What number is the atomic number of hydrogen? Hydrogen - what is this substance? Chemical and physical properties of hydrogen

Hydrogen  (lat. hydrogenium), N, chemical element, the first in the ordinal number in the periodic table; atomic mass 1.00797. Under normal conditions, V. - gas; It has no color, smell and taste.

History reference.   In the works of chemists of the 16th and 17th centuries. repeatedly mentioned the release of combustible gas by the action of acids on metals. In 1766 Cavendish  collected and investigated the evolved gas, calling it "combustible air." Being a supporter of the theory phlogiston, Cavendish believed that this gas is pure phlogiston. In 1783 A. Lavoisier  by analyzing and synthesizing water, he proved the complexity of its composition, and in 1787 defined “combustible air” as a new chemical element (B.) and gave it the modern name hydrog e ne (from Greek hydor - water and genn ao - give birth), which means "Giving birth to water"; this root is used in the names of B. compounds and processes with its participation (for example, hydrides, hydrogenation). The modern Russian name "V." was proposed by M. F. Soloviev in 1824.

Prevalence in nature . Century is widespread in nature, its content in the earth's crust (lithosphere and hydrosphere) is 1% by mass, and 16% by number of atoms. Century is a part of the most widespread substance on Earth - water (11.19% Century by weight), a compound of coal, oil, natural gas, clay, as well as organisms of animals and plants (i.e. proteins, nucleic acids, fats, carbohydrates, etc.). In its free state, V. is extremely rare; in small quantities it is found in volcanic and other natural gases. Minor amounts of free V. (0.0001% by the number of atoms) are present in the atmosphere. In the near-Earth space, V. forms an internal (proton) in the form of a proton flux earth's radiation belt. In space, V. is the most common element. As plasma  it makes up about half the mass of the sun and most stars, the bulk of the gases of the interstellar medium and gas nebulae. B. is present in the atmosphere of a number of planets and in comets in the form of free h 2, methane ch 4, ammonia nh 3, water h 2 o, radicals like ch, nh, oh, sih, ph, etc. In the form of a proton flux, V. is part of the corpuscular radiation of the Sun and cosmic rays.

Isotopes, atom and molecule. Ordinary V. consists of a mixture of 2 stable isotopes: light V., or protium (1 h), and heavy V., or deuterium(2 h, or d). In natural compounds of V. per 1 atom 2 h there is an average of 6800 atoms 1 h. A radioactive isotope is artificially obtained - superheavy V., or tritium  (3 h, or T), with soft? -Radiation and half-life t 1/2\u003d 12.262 years. In nature, tritium is formed, for example, from atmospheric nitrogen under the influence of cosmic ray neutrons; in the atmosphere it is negligible (4 · 10 -15% of the total number of B. atoms). The extremely unstable isotope 4 h was obtained. Mass numbers of isotopes 1 h, 2 h, 3 h and 4 h, respectively, 1,2, 3 and 4, indicate that the nucleus of a protium atom contains only 1 proton, deuterium - 1 proton and 1 neutron, tritium - 1 proton and 2 neutrons, 4 h - 1 proton and 3 neutrons. The large difference in the masses of V. isotopes causes a more noticeable difference in their physical and chemical properties than in the case of isotopes of other elements.

The atom of V. has the simplest structure among the atoms of all other elements: it consists of a nucleus and one electron. The binding energy of the electron with the nucleus (ionization potential) is 13.595 ev. The neutral atom of B. can also attach a second electron, forming a negative ion H -; the binding energy of the second electron with a neutral atom (electron affinity) is 0.78 ev. Quantum mechanics  allows you to calculate all possible energy levels of the atom B., and therefore, give a full interpretation of it atomic spectrum. The V. atom is used as a model in quantum mechanical calculations of the energy levels of other, more complex atoms. Molecule B. h 2 consists of two atoms connected by a covalent chemical bond. The energy of dissociation (i.e., decay into atoms) is 4.776 ev(1 ev  \u003d 1.6021010 -19 j) The interatomic distance at the equilibrium position of the nuclei is 0.7414 · a. At high temperatures, molecular B. dissociates into atoms (the degree of dissociation at 2000 ° C is 0.0013, at 5000 ° C 0.95). Atomic V. is also formed in various chemical reactions (for example, by the action of zn on hydrochloric acid). However, V.'s existence in the atomic state lasts only a short time; atoms recombine into h 2 molecules.

Physical and chemical properties . B. - the lightest of all known substances (14.4 times lighter than air), density 0.0899 g / l  at 0 ° С and 1 atm. V. boils (liquefies) and melts (hardens), respectively, at -252.6 ° C and -259.1 ° C (only helium has lower melting and boiling points). The critical temperature of V. is very low (-240 ° C), therefore its liquefaction is fraught with great difficulties; critical pressure 12.8 kgf / cm2 (12,8 atm), critical density 0.0312 g / cm3. Of all gases, B. has the highest thermal conductivity, equal at 0 ° C and 1 atm 0,174 tue /(m· TO), i.e., 4.16 · 0 -4 feces /(from· cm· ° C) Specific heat capacity V. at 0 ° C and 1 atmWith p  14,20810 3 j /(kg· TO), i.e., 3.394 feces /(g· ° C) B. Slightly soluble in water (0.0182 ml / g  at 20 ° C and 1 atm), but good - in many metals (ni, pt, pd, etc.), especially in palladium (850 volumes per 1 volume pd). V.'s solubility in metals is associated with its ability to diffuse through them; diffusion through a carbon alloy (for example, steel) is sometimes accompanied by the destruction of the alloy due to the interaction of carbon with carbon (the so-called decarbonization). Liquid V. is very light (density at -253 ° С 0.0708 g / cm3) and fluid (viscosity at - 253 ° С 13.8 spoise).

In most compounds, V. exhibits a valency (more precisely, an oxidation state) of +1, like sodium and other alkali metals; usually it is considered as an analog of these metals, heading 1 g. Mendeleev systems. However, in metal hydrides, B. ion is negatively charged (oxidation state -1), i.e., the hydride na + h - is built like chloride na + cl -. This and some other facts (the proximity of the physical properties of V. and halogens, the ability of halogens to replace V. in organic compounds) give reason to attribute V. also to the vii group of the periodic system. Under ordinary conditions, molecular B. is relatively little active, directly connecting only with the most active of non-metals (with fluorine, and in the light with chlorine). However, when heated, it reacts with many elements. Atomic V. possesses the increased chemical activity in comparison with molecular. With oxygen B. forms water: h 2 + 1/2 o 2 \u003d h 2 o with the release of 285,937 · 10 3 j / moli.e. 68.3174 kcal / mol  heat (at 25 ° C and 1 atm) At ordinary temperatures, the reaction proceeds extremely slowly, above 550 ° C - with an explosion. The explosion limits of the hydrogen-oxygen mixture are (by volume) from 4 to 94% h 2, and the hydrogen-air mixture is from 4 to 74% h 2 (a mixture of 2 volumes of h 2 and 1 volume of O 2 is called explosive gas) V. is used to restore many metals, as it takes oxygen from their oxides:

cuo + H 2 \u003d cu + h 2 o,

fe 3 o 4 + 4h 2 \u003d 3fe + 4h 2 o, etc.

With halogens B. forms hydrogen halides, for example:

h 2 + cl 2 \u003d 2hcl.

At the same time, V. explodes with fluorine (even in the dark and at -252 ° C), reacts with chlorine and bromine only when illuminated or heated, and with iodine only when heated. B. interacts with nitrogen to form ammonia: 3h 2 + n 2 \u003d 2nh 3 only on the catalyst and at elevated temperatures and pressures. When heated, V. reacts vigorously with sulfur: h 2 + s \u003d h 2 s (hydrogen sulfide), much more difficult with selenium and tellurium. With pure carbon, V. can react without a catalyst only at high temperatures: 2h 2 + C (amorphous) \u003d ch 4 (methane). V. directly reacts with some metals (alkaline, alkaline earth, etc.), forming hydrides: h 2 + 2li \u003d 2lih. Of great practical importance are V.'s reactions with carbon monoxide, in which various organic compounds are formed, depending on temperature, pressure, and catalyst, for example, hcho, ch 3 oh, etc. Unsaturated hydrocarbons react with V., turning into saturated, for example:

c n h 2 n + h 2 \u003d c n h 2 n +2.

The role of V. and its compounds in chemistry is exceptionally great. V. determines the acidic properties of the so-called protic acids. V. is inclined to form the so-called hydrogen bond, which has a decisive influence on the properties of many organic and inorganic compounds.

Getting . The main types of raw materials for industrial production B. - natural combustible gases, coke oven gas  (cm. Coke chemistry) and oil refining gasesas well as gasification products for solid and liquid fuels (mainly coal). B. are also obtained from water electrolysis (in places with cheap electricity). The most important ways of producing V. from natural gas are the catalytic interaction of hydrocarbons, mainly methane, with water vapor (conversion): ch 4 + h 2 o \u003d co + 3h 2, and incomplete oxidation of hydrocarbons by oxygen: ch 4 + 1/2 o 2 \u003d co + 2h 2. The resulting carbon monoxide also undergoes conversion: co + h 2 o \u003d co 2 + h 2. B., extracted from natural gas, the cheapest. A very common method of production of V. from water and vapor-air gases obtained by coal gasification. The process is based on the conversion of carbon monoxide. Water gas contains up to 50% h 2 and 40% co; in steam gas, in addition to h 2 and co, there is a significant amount of n 2, which is used together with the obtained B. for the synthesis of nh 3. V. is isolated from coke oven gas and oil refining gases by removing the remaining components of the gas mixture, liquefied more easily than V., with deep cooling. Electrolysis of water is carried out by direct current, passing it through a solution of koh or naoh (acids are not used to avoid corrosion of steel equipment). In laboratories B. receive by electrolysis of water, and also by reaction between zinc and hydrochloric acid. However, they often use a ready-made factory V. in cylinders.

Application . On an industrial scale, V. began to receive in the late 18th century. for filling balloons. Currently, V. is widely used in the chemical industry, mainly for production ammonia. A large consumer of V. is also the production of methyl and other alcohols, synthetic gasoline (synthine) and other products obtained by synthesis from B. and carbon monoxide. V. is used for hydrogenation of solid and heavy liquid fuels, fats, etc., for the synthesis of hcl, for hydrotreating oil products, in welding and cutting of metals with an oxygen-hydrogen flame (temperature up to 2800 ° C) and in atomic hydrogen welding  (up to 4000 ° C). V. isotopes — deuterium and tritium — have found very important applications in atomic energy.

Lit .: Nekrasov B.V., Course in General Chemistry, 14th ed., M., 1962; Remy G., Inorganic chemistry course, trans. with it., t. 1, M., 1963; Egorov A. P., Shereshevsky D. I., Shmanenkov I. V., General chemical technology of inorganic substances, 4th ed., M., 1964; General chemical technology. Ed. S. I. Wolfkovich, T. 1, M., 1952; Lebedev V.V., Hydrogen, its production and use, M., 1958; Nalbandyan A. B., Voevodsky V. V., The mechanism of oxidation and combustion of hydrogen, M. - L., 1949; Brief chemical encyclopedia, vol. 1, M., 1961, p. 619-24.

The most common chemical element in the universe is hydrogen. This is a kind of reference point, because in the periodic table its atomic number is equal to one. Mankind hopes that it will be able to learn more about it as one of the most affordable vehicles in the future. Hydrogen is the simplest, lightest, most common element, there are many everywhere - seventy-five percent of the total mass of the substance. It is in any star, especially a lot of hydrogen in gas giants. Its role in stellar fusion reactions is key. Without hydrogen there is no water, which means there is no life. Everyone remembers that a water molecule contains one oxygen atom, and two atoms in it contain hydrogen. This is the well-known formula of H 2 O.

How do we use it

Hydrogen was discovered in 1766 by Henry Cavendish when he analyzed the reaction of metal oxidation. After several years of observation, he realized that in the process of burning hydrogen, water forms. Previously, scientists isolated this element, but did not consider it independent. In 1783, hydrogen was named hydrogen (translated from Greek as "hydro" - water, and "gene" - to give birth). The element that generates water is hydrogen. This is a gas whose molecular formula is H 2. If the temperature is close to room temperature and the pressure is normal, this element is imperceptible. Hydrogen can not even be caught by the human sense organs - it is tasteless, colorless, odorless. But under pressure and at a temperature of -252.87 C (a very big cold!) This gas liquefies. This is how it is stored, since it takes up much more space in the form of gas. It is liquid hydrogen that is used as rocket fuel.

Hydrogen can become solid, metallic, but for this the pressure must be extremely high, and this is what the most prominent scientists - physicists and chemists - are doing now. Already, this element serves as an alternative fuel for transport. Its application is similar to how the internal combustion engine works: when hydrogen is burned, a lot of its chemical energy is released. A method has also been practically developed for creating a fuel cell based on it: when combined with oxygen, a reaction occurs, and through this, water and electricity are formed. Perhaps, soon the transport will "switch" instead of gasoline to hydrogen - the mass of car manufacturers are interested in creating alternative combustible materials, there are successes. But a purely hydrogen engine is still in the future, there are many difficulties. However, the advantages are such that the creation of a solid hydrogen fuel tank is in full swing, and scientists and engineers are not going to retreat.

Basic information

Hydrogenium (lat.) - hydrogen, the first serial number in the periodic table, is designated N. The hydrogen atom has a mass of 1.0079, it is a gas that, under ordinary conditions, has neither taste, nor smell, nor color. Chemists from the sixteenth century described a kind of combustible gas, designating it in different ways. But it turned out for everyone under the same conditions - when acid affects the metal. For many years, even Cavendish himself called hydrogen simply “combustible air”. It was only in 1783 that Lavoisier proved that water has a complex composition through synthesis and analysis, and after four years he also gave “combustible air” its modern name. The root of this compound word is widely used when it is necessary to name hydrogen compounds and any processes in which it participates. For example, hydrogenation, hydride and the like. And the Russian name was proposed in 1824 by M. Solovyov.

In nature, the distribution of this element is unrivaled. In the lithosphere and hydrosphere of the earth's crust, its mass is one percent, but hydrogen atoms - as much as sixteen percent. Water is the most common on Earth, and 11.19% by weight in it is hydrogen. Also, it is certainly present in almost all the compounds that make up oil, coal, all natural gases, clay. There is hydrogen in all organisms of plants and animals - in the composition of proteins, fats, nucleic acids, carbohydrates and so on. The free state for hydrogen is not characteristic and hardly occurs - it is very few in natural and volcanic gases. A very insignificant amount of hydrogen in the atmosphere is 0.0001%, by the number of atoms. But the whole streams of protons represent hydrogen in near-Earth space, from it consists of the inner radiation belt of our planet.

Space

In space, no element is found as often as hydrogen. The volume of hydrogen in the composition of the elements of the Sun is more than half of its mass. Most stars form hydrogen, which is in the form of plasma. The bulk of the diverse gases of nebulae and the interstellar medium also consists of hydrogen. It is present in comets, in the atmosphere of a number of planets. Naturally, not in its pure form, it’s like free H 2, like methane CH 4, like ammonia NH 3, even like water H 2 O. Very often there are radicals CH, NH, SiN, OH, PH and the like. As a stream of protons, hydrogen is part of corpuscular solar radiation and cosmic rays.

In ordinary hydrogen, a mixture of two stable isotopes is light hydrogen (or protium 1 N) and heavy hydrogen (or deuterium - 2 N or D). There are other isotopes: radioactive tritium - 3 N or T, otherwise - superheavy hydrogen. It is also very unstable 4 N. In nature, a hydrogen compound contains isotopes in the following proportions: 6800 protium atoms per deuterium atom. Tritium is formed in the atmosphere from nitrogen, which is affected by the neutrons of cosmic rays, but negligible. What do the isotope mass numbers mean? The figure indicates that the protium nucleus has only one proton, and deuterium has not only a proton, but also a neutron in the nucleus of an atom. Tritium already has two neutrons in the nucleus to one proton. But 4 N contains three neutrons per proton. Therefore, the physical and chemical properties of hydrogen isotopes are very different compared to the isotopes of all other elements — too much mass difference.

Structure and physical properties

By structure, the hydrogen atom is the simplest in comparison with all other elements: one core - one electron. The ionization potential is the binding energy of the nucleus with the electron - 13.595 electron volts (eV). It is because of the simplicity of this structure that the hydrogen atom is convenient as a model in quantum mechanics when it is necessary to calculate the energy levels of more complex atoms. In a H 2 molecule, there are two atoms that are connected by a chemical covalent bond. The decay energy is very high. Atomic hydrogen can form in chemical reactions, such as zinc and hydrochloric acid. However, the interaction with hydrogen practically does not occur - the atomic state of hydrogen is very short, the atoms immediately recombine into H 2 molecules.

From a physical point of view, hydrogen is lighter than all known substances - more than fourteen times lighter than air (remember the flying balloons on holidays - they have just hydrogen inside). However, it can boil, liquefy, melt, solidify, and only helium boils and melts at lower temperatures. It is difficult to liquefy it, you need a temperature below -240 degrees Celsius. But it has a very high thermal conductivity. It almost does not dissolve in water, but the interaction with metal hydrogen perfectly occurs - it dissolves in almost all, best of all, in palladium (eight hundred and fifty volumes of hydrogen take up one volume of hydrogen). Liquid hydrogen is light and fluid, and when it dissolves in metals, it often destroys alloys due to interaction with carbon (steel, for example), diffusion, decarbonization occurs.

Chemical properties

In compounds, for the most part, hydrogen shows an oxidation state (valency) of +1, like sodium and other alkali metals. He is considered as their counterpart, standing at the head of the first group of the Mendeleev system. But the hydrogen ion in metal hydrides is negatively charged, with an oxidation state of -1. Also, this element is close to halogens, which are even able to replace it in organic compounds. Therefore, hydrogen can also be attributed to the seventh group of the Mendeleev system. Under normal conditions, hydrogen molecules do not differ in activity, connecting only with the most active non-metals: good with fluorine, and if light, with chlorine. But when heated, hydrogen becomes different - it reacts with many elements. Atomic hydrogen, in comparison with molecular hydrogen, is very chemically active, so water is formed in connection with oxygen, and energy and heat are released along the way. At room temperature, this reaction is very slow, but when heated above five hundred and fifty degrees, an explosion occurs.

Hydrogen is used to reduce metals because it takes oxygen away from their oxides. With fluorine, hydrogen forms an explosion even in the dark and at minus two hundred fifty-two degrees Celsius. Chlorine and bromine excite hydrogen only when heated or lit, and iodine - only when heated. Hydrogen with nitrogen forms ammonia (this is how most fertilizers are produced). When heated, it interacts very actively with sulfur, and hydrogen sulfide is obtained. It is difficult to induce a hydrogen reaction with tellurium and selenium, but with pure carbon the reaction occurs at very high temperatures, and methane is obtained. With carbon monoxide, hydrogen forms various organic compounds, pressure, temperature, and catalysts influence here, and all this is of great practical importance. In general, the role of hydrogen, as well as its compounds, is extremely large, since it gives acidic properties to proton acids. With many elements, a hydrogen bond forms, affecting the properties of both inorganic and organic compounds.

Receiving and application

Hydrogen is produced on an industrial scale from natural gases - combustible, coke, and oil refining gases. It can also be obtained by electrolysis where electricity is not too expensive. However, the most important method for producing hydrogen is the catalytic interaction of hydrocarbons, mostly methane, with water vapor when a conversion is obtained. The method of oxidizing hydrocarbons with oxygen is also widely used. Hydrogen production from natural gas is the cheapest way. The other two are the use of coke oven gas and refinery gas - hydrogen is released when the remaining components are liquefied. They are more easily liquefied, and for hydrogen, as we recall, -252 degrees are needed.

Hydrogen peroxide is very popular in use. Treatment with this solution is used very often. The molecular formula of H 2 O 2 is unlikely to be called by all those millions of people who want to be blondes and lighten their hair, as well as those who love cleanliness in the kitchen. Even those who process scratches received from playing with a kitten, most often do not realize that they are using hydrogen treatment. But everyone knows the story: since 1852, hydrogen has long been used in aeronautics. The airship invented by Henry Giffard was created on the basis of hydrogen. They were called zeppelins. The zeppelins were supplanted from the sky by the rapid development of aircraft construction. In 1937, a major accident occurred when the Hindenburg airship burned down. After this incident, zeppelins were never used again. But at the end of the eighteenth century, the proliferation of balloons filled with hydrogen was widespread. In addition to the production of ammonia, today hydrogen is needed for the manufacture of methyl alcohol and other alcohols, gasoline, hydrogenated heavy liquid fuels and solid fuels. You can not do without hydrogen during welding, when cutting metals - it can be oxygen-hydrogen and atomic-hydrogen. And tritium and deuterium give birth to nuclear energy. These, as we recall, isotopes of hydrogen.

Neumyvakin

Hydrogen as a chemical element is so good that it could not fail to have its own fans. Ivan Pavlovich Neumyvakin - doctor of medical sciences, professor, laureate of the State Prize and still has many titles and awards, among them. As a doctor of traditional medicine, he is named the best folk healer of Russia. It was he who developed many methods and principles for providing medical assistance to astronauts in flight. It was he who created the unique hospital - a hospital on board a spacecraft. At the same time, he was the state coordinator of cosmetic medicine. Space and cosmetics. His passion for hydrogen is not aimed at making big money, as is now the case in domestic medicine, but on the contrary, is to teach people to recover from anything literally penny means, without an additional visit to pharmacies.

He advocates treatment with a drug that is present in literally every home. This is hydrogen peroxide. You can criticize Neumyvakin as much as you like, he will still insist on his own: yes, indeed, hydrogen peroxide can literally cure everything, because it saturates the body’s internal cells with oxygen, destroys toxins, normalizes acid and alkaline balance, and from here tissue is regenerated, all rejuvenated the body. Nobody has yet seen and has not yet examined hydrogen peroxide, but Neumyvakin claims that using this tool can completely get rid of viral, bacterial and fungal diseases, prevent the development of tumors and atherosclerosis, defeat depression, rejuvenate the body and never get sick SARS and a cold.

Panacea

Ivan Pavlovich is sure that with the proper use of this simplest drug and with all the simple instructions, many diseases can be defeated, including very serious ones. Their list is huge: from periodontal disease and tonsillitis to myocardial infarction, strokes and diabetes. Such trifles as sinusitis or osteochondrosis fly away from the first treatment sessions. Even cancerous tumors get scared and run away from hydrogen peroxide, because immunity is stimulated, the body’s life and its protection are activated.

Even children can be treated in this way, unless it is better for pregnant women to abstain from the use of hydrogen peroxide. Also, this method is not recommended for people with transplanted organs due to possible tissue incompatibility. The dosage should be observed clearly: from one drop to ten, adding one every day. Three times a day (thirty drops of a three percent solution of hydrogen peroxide per day, wow!) Half an hour before meals. You can enter the solution intravenously and under the supervision of a doctor. Sometimes hydrogen peroxide is combined for a more effective effect with other drugs. Inside, the solution is used only in diluted form - with clean water.

Outwardly

Compresses and rinses even before Professor Neumyvakin created his techniques were very popular. Everyone knows that, just like alcohol compresses, hydrogen peroxide cannot be used in its pure form, because it will result in tissue burns, but warts or fungal infections are lubricated locally and with a strong solution - up to fifteen percent.

With skin rashes, with headaches, they also do procedures in which hydrogen peroxide is involved. The compress should be done with a cotton cloth dipped in a solution of two teaspoons of three percent hydrogen peroxide and fifty milligrams of pure water. Cover the fabric with a film and wrap it with wool or a towel. The duration of the compress is from a quarter of an hour to an hour and a half in the morning and evening until recovery.

The opinion of doctors

Opinions are divided, far from all admire the properties of hydrogen peroxide, moreover, they not only do not believe them, they laugh at them. Among the physicians are those who supported Neumyvakin and even picked up the development of his theory, but they are a minority. Most doctors consider such a treatment plan not only ineffective, but also often fatal.

Indeed, there is so far no officially proven case where a patient would be cured by hydrogen peroxide. At the same time, there is no information about the deterioration of health due to the use of this method. But precious time is wasted, and a person who has received one of the serious illnesses and has completely relied on Neumyvakin's panacea risks being late for the beginning of his present traditional treatment.

Liquid

Hydrogen   (lat. Hydrogenium; indicated by H) Is the first element of the periodic system of elements. Widespread in nature. The cation (and nucleus) of the most common hydrogen isotope 1 H is the proton. The properties of the 1 H nucleus make it possible to widely use NMR spectroscopy in the analysis of organic substances.

Three isotopes of hydrogen have their own names: 1 H - protium (H), 2 H - deuterium (D) and 3 H - tritium (radioactive) (T).

The simple substance is hydrogen - H 2 - a light, colorless gas. When mixed with air or oxygen, it is flammable and explosive. Non toxic It is soluble in ethanol and a number of metals: iron, nickel, palladium, platinum.

Story

The evolution of combustible gas during the interaction of acids and metals was observed in the 16th and 17th centuries at the dawn of the emergence of chemistry as a science. Mikhail Vasilyevich Lomonosov directly pointed out his isolation, but he was definitely aware that this was not a phlogiston. The English physicist and chemist Henry Cavendish in 1766 investigated this gas and called it "combustible air." When burning, “combustible air” gave water, but Cavendish’s adherence to the theory of phlogiston prevented him from drawing the right conclusions. The French chemist Antoine Lavoisier, together with the engineer J. Meunier, using special gas meters, synthesized water in 1783 and then analyzed it by decomposing water vapor with hot iron. Thus, he established that "combustible air" is part of the water and can be obtained from it.

origin of name

Lavoisier gave hydrogen the name hydrogène - "giving birth to water." The Russian name "hydrogen" was proposed by the chemist M. F. Soloviev in 1824 - by analogy with the Broonosovsky "oxygen".

Prevalence

Hydrogen is the most common element in the universe. It accounts for about 92% of all atoms (8% are helium atoms, the share of all other elements taken together is less than 0.1%). Thus, hydrogen is the main component of stars and interstellar gas. Under stellar temperatures (for example, the surface temperature of the Sun ~ 6000 ° C), hydrogen exists in the form of plasma, in the interstellar space this element exists in the form of individual molecules, atoms and ions and can form molecular clouds that vary significantly in size, density and temperature.

Earth's crust and living organisms

The mass fraction of hydrogen in the earth's crust is 1% - this is the tenth most abundant element. However, its role in nature is determined not by mass, but by the number of atoms, the proportion of which among the remaining elements is 17% (second place after oxygen, the fraction of atoms of which is ~ 52%). Therefore, the value of hydrogen in chemical processes occurring on Earth is almost as great as oxygen. Unlike oxygen existing on Earth in both bound and free states, almost all of the hydrogen on Earth is in the form of compounds; only in a very small amount of hydrogen in the form of a simple substance is contained in the atmosphere (0.00005% by volume).

Hydrogen is a part of almost all organic substances and is present in all living cells. In living cells, almost 50% of the number of atoms in hydrogen is.

Getting

Industrial methods for producing simple substances depend on the form in which the corresponding element is in nature, that is, what can be the raw material for its production. So, oxygen, available in a free state, is obtained in a physical way - the allocation of liquid air. Hydrogen is almost all in the form of compounds, therefore, chemical methods are used to obtain it. In particular, decomposition reactions can be used. One of the methods for producing hydrogen is the decomposition of water by electric current.

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

CH 4 + 2H 2 O \u003d CO 2 + 4H 2 −165 kJ

In the laboratory, to obtain simple substances, not necessarily natural raw materials are used, but those starting materials are selected from which it is easier to isolate the necessary substance. For example, in a laboratory, oxygen is not obtained from air. The same applies to the production of hydrogen. One of the laboratory methods for producing hydrogen, which is sometimes used in industry, is the decomposition of water by electric current.

Usually in a laboratory, hydrogen is produced by reacting zinc with hydrochloric acid.

In industry

1. Electrolysis of aqueous solutions of 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.

Steam Conversion:

CH 4 + H 2 O? CO + 3H 2 (1000 ° C)

Catalytic oxidation by oxygen:

2CH 4 + O 2? 2CO + 4H 2

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

In the laboratory

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

Zn + 2HCl → ZnCl 2 + H 2

2.The interaction of calcium with water:

Ca + 2H 2 O → Ca (OH) 2 + H 2

3.Hydrolysis of hydrides:

NaH + H 2 O → NaOH + H 2

4.The action of alkalis on zinc or aluminum:

2Al + 2NaOH + 6H 2 O → 2Na + 3H 2

Zn + 2KOH + 2H 2 O → K 2 + H 2

5.By electrolysis.  During the electrolysis of aqueous solutions of alkalis or acids, hydrogen is generated at the cathode, for example:

2H 3 O + + 2e - → H 2 + 2H 2 O

Physical properties

Hydrogen can exist in two forms (modifications) - in the form of ortho- and para-hydrogen. In the orthohydrogen molecule o-H 2 (mp. −259.10 ° C, mp. −252.56 ° C) the nuclear spins are directed in the same way (parallel), and in parahydrogen p-H 2 (mp. −259.32 ° C, mp. −252.89 ° C) - opposite to each other (antiparallel). Equilibrium mixture o-H 2 and p-H 2 at a given temperature is called equilibrium hydrogen e-H 2.

Hydrogen modifications can be separated by adsorption on activated carbon at the temperature of liquid nitrogen. At very low temperatures, the equilibrium between orthohydrogen and parahydrogen is almost completely shifted toward the latter. At 80 K, the ratio of the forms is approximately 1: 1. Upon heating, the desorbed parahydrogen turns into orthohydrogen until an equilibrium mixture is formed at room temperature (ortho-vapor: 75:25). Without a catalyst, the transformation occurs slowly (under interstellar medium conditions, with characteristic times up to cosmological times), which makes it possible to study the properties of individual modifications.

Hydrogen is the lightest gas; it is 14.5 times lighter than air. Obviously, the smaller the mass of the molecules, the higher their speed at the same temperature. As the lightest, the hydrogen molecules move faster than the molecules of any other gas and thereby can transfer heat faster from one body to another. It follows that hydrogen has the highest thermal conductivity among gaseous substances. Its thermal conductivity is about seven times higher than the thermal conductivity of air.

The hydrogen molecule is diatomic - H 2. Under normal conditions, it is a gas without color, odor or taste. Density is 0.08987 g / l (n.a.), boiling point −252.76 ° C, specific heat of combustion 120.9 × 10 6 J / kg, slightly soluble in water - 18.8 ml / l. Hydrogen is readily soluble in many metals (Ni, Pt, Pd, etc.), especially in palladium (850 volumes per 1 volume of Pd). The solubility of hydrogen in metals is associated with its ability to diffuse through them; diffusion through a carbon alloy (e.g. steel) is sometimes accompanied by destruction of the alloy due to the interaction of hydrogen with carbon (the so-called decarbonization). Virtually insoluble silver.

Liquid hydrogenexists in a very narrow temperature range from −252.76 to −259.2 ° C. It is a colorless liquid, very light (density at −253 ° C 0.0708 g / cm 3) and flowing (viscosity at −253 ° C 13.8 spoise). The critical parameters of hydrogen are very low: temperature −240.2 ° C and pressure 12.8 atm. This explains the difficulties in liquefying hydrogen. In the liquid state, equilibrium hydrogen consists of 99.79% para-H 2, 0.21% ortho-H 2.

Solid hydrogen, melting point −259.2 ° C, density 0.0807 g / cm 3 (at −262 ° C) - snow-like mass, hexagonal crystals, space group P6 / mmc, cell parameters a=3,75 c\u003d 6.12. At high pressure, hydrogen goes into a metallic state.

Isotopes

Hydrogen is found in the form of three isotopes that have individual names: 1 H - protium (H), 2 H - deuterium (D), 3 H - tritium (radioactive) (T).

Protium and deuterium are stable isotopes with mass numbers 1 and 2. Their content in nature is respectively 99.9885 ± 0.0070% and 0.0115 ± 0.0070%. This ratio may vary slightly depending on the source and method of producing hydrogen.

The hydrogen isotope 3 H (tritium) is unstable. Its half-life is 12.32 years. Tritium is found in nature in very small quantities.

The literature also contains data on hydrogen isotopes with mass numbers of 4–7 and half-lives of 10–22–10–23 s.

Natural hydrogen consists of H 2 and HD molecules (deuterium hydrogen) in a ratio of 3200: 1. The content of pure deuterium hydrogen D 2 is even lower. The ratio of the concentrations of HD and D 2 is approximately 6400: 1.

Of all the isotopes of chemical elements, the physical and chemical properties of hydrogen isotopes differ most strongly from each other. This is due to the largest relative change in atomic masses.

	Temperature   melting   K	Temperature   boiling   K	Triple   point,   K / kPa	Critical   point,   K / kPa	Density   liquid / gas   kg / m³

Deuterium and tritium also have ortho and para modifications: p-D 2, o-D 2, p-T 2, o-T 2. Heteroisotopic hydrogen (HD, HT, DT) does not have ortho- and para-modifications.

Chemical properties

The proportion of dissociated hydrogen molecules

The hydrogen molecules of H 2 are quite strong, and in order for hydrogen to enter into a reaction, a lot of energy must be expended:

H 2 \u003d 2H - 432 kJ

Therefore, at ordinary temperatures, hydrogen reacts only with very active metals, for example, calcium, forming calcium hydride:

Ca + H 2 \u003d CaH 2

and with a single non-metal - fluorine, forming hydrogen fluoride:

With most metals and non-metals, hydrogen reacts at elevated temperatures or under other effects, for example, under lighting:

O 2 + 2H 2 \u003d 2H 2 O

It can "take" oxygen from certain oxides, for example:

CuO + H 2 \u003d Cu + H 2 O

The written equation reflects the reducing properties of hydrogen.

N 2 + 3H 2 → 2NH 3

With halogens forms hydrogen halides:

F 2 + H 2 → 2HF, the reaction proceeds with an explosion in the dark and at any temperature,

Cl 2 + H 2 → 2HCl, the reaction proceeds with an explosion, only in the light.

With soot interacts with strong heating:

C + 2H 2 → CH 4

Interaction with alkali and alkaline earth metals

When interacting with active metals, hydrogen forms hydrides:

2Na + H 2 → 2NaH

Ca + H 2 → CaH 2

Mg + H 2 → MgH 2

Hydrides  - salt-like, solid substances, are easily hydrolyzed:

CaH 2 + 2H 2 O → Ca (OH) 2 + 2H 2

Interaction with metal oxides (usually d-elements)

Oxides are reduced to metals:

CuO + H 2 → Cu + H 2 O

Fe 2 O 3 + 3H 2 → 2Fe + 3H 2 O

WO 3 + 3H 2 → W + 3H 2 O

Hydrogenation of Organic Compounds

Molecular hydrogen is widely used in organic synthesis for the reduction of organic compounds. These processes are called hydrogenation reactions. These reactions are carried out in the presence of a catalyst at elevated pressure and temperature. The catalyst can be either homogeneous (e.g. Wilkinson's catalyst) or heterogeneous (e.g. Raney nickel, palladium on carbon).

So, in particular, during the catalytic hydrogenation of unsaturated compounds, such as alkenes and alkynes, saturated compounds are formed - alkanes.

Geochemistry of hydrogen

Free hydrogen H 2 is relatively rare in terrestrial gases, but in the form of water it takes an extremely important part in geochemical processes.

Hydrogen can be a part of minerals in the form of ammonium ion, hydroxyl ion and crystalline water.

In the atmosphere, hydrogen is continuously formed as a result of the decomposition of water by solar radiation. Having a small mass, hydrogen molecules have a high diffusion motion speed (it is close to the second cosmic velocity) and, falling into the upper atmosphere, can fly into outer space.

Features of the appeal

Hydrogen when mixed with air forms an explosive mixture - the so-called explosive gas. This gas has the greatest explosiveness with a volumetric ratio of hydrogen and oxygen of 2: 1, or of hydrogen and air about 2: 5, since oxygen contains about 21% of oxygen. Also, hydrogen is fire hazard. Liquid hydrogen in contact with skin can cause severe frostbite.

Explosive concentrations of hydrogen with oxygen occur from 4% to 96% vol. When mixed with air from 4% to 75 (74)% by volume.

Economy

The cost of hydrogen in bulk deliveries ranges from $ 2-5 per kg.

Application

Atomic hydrogen is used for atomic hydrogen welding.

Chemical industry

• In the production of ammonia, methanol, soap and plastics
• In the production of margarine from liquid vegetable oils
• Registered as a dietary supplement E949  (packing gas)

Food industry

Aviation industry

Hydrogen is very light and always rises in the air. Once airships and balloons were filled with hydrogen. But in the 30s. XX century There were several catastrophes, during which the airships exploded and burned. Nowadays, airships are filled with helium, despite its significantly higher cost.

Fuel

Hydrogen is used as rocket fuel.

Research is underway on the use of hydrogen as a fuel for cars and trucks. Hydrogen engines do not pollute the environment and emit only water vapor.

Hydrogen-oxygen fuel cells use hydrogen to directly convert the energy of a chemical reaction into electrical energy.

"Liquid hydrogen" (“ZhV”) is a liquid aggregate state of hydrogen, with a low specific gravity of 0.07 g / cm³ and cryogenic properties with a freezing point of 14.01 K (−259.14 ° C) and a boiling point of 20.28 K (−252.87 ° C). It is a colorless, odorless liquid which, when mixed with air, is classified as explosive with a range of 4–75% ignition coefficient. The spin ratio of isomers in liquid hydrogen is: 99.79% —hydrogen; 0.21% - orthohydrogen. The hydrogen expansion coefficient when changing the state of aggregation to gaseous is 848: 1 at 20 ° C.

As for any other gas, the liquefaction of hydrogen leads to a decrease in its volume. After liquefaction, “LI” is stored in thermally insulated containers under pressure. Liquid hydrogen Liquid hydrogen, Lh2, Lh 2) is actively used in industry, as a form of gas storage, and in the space industry, as rocket fuel.

Story

The first documented use of artificial cooling in 1756 was made by the English scientist William Cullen, Gaspard Monge was the first to obtain a liquid state of sulfur oxide in 1784, Michael Faraday was the first to receive liquefied ammonia, the American inventor Oliver Evans was the first to develop a refrigeration compressor in 1805, Jacob Perkins was the first to patent a cooling machine in 1834 and John Gorey was the first in the United States to patent an air conditioner in 1851. Werner Siemens proposed the concept of regenerative cooling in 1857, Karl Linde patented equipment for producing liquid air using the cascading "Joule-Thomson expansion effect" and regenerative cooling in 1876. In 1885, the Polish physicist and chemist Sigmund Wroblewski published a critical hydrogen temperature of 33 K, a critical pressure of 13.3 atm. and a boiling point at 23 K. Hydrogen was first liquefied by James Dewar in 1898 using regenerative cooling and his invention, the Dewar flask. The first synthesis of the stable isomer of liquid hydrogen - hydrogen vapor - was carried out by Paul Hartek and Karl Bonhoeffer in 1929.

Spin Hydrogen Isomers

Hydrogen at room temperature consists mainly of the spin isomer, orthohydrogen. After production, liquid hydrogen is in a metastable state and must be converted to a para-hydrogen form in order to avoid the explosive exothermic reaction that occurs when it changes at low temperatures. The conversion to the para-hydrogen phase is usually carried out using catalysts such as iron oxide, chromium oxide, activated carbon, platinum-coated asbestos, rare earth metals or by using uranium or nickel additives.

Using

Liquid hydrogen can be used as a form of fuel storage for internal combustion engines and fuel cells. Various submarines (projects “212A” and “214”, Germany) and hydrogen transport concepts were created using this aggregate form of hydrogen (see, for example, “DeepC” or “BMW H2R”). Due to the proximity of the structures, the creators of the ZhV equipment can use or only modify systems using liquefied natural gas (“LNG”). However, due to the lower bulk density of energy for combustion, a larger volume of hydrogen than natural gas is required. If liquid hydrogen is used instead of LNG in piston engines, a more bulky fuel system is usually required. With direct injection, increased losses in the intake tract reduce cylinder filling.

Liquid hydrogen is also used to cool neutrons in neutron scattering experiments. The masses of the neutron and the hydrogen nucleus are almost equal, so the energy exchange in an elastic collision is most effective.

Benefits

The advantage of using hydrogen is the “zero emission” of its use. The product of its interaction with air is water.

Obstacles

One liter of ZhV weighs only 0.07 kg. That is, its specific gravity is 70.99 g / l at 20 K. Liquid hydrogen requires cryogenic storage technology, such as special thermally insulated containers and requires special handling, which is typical for all cryogenic materials. In this respect, it is close to liquid oxygen, but requires more caution due to fire hazard. Even in the case of containers with thermal insulation, it is difficult to keep it at that low temperature, which is required to keep it in a liquid state (usually it evaporates at a rate of 1% per day). When handling it, you also need to follow the usual safety measures when working with hydrogen - it is cold enough to liquefy air, which is explosive.

Rocket fuel

Liquid hydrogen is a common component of rocket fuels that is used to reactively accelerate launch vehicles and spacecraft. In most liquid hydrogen rocket engines, it is first used to regeneratively cool the nozzle and other parts of the engine, before mixing it with an oxidizing agent and burning it to produce traction. Used modern engines on H 2 / O 2 components consume a hydrogen-rich fuel mixture, which leads to a certain amount of unburned hydrogen in the exhaust. In addition to increasing the specific impulse of the engine by reducing molecular weight, this also reduces the erosion of the nozzle and combustion chamber.

Obstacles to the use of LH in other areas, such as cryogenic nature and low density, are also a limiting factor for use in this case. For 2009, there is only one launch vehicle (Delta-4 launch vehicle), which is entirely a hydrogen rocket. Basically, "LF" is used either on the upper stages of rockets, or on blocks that carry out a significant part of the work to bring the payload into space in a vacuum. As one of the measures to increase the density of this type of fuel, there are proposals for the use of sludge-shaped hydrogen, that is, a semi-frozen form of “LI”.

Hydrogen is the lightest and most common chemical element. Nowadays, everyone has heard about him, and, more recently, he was a great secret even to the best scientists. Agree, this is enough to learn more about the chemical element hydrogen.

Hydrogen: Distribution in Nature

As we said above, hydrogen is the most common element. And not only on Earth, but in the whole Universe! The sun is almost half composed of this chemical element, and most stars are based on hydrogen. In interstellar spaces, hydrogen is also the most common element. On Earth, hydrogen is in the form of compounds. It is part of oil, gases, even living organisms. The World Ocean contains about 11% hydrogen by weight. In the atmosphere it is very little, only about 5 ten thousandths of a percent.

History of the discovery of hydrogen

Even medieval alchemists guessed the existence of hydrogen. So, Paracelsus pointed out in his writings that under the action of acid and iron, “air” bubbles are released. But what kind of "air" he could not understand. In those days, scientists thought that in every combustible substance there is some kind of mystical fiery component that supports combustion. This hunch got the name of the phlogiston theory. Alchemists believed, for example, that a tree consists of ash, which remains after burning, and phlogiston, which is released by burning.
  For the first time, the properties of hydrogen were studied by English chemists Henry Cavendish and Joseph Priestley in the 18th century. But they did not fully realize the essence of their discovery. They thought that light gas (and hydrogen is 14 times lighter than air) is nothing more than a mystical phlogiston.
  And only Antoine Lavoisier proved that hydrogen is not phlogiston, but a real chemical element. During his experiments, he managed to get hydrogen from water and then proved that water is produced back when hydrogen is burned. Therefore, this chemical element has received such a name - "giving birth to water."

Chemical properties of hydrogen

Hydrogen is the very first chemical element in the periodic table is indicated by the symbol H. It is a light gas, odorless and colorless. Solid hydrogen is the lightest solid, and liquid is the lightest liquid. In addition, liquid hydrogen, upon contact with the skin, can cause severe frostbite. Atoms and hydrogen molecules are the smallest. Therefore, the balloon inflated by this gas is blown away very quickly - hydrogen seeps through the rubber. When hydrogen is mixed with atmospheric oxygen, a very explosive mixture is formed. It is called "explosive gas."
When breathing gas, the voice frequency becomes much higher than usual. For example, male coarse bass will be similar to the voices of Chip and Dale. However, such chemical experiments should not be carried out, due to the above. Hydrogen and oxygen form an explosive gas which, when exhaled, can easily explode!

Hydrogen application

Despite its flammability, hydrogen is widely used in many industries. It is mainly used in the production of ammonia for mineral fertilizers and in the production of alcohol and plastic. Once airships and balloons filled hydrogen, this light gas lifted them into the air without any difficulty. But now in aviation and space technology it is used only as fuel for space rockets. Created engines for cars that run on hydrogen. They are the most environmentally friendly, because only water is released during combustion. However, at the moment, hydrogen engines have a number of significant drawbacks, I do not fully meet the safety requirements, so their use is still completely negligible. In the food industry, hydrogen is used in the production of margarine, as well as for packaging products. It is even registered as a food supplement E949. In the energy sector, hydrogen is used to cool generators and to generate electricity in hydrogen-oxygen fuel cells.

In the periodic system has its own specific position, which reflects the properties shown by it and speaks of its electronic structure. However, among all there is one special atom, which occupies two cells at once. It is located in two completely opposite groups of elements in terms of their properties. This is hydrogen. Such features make it unique.

Hydrogen is not just an element, but also a simple substance, as well as an integral part of many complex compounds, a biogenic and organogenic element. Therefore, we consider its characteristics and properties in more detail.

Hydrogen as a chemical element

Hydrogen is an element of the first group of the main subgroup, as well as the seventh group of the main subgroup in the first small period. This period consists of only two atoms: helium and the element we are considering. Let us describe the main features of the position of hydrogen in the periodic system.

1. The ordinal number of hydrogen is 1, the number of electrons is the same, respectively, the number of protons is the same. Atomic mass - 1,00795. There are three isotopes of this element with mass numbers 1, 2, 3. However, the properties of each of them are very different, since an increase in mass even by one is exactly double for hydrogen.
2. The fact that it contains only one electron on the outside allows it to successfully exhibit both oxidizing and reducing properties. In addition, after the recoil of the electron, it remains with a free orbital, which takes part in the formation of chemical bonds by the donor-acceptor mechanism.
3. Hydrogen is a powerful reducing agent. Therefore, his main place is considered to be the first group of the main subgroup, where he leads the most active metals - alkaline.
4. However, when interacting with strong reducing agents, such as, for example, metals, it can also be an oxidizing agent, taking an electron. These compounds are called hydrides. On this basis, he leads a subgroup of halogens with which he is similar.
5. Due to its very small atomic mass, hydrogen is considered the lightest element. In addition, its density is also very low, so it is also a standard of lightness.

Thus, it is obvious that the hydrogen atom is completely unique, unlike all other elements. Therefore, its properties are also special, and the formed simple and complex substances are very important. Let's consider them further.

Simple substance

If we talk about this element as a molecule, then we must say that it is diatomic. That is, hydrogen (a simple substance) is a gas. Its empirical formula will be written as Н 2, and the graphic one through a single sigma-connection Н-Н. The mechanism of bonding between atoms is covalent non-polar.

1. Steam methane conversion.
2. Coal gasification - the process involves heating coal to 1000 0 C, resulting in the formation of hydrogen and high-carbon coal.
3. Electrolysis. This method can be used only for aqueous solutions of various salts, since melts do not lead to discharge of water at the cathode.

Laboratory methods for producing hydrogen:

1. Hydrolysis of metal hydrides.
2. The effect of dilute acids on active metals and medium activity.
3. The interaction of alkali and alkaline earth metals with water.

To collect the generated hydrogen, it is necessary to keep the tube upside down. After all, this gas cannot be collected as, for example, carbon dioxide. This is hydrogen, it is much lighter than air. Quickly disappears, and in large quantities when mixed with air explodes. Therefore, the tube should be turned over. After filling it, you need to close it with a rubber stopper.

To check the purity of the collected hydrogen, you should bring a lit match to the neck. If the cotton is deaf and quiet, then the gas is clean, with minimal air admixtures. If it is loud and whistling - dirty, with a large proportion of extraneous components.

Areas of use

When hydrogen is burned, so much energy (heat) is released that this gas is considered the most profitable fuel. In addition, environmentally friendly. However, to date, its use in this area is limited. This is due to ill-conceived and unsolved problems of the synthesis of pure hydrogen, which would be suitable for use as fuel in reactors, engines and portable devices, as well as heating boilers in residential buildings.

Indeed, the methods for producing this gas are quite expensive, therefore, it is first necessary to develop a special synthesis method. One that will allow you to receive the product in a large volume and at minimal cost.

There are several main areas in which the gas under consideration is used.

1. Chemical syntheses. Soaps, margarines, and plastics are obtained on the basis of hydrogenation. With the participation of hydrogen, methanol and ammonia are synthesized, as well as other compounds.
2. In the food industry - as an additive E949.
3. Aviation industry (rocket science, aircraft construction).
4. Power industry.
5. Meteorology.
6. Ecologically clean fuel.

Obviously, hydrogen is just as important as common in nature. The various compounds formed by him play an even greater role.

Hydrogen compounds

These are complex substances containing hydrogen atoms. There are several main types of similar substances.

1. Hydrogen halides. The general formula is HHal. Of particular importance among them is hydrogen chloride. This is a gas that dissolves in water to form a hydrochloric acid solution. This acid is widely used in almost all chemical syntheses. Moreover, both organic and inorganic. Hydrogen chloride is a compound that has the empirical formula HCL and is one of the largest in terms of production in our country annually. Hydrogen halides also include hydrogen iodide, hydrogen fluoride and hydrogen bromide. All of them form the corresponding acids.
2. Volatile Almost all of them are quite toxic gases. For example, hydrogen sulfide, methane, silane, phosphine and others. It’s very flammable.
3. Hydrides are compounds with metals. Belong to the class of salts.
4. Hydroxides: bases, acids and amphoteric compounds. They necessarily include hydrogen atoms, one or more. Example: NaOH, K 2, H 2 SO 4 and others.
5. Hydrogen hydroxide. This compound is better known as water. Another name is hydrogen oxide. The empirical formula looks like this - H 2 O.
6. Hydrogen peroxide. This is the strongest oxidizing agent, the formula of which is of the form H 2 O 2.
7. Numerous organic compounds: hydrocarbons, proteins, fats, lipids, vitamins, hormones, essential oils and others.

Obviously, the variety of compounds of the element under consideration is very large. This once again confirms its high value for nature and man, as well as for all living beings.

  is the best solvent

As mentioned above, the common name for this substance is water. It consists of two hydrogen atoms and one oxygen, interconnected by covalent polar bonds. The water molecule is a dipole; this explains many of its properties. In particular, the fact that it is a universal solvent.

It is in the aquatic environment that almost all chemical processes occur. Internal reactions of plastic and energy metabolism in living organisms are also carried out using hydrogen oxide.

Water is rightfully considered the most important substance on the planet. It is known that no living organism can live without it. On Earth, it is able to exist in three aggregate states:

• liquid;
• gas (steam);
• solid (ice).

Three types of water are distinguished depending on the isotope of hydrogen that is part of the molecule.

1. Light or prickly. An isotope with a mass number of 1. The formula is H 2 O. This is the familiar form that all organisms use.
2. Deuterium or heavy, its formula is D 2 O. Contains an isotope of 2 N.
3. Extra heavy or tritium. The formula looks like T 3 O, the isotope - 3 N.

The reserves of fresh protium water on the planet are very important. Already now in many countries its lack is felt. Methods are being developed for treating salt water in order to obtain potable water.

Hydrogen peroxide is a universal remedy.

This compound, as mentioned above, is an excellent oxidizing agent. However, with strong representatives, it can also act as a reducing agent. In addition, it has a pronounced bactericidal effect.

Another name for this compound is peroxide. It is in this form that it is used in medicine. The 3% solution of crystalline hydrate of the compound in question is a medical medicine that is used to treat small wounds in order to disinfect them. However, it has been proven that the healing of the wound increases over time.

Hydrogen peroxide is also used in rocket fuel, in industry for disinfection and bleaching, as a foaming agent for the production of appropriate materials (polystyrene, for example). In addition, peroxide helps cleanse aquariums, bleach hair, and whiten teeth. However, it harms tissues, therefore, it is not recommended by specialists for these purposes.