Purification of gasoline from water.
I poured gasoline into the can, then forgot about it and went home. The canister was left open. Rain is coming.
The next day, I wanted to ride an ATV and remembered the gas canister. When I approached it, I realized that the gasoline in it was mixed with water, since yesterday there was clearly less liquid in it. I needed to separate water and gasoline. Realizing that water freezes at a higher temperature than gasoline, I put a can of gasoline in the refrigerator. In the refrigerator, the temperature of gasoline is -10 degrees Celsius. After a while, I took the canister out of the refrigerator. The canister contained ice and gasoline. I poured gasoline through the mesh into another canister. Accordingly, all the ice remained in the first canister. Now I could pour refined gasoline into the ATV's gas tank and finally ride it. When freezing (under conditions of different temperatures), a separation of substances occurred.
Kulgashov Maxim.
In the modern world, human life cannot be imagined without chemical processes. Even in the time of Peter the Great, for example, there was chemistry.
If people did not learn how to mix different chemical elements, then there would be no cosmetics. Many girls are not as beautiful as they seem. Children would not be able to sculpt from plasticine. There would be no plastic toys. Cars don't run without gas. Washing things is much more difficult without washing powder.
Each chemical element exists in three forms: atoms, simple substances and complex substances. The role of chemistry in human life is enormous. Chemists extract many wonderful substances from mineral, animal and vegetable raw materials. With the help of chemistry, a person receives substances with predetermined properties, and from them, in turn, they produce clothes, shoes, equipment, modern means of communication, and much, much more.
As never before, the words of M.V. Lomonosov: “Chemistry stretches its hands wide into human affairs ...”
The production of such products of the chemical industry as metals, plastics, soda, etc., pollutes the environment with various harmful substances.
Achievements in chemistry are not only good. It is important for a modern person to use them correctly.
Makarova Katya.
Can I live without chemical processes?
Chemical processes are everywhere. They surround us. Sometimes we don't even notice their presence in our daily lives. We take them for granted, without thinking about the true nature of the reactions taking place.
Every moment, countless processes take place in the world, which are called chemical reactions.
When two or more substances interact with each other, new substances are formed. There are chemical reactions that are very slow and very fast. An explosion is an example of a rapid reaction: in an instant, solid or liquid substances decompose with the release of a large amount of gases.
The steel plate retains its luster for a long time, but gradually reddish rust patterns appear on it. This process is called corrosion. Corrosion is an example of a slow but extremely insidious chemical reaction.
Very often, especially in industry, it is necessary to speed up a particular reaction in order to get the desired product faster. Then catalysts are used. These substances themselves do not participate in the reaction, but significantly accelerate it.
Any plant absorbs carbon dioxide from the air and releases oxygen. At the same time, many valuable substances are created in the green leaf. This process takes place - photosynthesis in their laboratories.
The evolution of the planets and the entire universe began with chemical reactions.
Belialova Julia.
Sugar
Sugar is the common name for sucrose. There are many types of sugar. These are, for example, glucose - grape sugar, fructose - fruit sugar, cane sugar, beet sugar (the most common granulated sugar).
At first, sugar was obtained only from cane. It is believed that it originally appeared in India, in Bengal. However, due to conflicts between Britain and France, cane sugar became very expensive, and many chemists began to think about how to get it from something else. The first to do this was the German chemist Andreas Marggraf in the early 18th century. He noticed that the dried tubers of some plants have a sweet taste, and when viewed under a microscope, white crystals are visible on them, very similar in appearance to sugar. But Marggraf could not bring his knowledge and observations to life, and mass production of sugar was only started in 1801, when Marggraf's student Franz Karl Arhard bought the Kunern estate and started building the first sugar beet factory. To increase profits, he studied different varieties of beets and identified the reasons why their tubers acquired a high sugar content. In the 1880s, sugar production began to make a big profit, but Archard did not live to see it.
Now beet sugar is mined as follows. The beets are cleaned and crushed, the juice is extracted from it with the help of a press, then the juice is purified from non-sugar impurities and evaporated. Syrup is obtained, boiled until sugar crystals form. With cane sugar, things are more complicated. Sugar cane is also crushed, juice is also extracted, it is cleaned of impurities and boiled until crystals appear in the syrup. However, in this case, only raw sugar is obtained, from which sugar is then made. This raw sugar is refined, removing excess and coloring matter, and the syrup is boiled again until it crystallizes. There is no formula for sugar as such: for chemistry, sugar is a sweet, soluble carbohydrate.
Umansky Kirill.
Salt
Salt - food product. In the ground form, it is small white crystals. Table salt of natural origin almost always has impurities of other mineral salts, which can give it shades of different colors (usually gray). It is produced in different forms: purified and unrefined (rock salt), coarse and fine grinding, pure and iodized, sea salt, etc.
In ancient times, salt was obtained by burning certain plants in fires; the resulting ash was used as seasoning. To increase the salt yield, they were additionally doused with salty sea water. At least two thousand years ago, the extraction of table salt began to be carried out by evaporating sea water. This method first appeared in countries with a dry and hot climate, where the evaporation of water occurred naturally; as it spread, the water began to be heated artificially. In the northern regions, in particular on the shores of the White Sea, the method has been improved: as you know, fresh water freezes earlier than salt water, and the salt concentration in the remaining solution increases accordingly. Thus, fresh and concentrated brine was simultaneously obtained from sea water, which was then evaporated with less energy costs.
Table salt is an important raw material for the chemical industry. It is used to produce soda, chlorine, hydrochloric acid, sodium hydroxide and sodium metal.
A solution of salt in water freezes at temperatures below 0 °C. Being mixed with pure water ice (including in the form of snow), salt causes it to melt due to the selection of thermal energy from the environment. This phenomenon is used to clear roads from snow.
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FSBEI HPE "Bashkir State University"
Scenario of an extracurricular eventin chemistry
“Chemistry spreads its hands wide in human affairs…”
Goals:
1. Expand knowledge of chemistry, instill interest in science.
2. Develop creative abilities.
3. Cultivate the ability to work in a team.
Members: 9th grade students.
Conduct form: KVN.
Order of conduct:
1. Oath of captains.
2. Warm up.
3. Competition "Guessing game".
4. Competition "Table of D.I. Mendeleev".
5. Competition "Draw it yourself."
6. Competition of captains.
7. Competition "Experimenters".
8. Musical competition.
9. Competition "Assignment from the envelope."
10. Homework.
11. Summing up.
Leading:
O you happy sciences!
Stretch out your hands diligently
And look to the farthest places
Pass the earth and the abyss
And steppes and deep forest
And the very height of heaven.
Everywhere explore all the time,
What is great and beautiful
What the world has never seen...
Into the bowels of the earth you, chemistry,
Penetrate the eye with sharpness
And what does Russia contain in it
Open treasure treasures.
M.V. Lomonosov.
Good evening, dear friends. We invited you today to witness the competition in resourcefulness, gaiety, and also in knowledge of the subject of chemistry between the 9th grade teams.
We invite the team "Chemists" (representation of the team, greeting) We invite the team "Lyrics" (representation of the team, greeting)
Leading:
Before the start of the competition, the team captains take an oath.
Oath of captains.
We, the captains of the Chemists (Lyrics) team, have gathered our teams on the chemical duel field and in the face of our teams, fans, the jury and the wise book of chemistry, we solemnly swear:
1) Be honest. extracurricular chemistry education creative
2) Do not pour acid on each other physically and morally.
3) Do not use wrestling, boxing and karate methods when solving chemical tasks.
4) Do not lose your sense of humor until the end of the evening.
Leading:
And now the workout. Warm-up topic: “Ecological problems and chemistry. Who is guilty?" The teams prepared 4 questions for each other.
Chemists start first.
A question sounds - 1 min. for discussion.
Team response.
The Lyrika team asks its first question.
(Etc. for 4 questions).
Leading:
Let's move on to competitions.
1. "Guessing game".
We announce an exit competition within the school. We invite 2 people. Assignment: “Go there, I don’t know where, bring something, I don’t know what.” (Time 25 min).
2. “Table D.I. Mendeleev".
The 2nd competition requires students to know the periodic system. From the chaos of signs, select and write down chemical elements and name them. Hand over the cards to the jury.
3. "Draw yourself."
The 3rd competition invites those who can draw. Blindfolded, draw what the presenter reads. (1 minute.).
In the chemistry room, there is a table by the blackboard, a flask is on the table, brown gas is emitted from the flask.
Have drawn. What kind of gas could it be? (NO2).
Jury word.
Leading:
Captains competition. (Invite to the stage, offer to sit down, give a piece of paper and a pen).
You will listen to a story in which chemical elements or chemicals will be named. Write them down using chemical symbols.
Chemistry story.
It was in Europe, and maybe in America. We sat with Bohr and Berkeley at Fermia. Sat and Kali. I say: “Stop spoiling Oxygen, and so is Sulfur in my soul. Let's go Rubidium." And Berkel: “I am from Gaul, therefore, alone. And I won't give you two Rubidiums. Why should I leave Fermius at all?” Here I am, like Actiny himself, and I say: "Platinum, and that's it!" Finally Palladium. They began to think about who should go to Bariy. Berkeley and says: "I'm completely lame." Then Bor Plumbum came at us, scooped up our Rubidia under Arsenic and went. We are Radius. We are sitting Curium, waiting for Bor. Suddenly we hear: "Aurum, Aurum!". I say: "No Bor!" And Berkeley: "No, Neon!" And he himself is cunning, standing with Gallium, hand on Thalia and Lithium to her, something about Francius. Old Plutonium. And here again: "Aurum, Aurum!" We look, Boron is running, and behind him is the neighboring Cobalt, Argon and Hafnium on him, and his Terbium beyond Arsenic, where our Rubidiums lie. Bor completely Lutetsky became. Screaming, waving his arms. Suddenly we look, and our Rubidium is with Argon in Mercury. This is where Berkeley let us down. He will stand on all fours, and he himself is such a Strontsky, Strontsky and says: "Argonchik, tell Hafnius." Argon is silent and only Cesium through his teeth his “Rrr”. Then Berkliy, too, Lyutetsky stood up and, as if yelling: "Get out," Argon ran away. And Berkelium says to Boru: "Give me Rubidium." A bor: “Not Beryllium, I am your Rubidium. What, am I their Rhodium or what? Astatine me at peace. And Berkel to him: "If I see you again at Fermia, Sodium is your ears."
The captains hand over leaflets with written signs of the chemical elements that were named in the story.
4. 4th competition "Experimenters". Invite 2 people from the team. From the jury, 1 representative for observation.
Experience: "Separation of mixtures"
a) sand and iron filings
a) wood and iron filings
b) sand and sugar
b) salt and clay
Experience: "Recognize substances"
a) KOH, H2SO4, KCl
a) NaOH, Ba(OH)2, H2SO4
Experience: "Get the following substances"
Summing up the competition of captains.
Jury word.
5. Musical competition. The teams were given to prepare a song and dance on a chemical theme.
Summing up the results of the competition "Experimenters".
6. Competition "Assignment from the envelope."
1) What kind of milk do not drink?
2) What element is the basis of inanimate nature?
3) In what water does gold dissolve?
4) For which element in the form of a simple substance, they either pay more than gold, or vice versa, pay to get rid of it?
5) What is the name of the Scientific Society of Soviet Chemists?
6) What is allotropy? Give examples.
Leading:
We listen to the participants of the exit competition.
Preparing for homework.
At this time, the jury sums up the latest competitions.
If the teams are not yet ready, then questions are asked to the fans. For each correct answer, the fan is given a circle, and the team gets 1 point.
1. Is there any metal that melts in the hand?
2. What is glacial acid?
3. What is white gold?
4. What kind of alcohol does not burn?
Leading:
Homework is demonstrated by the team of Chemists (Lyrics)
Topic: "Chemistry lesson in the last century."
Summarizing.
Participant awards.
Literature:
1. Blokhina O.G. I'm Going to Chemistry Lesson: A Teacher's Book. - M .: Publishing house "First of September", 2001.
2. Bocharova S.I. Extracurricular work in chemistry. Grades 8-9. - Volgograd: ITD "Corifey", 2006
3. Kurgansky S.M. Extracurricular work in chemistry: Quizzes and chemical evenings. - M .: 5 for knowledge, 2006.
4. CER in chemistry, disk for grade 9. 1C Education 4th school: ZAO 1C, 2006
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Purpose: to find out why chemistry was Lomonosov's favorite science, and what contribution Mikhail Vasilievich made to it Contents: Biography Biography University of Marburg Lomonosov's merits Lomonosov's merits The law of conservation of mass of substances The law of conservation of mass of substances areas in which Lomonosov left his mark areas in which Lomonosov left their trace of Moscow State University. Lomonosov Moscow State University Lomonosov's office Chemist M.V. Lomonosov's office Chemist M.V. Alexander - Nevsky Lavra The grave of M.V. Lomonosov in the Alexander - Nevsky Lavra
Mikhail Vasilyevich Lomonosov was born on November 8, 1711 in the village of Denisovka near Kholmogory. His father, Vasily Dorofeevich, was a well-known person in Pomorie, the owner of a fish artel and a successful merchant. Mikhail Vasilyevich Lomonosov was born on November 8, 1711 in the village of Denisovka near Kholmogory. His father, Vasily Dorofeevich, was a well-known person in Pomorie, the owner of a fish artel and a successful merchant.
In 1735, 12 of the most capable students were called from the Moscow Academy to the Academy of Sciences. Three of them, including Lomonosov, were sent to Germany, to the University of Marburg, then he continued his education in Freiburg. In 1735, 12 of the most capable students were called from the Moscow Academy to the Academy of Sciences. Three of them, including Lomonosov, were sent to Germany, to the University of Marburg, then he continued his education in Freiburg.
Lomonosov's merits Lomonosov's favorite science is chemistry. He created a chemical laboratory in St. Petersburg and discovered a new law; Lomonosov's favorite science is chemistry. He created a chemical laboratory in St. Petersburg and discovered a new law; While studying physics, he uncovered the riddle of thunderstorms and northern lights; While studying physics, he uncovered the riddle of thunderstorms and northern lights; He loved to watch the stars, improved the telescope; He loved to watch the stars, improved the telescope; Observing Venus, he established that this planet has an atmosphere; Observing Venus, he established that this planet has an atmosphere; He is the first polar geographer in the world; He is the first polar geographer in the world; He was engaged in the history of the ancient Slavs, the history of the manufacture of porcelain; He was engaged in the history of the ancient Slavs, the history of the manufacture of porcelain; And how much he did to improve the Russian language! And how much he did to improve the Russian language! Wrote poetry; Wrote poetry; He revived the production of colored glass and made mosaic paintings ("Portrait of Peter I", "Poltava Battle"); He revived the production of colored glass and made mosaic paintings ("Portrait of Peter I", "Poltava Battle"); Opened the first Russian university in Moscow. Opened the first Russian university in Moscow.
He created the first university. It is better to say, he was our first university. A. S. Pushkin. In 1748 he formulated the most important law of chemistry - the law of conservation of the mass of matter in chemical reactions. The mass of the substances that entered into the reaction is equal to the mass of the substances resulting from it.
The history of mankind knows many versatile gifted people. And among them, one of the first places should be put the great Russian scientist Mikhail Vasilyevich Lomonosov. The history of mankind knows many versatile gifted people. And among them, one of the first places should be put the great Russian scientist Mikhail Vasilyevich Lomonosov. Optics and heat, electricity and gravity, meteorology and art, geography and metallurgy, history and chemistry, philosophy and literature, geology and astronomy are the areas in which Lomonosov left his mark. Optics and heat, electricity and gravity, meteorology and art, geography and metallurgy, history and chemistry, philosophy and literature, geology and astronomy are the areas in which Lomonosov left his mark.
The goal of Lomonosov's life until the very last day was "the establishment of science in the fatherland", which he considered the key to the prosperity of his homeland. The goal of Lomonosov's life until the very last day was "the establishment of science in the fatherland", which he considered the key to the prosperity of his homeland.
Page 7 of 8
Chemistry spreads widely ...
More about the diamond
Raw, rough diamond is the champion of "all minerals, materials and other" in terms of hardness. Modern technology without diamonds would have a hard time.
A finished, polished diamond turns into a diamond, and it has no equal among precious stones.
Blue diamonds are especially valued by jewelers. They are insanely rare in nature, and therefore they pay absolutely crazy money for them.
But God bless them, with diamond jewelry. Let there be more ordinary diamonds so that you do not have to tremble over every tiny crystal.
Alas, there are only a few diamond deposits on Earth, and even fewer rich ones. One of them is in South Africa. And it still provides up to 90 percent of the world's diamond production. Except for the Soviet Union. Ten years ago we discovered the largest diamond-bearing area in Yakutia. Now industrial diamond mining is underway there.
Extraordinary conditions were required for the formation of natural diamonds. Giant temperatures and pressures. Diamonds were born in the depths of the earth's thickness. In places, diamond-bearing melts burst to the surface and solidified. But this happened very rarely.
Is it possible to do without the services of nature? Can a person create diamonds himself?
The history of science has recorded more than a dozen attempts to obtain artificial diamonds. (By the way, one of the first “seekers of happiness” was Henri Moissan, who isolated free fluorine.) Every single one was unsuccessful. Either the method was fundamentally wrong, or the experimenters did not have equipment that could withstand the combination of the highest temperatures and pressures.
Only in the mid-1950s did the latest technology finally find the keys to solving the problem of artificial diamonds. The raw material, as expected, was graphite. He was subjected to simultaneous pressure of 100,000 atmospheres and a temperature of about 3,000 degrees. Now diamonds are prepared in many countries of the world.
But chemists here can only rejoice together with everyone. Their role is not so great: physics took over the main.
But chemists have succeeded in another. They significantly helped to improve the diamond.
How to improve like that? Is there anything more perfect than a diamond? Its crystal structure is the very perfection in the world of crystals. It is thanks to the ideal geometric arrangement of carbon atoms in diamond crystals that the latter are so hard.
You can't make a diamond harder than it is. But it is possible to make a substance harder than diamond. And chemists have created raw materials for this.
There is a chemical compound of boron with nitrogen - boron nitride. Outwardly, it is unremarkable, but one of its features is alarming: its crystal structure is the same as that of graphite. "White graphite" - this name has long been attached to boron nitride. True, no one tried to make pencil leads out of it ...
Chemists have found a cheap way to synthesize boron nitride. Physicists subjected him to cruel tests: hundreds of thousands of atmospheres, thousands of degrees... The logic of their actions was extremely simple. Since “black” graphite has been turned into diamond, is it possible to obtain a substance similar to diamond from “white” graphite?
And they got the so-called borazon, which surpasses diamond in its hardness. It leaves scratches on smooth diamond edges. And it can withstand higher temperatures - you can’t just burn the borazon.
Borazon is still expensive. There is a lot of work to be done to make it cheaper. But the main thing has already been done. Man again proved capable of nature.
…And here is another message that recently came from Tokyo. Japanese scientists have managed to prepare a substance that is much stronger than diamond in hardness. They subjected magnesium silicate (a compound made up of magnesium, silicon and oxygen) to a pressure of 150 tons per square centimeter. For obvious reasons, the details of the synthesis are not advertised. The newborn "king of hardness" does not yet have a name. But that doesn't matter. Another thing is more important: there is no doubt that in the near future diamond, which for centuries headed the list of the hardest substances, will not be in the first place in this list.
Endless molecules
Rubber is known to everyone. These are balls and galoshes. It's a hockey puck and surgeon's gloves. These are, finally, car tires and heating pads, waterproof raincoats and water hoses.
Now rubber and products from it are produced at hundreds of plants and factories. And a few decades ago, natural rubber was used all over the world to make rubber. The word "rubber" comes from the Native American "kao-chao", which means "tears of hevea." And hevea is a tree. Collecting and processing its milky juice in a certain way, people got rubber.
Many useful things can be made from rubber, but it is a pity that its extraction is very laborious and hevea grows only in the tropics. And it was impossible to meet the needs of industry with natural raw materials.
This is where chemistry comes to the rescue. First of all, chemists asked themselves the question: why is rubber so elastic? For a long time they had to investigate the "tears of Hevea", and, finally, they found a clue. It turned out that rubber molecules are built in a very peculiar way. They consist of a large number of repeating identical links and form giant chains. Of course, such a "long" molecule, containing about fifteen thousand units, is able to bend in all directions, and it also has elasticity. The link in this chain turned out to be carbon, isoprene C5H8, and its structural formula can be represented as follows:
It would be more correct to say that isoprene, as it were, represents the original natural monomer. In the process of polymerization, the isoprene molecule changes somewhat: double bonds between carbon atoms are broken. Due to such released bonds, individual links are combined into a giant rubber molecule.
The problem of obtaining artificial rubber has long worried scientists and engineers.
It would seem that the matter is not so hot what a tricky one. First get isoprene. Then make it polymerize. Tie individual isoprene units into long and flexible artificial rubber chains.
It seemed one thing, it turned out another. It was not without difficulty that chemists synthesized isoprene, but as soon as it came to polymerization, rubber did not work out. The links were connected to each other, but haphazardly, and not in any particular order. And artificial products were created, somewhat similar to rubber, but in many ways different from it.
And chemists had to invent ways to get the isoprene units to twist into a chain in the right direction.
The world's first industrial artificial rubber was obtained in the Soviet Union. Academician Sergei Vasilyevich Lebedev chose another substance for this - butadiene:
Very similar in composition and structure to isoprene, but the polymerization of butadiene is easier to control.
A fairly large number of artificial rubbers are now known (unlike natural rubbers, they are now often called elastomers).
Natural rubber itself and products made from it have significant drawbacks. So, it swells strongly in oils and fats, and is not resistant to the action of many oxidizing agents, in particular ozone, traces of which are always present in the air. In the manufacture of products from natural rubber, it has to be vulcanized, that is, subjected to high temperature in the presence of sulfur. This is how rubber is turned into rubber or ebonite. During the operation of natural rubber products (for example, car tires), a significant amount of heat is released, which leads to their aging and rapid wear.
That is why scientists had to take care of creating new, synthetic rubbers that would have more advanced properties. There is, for example, a family of rubbers called "buna". It comes from the initial letters of two words: "butadiene" and "sodium". (Sodium plays the role of a polymerization catalyst.) Some of the elastomers in this family have proven to be excellent. They went mainly to the manufacture of car tires.
Of particular importance is the so-called butyl rubber, which is obtained by the joint polymerization of isobutylene and isoprene. First, it turned out to be the cheapest. And secondly, unlike natural rubber, it is almost not affected by ozone. In addition, butyl rubber vulcanizates, which are now widely used in the manufacture of chambers, are ten times more airtight than natural product vulcanizates.
So-called polyurethane rubbers are very peculiar. Possessing high tensile and tensile strength, they are almost not subject to aging. From polyurethane elastomers prepare the so-called foam rubber, suitable for seat upholstery.
In the last decade, rubbers have been developed that scientists had not thought of before. And above all, elastomers based on organosilicon and fluorocarbon compounds. These elastomers are characterized by high temperature resistance, twice that of natural rubber. They are resistant to ozone, and the rubber based on fluorocarbon compounds is not afraid even of fuming sulfuric and nitric acids.
But that's not all. More recently, so-called carboxyl-containing rubbers, copolymers of butadiene and organic acids, have been obtained. They proved to be exceptionally strong in tension.
We can say that here, too, nature has lost its primacy to materials created by man.
Diamond heart and rhinoceros skin
There is a class of compounds in organic chemistry called hydrocarbons. These are really hydrocarbons - in their molecules, except for carbon and hydrogen atoms, there is nothing else. Typical of their most famous representatives is methane (it makes up about 95 percent of natural gas), and from liquid hydrocarbons - oil, from which various grades of gasoline, lubricating oils and many other valuable products are obtained.
Let's take the simplest of the hydrocarbons, methane CH 4 . What happens if the hydrogen atoms in methane are replaced by oxygen atoms? Carbon dioxide CO 2 . And if on sulfur atoms? Highly volatile poisonous liquid, carbon sulfide CS 2 . Well, what if we replace all hydrogen atoms with chlorine atoms? We also get a well-known substance: carbon tetrachloride. And if you take fluorine instead of chlorine?
Three decades ago, few people could answer anything intelligible to this question. However, in our time, fluorocarbon compounds are already an independent branch of chemistry.
According to their physical properties, fluorocarbons are almost complete analogues of hydrocarbons. But this is where their common properties end. Fluorocarbons, unlike hydrocarbons, turned out to be extremely reactive substances. In addition, they are extremely resistant to heat. No wonder they are sometimes called substances that have a “diamond heart and rhinoceros skin”.
The chemical essence of their stability in comparison with hydrocarbons (and other classes of organic compounds) is relatively simple. Fluorine atoms are much larger than those of hydrogen, and therefore tightly “close” the access of other reactive atoms to the carbon atoms that surround them.
On the other hand, fluorine atoms that have turned into ions are extremely difficult to give up their electron and "do not want" to react with any other atoms. After all, fluorine is the most active of non-metals, and practically no other non-metal can oxidize its ion (take away an electron from its ion). Yes, and the carbon-carbon bond is stable in itself (remember the diamond).
It is precisely because of their inertness that fluorocarbons have found the widest application. For example, fluorocarbon plastic, the so-called Teflon, is stable when heated up to 300 degrees, it is not affected by sulfuric, nitric, hydrochloric and other acids. It is not affected by boiling alkalis, it does not dissolve in all known organic and inorganic solvents.
It is not for nothing that fluoroplastic is sometimes called “organic platinum”, because it is an amazing material for making dishes for chemical laboratories, various industrial chemical equipment, and pipes for various purposes. Believe me, many things in the world would be made of platinum if it were not so expensive. Fluoroplastic is relatively cheap.
Of all substances known in the world, fluoroplast is the most slippery. A fluoroplast film thrown on the table literally "flows" onto the floor. PTFE bearings practically do not need lubrication. Finally, fluoroplastic is a wonderful dielectric, and, moreover, extremely heat-resistant. Fluoroplastic insulation withstands heating up to 400 degrees (above the melting point of lead!).
Such is fluoroplast - one of the most amazing artificial materials created by man.
Liquid fluorocarbons are non-flammable and do not freeze to very low temperatures.
Union of carbon and silicon
Two elements in nature can claim a special position. First, carbon. He is the basis of all living things. And first of all, because carbon atoms are able to firmly connect with each other, forming chain-like compounds:
Secondly, silicon. He is the basis of all inorganic nature. But silicon atoms cannot form such long chains as carbon atoms, and therefore there are fewer silicon compounds found in nature than carbon compounds, although much more than compounds of any other chemical elements.
Scientists decided to "correct" this lack of silicon. Indeed, silicon is as tetravalent as carbon. True, the bond between carbon atoms is much stronger than between silicon atoms. But silicon is not such an active element.
And if it were possible to obtain compounds similar to organic ones with his participation, what amazing properties they could have!
At first, scientists were not lucky. True, it has been proven that silicon can form compounds in which its atoms alternate with oxygen atoms:
However, they proved to be unstable.
Success came when silicon atoms decided to combine with carbon atoms. Such compounds, called organosilicon, or silicones, do have a number of unique properties. On their basis, various resins were created that make it possible to obtain plastic masses that are resistant to high temperatures for a long time.
Rubbers made on the basis of organosilicon polymers have the most valuable qualities, such as heat resistance. Some grades of silicone rubber are resistant up to 350 degrees. Imagine a car tire made from such rubber.
Silicone rubbers do not swell at all in organic solvents. From them began to produce various pipelines for pumping fuel.
Some silicone fluids and resins hardly change viscosity over a wide temperature range. This paved the way for their use as lubricants. Due to their low volatility and high boiling point, silicone fluids are widely used in high vacuum pumps.
Silicone compounds have water-repellent properties, and this valuable quality has been taken into account. They began to be used in the manufacture of water-repellent fabric. But it's not just the fabrics. There is a well-known proverb “water wears away a stone”. At the construction of important structures, they tested the protection of building materials with various organosilicon liquids. The experiments were successful.
On the basis of silicones, strong temperature-resistant enamels have recently been created. Plates of copper or iron coated with such enamels can withstand heating up to 800 degrees for several hours.
And this is only the beginning of a kind of union of carbon and silicon. But such a "dual" union no longer satisfies chemists. They set the task of introducing other elements into the molecules of organosilicon compounds, such as, for example, aluminum, titanium, and boron. Scientists have successfully solved the problem. Thus, a completely new class of substances was born - polyorganometallosiloxanes. In the chains of such polymers, there can be different links: silicon - oxygen - aluminum, silicon - oxygen - titanium, silicon - oxygen - boron, and others. Such substances melt at temperatures of 500-600 degrees and in this sense compete with many metals and alloys.
In the literature, a message somehow flashed that Japanese scientists allegedly managed to create a polymer material that can withstand heating up to 2000 degrees. Perhaps this is a mistake, but a mistake that is not too far from the truth. For the term "heat-resistant polymers" should soon be included in a long list of new materials of modern technology.
Amazing sieves
These sieves are arranged in a rather original way. They are giant organic molecules with a number of interesting properties.
First, like many plastics, they are insoluble in water and organic solvents. And secondly, they include the so-called ionogenic groups, that is, groups that in a solvent (in particular in water) can give one or another ion. Thus, these compounds belong to the class of electrolytes.
The hydrogen ion in them can be replaced by some metal. This is how ions are exchanged.
These peculiar compounds are called ion exchangers. Those that are able to interact with cations (positively charged ions) are called cation exchangers, and those that interact with negatively charged ions are called anion exchangers. The first organic ion exchangers were synthesized in the mid-1930s. And immediately won the widest recognition. Yes, this is not surprising. Indeed, with the help of ion exchangers, it is possible to turn hard water into soft, salty - into fresh.
Imagine two columns - one of them is filled with cation exchange resin, the other with anion exchange resin. Suppose we set out to purify water containing ordinary table salt. We pass water first through the cation exchanger. In it, all sodium ions will be “exchanged” for hydrogen ions, and instead of sodium chloride, hydrochloric acid will already be present in our water. Then we pass the water through the anion resin. If it is in its hydroxyl form (that is, its exchangeable anions are hydroxyl ions), all chloride ions will be replaced in solution by hydroxyl ions. Well, hydroxyl ions with free hydrogen ions immediately form water molecules. Thus, the water, which originally contained sodium chloride, after passing through the ion-exchange columns, became completely desalinated. In terms of its qualities, it can compete with the best distilled water.
But not only water desalination brought wide popularity to ion exchangers. It turned out that ions are held in different ways, with different strengths, by ion exchangers. Lithium ions are stronger than hydrogen ions, potassium ions are stronger than sodium, rubidium ions are stronger than potassium, and so on. With the help of ion exchangers, it became possible to carry out the separation of various metals very easily. Ion exchangers now play an important role in various industries. For example, in photographic factories for a long time there was no suitable way to capture precious silver. It was ion exchangers that solved this important problem.
Well, will a person ever be able to use ion exchangers to extract valuable metals from sea water? This question must be answered in the affirmative. And although sea water contains a huge amount of various salts, it seems that obtaining noble metals from it is a matter of the near future.
Now the difficulty is that when passing sea water through the cation exchanger, the salts that it contains actually do not allow small impurities of valuable metals to settle on the cation exchanger. Recently, however, so-called electron exchange resins have been synthesized. Not only do they exchange their ions for metal ions from solution, but they are also capable of reducing this metal by donating electrons to it. Recent experiments with such resins have shown that if a solution containing silver is passed through them, then not silver ions, but metallic silver are soon deposited on the resin, and the resin retains its properties for a long period. Thus, if a mixture of salts is passed through an electron exchanger, the ions that are most easily reduced can turn into pure metal atoms.
Chemical pincers
As the old joke goes, catching lions in the desert is easy. Since the desert is made of sand and lions, one must take a sieve and sift the desert. The sand will pass through the holes, and the lions will remain on the grate.
But what if there is a valuable chemical element mixed with a huge amount of those that do not represent any value for you? Or it is necessary to purify a substance from a harmful impurity contained in very small quantities.
This happens quite often. The admixture of hafnium in zirconium, which is used in the design of nuclear reactors, should not exceed a few ten thousandths of a percent, and in ordinary zirconium it is about two tenths of a percent.
These elements are very similar in chemical properties, and the usual methods here, as they say, do not work. Even the amazing chemical sieve. Meanwhile, zirconium of an exceptionally high degree of purity is required ...
For centuries, chemists followed the simple recipe: "Like dissolves like." Inorganic substances dissolve well in inorganic solvents, organic - in organic. Many salts of mineral acids dissolve well in water, anhydrous hydrofluoric acid, in liquid hydrocyanic (hydrocyanic) acid. Very many organic substances are quite soluble in organic solvents - benzene, acetone, chloroform, carbon sulfide, etc., etc.
And how will a substance behave, which is something intermediate between organic and inorganic compounds? In fact, chemists were familiar to some extent with such compounds. So, chlorophyll (the coloring matter of a green leaf) is an organic compound containing magnesium atoms. It is highly soluble in many organic solvents. There is a huge number of artificially synthesized organometallic compounds unknown to nature. Many of them are able to dissolve in organic solvents, and this ability depends on the nature of the metal.
This is where the chemists decided to play.
During the operation of nuclear reactors, from time to time it becomes necessary to replace spent uranium blocks, although the amount of impurities (uranium fission fragments) in them usually does not exceed a thousandth of a percent. First, the blocks are dissolved in nitric acid. All uranium (and other metals formed as a result of nuclear transformations) passes into nitrate salts. In this case, some impurities, such as xenon, iodine, are automatically removed in the form of gases or vapors, while others, such as tin, remain in the sediment.
But the resulting solution, in addition to uranium, contains impurities of many metals, in particular plutonium, neptunium, rare earth elements, technetium, and some others. This is where organic matter comes in. A solution of uranium and impurities in nitric acid is mixed with a solution of organic matter - tributyl phosphate. In this case, almost all uranium passes into the organic phase, while impurities remain in the nitric acid solution.
This process is called extraction. After two extractions, the uranium is almost free of impurities and can be used again for the manufacture of uranium blocks. And the remaining impurities go to further separation. The most important parts will be extracted from them: plutonium, some radioactive isotopes.
Similarly, zirconium and hafnium can be separated.
Extraction processes are now widely used in technology. With their help, they carry out not only the purification of inorganic compounds, but also many organic substances - vitamins, fats, alkaloids.
Chemistry in a white coat
He bore a sonorous name - Johann Bombast Theophrastus Paracelsus von Hohenheim. Paracelsus is not a surname, but rather a kind of title. Translated into Russian, it means "super-great". Paracelsus was an excellent chemist, and popular rumor dubbed him a miraculous healer. Because he was not only a chemist, but also a doctor.
In the Middle Ages, the union of chemistry and medicine grew stronger. Chemistry had not yet earned the right to be called a science. Her views were too vague, and her powers were scattered in a futile search for the notorious philosopher's stone.
But, floundering in the nets of mysticism, chemistry learned to heal people from serious illnesses. Thus, iatrochemistry was born. Or medical chemistry. And many chemists in the sixteenth, seventeenth, eighteenth centuries were called pharmacists, pharmacists. Although they were engaged in pure chemistry, they prepared various healing potions. True, they were blind. And not always these “medicines” have benefited a person.
Among the "pharmacists" Paracelsus was one of the most prominent. The list of his medicines included mercury and sulfur ointments (by the way, they are still used to treat skin diseases), iron and antimony salts, and various vegetable juices.
At first, chemistry could only provide doctors with substances that are found in nature. And that is in very limited quantities. But medicine was not enough.
If we leaf through modern prescription guides, we will see that 25 percent of medicines are, so to speak, natural preparations. Among them are extracts, tinctures and decoctions prepared from various plants. Everything else is artificially synthesized medicinal substances unfamiliar to nature. Substances created by the power of chemistry.
The first synthesis of a medicinal substance was carried out about 100 years ago. The healing effect of salicylic acid in rheumatism has long been known. But extracting it from vegetable raw materials was both difficult and expensive. Only in 1874 was it possible to develop a simple method for obtaining salicylic acid from phenol.
This acid formed the basis of many drugs. For example, aspirin. As a rule, the term of "life" of drugs is short: the old ones are replaced by new ones, more advanced, more sophisticated in the fight against various ailments. Aspirin is an exception in this respect. Every year it reveals new, previously unknown amazing properties. It turns out that aspirin is not only an antipyretic and pain reliever, the range of its applications is much wider.
A very “old” medicine is the well-known pyramidon (the year of his birth is 1896).
Now, within a single day, chemists synthesize several new drugs. With a variety of qualities, against a wide variety of diseases. From drugs that fight pain to drugs that help cure mental illness.
To heal people - there is no nobler task for chemists. But there is no more difficult task.
For several years, the German chemist Paul Ehrlich tried to synthesize a drug against a terrible disease - sleeping sickness. In each synthesis, something worked out, but each time Ehrlich remained unsatisfied. Only in the 606th attempt was it possible to obtain an effective remedy - salvarsan, and tens of thousands of people were able to recover not only from sleeping, but also from another insidious disease - syphilis. And in the 914th attempt, Erlich received an even more powerful drug - neosalvarsan.
The path of the medicine from the chemical flask to the pharmacy counter is long. This is the law of medicine: until the medicine has been thoroughly tested, it cannot be recommended for practice. And when this rule is not followed, there are tragic mistakes. Not so long ago, West German pharmaceutical firms advertised a new sleeping pill - tolidomide. A small white pill plunged into a quick and deep sleep a person suffering from persistent insomnia. Praises were sung tolidomide, and he turned out to be a terrible enemy for babies who had not yet been born. Tens of thousands of born freaks - people paid such a price for the fact that they hastened to put an insufficiently tested medicine on sale.
And therefore, it is important for chemists and physicians to know not only that such and such a medicine successfully cures such and such a disease. They need to carefully understand how it works, what is the subtle chemical mechanism of its fight against the disease.
Here is a small example. Now, derivatives of the so-called barbituric acids are often used as sleeping pills. These compounds contain carbon, hydrogen, nitrogen and oxygen atoms. In addition, two so-called alkyl groups, that is, hydrocarbon molecules devoid of one hydrogen atom, are attached to one of the carbon atoms. And this is what the chemists came to. Only then barbituric acid has a hypnotic effect when the sum of carbon atoms in the alkyl groups is not less than four. And the larger this amount, the longer and faster the drug works.
The deeper scientists penetrate into the nature of diseases, the more thorough the research carried out by chemists. And more and more precise science is becoming pharmacology, previously engaged only in the preparation of various drugs and the recommendation of their use against various diseases. Now a pharmacologist should be a chemist, a biologist, a doctor, and a biochemist. To never repeat the tolidomide tragedies.
The synthesis of medicinal substances is one of the main achievements of chemists, the creators of the second nature.
... At the beginning of our century, chemists stubbornly tried to make new dyes. And the so-called sulfanilic acid was taken as the starting product. It has a very “flexible” molecule capable of various rearrangements. In some cases, chemists reasoned, a sulfanilic acid molecule could be transformed into a valuable dye molecule.
And so it turned out in reality. But until 1935, no one thought that synthetic sulfanyl dyes were also powerful drugs. The pursuit of coloring substances faded into the background: chemists began to hunt for new drugs, which were collectively called sulfa drugs. Here are the names of the most famous: sulfidine, streptocid, sulfazol, sulfadimezin. Currently, sulfonamides occupy one of the first places among the chemical means of combating microbes.
... The Indians of South America from the bark and roots of the chilibukha plant produced a deadly poison - curare. The enemy, struck by an arrow, the tip of which was dipped in curare, instantly died.
Why? To answer this question, chemists had to thoroughly understand the mystery of the poison.
They found that the main active principle of curare is the alkaloid tubocurarine. When it enters the body, the muscles cannot contract. Muscles become immobile. The person loses the ability to breathe. Death is coming.
However, under certain conditions, this poison can be beneficial. It can be useful for surgeons when performing some very complex operations. For example, in the heart. When you need to turn off the pulmonary muscles and transfer the body to artificial respiration. So a mortal enemy acts as a friend. Tubocurarine is entering clinical practice.
However, it is too expensive. And we need a drug that is cheap and affordable.
The chemists intervened again. In all respects, they studied the tubocurarine molecule. They split it into various parts, examined the resulting "fragments" and, step by step, found out the relationship between the chemical structure and the physiological activity of the drug. It turned out that its action is determined by special groups that contain a positively charged nitrogen atom. And that the distance between groups should be strictly defined.
Now chemists could embark on the path of imitation of nature. And even try to surpass it. First, they received a drug that is not inferior in its activity to tubocurarine. And then they improved it. Thus was born sinkurin; it is twice as active as tubocurarine.
And here is an even more striking example. Fight against malaria. She was treated with quinine (or, scientifically, quinine), a natural alkaloid. Chemists also managed to create plasmoquine - a substance sixty times more active than quinine.
Modern medicine has a huge arsenal of tools, so to speak, for all occasions. Against almost all known diseases.
There are powerful remedies that calm the nervous system, restoring calm even to the most irritated person. There is, for example, a drug that completely removes the feeling of fear. Of course, no one would recommend it to a student who is afraid of an exam.
There is a whole group of so-called tranquilizers, sedative drugs. These include, for example, reserpine. Its use for the treatment of certain mental illnesses (schizophrenia) played a huge role in its time. Chemotherapy now occupies the first place in the fight against mental disorders.
However, the achievements of medicinal chemistry do not always turn into a positive side. There is, say, such an ominous (otherwise it is difficult to call it) remedy as LSD-25.
In many capitalist countries, it is used as a drug that artificially causes various symptoms of schizophrenia (all kinds of hallucinations that allow you to renounce "earthly hardships" for some time). But there were many cases when people who took LSD-25 pills never returned to their normal state.
Modern statistics show that the majority of deaths in the world are the result of heart attacks or cerebral hemorrhages (strokes). Chemists are fighting these enemies by inventing various heart medicines, preparing drugs that dilate the vessels of the brain.
With the help of Tubazid and PAS synthesized by chemists, doctors successfully defeat tuberculosis.
And finally, scientists are stubbornly looking for ways to fight cancer - this terrible scourge of the human race. There is still a lot of obscure and unknown here.
Doctors are waiting for new miraculous substances from chemists. They wait in vain. Here chemistry has yet to show what it is capable of.
Mold Miracle
This word has been known for a long time. Physicians and microbiologists. Mentioned in special books. But absolutely nothing said to a person far from biology and medicine. And a rare chemist knew its meaning. Now everyone knows him.
The word is "antibiotics".
But even earlier than with the word "antibiotics", a person got acquainted with the word "microbes". It was found that a number of diseases, for example, pneumonia, meningitis, dysentery, typhus, tuberculosis and others, owe their origin to microorganisms. Antibiotics are needed to fight them.
Already in the Middle Ages, it was known about the healing effect of certain types of molds. True, the representations of the medieval Aesculapius were quite peculiar. For example, it was believed that only molds taken from the skulls of people hanged or executed for crimes help in the fight against diseases.
But this is not essential. Significantly different: the English chemist Alexander Fleming, studying one of the types of mold, isolated the active principle from it. This is how penicillin, the first antibiotic, was born.
It turned out that penicillin is an excellent weapon in the fight against many pathogens: streptococci, staphylococci, etc. It is able to defeat even pale spirochete, the causative agent of syphilis.
But although Alexander Fleming discovered penicillin in 1928, the formula of this drug was deciphered only in 1945. And already in 1947, it was possible to carry out a complete synthesis of penicillin in the laboratory. It seemed that man caught up with nature this time. However, it was not there. Conducting a laboratory synthesis of penicillin is not an easy task. Much easier to get it from the mold.
But the chemists did not back down. And here they were able to have their say. Perhaps not a word to say, but a deed to do. The bottom line is that the mold from which penicillin was usually obtained is very little "productive". And scientists decided to increase its productivity.
They solved this problem by finding substances that, when introduced into the hereditary apparatus of a microorganism, changed its characteristics. Moreover, new signs were able to be inherited. It was with their help that they managed to develop a new "breed" of mushrooms, which was much more active in the production of penicillin.
Now the set of antibiotics is very impressive: streptomycin and terramycin, tetracycline and aureomycin, biomycin and erythromycin. In total, about a thousand of the most diverse antibiotics are now known, and about a hundred of them are used to treat various diseases. And chemistry plays a significant role in their preparation.
After microbiologists have accumulated the so-called culture liquid containing colonies of microorganisms, it is the turn of chemists.
It is they who are faced with the task of isolating antibiotics, the “active principle”. Various chemical methods are being mobilized to extract complex organic compounds from natural "raw materials". Antibiotics are absorbed using special absorbers. Researchers use "chemical claws" - they extract antibiotics with various solvents. Purified on ion-exchange resins, precipitated from solutions. This is how a raw antibiotic is obtained, which is again subjected to a long cycle of purification, until finally it appears in the form of a pure crystalline substance.
Some, such as penicillin, are still synthesized with the help of microorganisms. But getting others is only half the work of nature.
But there are also such antibiotics, for example, synthomycin, where chemists completely dispense with the services of nature. The synthesis of this drug from beginning to end is carried out in factories.
Without the powerful methods of chemistry, the word "antibiotic" would never have been able to gain such wide popularity. And there would not have been that genuine revolution in the use of drugs, in the treatment of many diseases, which these antibiotics have produced.
Microelements - plant vitamins
The word "element" has many meanings. So, for example, are called atoms of the same kind, having the same nuclear charge. What are "micronutrients"? So called chemical elements that are contained in animal and plant organisms in very small quantities. So, in the human body, 65 percent oxygen, about 18 percent carbon, 10 percent hydrogen. These are macronutrients, there are many of them. But titanium and aluminum are only one thousandth of a percent each - they can be called microelements.
In the early days of biochemistry, such trifles were ignored. Just think, some hundredths or thousandths of a percent. Such quantities could not be determined then.
The technique and methods of analysis improved, and scientists found more and more elements in living objects. However, the role of trace elements could not be established for a long time. Even now, despite the fact that chemical analysis makes it possible to determine millionths and even hundred millionths of a percent of impurities in almost any sample, the significance of many microelements for the vital activity of plants and animals has not yet been elucidated.
But some things are already known. For example, that in various organisms there are elements such as cobalt, boron, copper, manganese, vanadium, iodine, fluorine, molybdenum, zinc and even ... radium. Yes, it is radium, although in negligible quantities.
By the way, about 70 chemical elements have now been found in the human body, and there is reason to believe that the entire periodic system is contained in human organs. Moreover, each element plays some very specific role. There is even a point of view that many diseases arise due to a violation of the microelement balance in the body.
Iron and manganese play an important role in the process of plant photosynthesis. If you grow a plant in soil that does not contain even traces of iron, its leaves and stems will be white as paper. But it is worth spraying such a plant with a solution of iron salts, as it takes on its natural green color. Copper is also necessary in the process of photosynthesis and affects the absorption of nitrogen compounds by plant organisms. With an insufficient amount of copper in plants, proteins are formed very weakly, which include nitrogen.
Complex organic compounds of molybdenum are included as components in various enzymes. They contribute to better absorption of nitrogen. The lack of molybdenum sometimes leads to leaf burns due to the large accumulation of nitric acid salts in them, which, in the absence of molybdenum, are not absorbed by plants. And molybdenum has an effect on the content of phosphorus in plants. In its absence, there is no conversion of inorganic phosphates into organic ones. The lack of molybdenum also affects the accumulation of pigments (coloring substances) in plants - spotting and pale color of the leaves appear.
In the absence of boron, plants do not absorb phosphorus well. Boron also contributes to better movement of various sugars through the plant system.
Trace elements play an important role not only in plant but also in animal organisms. It turned out that the complete absence of vanadium in the food of animals causes loss of appetite and even death. At the same time, the increased content of vanadium in the diet of pigs leads to their rapid growth and to the deposition of a thick layer of fat.
Zinc, for example, plays an important role in metabolism and is a constituent of animal red blood cells.
The liver, if an animal (and even a person) is in an excited state, releases manganese, silicon, aluminum, titanium and copper into the general circulation, but when the central nervous system is inhibited - manganese, copper and titanium, and the release of silicon and aluminum delays. In addition to the liver, the brain, kidneys, lungs and muscles take part in regulating the content of microelements in the blood of the body.
Establishing the role of microelements in the processes of growth and development of plants and animals is an important and fascinating task of chemistry and biology. In the near future, this will certainly lead to very significant results. And it will open to science one more way to create a second nature.
What do plants eat and what does chemistry have to do with it?
Even the chefs of antiquity were famous for their culinary successes. The tables of the royal palaces were bursting with delicious dishes. Wealthy people became picky eaters.
The plants seemed to be much more unpretentious. And in the sultry desert and in the polar tundra grasses and shrubs coexisted. Let stunted, even miserable, but got along.
Something was needed for their development. But what? Scientists have been looking for this mysterious “something” for many years. They set up experiments. Discussed the results.
But there was no clarity.
It was introduced in the middle of the last century by the famous German chemist Justus Liebig. He was helped by chemical analysis. The scientist “decomposed” the most diverse plants into separate chemical elements. There weren't many of them at first. Only ten: carbon and hydrogen, oxygen and nitrogen, calcium and potassium, phosphorus and sulfur, magnesium and iron. But this ten made the green ocean rage on planet Earth.
Hence the conclusion followed: in order to live, the plant must somehow assimilate, “eat” the named elements.
How exactly? Where are the plant food stores located?
In soil, in water, in air.
But amazing things happened. On some soils, the plant developed rapidly, blossomed and bore fruit. On others, it grew sickly, dried up and became a faded freak. Because these soils lacked some elements.
Even before Liebig, people knew something else. Even if the same agricultural crops are sown year after year on the most fertile soil, the harvest becomes worse and worse.
The soil was depleted. Plants gradually “ate up” all the reserves of the necessary chemical elements contained in it.
It was necessary to "feed" the soil. Introduce the missing substances, fertilizers into it. They have been used since antiquity. Applied intuitively, based on the experience of ancestors.
Liebig elevated the use of fertilizers to the rank of science. Thus, agrochemistry was born. Chemistry has become the servant of crop production. The task arose before her: to teach people to use well-known fertilizers correctly and to invent new ones.
Now dozens of different fertilizers are used. And the most important of them are potassium, nitrogen and phosphorus. Because it is potassium, nitrogen and phosphorus that are the elements without which no plant grows.
A little analogy, or how chemists fed plants with potassium
... There was a time when the now so famous uranium huddled somewhere in the backyard of the interests of chemistry. Only the coloring of the glasses and the photography made timid claims against him. Later, radium was found in uranium. From thousands of tons of uranium ores, an insignificant grain of silver metal was extracted. And waste, containing huge amounts of uranium, continued to clutter up the factory warehouses. At last the hour of uranium has struck. It turned out that it is he who gives man power over the use of atomic energy. Waste has become a treasure.
... The Stassfurt salt deposits in Germany have long been known. They contained many salts, mainly potassium and sodium. Sodium salt, table salt, immediately found use. Potassium salts were discarded without regret. Huge mountains of them piled up near the mines. And people didn't know what to do with them. Agriculture was in great need of potash fertilizers, but the Stassfurt waste could not be used. They contained a lot of magnesium. And he, useful to plants in small doses, turned out to be disastrous in large doses.
This is where chemistry helps. She found a simple method for removing magnesium from potassium salts. And the mountains surrounding the Stassfurt mines began to melt before our very eyes. Historians of science report the following fact: in 1811, the first potash processing plant was built in Germany. A year later there were already four of them, and in 1872 thirty-three factories in Germany processed more than half a million tons of raw salt.
Shortly thereafter, plants for the production of potash fertilizers were established in many countries. And now, in many countries, the extraction of potash raw materials is many times greater than the extraction of table salt.
"Nitrogen catastrophe"
About a hundred years after the discovery of nitrogen, one of the major microbiologists wrote: "Nitrogen is more precious from a general biological point of view than the rarest of the noble metals." And he was absolutely right. After all, nitrogen is an integral part of almost any protein molecule, both plant and animal. No nitrogen, no protein. And no protein - no life. Engels said that "life is a form of existence of protein bodies."
Plants need nitrogen to create protein molecules. But where do they get it from? Nitrogen is distinguished by low chemical activity. Under normal conditions, it does not react. Therefore, plants cannot use nitrogen from the atmosphere. Just the same, "... even though the eye sees, but the tooth is numb." So, the nitrogen pantry of plants is the soil. Alas, the pantry is rather poor. There are not enough compounds containing nitrogen in it. That is why the soil quickly wastes its nitrogen, and it needs to be further enriched with it. Apply nitrogen fertilizers.
Now the concept of "Chilean saltpeter" has become the lot of history. And about seventy years ago, it did not leave the lips.
In the vast expanses of the Republic of Chile, the bleak Atacama Desert stretches. It stretches for hundreds of kilometers. At first glance, this is the most ordinary desert, but one curious circumstance distinguishes it from other deserts of the globe: under a thin layer of sand there are powerful deposits of sodium nitrate, or sodium nitrate. These deposits have been known for a long time, but, perhaps, they were first remembered when there was a shortage of gunpowder in Europe. Indeed, for the production of gunpowder, coal, sulfur and saltpeter were previously used.
An expedition was urgently equipped to deliver an overseas product. However, the entire cargo had to be thrown into the sea. It turned out that only potassium nitrate was suitable for the production of gunpowder. Sodium greedily absorbed moisture from the air, the gunpowder dampened, and it was impossible to use it.
Not for the first time, Europeans had to throw overseas cargo into the sea. In the 17th century, on the banks of the Platino del Pino river, grains of a white metal called platinum were found. Platinum first came to Europe in 1735. But they didn't really know what to do with her. Of the noble metals at that time, only gold and silver were known, and platinum did not find a market for itself. But dexterous people noticed that platinum and gold are quite close to each other in terms of specific gravity. They took advantage of this and began to add platinum to gold, which was used to make coins. It was already fake. The Spanish government banned the import of platinum, and those reserves that still remained in the state were collected and drowned in the sea in the presence of numerous witnesses.
But the story with Chilean saltpeter did not end there. It turned out to be an excellent nitrogen fertilizer, favorably provided to man by nature. Other nitrogen fertilizers were not known at that time. Intensive development of natural deposits of sodium nitrate began. From the Chilean port of Ikvikwe, ships sailed daily, delivering such valuable fertilizer to all corners of the globe.
... In 1898, the world was shocked by the gloomy prediction of the famous Crookes. In his speech, he predicted death from nitrogen starvation for mankind. Every year, along with the harvest, the fields are deprived of nitrogen, and the deposits of Chilean saltpeter are gradually developed. Treasures of the Atacama Desert turned out to be a drop in the ocean.
Then scientists remembered the atmosphere. Perhaps the first person to pay attention to the unlimited reserves of nitrogen in the atmosphere was our famous scientist Kliment Arkadyevich Timiryazev. Timiryazev deeply believed in science and the power of human genius. He did not share Crookes' concerns. Humanity will overcome the nitrogen catastrophe, get out of trouble, Timiryazev believed. And he turned out to be right. Already in 1908, the scientists Birkeland and Eide in Norway, on an industrial scale, fixed atmospheric nitrogen using an electric arc.
Around the same time in Germany, Fritz Haber developed a method for producing ammonia from nitrogen and hydrogen. Thus, the problem of bound nitrogen, which is so necessary for plant nutrition, was finally solved. And there is a lot of free nitrogen in the atmosphere: scientists have calculated that if all the nitrogen in the atmosphere is turned into fertilizer, then this will be enough for plants for more than a million years.
What is phosphorus for?
Justus Liebig believed that a plant can absorb nitrogen from the air. It is necessary to fertilize the soil only with potassium and phosphorus. But it was precisely with these elements that he was not lucky. His "patented fertilizer", which one of the English firms undertook to produce, did not lead to an increase in yield. Only after many years did Liebig understand and openly admit his mistake. He used insoluble phosphate salts, fearing that highly soluble ones would be quickly washed out of the soil by rain. But it turned out that plants cannot absorb phosphorus from insoluble phosphates. And man had to prepare a kind of "semi-finished product" for plants.
Every year, around 10 million tons of phosphoric acid are taken from the fields in the world's crops. Why do plants need phosphorus? After all, it is not part of either fats or carbohydrates. And many protein molecules, especially the simplest ones, do not contain phosphorus. But without phosphorus, all these compounds simply cannot form.
Photosynthesis is not just the synthesis of carbohydrates from carbon dioxide and water, which the plant "jokingly" produces. This is a complex process. Photosynthesis takes place in the so-called chloroplasts - a kind of "organs" of plant cells. The composition of chloroplasts just includes a lot of phosphorus compounds. Roughly approximately, chloroplasts can be imagined in the form of the stomach of an animal, where digestion and assimilation of food takes place, because it is they who deal with the direct “building” blocks of plants: carbon dioxide and water.
The absorption of carbon dioxide from the air by plants occurs with the help of phosphorus compounds. Inorganic phosphates convert carbon dioxide into carbonic acid anions, which later go to the construction of complex organic molecules.
Of course, the role of phosphorus in the life of plants is not limited to this. And it cannot be said that its significance for plants has already been fully elucidated. However, even what is known shows its important role in their life.
Chemical warfare
This is really a war. Only without guns and tanks, rockets and bombs. This is a “quiet”, sometimes invisible to many, war not for life, but for death. And victory in it is happiness for all people.
How much harm does, for example, an ordinary gadfly? It turns out that this malicious creature brings a loss, in our country alone, estimated at millions of rubles a year. What about weeds? In the US alone, their existence is worth four billion dollars. Or take locusts, a real disaster that turns flowering fields into bare, lifeless land. If we calculate all the damage that plant and animal predators cause to the agriculture of the world in one single year, an unimaginable amount will turn out. With this money, 200 million people could be fed for free for a whole year!
What is "cide" in translation into Russian? It means killer. And so the creation of various "cides" was taken up by chemists. They created insecticides - "killing insects", zoocides - "killing rodents", herbicides - "killing grass". All these "cides" are now widely used in agriculture.
Prior to World War II, inorganic pesticides were widely used. Various rodents and insects, weeds were treated with arsenic, sulfur, copper, barium, fluoride and many other toxic compounds. However, starting from the mid-forties, organic pesticides are becoming more widespread. Such a "roll" in the direction of organic compounds was made quite deliberately. The point is not only that they turned out to be more harmless to humans and farm animals. They have more versatility, and they require significantly less than inorganic ones to obtain the same effect. So, just a millionth of a gram of DDT powder per square centimeter of surface completely destroys some insects.
There were some oddities in the use of organic pesticides. One of the effective pesticides is currently considered hexachloran. However, probably few people know that this substance was first obtained by Faraday in 1825. Chemists have been researching hexachlorane for more than a hundred years, not even suspecting its miraculous properties. And only after 1935, when biologists began to study it, this insecticide began to be produced on an industrial scale. The best insecticides at present are organophosphorus compounds, such as phosphamide or M-81.
Until recently, external preparations were used to protect plants and animals. However, judge for yourself: it rained, the wind blew, and your protective substance disappeared. Everything must start over. Scientists thought about the question - is it possible to introduce pesticides into the protected organism? They vaccinate a person - and he is not afraid of diseases. As soon as microbes enter such an organism, they are immediately destroyed by the invisible “health guardians” that appeared there as a result of the administration of the serum.
It turned out that it is quite possible to create pesticides of internal action. Scientists have played on the different structure of the organisms of insect pests and plants. For plants, such a pesticide is harmless, for an insect it is a deadly poison.
Chemistry protects plants not only from insects, but also from weeds. So-called herbicides have been created, which have a depressing effect on weeds and practically do not harm the development of a cultivated plant.
Perhaps one of the first herbicides, oddly enough, were ... fertilizers. So, it has long been noted by agricultural practitioners that if increased amounts of superphosphate or potassium sulfate are applied to the fields, then with the intensive growth of cultivated plants, the growth of weeds is inhibited. But here, as in the case of insecticides, organic compounds play a decisive role in our time.
Farmer's helpers
The boy is over sixteen. And here he is, perhaps for the first time in the perfume department. He's not here out of curiosity, but out of necessity. His mustache has already begun to break through, and they need to be shaved.
For beginners, this is quite an interesting operation. But in about ten or fifteen years, she will get so bored that sometimes you want to grow a beard.
Take, for example, grass. It is not allowed on the railroad tracks. And people from year to year "shave" it with sickles and scythes. But imagine the railway Moscow - Khabarovsk. This is nine thousand kilometers. And if all the grass along its length is mowed, and more than once during the summer, almost a thousand people will have to be kept on this operation.
Is it possible to come up with some kind of chemical way to "shave"? It turns out you can.
To mow the grass on one hectare, it is necessary that 20 people work all day. Herbicides complete a "kill operation" in the same area in a few hours. And destroy the grass completely.
Do you know what defoliants are? "Folio" means "leaf". A defoliant is a substance that causes them to fall off. Their use made it possible to mechanize cotton harvesting. From year to year, from century to century, people went out to the fields and manually picked cotton bushes. Anyone who has not seen manual cotton picking can hardly imagine the full burden of such work, which, above all, takes place in a desperate heat of 40-50 degrees.
Now everything is much easier. A few days before opening the cotton bolls, cotton plantations are treated with defoliants. The simplest of them is Mg 2 . Leaves fall from the bushes, and now cotton harvesters are working in the fields. By the way, CaCN 2 can be used as a defoliant, which means that when the bushes are treated with it, nitrogen fertilizer is additionally introduced into the soil.
But in its assistance to agriculture, in "correcting" nature, chemistry went even further. Chemists discovered the so-called auxins - plant growth accelerators. True, at first natural. The simplest of them, such as heteroauxin, chemists have learned to synthesize in their laboratories. These substances not only accelerate the growth, flowering and fruiting of plants, but increase their stability and viability. In addition, it turned out that the use of auxins in high concentrations has the opposite effect - it inhibits the growth and development of plants.
There is an almost complete analogy with medicinal substances. Thus, drugs containing arsenic, bismuth, mercury are known, but in large (rather elevated) concentrations, all these substances are poisonous.
For example, auxins can greatly lengthen the flowering time of ornamental plants, and primarily flowers. With sudden spring frosts, slow down the bud break and flowering of trees, and so on and so forth. On the other hand, in cold areas with short summers, this will allow the "fast" method to grow crops of many fruits and vegetables. And although these abilities of auxins have not yet been implemented on a large scale, but are only laboratory experiments, there can be no doubt that in the near future the helpers of farmers will come to wide open spaces.
Serving ghosts
Here is a fact for a newspaper sensation: grateful colleagues present a venerable scientist with ... an aluminum vase. Any gift deserves gratitude. But isn't it true, to give an aluminum vase ... There is something to be ironic about ...
It is now. A hundred years ago, such a gift would have seemed exceptionally generous. It was really presented by English chemists. And not to anyone, but to Dmitri Ivanovich Mendeleev himself. As a sign of great services to science.
See how everything in the world is relative. In the last century, they did not know a cheap way to extract aluminum from ores, and therefore the metal was expensive. We found a way, and prices quickly flew down.
Many elements of the periodic system are still expensive. And this often limits their application. But we are sure, for the time being. Chemistry and physics will more than once carry out a "price reduction" for elements. They will definitely conduct it, because the further, the more inhabitants of the periodic table the practice involves in the scope of its activities.
But among them there are those that are either not found in the earth's crust, or they are insanely few, almost non-existent. Say, astatine and francium, neptunium and plutonium, promethium and technetium…
However, they can be prepared artificially. And as soon as a chemist holds a new element in his hands, he begins to think: how to give him a start in life?
So far, the most important artificial element in practice is plutonium. And its world production now exceeds the extraction of many "ordinary" elements of the periodic system. We add that chemists consider plutonium to be one of the most studied elements, although it is a little more than a quarter of a century old. All this is not accidental, since plutonium is an excellent "fuel" for nuclear reactors, in no way inferior to uranium.
On some American earth satellites, americium and curium served as energy sources. These elements are highly radioactive. When they break up, a lot of heat is released. With the help of thermocouples, it is converted into electricity.
And what about promethium, which has not yet been found in terrestrial ores? Miniature batteries, slightly larger than the cap of an ordinary pushpin, are created with the participation of promethium. Chemical batteries, at best, last no more than six months. A promethium atomic battery operates continuously for five years. And the range of its applications is very wide: from hearing aids to guided projectiles.
Astat is ready to offer its services to doctors to combat thyroid diseases. They are now trying to treat it with the help of radioactive radiation. It is known that iodine can accumulate in the thyroid gland, but astatine is a chemical analogue of iodine. Introduced into the body, astatine will be concentrated in the thyroid gland. Then its radioactive properties will say a weighty word.
So some artificial elements are by no means an empty place for the needs of practice. True, they serve a person one-sidedly. People can only use their radioactive properties. The hands have not yet reached the chemical features. The exception is technetium. Salts of this metal, as it turned out, can make steel and iron products resistant to corrosion.
Brain ring in chemistry
"Chemistry stretches its hands wide into the affairs of men."
Expand knowledge of chemistry, instill interest in science
Develop creative abilities
Develop the ability to work in pairs
Participants: students in grades 9-10
1. Introductory speech of the teacher.
Hello guys! We invited you today to witness the competition in resourcefulness, gaiety, as well as knowledge of the subject of chemistry between teams of 9th and 10th grades.
And so let me remind you that today we are holding a “BRAIN RING” of 6 rounds.
Dear fans, today you are allowed to prompt, give independent answers, and you can become participants in the 6th round, fight with future winners.
Our brain ring will be watched by our JURY:…….
Team greetings are evaluated on a five-point system
SO, let's now give the floor to our teams.
I. ROUND "Great chemists"
1. Read the law of the constancy of the composition of chemical compounds and name the French scientist who discovered this law. (Answer: Proust Joseph Louis)
2. Add a numeral to the name of the chemical elements of the 3rd group to get the name of the Russian scientist - chemist and composer.
(Answer: Bor-one \u003d Borodin Alexander Porfiryevich 12. 11. 1833–27. 02. 87)
3. Peter the Great said: “I foresee that the Russians, someday, and perhaps even during our lifetime, will shame the most enlightened peoples with their successes in the sciences, indefatigability in labor and the majesty of firm and loud glory.”
Question. Now you have to decide who these verses belong to and very briefly tell what kind of person this is.
"O you who await
Fatherland from its bowels
And wants to see them
Which he calls from the camps of strangers,
Oh, your days are blessed!
Dare now encouraged,
Show with your care
What can own Platos
And quick mind of the Newtons
Russian land to give birth. Answer. M. V. Lomonosov
5. A. A. Voskresensky worked at the St. Petersburg Main Pedagogical Institute, lectured at the Institute of Communications, the Corps of Pages, and the Engineering Academy. In 1838–1867 taught at Petersburg University.
Question. What is the name of his most famous student? The grateful student called his teacher "the grandfather of Russian chemistry."
Answer: D. I. Mendeleev.
6. Give your favorite saying by A. A. Voskresensky, which was often repeated by D. I. Mendeleev”
Answer: "Gods do not burn pots and make bricks."
7. Who and when proposed a simple and understandable system of alphabetic characters for expressing the atomic composition of chemical compounds. How many years have chemical symbols been used.
Answer: 1814 Swedish scientist Jan Berzelius. The signs have been used for 194 years.
Word of the JURY
II ROUND "Acids"
1. What acid and its salts served the cause of war and destruction for several centuries.
Answer: Nitric acid.
2. Name at least 5 acids that a person eats.
Answer: Ascorbic, citric, acetic, lactic, malic, valerian, oxalic ...
3. What is "vitriol"?
Answer: sulfuric acid (pl. 1, 84, 96, 5%, due to its oily appearance, was obtained from iron sulfate (until the middle of the 18th century.)
4. There is the concept of acid rain. Is it possible for acid snow, fog or dew to exist? Explain this phenomenon.
We'll call the cat first
The second is to measure the water column,
Union for the third will go to us
And become whole
Answer. Acid
"The Secret of the Black Sea" Yu. Kuznetsov.
Shaking Crimea in the twenty-eighth year,
And the sea reared up
Emitting to the horror of the peoples,
Fiery sulfur pillars.
Everything is gone. Again the foam is walking,
But since then, everything is higher, everything is denser
Gloomy Sulfur Gehenna
Approaches the bottoms of the ships.
(!?) Write diagrams of possible OVR that take place in this episode.
Answer: 2H2S+O2=2H2O+2S+Q
S+O2=SO2
2H2+3O2=H2O+3O2+Q
III. ROUND (P, S, O, N,)
1. "Yes! It was a dog, huge, black as pitch. But none of us mortals had ever seen such a dog. Flames burst out of its mouth, eyes threw sparks, a flickering fire poured over its muzzle and nape. inflamed brain could not have a vision more terrible, more disgusting than this infernal creature that jumped out of the fog at us ... A terrible dog, the size of a young lioness. His huge mouth still glowed with a bluish flame, deep-set eyes were I touched this luminous head and, taking my hand away, I saw that my fingers also glowed in the darkness.
Learned? Arthur Conan Doyle "The Hound of the Baskervilles"
(!?) What element is involved in this bad story? Give a brief description of this element.
Answer: Characteristic according to the position in the PSHE.1669, the alchemist Brand discovered white phosphorus. For its ability to glow in the dark, he called it "cold fire"
2. How to remove nitrates from vegetables? Suggest at least three ways.
Answer: 1. Nitrates are soluble in water, vegetables can be soaked in water.2. When heated, nitrates decompose, therefore, it is necessary to cook vegetables.
3. What city in Russia is called a rock-raw material for the production of phosphate fertilizers?
Answer: Apatity, Murmansk region.
4. As you know, the outstanding naturalist of antiquity Pliny the Elder died in 79 AD. during a volcanic eruption. His nephew wrote in a letter to the historian Tacitus “...Suddenly thunder rumbled, and black sulfuric vapors rolled down from the mountain flame. Everyone fled. Pliny got up and, leaning on two slaves, thought to leave too; but the deadly steam surrounded him on all sides, his knees gave way, he fell again and suffocated.
Question. What was the sulfur fumes that killed Pliny?
Answer: 1) 0.01% hydrogen sulfide in the air kills a person almost instantly. 2) sulfur oxide (IV).
5. Whether you want to whitewash ceilings, copper an item, or kill pests in your garden, dark blue crystals are a must.
Question. Give the formula of the compound that forms these crystals.
Answer. Copper vitriol. CuSO4 * 5 H2O.
Word of the JURY
IV. ROUND - question - answer
Which element is always happy? (radon)
Which elements claim to "may give birth to other substances" (carbon, hydrogen, oxygen)
What will be the environment when sodium carbonate is dissolved in water? (alkaline)
What is the name of the positively charged particle that is formed when current is passed through an electrolyte solution (cation)
What chemical element is part of the structure that Tom Sawyer had to paint (fence - boron)
The name of which metal carries the magician (magnesium magician)
V. ROUND (As , Sb ,Bi )
1. Criminal law legislation has always singled out poisoning from among other types of murders as a particularly serious crime. Roman law saw poisoning as a combination of murder and betrayal. Canon law placed poisoning on a par with witchcraft. In the codes of the XIV century. For poisoning, a particularly frightening death penalty was established - wheeling for men and drowning with preliminary torture for women.
At different times, in different circumstances, in different forms, it acts as a poison and as a unique healing agent, as a harmful and dangerous waste product, as a component of the most useful, irreplaceable substances.
Question. What chemical element are we talking about, what is the serial number and its relative atomic mass.
Answer. Arsenic. Ar =34.
2. What chronic disease does tin suffer from? What metal is able to cure the disease?
Answer. Tin turns to powder at low temperatures – “tin plague”. Bismuth (antimony and lead) atoms, when added to tin, cement its crystal lattice, stopping the “tin plague”.
3. What chemical element did the alchemists depict as a writhing snake?
Answer. With the help of a wriggling snake in the Middle Ages, arsenic was depicted, emphasizing its poisonousness.
5. What chemical element did the alchemists depict as a wolf with an open mouth?
Answer. Antimony was depicted in the form of a wolf with an open mouth. She received this symbol because of her ability to dissolve metals, and in particular gold.
6. By connecting what chemical e.g. Was Napoleon poisoned?
Answer. Arsenic.
VI. ROUND (Chemistry in everyday life)
1. What can't you bake a sour apple pie without?
Answer. No soda.
2. Without what substance is it impossible to iron overdried things?
Answer. Without water.
3. Name the metal that is in a liquid state at room temperature.
Answer. Mercury.
4. What substance is used to treat too acidic soils.
Answer. Lime.
5. Does sugar burn? Try it.
Answer. All substances burn. But to ignite sugar, you need a catalyst - ash from a cigarette.
6. Since ancient times, mankind has used preservatives to preserve food. Name the main preservatives.
Answer. Salt, smoke, honey, oil, vinegar.
While the JURY is counting the results of the competitions and will announce the winner, I will ask the fans questions:
What kind of milk do not drink? (limestone)
What element is the basis of inanimate nature? (hydrogen)
What water dissolves gold? (aqua regia)
For which element in the form of a simple substance, sometimes they pay more than for gold, then vice versa, they pay to get rid of it? (mercury)
What is allotropy? Give examples.
What is glacial acid? (vinegar)
Which alcohol does not burn? (ammonia)
What is white gold? (alloy of gold with platinum, nickel or silver)
Word of the JURY.
Winner's reward ceremony
