Production and presence of hydrogen in space. Which chemical element is the most common and why? The Ten Most Common Elements in the Milky Way Galaxy

Space agencies and private companies are already developing plans to send humans to Mars in the next few years, eventually leading to its colonization. And with the increasing number of discovered Earth-like planets around nearby stars, long-distance space travel is becoming increasingly relevant.

However, it is not easy for humans to survive in space for long periods of time. One of the major challenges of long-distance spaceflight is transporting enough oxygen for astronauts to breathe and enough fuel to operate complex electronics. Unfortunately, there is practically no oxygen in space, so it needs to be stored on Earth.

But new research published in Nature Communications shows that it is possible to produce hydrogen (for fuel) and oxygen (for respiration) from water using only semiconductor material, sunlight (or starlight) and weightlessness, making long-distance travel more feasible.

Using the unlimited resource of the Sun to power our daily lives is one of the most global challenges on Earth. As we slowly move away from oil and toward renewable energy sources, researchers are interested in the possibility of using hydrogen as a fuel. The best way to do this would be to separate water (H2O) into its components: hydrogen and oxygen. This is possible using a process known as electrolysis, which involves passing a current through water containing some soluble electrolyte (such as salt - approx. translation). As a result, water breaks down into oxygen and hydrogen atoms, which are each released at its own electrode.

Electrolysis of water.

Although this method is technically possible and has been known for centuries, it is still not readily available on Earth because we need more hydrogen-related infrastructure - such as hydrogen refueling stations.

Hydrogen and oxygen obtained from water in this way can also be used as fuel in spacecraft. Launching a rocket with water would actually be much safer than launching it with extra propellant and oxygen on board, since the mixture could be explosive in an accident. Now in space, special technology will be able to separate water into hydrogen and oxygen, which, in turn, can be used to maintain breathing and the functionality of electronics (for example, using fuel cells).

There are two options for this. One is electrolysis, as on Earth, using electrolytes and solar cells to produce current. But, alas, electrolysis is a very energy-intensive process, and energy in space is already “worth its weight in gold.”

An alternative is to use photocatalysts, which work by absorbing photons by a semiconductor material placed in water. The photon energy “knocks” an electron out of the material, leaving a “hole” in it. A free electron can interact with protons in water to form hydrogen atoms. Meanwhile, the “hole” can absorb electrons from the water to form protons and oxygen atoms.



The process of photocatalysis in terrestrial conditions and in microgravity (a million times less than on Earth). As can be seen, in the second case the number of gas bubbles appearing is greater.

This process can be reversed. Hydrogen and oxygen can be recombined (combined) using a fuel cell, resulting in the return of solar energy spent on photocatalysis and the formation of water. Thus, this technology is the real key to deep space travel.

The process using photocatalysts is the best option for space travel because the equipment weighs much less than what is needed for electrolysis. In theory, working with it in space is also easier. This is partly due to the fact that the intensity of sunlight outside the Earth's atmosphere is much higher, since in the latter a fairly large part of the light is absorbed or reflected on the way to the surface.

In a new study, scientists dropped a fully operational photocatalysis experimental facility from a 120-meter-tall tower, creating conditions called microgravity. As objects fall to Earth in free fall, the effect of gravity decreases (but gravity itself does not disappear, which is why it is called microgravity, not no gravity - approx. translation), since there are no forces that compensate for the Earth’s gravity - thus, during the fall, conditions are created in the installation as on the ISS.

Experimental setup and experimental process.

Researchers were able to show that under such conditions it is indeed possible to split water. However, since this process produces gas, bubbles form in the water. An important task is to get rid of the catalyst material bubbles as they interfere with the gas creation process. On Earth, gravity causes bubbles to float to the surface (water near the surface is denser than bubbles, allowing them to float on the surface), freeing up space at the catalyst for further bubbles to form.

In zero gravity this is impossible, and gas bubbles remain on or near the catalyst. However, the scientists adjusted the shape of the catalyst at the nanoscale, creating pyramidal zones where the bubble could easily break away from the top of the pyramid and enter the water without interfering with the process of formation of new bubbles.

But one problem remains. In the absence of gravity, the bubbles will remain in the liquid even though they have been forced to leave the catalyst. Gravity allows the gas to easily escape from the liquid, which is critical for the use of pure hydrogen and oxygen. Without gravity, no gas bubbles float on the surface and separate from the liquid - instead, the equivalent of foam forms.

This dramatically reduces the efficiency of the process by blocking the catalysts or electrodes. Engineering solutions around this problem will be key to the successful implementation of the technology in space - one possible solution is to rotate the installation: in this way, centrifugal forces will create artificial gravity. But nevertheless, thanks to this new research, we are one step closer to long-duration human spaceflight.

Hydrogen (H) is a very light chemical element, with a content of 0.9% by weight in the Earth's crust and 11.19% in water.

Characteristics of hydrogen

It is the first among gases in lightness. Under normal conditions, it is tasteless, colorless, and absolutely odorless. When it enters the thermosphere, it flies off into space due to its low weight.

In the entire universe, it is the most numerous chemical element (75% of the total mass of substances). So much so that many stars in outer space are made entirely of it. For example, the Sun. Its main component is hydrogen. And heat and light are the result of the release of energy when the nuclei of a material merge. Also in space there are entire clouds of its molecules of various sizes, densities and temperatures.

Physical properties

High temperature and pressure significantly change its qualities, but under normal conditions it:

It has high thermal conductivity when compared with other gases,

Non-toxic and poorly soluble in water,

With a density of 0.0899 g/l at 0°C and 1 atm.,

Turns into liquid at a temperature of -252.8°C

Becomes hard at -259.1°C.,

Specific heat of combustion 120.9.106 J/kg.

It requires high pressure and very low temperatures to turn into a liquid or solid. In a liquefied state, it is fluid and light.

Chemical properties

Under pressure and upon cooling (-252.87 degrees C), hydrogen acquires a liquid state, which is lighter in weight than any analogue. It takes up less space in it than in gaseous form.

It is a typical non-metal. In laboratories, it is produced by reacting metals (such as zinc or iron) with dilute acids. Under normal conditions it is inactive and reacts only with active non-metals. Hydrogen can separate oxygen from oxides, and reduce metals from compounds. It and its mixtures form hydrogen bonds with certain elements.

The gas is highly soluble in ethanol and in many metals, especially palladium. Silver does not dissolve it. Hydrogen can be oxidized during combustion in oxygen or air, and when interacting with halogens.

When it combines with oxygen, water is formed. If the temperature is normal, then the reaction proceeds slowly; if it is above 550°C, it explodes (it turns into detonating gas).

Finding hydrogen in nature

Although there is a lot of hydrogen on our planet, it is not easy to find in its pure form. A little can be found during volcanic eruptions, during oil production and where organic matter decomposes.

More than half of the total amount is in the composition with water. It is also included in the structure of oil, various clays, flammable gases, animals and plants (presence in every living cell is 50% by the number of atoms).

Hydrogen cycle in nature

Every year, a colossal amount (billions of tons) of plant residues decomposes in water bodies and soil, and this decomposition releases a huge mass of hydrogen into the atmosphere. It is also released during any fermentation caused by bacteria, combustion and, along with oxygen, participates in the water cycle.

Hydrogen Applications

The element is actively used by humanity in its activities, so we have learned to obtain it on an industrial scale for:

Meteorology, chemical production;

Margarine production;

As rocket fuel (liquid hydrogen);

Electric power industry for cooling electric generators;

Welding and cutting of metals.

A lot of hydrogen is used in the production of synthetic gasoline (to improve the quality of low-quality fuel), ammonia, hydrogen chloride, alcohols, and other materials. Nuclear energy actively uses its isotopes.

The drug “hydrogen peroxide” is widely used in metallurgy, the electronics industry, pulp and paper production, for bleaching linen and cotton fabrics, for the production of hair dyes and cosmetics, polymers and in medicine for the treatment of wounds.

The "explosive" nature of this gas can become a lethal weapon - a hydrogen bomb. Its explosion is accompanied by the release of a huge amount of radioactive substances and is destructive for all living things.

Contact of liquid hydrogen and skin can cause severe and painful frostbite.

Generalizing scheme "HYDROGEN"

a) Position in PSHE

• serial number No. 1
• period 1
• group I (main subgroup “A”)
• relative mass Ar(H)=1
• Latin name Hydrogenium (giving birth to water)

b) The prevalence of hydrogen in nature

c) Valence of hydrogen in compounds

II. Hydrogen is a simple substance (H 2)

Receipt

Finding hydrogen in nature.

Hydrogen is widespread in nature; its content in the earth's crust (lithosphere and hydrosphere) is 1% by mass and 16% by number of atoms. Hydrogen is part of the most common substance on Earth - water (11.19% of Hydrogen by mass), in the composition of compounds that make up coal, oil, natural gases, clays, as well as animal and plant organisms (that is, in the composition of proteins, nucleic acids , fats, carbohydrates and others). Hydrogen is extremely rare in its free state; it is found in small quantities in volcanic and other natural gases. Minor amounts of free Hydrogen (0.0001% by number of atoms) are present in the atmosphere. In near-Earth space, Hydrogen in the form of a flow of protons forms the internal (“proton”) radiation belt of the Earth. In space, Hydrogen is the most abundant element. In the form of plasma, it makes up about half the mass of the Sun and most stars, the bulk of the gases of the interstellar medium and gaseous nebulae. Hydrogen 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, and radicals. In the form of a stream of protons, Hydrogen is part of the corpuscular radiation of the Sun and cosmic rays.

There are three isotopes of hydrogen:
a) light hydrogen - protium,
b) heavy hydrogen – deuterium (D),
c) superheavy hydrogen – tritium (T).

Tritium is an unstable (radioactive) isotope, so it is practically never found in nature. Deuterium is stable, but it is very small: 0.015% (of the mass of all terrestrial hydrogen).

Valence of hydrogen in compounds

In compounds, hydrogen exhibits valence I.

Physical properties of hydrogen

The simple substance hydrogen (H 2) is a gas, lighter than air, colorless, odorless, tasteless, boiling point = – 253 0 C, hydrogen is insoluble in water, flammable. Hydrogen can be collected by displacing air from a test tube or water. In this case, the test tube must be turned upside down.

Hydrogen production

In the laboratory, hydrogen is produced as a result of the reaction

Zn + H 2 SO 4 = ZnSO 4 + H 2.

Instead of zinc, you can use iron, aluminum and some other metals, and instead of sulfuric acid, you can use some other dilute acids. The resulting hydrogen is collected in a test tube by displacing water (see Fig. 10.2 b) or simply in an inverted flask (Fig. 10.2 a).

In industry, hydrogen is produced in large quantities from natural gas (mainly methane) by reacting it with water vapor at 800 °C in the presence of a nickel catalyst:

CH 4 + 2H 2 O = 4H 2 +CO 2 (t, Ni)

or treat coal at high temperature with water vapor:

2H 2 O + C = 2H 2 + CO 2. (t)

Pure hydrogen is obtained from water by decomposing it with electric current (subjecting to electrolysis):

2H 2 O = 2H 2 + O 2 (electrolysis).

A colorless, odorless, flammable gas. The density of hydrogen under normal conditions is 0.09 kg/m3; air density - 0.07 kg/m3; calorific value - 28670 kcal/kg; minimum ignition energy - 0.017 mJ. Forms an explosive mixture with air and oxygen. A mixture with chlorine (1:1) explodes in the light; with fluoride hydrogen connects with an explosion in the dark; mixture with (2:1) - explosive gas. Explosion limits: from 4 - 75 vol. %, with oxygen 4.1 - 96 vol. %.

The day its reserves run out, life in the Universe will cease. The substance, without which life is impossible, “sits” in the very center of our planet - in and around the core, and from there “migrates” outward. This gas is the beginning of all beginnings. His name - " hydrogen».
Hydrogen found in and around the core. Next comes the dense mantle. But this gas quietly migrates through the rock mass. When the Earth was young, there was much more hydrogen in the depths, and from the depths it went out throughout the Earth. When it became smaller, the process became relatively stabilized, and hydrogen began to “go out” in special zones, along the faults of oceanic ridges.
Of course, modern life on Earth arose at a certain oxygen potential. But to be objective, we owe the beginning of all beginnings on our planet to hydrogen. It was the dynamic cycle of hydrogen, the process of its entry from the bowels of the Earth, and not carbon, as was previously believed, that became the source of the origin of life on Earth.

Hydrogen and the Universe

Usually, in order to emphasize the significance of a particular element, they say: if it were not there, then such and such would have happened. But, as a rule, this is nothing more than a rhetorical device. And here hydrogen may someday really not become, because it continuously burns in the bowels of stars, turning into inert.
Hydrogen is the most abundant element in space. It accounts for about half the mass of the Sun and most other stars. It is found in gas nebulae, in interstellar gas, and is part of stars. In the depths of stars, the transformation of atomic nuclei occurs hydrogen into the nuclei of helium atoms. This process occurs with the release of energy; For many stars, including the Sun, it serves as the main source of energy.
Every second, the Sun emits energy equivalent to four million tons of mass into outer space. This energy is created during the fusion of four nuclei hydrogen, protons, into the nucleus. The “combustion” of one gram of protons releases twenty million times more energy than the combustion of a gram of coal. No one has ever observed such a reaction on Earth: it occurs at a temperature and pressure that exists only in the depths of stars and has not yet been mastered by humans.
A power equivalent to a mass loss of four million tons every second is impossible to imagine: even with the most powerful thermonuclear explosion, only about a kilogram of matter is converted into energy. However, the speed of the process, i.e. Number of Cores hydrogen, turning into helium nuclei in one cubic meter in one second, is small. Therefore, the amount of energy released per unit time per unit volume is small. Thus, it turns out that the specific power of the Sun is negligible - much less than the power of such a “heat-generating device” as a person himself! And calculations show that the Sun will continue to shine unabated for at least another thirty billion years. Enough for our lifetime.

Giving birth to water

Hydrogen was discovered in the first half of the 16th century by the German physician and naturalist Paracelsus. In the works of chemists of the 16th–18th centuries. "flammable gas" or "flammable air" was mentioned, which, when combined with ordinary gas, produced explosive mixtures. It was obtained by acting on certain metals (iron, zinc, tin) with dilute solutions of acids - sulfuric and hydrochloric.
The first scientist to describe the properties of this gas was the English scientist Henry Cavendish. He determined its density and studied combustion in air, but adherence to the phlogiston theory* prevented the researcher from understanding the essence of the processes occurring.
In 1779 Antoine Lavoisier received hydrogen when decomposing water, passing its vapors through a red-hot iron tube. Lavoisier also proved that when “combustible air” interacts with oxygen, water is formed, and the gases react in a volumetric ratio of 2:1. This allowed the scientist to determine the composition of water - H2O. Lavoisier and his colleagues derived the name of the element – ​​Hydrogenium – from the Greek words “gidor” - water and “gennao” - I give birth. Russian name "hydrogen" was proposed by the chemist M.F. Soloviev in 1824 - by analogy with Lomonosov’s “oxygen”.
Hydrogen- a colorless gas, tasteless and odorless, slightly soluble in water. It is 14.5 times lighter than air - the lightest of gases. That's why hydrogen They used to fill balloons and airships. At a temperature of -253°C, hydrogen liquefies. This colorless liquid is the lightest of all known: 1 ml weighs less than a tenth of a gram. At -259°C, liquid hydrogen freezes, turning into colorless crystals.
Molecules H2 so small that they can easily pass not only through small pores, but also through metals. Some of them, such as nickel, can absorb large amounts hydrogen and hold it in atomic form in the voids of the crystal lattice. Palladium foil heated to 250°C freely passes hydrogen; This is used to thoroughly clean it from other gases.
With solubility hydrogen in metals is related to its ability to diffuse through metals. Moreover, being the lightest gas, hydrogen has the highest diffusion rate: its molecules spread faster than the molecules of all other gases in the environment of another substance and pass through various kinds of partitions.
Hydrogen- an active substance that easily enters into chemical reactions. When it burns, a lot of heat is released, and the only reaction product is water: 2H2 + O2 = 2H2O. One can only dream of such environmentally friendly fuel!
Today (though in limited quantities for now) cars with hydrogen engines. This is the BMW Hydrogen 7, which uses liquid fuel as fuel. hydrogen; a Mercedes Citaro bus and a Mazda RX-8 Hydrogen passenger car, running simultaneously on gasoline and hydrogen. And the Boeing company is developing an unmanned aircraft of high altitude and flight duration (High Altitude Long Endurance (HALE). The aircraft is equipped with hydrogen engine manufactured by Ford Motor Company. However, development hydrogen energy sector is hampered by the high degree of risk when working with this gas, as well as the difficulties of storing it.

An experience that almost cost your life

With air oxygen hydrogen forms an explosive mixture - explosive gas. Therefore, when working with hydrogen special care must be taken. Clean hydrogen It burns almost silently, and when mixed with air it produces a characteristic loud bang. An explosion of detonating gas in a test tube does not pose a danger to the experimenter, but serious injury can occur when using a flat-bottomed flask or thick glass container.
Hydrogen has a dual chemical nature, exhibiting both oxidizing and reducing properties. In most reactions it acts as a reducing agent, forming compounds in which its oxidation state is +1. But in reactions with active metals it acts as an oxidizing agent: its oxidation state in compounds with metals is -1.
Thus, by giving up one electron, hydrogen shows similarity with the metals of the first group of the periodic table, and by adding an electron, with non-metals of the seventh group. That's why hydrogen in the periodic table they are usually placed either in the first group and at the same time in brackets in the seventh, or in the seventh group and in brackets in the first.

Use and production of hydrogen

Used hydrogen in the production of methanol, hydrogen chloride, for the hydrogenation of vegetable fats (in the production of margarine), also for the recovery of metals (molybdenum, tungsten, indium) from oxides. Refractory metals and alloys are welded and cut using a hydrogen-oxygen flame (3000°C). Liquid hydrogen serves as rocket fuel.
During hydrogenation of coal and oil, poor hydrogen low-grade fuels are transformed into high-quality ones.
Hydrogen used to cool powerful electric current generators, and its isotopes are used in nuclear energy.
In industry, hydrogen is produced by electrolysis of aqueous solutions of salts (for example, NaCl, Na2CO4), as well as during the conversion of solid and gaseous fuels - coal and natural gas. Conversion processes take place at a temperature of about 1000°C in the presence of catalysts. The resulting gas mixture is called synthesis gas.

Almost every home medicine cabinet contains a bottle of 3% peroxide solution. hydrogen H2O2. It is used to disinfect wounds and stop bleeding.

Depending on the purpose, technical hydrogen Available in compressed and uncompressed form in two brands:

Hydrogen gas grade “A”- used in the electronic, pharmaceutical, chemical industries, in powder metallurgy: for deposition of refractory compounds from metal oxides; when sintering products made from powder materials containing chromium and stainless steel.
- used in energy, electronics, chemical, non-ferrous metallurgy, pharmaceutical industries.