Video "Gores of hydrogen"

2N 2 + O 2 \u003d 2N 2 O + Q

At normal temperatures, the reaction proceeds extremely slowly, above 550 ° C - with an explosion (mixture 2 volumes H 2 and 1 volume O 2 is called razchim gas) .

Video "Explosion of Radio Gas"

Video "Preparation and explosion of the rattling mixture"

2). With halogen Hydrogen forms halogen breeds, for example:

H 2 + CL 2 \u003d 2NSL

At the same time with fluorine, hydrogen explodes (even in dark and at 252 ° C), with chlorine and bromine reacts only when illuminated or heating, and with iodine only when heated.

3). With nitrogen Hydrogen interacts with the formation of ammonia:

ZN 2 + N 2 \u003d 2NN 3

only on the catalyst and at elevated temperatures and pressures.

four). When heated, hydrogen reacts vigorously with gray:

H 2 + S \u003d H 2 S (hydrogen sulfide),

it is much more difficult with Selenium and Tellur.

5). With pure carbon Hydrogen can react without catalyst only at high temperatures:

2N 2 + C (amorphous) \u003d CH 4 (methane)

- Hydrogen enters react substitution with metals oxides At the same time, water is formed in products and the metal is restored. Hydrogen - Exhibits the properties of the reducing agent:

Hydrogen is used to restore many metalsSince it takes oxygen from their oxides:

Fe 3 O 4 + 4H 2 \u003d 3FE + 4N 2 O, etc.

The use of hydrogen

Video "Application of hydrogen"

Currently, hydrogen is obtained in huge quantities. It is very large in the synthesis of ammonia, hydrogenation of fats and hydrogenation of coal, oils and hydrocarbons. In addition, hydrogen is used for the synthesis of hydrochloric acid, methyl alcohol, blue acid, with welding and forging metals, as well as in the manufacture of incandescent lamps and precious stones. For sale, hydrogen enters the cylinders under pressure over 150 atm. They are painted in a dark green color and are supplied with a red inscription "hydrogen".

Hydrogen is used to convert liquid fats into solid (hydrogenation), production of liquid fuel by hydrogenation of coal and fuel oil. In metallurgy, hydrogen is used as a reducing agent of oxides or chlorides to obtain metals and non-metals (Germany, silicon, gallium, zirconium, hafnium, molybdenum, tungsten, etc.).

The practical use of hydrogen is diverse: they usually fill balls-probes, in the chemical industry, it serves as a raw material to obtain many very important products (ammonia, etc.), in food - for the production of solid fats, and so on. High temperatures (up to 2600 ° C), obtained by burning hydrogen in oxygen, is used to melting refractory metals, quartz, etc. Liquid hydrogen is one of the most efficient jet fuels. The annual global consumption of hydrogen exceeds 1 million tons.

Simulators

№2. Hydrogen

Tasks for fixing

Task number 1
Make the equation of hydrogen reaction reactions with the following substances: F 2, Ca, Al 2 O 3, mercury oxide (II), tungsten oxide (VI). Name the reaction products, specify the types of reactions.

Task number 2.
Transform the scheme:
H 2 O -\u003e H 2 -\u003e H 2 S -\u003e SO 2

Task number 3.
Calculate the mass of water, which can be obtained when burning 8 g of hydrogen?

History of discovery of hydrogen

If it is the most common chemical element on Earth, the hydrogen is the most common element throughout the universe. Our (and other stars) about half consists of hydrogen, and as for the interstellar gas, it consists of 90% of hydrogen atoms. Considerable place this chemical element occupies on Earth, because with oxygen it is part of the water, and its very name "hydrogen" comes from two ancient Greek words: "Water" and "Gignify". In addition to the water, hydrogen is present in most organic substances and cells, without it, as without oxygen, life itself would be unthinkable.

History of discovery of hydrogen

The first among scientists, hydrogen, the Great Alchemist and the Middle Ages Theophrast Paracels were noticed. In their alchemical experiments, in the hope of finding the "philosopher's stone" mixing with the acids of Paracels received a certain unknown to be combustible gas. True, it was not possible to separate this gas from the air.

Only after a century after Paracella, the French chemist Lemerie was able to separate hydrogen from the air and prove its flamminess. True Lecheri did not understand that the gas obtained by them is pure hydrogen. In parallel, the Russian scientist of Lomonosov was also engaged in such chemical experiences, but the real breakthrough in the hydrogen study was made by the British chemist Henry Cavendish, who is rightfully considered to be a hydrogen discoverer.

In 1766, Cavendish managed to get pure hydrogen, which he called "flammable air". After 20 years, the talented French chemist Antoine Lavoisier could synthesize the water and allocate this most "combustible air" from it - hydrogen. And by the way, the Lavoisier suggested its name hydrogen - "Hydrogenium", he is "hydrogen".

Antoine Lavauzier with his wife, who helped him carry out chemical experiments, including the synthesis of hydrogen.

The basis of the location of the chemical elements in the periodic system of Mendeleev is their atomic weight, calculated relative to the atomic weight of hydrogen. That is, in other words, hydrogen and its atomic weight is the cornerstone of the Mendeleev table, the point of support, on the basis of which the great chemist created its system. Therefore, it is not surprising that in the Table of Mendeleev, hydrogen occupies an honorable place.

In addition, hydrogen has such characteristics:

• The atomic mass of hydrogen is 1.00795.
• In hydrogen, there are three isotopes, each of which has individual properties.
• Hydrogen is a lightweight element having a small density.
• Hydrogen has restorative and oxidative properties.
• When entering into with metals, hydrogen takes their electron and becomes the oxidizing agent. Such compounds are called hydrates.

Hydrogen is gas, its molecule consists of two atoms.

So schematically looks hydrogen molecule.

Molecular hydrogen, formed from such ductomic molecules, explodes with a brought up burning match. The hydrogen molecule during the explosion disintegrates atoms, which are converted into the helium nucleus. It is in this way that happened in the sun and other stars - due to the constant breakdown of hydrogen molecules, our luminaire burns and heats us with its warmth.

Physical properties of hydrogen

At hydrogen in the presence of the following physical properties:

• The boiling point of hydrogen is 252.76 ° C;
• And at a temperature of 259.14 ° C, it is already starting to melt.
• In water, hydrogen dissolves weakly.
• Pure hydrogen is a very dangerous explosive and fuel.
• Hydrogen is lighter than air 14.5 times.

Chemical properties of hydrogen

Since hydrogen can be used in different situations and the oxidizing agent and the reducing agent for reactions and synthesis.

Oxidative properties Hydrogen interacts with active (usually alkaline and alkaline earth) metals, the result of these interactions is the formation of hydrides - sip-like compounds. However, hydrides are formed in hydrogen reactions with low-active metals.

The reducing properties of hydrogen have the ability to restore metals to simple substances From their oxides, in industry this is called hydrogen heroes.

How to get hydrogen?

Among the industrial means of obtaining hydrogen can be allocated:

• coal gasification
• steam conversion of methane,
• electrolysis.

In the laboratory, hydrogen can be obtained:

• with hydrolysis of metal hydrides,
• when reactions with water alkali and alkaline earth metals,
• in the interaction of diluted acids with active metals.

The use of hydrogen

As hydrogen is 14 times lighter than air, then in the old days they started balloons and airships. But after the series of disasters that occurred with the airships, designers had to look for hydrogen to replace (reminding, pure hydrogen - an explosive substance, and the slightest spark was enough to have an explosion).

The explosion of the airship of Hindenburg in 1937, the cause of the explosion just became the ignition of hydrogen (due to short circuit), which flew this huge airship.

Therefore, it began to use helium instead of hydrogen for such aircraft instead of hydrogen, which is also lighter than air, the receipt of helium is more laborious, but it is not so explosive as hydrogen.

Also with hydrogen cleaning is cleaned different species Fuel, especially on the basis of oil and petroleum products.

Hydrogen, video

And at the end of the educational video on our article.

Building and physical properties of hydrogenHydrogen - Dihomanny GAZ H2. It has no color, no smell. This is the easiest gas. Due to this property, it was used in aerostats, airships and similar devices, but its explosion hazard in the mixture with air interferes with widespread use of hydrogen.

Hydrogen molecules are non-polar and very small, so there is little interaction between them. In this regard, it has very low melting points (-259 ° C) and boiling (-253 ° C). Hydrogen is practically insoluble in water.

Hydrogen has 3 isotope: normal 1H, deuterium 2H or D, and radioactive tritium 3N or T. Heavy isotopes of hydrogen are unique in that heavier than the usual hydrogen in 2 or even 3 times! That is why the replacement of ordinary hydrogen on deuterium or tritium is noticeably affected by the properties of the substance (so, the boiling point of conventional hydrogen H2 and the deuterium D2 differ by 3.2 degrees). The interaction of hydrogen with simple substances Hydrogen - non-metal of the middle electrical negativity. Therefore, it is also inherent in oxidative, and rehabilitation properties.

The oxidative properties of hydrogen are manifested in reactions with typical metals - elements of the main subgroups of the I-II group of the Mendeleev table. The most active metals (alkaline and alkaline earth) when heating with hydrogen give hydrides - solid saline substances containing hydride ion-ion in the crystal lattice. 2NA + H2 \u003d 2NA ; Ca + H2 \u003d San2 The reducing properties of hydrogen are manifested in reactions with more typical non-metals than hydrogen: 1) Interaction with halogens H2 + F2 \u003d 2HF

Similarly, interaction with analogs of fluorine - chlorine, bromine, iodine. As the halogen activity decreases, the intensity of the reaction is reduced. The reaction with fluorine occurs under normal conditions with an explosion, for reaction with chlorine requires lighting or heating, and the reaction with iodine proceeds only with strong heating and reversible. 2) interaction with oxygen2N2 + O2 \u003d 2N2O The reaction proceeds with high heat release, sometimes with an explosion. 3) interaction with gray H2 + S \u003d H2S sulfur - much less active nonmetall than oxygen, and the interaction with hydrogen proceeds calmly. 4) interaction with nitrogen 3H2 + N2↔ 2NH3 Reaction is reversible, proceeds to a noticeable extent in the presence of a catalyst, when heated and under pressure. The product is called ammonia. 5) Cooperation with carbon C + 2N2↔ CH4 reaction proceeds in an electric arc or at very high temperatures. Other hydrocarbons are formed as by-products. 3. The interaction of hydrogen with complex substances Hydrogen shows reducing properties and in reactions with complex substances: 1) restoration of metal oxides facing the electrochemical row of stresses to the right of aluminum, as well as non-metallic oxides: Fe2O3 + 2H2 2fe + 3H2O ; Cuo + H2 Cu + H2Ocarrow is used as a reducing agent for extracting metals from oxide ores. Reactions go when heated.2) attach to organic unforeseen substances; C2H4 + H2 (T; P) → C2H6 reactions are processed in the presence of a catalyst and under pressure. We will not concern other hydrogen reactions yet. 4. Obtaining hydrogenIn industry, hydrogen is obtained by processing hydrocarbon raw materials - natural and associated gas, coke, etc. Laboratory methods for producing hydrogen:

1) the interaction of metals in the electrochemical row of metal voltages to the left of hydrogen, with acids. Li K Ba Sr Ca Na Mg Al Mn Zn Cr Fe CD CO Ni Sn Pb (H2) Cu Hg AG PT MG + 2HCl \u003d MgCl2 + H22) The interaction of metals in the electrochemical row of metal voltages to the left of magnesium, with cold water. It also forms alkali.

2NA + 2H2O \u003d 2NAOH + H2 Metal, which is in the electrochemical row of metal voltages to the left of manganese, is able to exhibit hydrogen from water under certain conditions (magnesium - from hot water, aluminum - subject to the removal of the oxide film from the surface).

Mg + 2H2O MG (OH) 2 + H2

Metal, located in the electrochemical row of stresses of metals to the left cobalt, is able to exhibit hydrogen from water vapor. This also forms oxide.

3Fe + 4H2OPar Fe3O4 + 4H23) Metal reaction, hydroxides of amphoterns, with alkalis solutions.

Metals, hydroxides of which are amphoterns, squeeze hydrogen from alkalis solutions. You need to know 2 such metal - aluminum and zinc:

2AL + 2NAOH + 6H2O \u003d 2NA + + 3H2

Zn + 2KOH + 2H2O \u003d K2 + H2

At the same time, complex salts are formed - hydroxyaluminates and hydroxotocytes.

All methods listed so far are based on the same process - metal oxidation at the hydrogen atom in the degree of oxidation +1:

M0 + nn + \u003d mn + + n / 2 h2

4) The interaction of hydrides of active metal metals:

San2 + 2N2O \u003d sa (it) 2 + 2N2

This process is based on the interaction of hydrogen into the degree of oxidation -1 with hydrogen into the degree of oxidation +1:

5) Electrolysis aqueous solutions Alkali, acids, some salts:

2N2O 2N2 + O2

5. Hydrogen compoundsIn this table, the cells of the elements forming with hydrogen-hydrides are isolated on the left shadow. These substances are in their composition hydride ion N-. They are solid colorless saline substances and react with water with hydrogen release.

Elements of the main subgroups of IV-VII groups form with hydrogen compounds of the molecular structure. Sometimes they are also called hydrides, but it is incorrect. In their composition there is no hydride ion, they consist of molecules. As a rule, the simplest hydrogen compounds of these elements are colorless gases. Exceptions - water, which is liquid, and fluoride fluoride, which at room temperature gaseous, but under normal conditions - liquid.

Dark cells marked elements that form with hydrogen compounds showing acid properties.

Dark cells with a cross are elements forming with hydrogen compounds that show the basic properties.

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29). general characteristics Properties of elements of the main subgroup of 7g. Chlorine. Properties of Laura. Hydrochloric acid.In the subgroup of halogens, the fluorine, chlorine, bromine, iodine and astat (Astat is a radioactive element, is studied little). These are p-elements of the group VII periodic system D.I. Imeleeeva. At the external energy level, their atoms have 7 NS2NP5 electrons. This explains the commonality of their properties.

They easily join one electron, showing the degree of oxidation -1. Such a degree of oxidation of halogens have in compounds with hydrogen and metals.

However, halogen atoms, except fluoride, can also show positive degrees of oxidation: +1, +3, +5, +7. Possible values \u200b\u200bof oxidation are explained by the electron structure, which at the fluorine atoms can be represented

Being the most electronegative element, the fluorine can only take one electron on a 2r sublayer. It is one unpaired electron, so fluoride is only monovalent, and the degree of oxidation is always -1.

The electronic structure of the chlorine atom is expressed by the chlorine atom scheme one unpaired electron on a 3p pioneer and a conventional (unexcited) state of chlorine monovalent. But since Chlorine is in the third period, he has five more orbitals 3D-sublevels, in which 10 electrons can accommodate.

Fluor has no free orbital, and therefore chemical reactions No disconnection of paired electrons in the atom is not separated. Therefore, during the examination of halogen, it is always necessary to take into account the features of fluorine and compounds.

Aqueous solutions hydrogen compounds Halogens are acids: HF - fluoride hydrogen (plumbing), HCL - chloride (hydrogen), HBR - brominery, Ni - iodium hydrogen.

Chlorine (lat.chlorum), cl, chemical element VII group of periodic Mendeleev system, atomic number 17, atomic weight 35,453; refers to the family of halogens. Under normal conditions (0 ° C, 0.1 mn / m2, or 1 kgf / cm2), yellow-green gas with a sharp annoying smell. Natural chlorine consists of two stable isotopes: 35SL (75.77%) and 37CL (24.23%).

Chemical properties chlorine. Exterior electronic configuration Atom Cl 3S2ZR5. In accordance with this, chlorine in the compounds exhibits the degree of oxidation -1, + 1, +3, +4, +5, +6 and +7. The covalent radius of the atom of 0.99Å, the ion radius of CL- 1.82Å, the affinity of the chlorine atom to the electron is 3.65 eV, the ionization energy is 12.97 eV.

Chemically chlorine is very active, directly connects with almost all metals (with some only in the presence of moisture or when heated) and with non-metals (except carbon, nitrogen, oxygen, inert gases), forming appropriate chlorides, react with many compounds, replaces hydrogen In limit hydrocarbons and joins unsaturated compounds. Chlorine displaces bromine and iodine from their compounds with hydrogen and metals; From chlorine compounds with these elements, it is supplanted with fluorine. Alkaline metals in the presence of moisture traces interact with chlorine with ignition, most of the metals react with dry chlorine only when the phosphorus is heated, the phosphorus is flammable in the chlorine atmosphere, forming PCl3, and with further chlorination - RSL5; The chlorine sulfur when heated gives S2Cl2, SCL2 and other SNCLM. Arsenic, antimony, bismuth, strontium, Tellur interact vigorously with chlorine. A mixture of chlorine with hydrogen burns with a colorless or yellow-green flame with the formation of hydrogen chloride (this chain reaction). With oxygen chlorine forms oxides: CL2O, CLO2, CL2O6, CL2O7, CL2O8, as well as hypochlorites (chlorothic acid salts), chlorite, chlorates and perchlorates. All chlorine oxygen compounds form explosive mixtures with easily oxidizing substances. Chlorine in water is hydrolyzed, forming a chloronous and hydrochloric acid: CL2 + H2O \u003d NCLO + HCl. When chloroing aqueous solutions, hypochlorites and chlorides are formed by alkali: 2NAOH + CL2 \u003d NACLO + NaCl + H2O, and when heated is chlorates. Calcium hydroxide chlorination is obtained by chlorine lime. In the interaction of ammonia with chlorine, three chloride nitrogen is formed. In chlorination of organic compounds, chlorine either replaces hydrogen, or is attached to multiple bonds, forming various chlorine-containing organic compounds. Chlorine forms interground compounds with other halogens. Fluorides CLF, CLF3, CLF3 are very reactive; For example, in the CLF3 atmosphere, glass wool is self-proposal. Known chlorine compounds with oxygen and fluorine - chlorine oxyfluorides: CLO3F, CLO2F3, CLOF, CLOF3 and fluorine perchlorate FCLO4. Hydrochloric acid (hydrogen chloride, hydrogen chloride, hydrogen chloride) - HCl, solution of hydrogen chloride in water; Strong monoise acid. Colorless (technical hydrochloric acid is yellowish due to impurities Fe, CL2, etc.), "smoking" in the air, caustic liquid. The maximum concentration at 20 ° C is 38% by weight. Salt hydrochloric acid are called chlorides.

Interaction with strong oxidizing agents (potassium permanganate, manganese dioxide) with the release of gaseous chlorine:

Interaction with ammonia with the formation of thick white smoke consisting of the smallest crystals of ammonium chloride:

Qualitative reaction to hydrochloric acid and its salt is its interaction with silver nitrate, in which the forms of silver chloride precipitate is insoluble in nitric acid:

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Hydrogen was opened in the second half of the 18th century English scientists in the field of physics and chemistry of Cavendish. He managed to highlight the substance in its pure state, he studied it and described the properties.

Such is the history of the opening of hydrogen. During the experiments, the researcher determined that this is a combustible gas, the combustion of which in the air gives water. This led to the definition of high-quality water composition.

What is hydrogen

About hydrogen, as a simple substance, for the first time, the French chemist A. Lavoisier in 1784, since it determined that the atoms of one species were part of its molecule.

The name of the chemical element of Latin sounds like Hydrogenium (read "hydrogenium"), which means "water-feeding". The name refers to the combustion reaction, as a result of which water is formed.

Hydrogen characteristic

Designation of hydrogen N. Mendeleev assigned it chemical element The first sequence number, placing it in the main subgroup of the first group and the first period and conditionally in the main subgroup of the seventh group.

Atomic weight (atomic weight) of hydrogen is 1.00797. The molecular weight H 2 is 2 a. e. Molar mass is numerically equal to her.

Presents three isotopes that have a special name: the most common diet (H), severe deuterium (D), radioactive tritium (T).

This is the first element that can be fully divided into isotopes. simple way. It is based on a high difference of masters of isotopes. The process was first implemented in 1933. It is explained by the fact that only in 1932 an isotope was revealed with a mass 2.

Physical properties

Under normal conditions, a simple substance of hydrogen in the form of two-heed molecules is gas, without color, which has no taste and smell. Little soluble in water and other solvents.

Crystallization temperature - 259.2 o C, Boiling point - 252.8 o C. The diameter of hydrogen molecules is so small that they have the ability to slow diffusion through a number of materials (rubber, glass, metals). This property finds use when it is necessary to clean hydrogen from gaseous impurities. With n. y Hydrogen has a density equal to 0.09 kg / m3.

Is it possible to transform hydrogen into metal by analogy with elements located in the first group? Scientists have established that hydrogen under conditions when the pressure is approaching 2 million atmospheres, begins to absorb infrared rays, which indicates the polarization of the substance molecules. Perhaps with even higher pressures, hydrogen will become a metal.

It is interesting: There is an assumption that on planets-giants, Jupiter and Saturn, hydrogen is in the form of a metal. It is assumed that metallic solid hydrogen is also present in the composition of the terrestrial nucleus, due to the ultrahigh pressure generated by the earth's mantle.

Chemical properties

In chemical interaction with hydrogen, both simple and complex substances enter. But the small activity of hydrogen is required to increase the creation of appropriate conditions - an increase in temperature, the use of catalysts, etc.

When heated to the reaction with hydrogen, such simple substances are entering such as oxygen (O 2), chlorine (Cl 2), nitrogen (N 2), sulfur (S).

If you set fire to clean hydrogen at the end of the gas pipe in the air, it will burn smoothly, but barely noticeably. If you place the gas feed tube into the atmosphere of pure oxygen, then the combustion will continue with the formation of water droplets on the walls of the vessel, as the result of the reaction:

The burning of water is accompanied by the release of a large amount of heat. This is an exothermic compound reaction, in the process of which hydrogen is oxidized by oxygen to form H 2 O oxide. It is also a redox reaction in which hydrogen is oxidized, and oxygen is restored.

Similarly, a reaction with CL 2 with the formation of chloroodorodor.

To implement the interaction of nitrogen with hydrogen, high temperature is required and high blood pressureas well as the presence of the catalyst. The result is ammonia.

As a result of the reaction with sulfur, hydrogen sulfide is formed, the recognition of which facilitates the characteristic smell of rotten eggs.

The degree of hydrogen oxidation in these reactions is +1, and in the hydrides described below, 1.

When reactions with some metals, hydrides are formed, for example, sodium hydride - NaH. Some of these complex compounds are used as fuel for missiles, as well as in thermonuclear energy.

Hydrogen reacts with substances from the complex category. For example, with copper oxide (II), Cuo formula. To carry out the reaction, the hydrogen of the copper is passed above the heated powdered copper oxide (II). During the interaction, the reagent changes its color and becomes red-brown, and on the cold walls of the test tubes, water droplets are settled.

The hydrogen during the reaction is oxidized, forming water, and copper is restored from oxide to a simple substance (CU).

Areas of use

Hydrogen has great importance For a person and finds use in a variety of spheres:

1. In chemical production is raw materials, in other industries - fuel. Do not cost without hydrogen and enterprises of petrochemistry and refining.
2. In the electric power industry, this simple substance performs the function of the cooling agent.
3. In black and non-ferrous metallurgy, hydrogen shall be given the role of the reducing agent.
4. To create an inert medium when packing products.
5. The pharmaceutical industry - uses hydrogen as a reagent in the production of hydrogen peroxide.
6. This light gas fill meteorological probes.
7. Known this element and as a fuel reducing agent for rocket engines.

Scientists unanimously prophesy to hydrogen fuel palm championship in power engineering.

Receipt in industry

In industry, hydrogen is obtained by electrolysis using either hydroxides subjected to chlorides alkali metalsdissolved in water. You can also get hydrogen in this way directly from the water.

Used for these purposes conversion of coke or methane with water vapor. The decomposition of methane at elevated temperature also gives hydrogen. Fractional gas liquefaction with a fractional method is also used for industrial hydrogen production.

Getting in the laboratory

The laboratory for hydrogen is used by the Cypa apparatus.

Salt or sulfuric acid and zinc. As a result of the reaction, hydrogen is formed.

Finding hydrogen in nature

Hydrogen more often occurs in the universe. The main mass of the stars, including the sun, and other cosmic bodies is hydrogen.

In the earth's crust of it only 0.15%. It is present in many minerals in all organic substancesAs well as in water covering on 3/4 surface of our planet.

In the upper layers of the atmosphere, it is possible to detect traces of hydrogen in its pure form. Find it in a number of combustible natural gases.

Gaseous hydrogen is the most loose, and the liquid is the most dense substance on our planet. With hydrogen, you can change the voice of the voice, if you breathe it, and to speak out.

The basis of the most powerful hydrogen bomb is the splitting of the easiest atom.

Industrial methods of obtaining simple substances depend on what form the corresponding element is in nature, that is, that may be raw materials for its preparation. Thus, oxygen existing in free state is obtained by a physical method - separation from liquid air. Hydrogen is almost entirely in the form of compounds, therefore, chemical methods are used to obtain it. In particular, decomposition reactions can be used. One of the methods of obtaining hydrogen is the reaction of water decomposition by electric shock.

The main industrial method for the preparation of hydrogen is a reaction with water methane, which is part of natural Gas. It is carried out at high temperatures (it is easy to make sure that when methane passes, even through boiling water, no reaction occurs):

CH 4 + 2N 2 0 \u003d CO 2 + 4N 2 - 165 kJ

In the laboratory, not necessarily natural raw materials are used to obtain simple substances, but choose the source substances, of which it is easier to select the necessary substance. For example, in the laboratory oxygen is not obtained from the air. The same applies to the preparation of hydrogen. One of the laboratory methods for producing hydrogen, which is sometimes used in the industry - expansion of water with electric stroke.

Usually, hydrogen laboratories are obtained by the interaction of zinc with hydrochloric acid.

In industry

1.Electrolysis of aqueous salts:

2NACL + 2H 2 O → H 2 + 2NAOH + CL 2

2.Transmission of water vapor over hot coke at a temperature of about 1000 ° C:

H 2 O + C ⇄ H 2 + CO

3.From natural gas.

Conversion by water steam: CH 4 + H 2 O ⇄ CO + 3H 2 (1000 ° C) Catalytic oxidation with oxygen: 2CH 4 + O 2 ⇄ 2CO + 4H 2

4. Crequen and reforming hydrocarbons in the process of oil refining.

In the laboratory

1.The effect of diluted acids to metals. To carry out such a reaction, zinc and hydrochloric acid are most often used:

Zn + 2hcl → ZnCl 2 + H 2

2.Calcium interaction with water:

CA + 2H 2 O → Ca (OH) 2 + H 2

3.Hydrolysis hydrides:

NAH + H 2 O → NaOH + H 2

4.Action alkalis for zinc or aluminum:

2AL + 2NAOH + 6H 2 O → 2NA + 3H 2 Zn + 2KOH + 2H 2 O → K 2 + H 2

5.With the help of electrolysis. With the electrolysis of the aqueous solutions of alkali or acids on the cathode, hydrogen is released, for example:

2H 3 O + + 2e - → H 2 + 2H 2 O

• Bioreactor for hydrogen production

Physical properties

Gaseous hydrogen can exist in two forms (modifications) - in the form of ortho and para-hydrogen.

In the orthodorod molecule (so pl. -259.10 ° C, t. Kip. -252.56 ° C) nuclear spins are directed equally (parallel), and at Paravodorod (m. Pl. -259,32 ° C, t . Kip. -252,89 ° C) - opposite to each other (anti-parallel).

It is possible to split alto hydrogen altropy forms at an active angle at liquid nitrogen temperature. At very low temperatures, the equilibrium between the orthopomy and the waterproof is almost aimed towards the latter. At 80 to the form ratio of approximately 1: 1. The desorbed paralodine under heating turns into an orthodoxide up to the formation of equilibrium at room temperature of the mixture (ortho-steam: 75:25). Without a catalyst, the transformation occurs slowly, which makes it possible to study the properties of individual allotropic forms. Hydrogen molecule Dvkhatomna - H₂. Under normal conditions, it is gas without color, smell and taste. Hydrogen is the easiest gas, its density is many times less than air density. Obviously, the less weight of molecules, the higher their speed at the same temperature. As the easiest, hydrogen molecules are moving faster than molecules of any other gas and thus faster can transmit heat from one body to another. It follows that hydrogen has the highest thermal conductivity among gaseous substances. Its thermal conductivity is approximately seven times higher than thermal conductivity of air.

Chemical properties

Hydrogen molecules H₂ are quite durable, and in order for hydrogen to enter into the reaction, a large energy should be spent: H 2 \u003d 2N - 432 kJ so, at normal temperatures, hydrogen reacts with very active metals, for example with calcium, forming calcium hydride: CA + H 2 \u003d SAN 2 and with a single non-metallol - fluorine, forming fluorine hydrogen: F 2 + H 2 \u003d 2HF with most metals and non-metals hydrogen reacts at elevated temperatures or with a different effect, for example when lighting. It can "take away" oxygen from some oxides, for example: Cuo + H 2 \u003d Cu + H 2 0 The recorded equation reflects the recovery reaction. Recovery reactions are called processes, as a result of which oxygen is taken from the compound; Oxygen consistent substances are called reducing agents (at the same time they themselves are oxidized). Next, another definition of the concepts of "oxidation" and "recovery" will be given. And this definition, historically first, retains the meaning and now, especially in organic Chemistry. Recovery response is the opposite of the oxidation reaction. Both of these reactions always proceed at the same time as one process: when oxidizing (recovery) of a single substance, it is defined simultaneously recovery (oxidation) of another.

N 2 + 3H 2 → 2 NH 3

With halogens forms halogen breeding:

F 2 + H 2 → 2 HF, the reaction proceeds with an explosion in the dark and at any temperature, CL 2 + H 2 → 2 HCl, the reaction proceeds with an explosion, only in the light.

With soot interact with strong heating:

C + 2H 2 → CH 4

Interaction with alkaline and lump-earth metals

Hydrogen forms with active metals hydrides:

Na + H 2 → 2 NAH CA + H 2 → CAH 2 MG + H 2 → MGH 2

Hydrides - saline, solids, easily hydrolyzed:

CAH 2 + 2H 2 O → CA (OH) 2 + 2H 2

Interaction with metals oxides (usually D-elements)

Oxides are restored to metals:

Cuo + H 2 → Cu + H 2 O FE 2 O 3 + 3H 2 → 2 Fe + 3H 2 O WO 3 + 3H 2 → W + 3H 2 O

Hydrogenation of organic compounds

Under the action of hydrogen on unsaturated hydrocarbons in the presence of a nickel catalyst and an elevated temperature, a reaction occurs hydrogenation:

CH 2 \u003d CH 2 + H 2 → CH 3 -CH 3

Hydrogen restores aldehydes to alcohols:

CH 3 CHO + H 2 → C 2 H 5 OH.

Geochemistry of hydrogen

Hydrogen is the main building material of the universe. This is the most common element, and all the elements are formed from it as a result of thermonuclear and nuclear reactions.

The free hydrogen H 2 is relatively rarely found in the earth's gases, but in the form of water it takes extremely important participation in geochemical processes.

The hydrogen minerals can be included in the form of ammonium ion, hydroxyl ion and crystalline water.

In the atmosphere, hydrogen is continuously formed as a result of water decomposition by solar radiation. It migrates to the upper layers of the atmosphere and disappears into space.

Application

• Hydrogen energy

Atomic hydrogen is used for atomic hydrogen welding.

IN food Industry hydrogen is registered as a food additive E949.like packaging gas.

Features of circulation

Hydrogen at a mixture with air forms an explosive mixture - the so-called rat gas. This gas has the greatest explosiveness with a volume of hydrogen and oxygen 2: 1, or hydrogen and air approximately 2: 5, since in the air of oxygen contains approximately 21%. Also hydrogen is fire hazardous. Liquid hydrogen when popping on the skin can cause severe frostbite.

Explosive concentrations of hydrogen with oxygen arise from 4% to 96% of volumetric. With a mixture with air from 4% to 75 (74)% of volumetric.

Using hydrogen

In the chemical industry, hydrogen is used in the production of ammonia, soap and plastics. In the food industry with hydrogen from liquid vegetable oils make margarine. Hydrogen is very lung and in the air always rises up. Once upon agencies and balloons were filled with hydrogen. But in the 30s. XX century There were several terrible catastrophes when the airships exploded and burned. Nowadays, the airships are filled with gas helium. Hydrogen is also used as rocket fuel. Someday hydrogen may be widely used as fuel for passenger and trucks. Hydrogen engines do not pollute ambient and allocate only water vapor (though, the very obtaining hydrogen leads to some environmental pollution). Our sun mainly consists of hydrogen. Solar heat and light is the result of nuclear energy release during the merger of hydrogen nuclei.

Using hydrogen as fuel (economic efficiency)

The most important characteristic of the substances used as fuel is their heat of combustion. From the course general Chemistry It is known that the reaction of the interaction of hydrogen with oxygen occurs with heat release. If you take 1 mol H 2 (2 g) and 0.5 mol O 2 (16 g) under standard conditions and excite the reaction, then according to the equation

H 2 + 0.5 o 2 \u003d H 2 o

after completion of the reaction, 1 mol h 2 o (18 g) is formed with an energy release of 285.8 kJ / mol (for comparison: the heat of the combustion of acetylene is 1300 kJ / mol, propane - 2200 kJ / mol). 1 m³ of hydrogen weighs 89.8 g (44.9 mol). Therefore, 12832.4 kJ of energy will be spent to obtain 1 m³ of hydrogen. Taking into account the fact that 1 kW · h \u003d 3600 kJ, we get 3.56 kWh of electricity. Knowing the tariff for 1 kW of electricity and the cost of 1 m³ of gas, it is possible to conclude about the feasibility of the transition to hydrogen fuel.

For example, the experimental model of Honda FCX 3 generations with a hydrogen tank 156 l (contains 3.12 kg of hydrogen under pressure of 25 MPa) 355 km drives. Accordingly, 123.8 kWh is obtained from 3.12 kg H2. At 100 km, energy consumption will be 36.97 kWh. Knowing the cost of electricity, the cost of gas or gasoline, their consumption for a car per 100 km is easy to calculate the negative economic effect of car transition to hydrogen fuel. Let's say (Russia 2008), 10 cents per kWh of electricity lead to the fact that 1 m³ of hydrogen leads to the price of 35.6 cents, and taking into account the efficiency of water decomposition of 40-45 cents, the same number of kWh · h from gasoline burning 12832,4kg / 42000kj / 0.7kg / l * 80tesunts / l \u003d 34 cents at retail prices, whereas for hydrogen, we calculated the perfect option, without taking into account the transportation, depreciation of equipment, etc. For methane with the combustion energy of about 39 MJ On m³ the result will be below two to four times due to the difference in price (1m³ for Ukraine costs $ 179, and for Europe $ 350). That is, an equivalent amount of methane will cost 10-20 cents.

However, we should not forget that when burning hydrogen, we get clean waterfrom which it was mined. That is, we have renewable pplash Energy without harm to the environment, in contrast to gas or gasoline, which are primary energy sources.

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