Grosse E., Weissmantel H. Chemistry for the curious Chemistry for the curious

Grosse E., Weissmantel H.

Chemistry for the curious. Basics of chemistry and entertaining experiments.

Erich Grosse, Christian Weissmantel

Chemie selbst erlebt. Das kannst auch du das chemie-experimentierbuch 2nd Russian ed. - L.: Chemistry, 1985-

Leipzig, 1974.

Translation from German by L. N. Isaeva, ed. R. B. Dobrotina (Ch. 1-3) and A. B. Tomchina (Ch. 4-8)

(c) Urania-Verlag Leipzig-Jena-Berlin. Verlag fur popularwissenchaftliche Literatur. Leipzig, 1968

(c) Translation into Russian, Khimiya Publishing House, 1978 OCR and Spellcheck Afanasyev Vladimir and [email protected]

IN The book outlines the basics of inorganic and organic chemistry in a popular and entertaining manner. The experiments described in it, which can be done in a chemistry circle and even at home, will help to actively master the material and awaken interest in chemistry. The uniqueness of the book lies in the fact that it is accessible for independent study, and the choice of experiments is determined not so much by their external effect as by their cognitive value.

The purpose of the book is to captivate the young reader with chemistry and prepare him for practical work in a laboratory or enterprise.

FROM THE PUBLISHER Releasing the first Russian edition this book, we felt some anxiety -

after all, the book is intended for German schoolchildren; it often mentions industrial enterprises GDR, examples from life and everyday life are given that are close to the young citizen of this country... Will these details not obscure the main content of the book? But the lively reader interest, manifested in letters and discussions, and most importantly, in the speed with which “Chemistry for the Curious” disappeared from book shelves, convinced us of the opposite.

Over the years, the first readers became adults, and the books, naturally, became worn out. And now we are pleased to offer the second (mass) edition to a new generation of readers.

Not only to captivate the young reader with science, not only to instill in him the practical skills necessary to work in a laboratory or in production, but also to help him seriously, in an adult way, decide whether he wants and can connect his destiny with chemistry - that is the goal of this books.

As for the details of the economic geography of the GDR, some details of life specific to this country, the organization of production, etc., they themselves are of considerable educational value.

I WANT TO BECOME A CHEMIST - I want to become a chemist! - this is how high school student Justus Liebig (he was born in 1803) answered the question

director of the Darmstadt Gymnasium about the choice future profession. This caused laughter from the teachers and schoolchildren present during the conversation. The fact is that at the beginning of the last century in Germany and in most other countries such a profession was not taken seriously. Chemistry was viewed as an applied part of natural science, and although theoretical ideas about substances were developed, experimentation was most often not given due importance.

But Liebig, while still studying at the gymnasium, was engaged in experimental chemistry. His passion for chemical experiments helped him in his future research work. Already at the age of 21, Liebig became a professor in Giessen and organized a one-of-a-kind chemical school, which attracted young adherents of this science from different countries. It served as a prototype for modern special educational institutions. The innovation of teaching was, in fact, that students paid a lot of attention to experiments. It was only thanks to Liebig that the center of gravity of the chemistry course was transferred from the classroom to the laboratory.

IN Nowadays, the desire to become a chemist does not make anyone laugh; on the contrary, the chemical industry is constantly in need of people who combine extensive knowledge and experimental skills with a love of chemistry.

This book should help young chemists delve deeper into modern problems chemistry. The experiments discussed here are mostly borrowed from practice. We will try to reproduce complex processes of chemical technology using simple auxiliary means.

Anyone who has ever been to a chemical plant has seen huge apparatus, high-pressure boilers, electric and flame furnaces, a network of pipelines - all this makes up the appearance of modern chemical production. But any chemical technological process begins in the laboratory. A few test tubes, glass tubes and flasks are often the first functioning model of a modern process plant. Of course, a modern researcher also needs complex and expensive instruments: analytical balances, special ovens, thermostats, autoclaves, spectrographs, electron microscopes. But when an experimental chemist enters an unknown area, he cannot rely only on instruments and apparatus, he must improvise and, using simple equipment, carry out more and more new experiments. Only the one who can assemble working installations, who will work with unflagging tenacity on every experiment and overcome the failures that await every experimenter, will become a good chemist.

The experiments described here do not use dangerous poisons or explosives, but this does not mean that the drugs recommended in the book are completely harmless. In chemistry, such irreplaceable reagents as, for example, some acids and alkalis are constantly used. Before starting the experiments, it is necessary to carefully study the last chapter, which comments on the use of individual drugs and devices. Of course, using the book as a guide, you can conduct many experiments, but it is much more important to prepare thoroughly, carefully assemble the equipment and carefully observe the progress of the process. Preliminary preparations, a sketch of the equipment, all observations and results of the experiment - all this must be recorded in the protocol.

I would like to object in advance to those parents who believe that chemical experiments are a frivolous game with health. To avoid danger, you must follow all specified precautions and do not experiment with hazardous substances at your own peril and risk. Frivolity is unacceptable in any case - whether it relates to chemical experiments, behavior on the street or sports.

We hope that our reader will first of all thoroughly study the school chemistry course, read and special literature(a list of recommendations is given at the end of the book). The purpose of this book is to complement the basic systematic ideas. Experiments are necessary for the practical consolidation and creative development of theoretical knowledge.

The proposed experiments cover various areas of chemistry. Therefore, our book is useful not only for future chemists, but also for those who will become builders, metallurgists, agronomists, textile workers...

The role of chemistry in various fields of technology and Agriculture is increasing all the time - this is the chemicalization of the national economy. Without numerous chemicals and materials it would be impossible to increase the power of mechanisms and Vehicle, expand the production of consumer goods and increase labor productivity. The chemical-pharmaceutical industry produces a variety of medicines that improve human health and prolong life.

Now in the chemical industry of the GDR, more than three hundred thousand people are employed at such plants as, for example, Leina, Schwedt, Schkopau, Bitterfeld, Wolfen, Guben and others.

For the further development of the chemical industry, integration within the framework of the socialist community is very useful (for example, oil from the USSR is supplied via an oil pipeline to the GDR, Poland and Czechoslovakia). In accordance with the comprehensive program of socialist economic integration, many giant chemical enterprises have already been built, for example, a huge pulp mill in Eastern Siberia, an installation for producing high-density polyethylene, etc.

To improve the well-being and better meet the needs of workers, skilled workers, engineers and scientists are needed. And for sure many of our young readers will take part in the implementation of this program.

1. WATER AND AIR ARE THE CHEAPEST RAW MATERIALS WATER IS SUBSTANCE NO. 1

Water is found almost everywhere on Earth; 70% of the earth's surface is occupied by the world's oceans; more than 1.5 trillion tons of water are contained in this gigantic reservoir. Under the influence of solar heat, part of the sea water constantly evaporates, and the resulting water vapor rises into the air. If air containing water vapor cools, tiny water droplets will be released. These droplets make up clouds that are carried by wind currents from the sea to the continent. Under certain conditions, small droplets merge into larger ones, and rain, snow or hail falls on the Earth. The soil absorbs this precipitation and collects it in groundwater. Excess water comes out of

soils in the form of springs, from which streams flow, merging into small and large rivers. And the rivers carry the water back to the sea, and this is how this water cycle in nature ends.

Without the water cycle, the Earth would have a completely different appearance. The modern structure of mountains and valleys, sea coasts and areas remote from the sea - all this arose under the influence of the mechanical and chemical effects of water.

Without water there would be no life on Earth. All living things need water, which is also the most important component of plants and animals. Our body is approximately 65% ​​water; in some jellyfish its content even reaches 99%. If water suddenly disappeared from the surface of the Earth, it would turn into a dead desert.

EXPERIMENTS WITH WATER Anyone who has ever studied chemistry for at least a few hours knows that water IS a chemical

compound. And her chemical formula- H2O is well known to everyone. Water consists of two elements - hydrogen and oxygen. But we still want to experiment! Let's try to decompose the compound "water" into its component parts and then create it again. We warn you: this problem is not easy to solve; water is a very stable compound. To separate a hydrogen atom from an oxygen atom, very strong auxiliary means are needed, and on the contrary, hydrogen combines with oxygen easily

And extremely stormy. In this case, the (usually incorrect) saying is justified: chemistry is where something sparkles and rumbles.

Let's break down the water

IN fill a test tube made of refractory glass with iron powder (metal powder is available for sale, you can also take very thin metal filings) in a layer 2-3 cm. Then add 0.5 ml of water drop by drop. Iron powder absorbs water. Sprinkle another three centimeter layer of dry iron powder onto the wet mixture. We close the test tube with a rubber stopper, through which we pass a curved glass tube with an internal cross-section of 3-6 mm. We will protect the inner side of the plug from strong heating with a piece of sheet asbestos, asbestos or glass wool. Then we fix the test tube at an angle on a stand or in a test tube holder, as shown in the figure. We immerse the gas outlet tube in water and attach an inverted test tube filled with water above its end. This device for trapping gases is called a pneumatic bath.

For the experiment to be successful, it is necessary that the iron powder, starting from the dry end of the column, be heated as hot as possible. This requires a strong Bunsen burner. With the gas pressure not too low, let us increase the air supply as much as possible, so that the flame is divided into an inner cone and a “non-luminous” outer part. However, one should not allow the flame to slip through (this is indicated by a weak whistle), since in this case combustion begins already inside the burner and it becomes very hot. It is necessary to immediately extinguish the burner, closing off the gas access, and then relight it, after first limiting the air supply.

Place the burner under the test tube so that the hottest outer edge of the non-luminous flame flows around the test tube. First, we will heat the area located slightly above the dry column of iron powder until the test tube noticeably heats up. Then slowly bring the flame under the area of ​​dry iron powder.

The wet layer heats up, the water evaporates, and the water vapor interacts with the hot iron powder. In this case, iron captures oxygen in the water, and hydrogen is released. It passes through a glass tube, and bubbles are formed in the trapping device, which are collected in a test tube filled with water. This happens so quickly that we will have time to fill the second test tube. Each test tube that is being filled directly under water must be capped and only then removed from the pneumatic bath.

If gas bubbles stop forming, stop heating and ignite the formed hydrogen. To do this, turn the test tube upside down, open it and bring the flame from below into the hole. The gas will burn quickly. We will see blue flames and hear a whistling sound, and maybe a loud bang. If it pops, it means that the test tube contains not pure hydrogen, but mixed with air. Air can get in when it is displaced from the equipment at the beginning of the experiment or when using low-quality test tubes. Just in case, in order not to be injured by shrapnel in a possible explosion, before igniting the gas, wrap the test tube with a damp cloth.

Iron combines easily with oxygen, so it can displace hydrogen from water. At room temperature this process proceeds very slowly, on the contrary, at red-hot temperatures it proceeds rapidly. Hydrogen burns when ignited. It combines with oxygen in the air,

And water is formed again. If hydrogen is not mixed with oxygen or air from the beginning, combustion

proceeds calmly. A mixture of hydrogen with air or pure oxygen explodes. Such a mixture is called detonating gas, and the test tube test described above is a test for detonating gas. If we are working with hydrogen, then before the experiment it is necessary to use this test to make sure that the hydrogen does not contain air.

Based on our first experience, we can give a general recipe for the decomposition of a chemical compound: in order to free component A from compound AB, you need to react with it substance C, which combines with B more easily than A. Iron is more prone to form a compound with oxygen, than hydrogen, and as a result displaces it from water. Other metals are also capable of this, such as zinc, aluminum, magnesium or sodium. Such metals are called active, while inactive metals: copper, silver, gold and platinum cannot decompose water (All of the above applies to certain conditions. Indeed, at ordinary temperatures, iron does not combine with water, at least not as quickly as as it happens in the experiment described. At the same time, even liquid water interacts with sodium without heating. The indicated series of metals can be quite strictly composed if the conditions are clearly defined. It is in this way that the voltage series, which will be discussed below, is constructed. - Approx. ed. Metals, according to their ability to combine with oxygen, can be placed in a series that begins with the most noble metal - gold, and ends with the most reactive alkali metals - sodium, potassium, etc. The tendency to combine with an element is called affinity in chemistry. Gold has a weak, and sodium has a very strong affinity for oxygen. Those metals whose affinity for oxygen is greater than the affinity for hydrogen can displace hydrogen from water.

Magnesium is active but protected Base metals such as sodium or potassium react violently with water to form

grounds. Magnesium can also decompose water even at room temperature: 2Mg + 2H2O? 2Mg(OH)2 + H2

However, the resulting magnesium hydroxide is very poorly soluble in water. It remains on the metal in the form of a thin film, which delays further dissolution. Due to this inhibition of the reaction, many metals do not dissolve in water. However, if you boil a little magnesium powder in a flask with 5 ml of water and a few drops of an alcohol solution of phenolphthalein for several minutes, the liquid will turn red. A very small amount of magnesium hydroxide (less than 0.1 mg/l) is enough for the indicator to show the main reaction. This little experience gives an idea of ​​the high sensitivity of many chemical reactions.

Now we need to detect hydrogen, which was obtained as a result of the decomposition of water by magnesium. Since in pure water decomposition practically ceases due to the formation of a protective film, care must be taken to ensure that the hydroxide layers are continuously destroyed. We use additives for this. We achieve the desired effect with very small amounts of acid or salts such as iron (III) chloride or magnesium chloride. Place several pieces of magnesium or a little magnesium powder, or a piece of magnesium strip, into wide test tubes. Fill one of these test tubes with tap water, the other with water to which very small amounts of acid or vinegar have already been added, and the third with a diluted solution of iron (III) chloride or table salt. Gas bubbles form in acidified water and salt solutions, and magnesium dissolves vigorously. If you fill a narrow test tube with water and, turning it upside down, immerse it in a wide test tube, you can collect the gas released. From acidified water we will get so much of it that we will be able to test for detonating gas.

The formation of a surface inert film is called passivation. If it were not for this phenomenon, chromium, aluminum and many other metals would be destroyed in a very short time by atmospheric oxygen or water vapor.

Electrolytic decomposition of water For the decomposition of water by electric current, the Hoffmann apparatus is most often used. Who doesn't

has such an apparatus, he can easily build such a device himself. Take a piece of very wide glass tube (for example, a beaker or a wide-necked flask without a bottom. How to remove the bottom is described in Chapter 8, and the sharp edges must be melted on the flame of a Bunsen burner). Close the opening of the tube or the neck of the bottle with a very tightly fitted rubber stopper. In the cork, at a not too close distance from each other, we will drill two holes into which we will insert two carbon rods as electrodes. Such rods can be purchased or taken from a battery for an electric flashlight. Before use, clean the carbon rods by boiling them in water for a long time. To the lower ends of the carbon rods we will connect current leads from insulated

copper wire. It is best to get suitable terminals from an electrician and solder the stripped ends of the wires to them. As a last resort, wrap the rod with wire. The insulating varnish from the wire must be thoroughly cleaned, and the number of turns must be large enough. We will connect the wires to a flashlight battery or, better yet, to a lead-acid battery. If we find a variable resistance of several ohms, we will include it in the circuit. Then the electrolysis speed will be well regulated.

Fill the prepared electrolysis vessel approximately two-thirds with water, to which we add a little diluted sulfuric acid. Clean water is carried out electricity very bad. Even a small amount of acid greatly increases the conductivity. It is best that the concentration of sulfuric acid is 2-4%. Be careful - even dilute sulfuric acid will corrode the skin. Remember forever: when diluting an acid, it should be poured into water very slowly; In no case should you do the opposite - pour water into acid.

The cell is ready. Now let's close the electrical circuit. Gas is released at both electrodes: weaker at the positive pole (anode), stronger at the negative pole (cathode). Let's collect gases to study them. To do this, place inverted test tubes filled with water over the electrodes - just so that they do not stand on the rubber stopper, otherwise electrical circuit will be interrupted.

IN Gas will collect in both test tubes. Ideally, you should expect that exactly half as much gas will form at the anode as at the cathode. After all, oxygen is released at the anode, and hydrogen is released at the cathode. Since the formula of water is H2O, there are two hydrogen atoms per oxygen atom, and the decomposition of water should produce twice as many hydrogen atoms as oxygen. On the other hand, we know from the school course that equal volumes of gases always contain an equal number of molecules (Avogadro’s law), and both the hydrogen molecule and the oxygen molecule contain two atoms of the element.

Despite the correctness of this theory, we will be somewhat disappointed when we compare the resulting volumes of gases. There will be little oxygen, since some of it will combine with the carbon of the electrode. For accurate studies, it is necessary to use electrodes made of noble metal (preferably platinum).

Let's experiment with gases. If you use a sufficiently powerful current source (for example, a battery) during electrolysis, then

Significant quantities of both gases can be obtained and simple experiments can be carried out with them.

IN In a test tube filled with hydrogen, we will test for detonating gas. In general, it gives a negative result, and the resulting pure hydrogen burns quietly. True, you can also get a positive reaction - if hydrogen is mixed with oxygen dissolved in the water of the pneumatic bath. This can happen when the tubes are placed carelessly or, most often, when the electrodes are close together. Oxygen can be easily detected using a smoldering splinter. Let's light a wooden splinter, leave it to burn in the air for a while, then extinguish the flame by quickly blowing on it. We introduce the smoldering, charred end of the splinter into a test tube with oxygen. We will see how the smoldering splinter ignites. We will continue our research as long as there is gas in the test tubes. With our electrolysis device we can also obtain pure detonating gas and explode it. To do this, place a thick-walled glass filled with water simultaneously over both electrodes. During electrolysis, a mixture of oxygen and hydrogen will accumulate in it. As soon as the glass begins to fill, carefully bring it, with the hole down, to the flame of the Bunsen burner. A strong pop will follow and the walls of the vessel will become moist. From individual elements, as a result of a compound reaction, we obtained water.

Just be sure to carry out this experiment wearing safety glasses! To avoid an accident, you should get instructions from a knowledgeable specialist before experimenting. In addition, it is possible to obtain a gas mixture only in small quantities, using, as a last resort, a glass with a capacity of no more than 250 ml. Wrap the glass in a damp, thick cloth (preferably a towel) so as not to get hurt if it breaks. And one more thing: before setting fire to the mixture, as a precaution, let's open our mouth to protect our eardrums. Please also note that electrolytic hydrogen production is often accompanied by explosions. This explosive gas spontaneously ignites under the influence of an electric spark or catalytically active impurities. For this reason, you can only obtain small amounts of gas and keep a sufficient distance during the experiment.

WATER IN CRYSTALS Chemicals are considered especially pure if they are homogeneous, sufficiently large

And well formed crystals. Contaminated substances do not form crystals at all or they are small and irregular in shape. Of course, this does not mean that every non-crystalline

the substance is contaminated. And it is precisely the largest and most beautiful crystals that often contain water of crystallization, which is bound in the crystal and can only be removed with great difficulty; in this case the crystals are destroyed. Chemists do not classify water of crystallization as a contaminant of a chemical compound. In all experiments, however, if we want to obtain quantitatively correct results, we must take into account the presence of water of crystallization in solids. For example, blue crystals of copper sulfate [copper (II) sulfate] contain up to 30% water, and the so-called soda ash (sodium carbonate) - even 60%. Consequently: 100 g of crystalline copper sulfate contains only 64 g of anhydrous salt, and when buying 1 kg of soda ash, we buy twice as much water as soda.

We detect crystallization water. Add some salt (on the tip of a knife) into a heat-resistant, well-dried test tube and

Let's heat it first weakly and then more strongly on the flame of a Bunsen burner. Take, for example, copper sulfate, sodium carbonate, magnesium chloride, sodium chloride (table salt) and other salts. In most cases, the crystals will crack and droplets of water will appear in the cold upper part of the test tube. Of these salts, only pure table salt does not contain water of crystallization. After heating copper sulfate, a white precipitate of anhydrous salt remains; the blue color completely disappears with the departure of the water of crystallization. Cobalt salts, adding water of crystallization, change color from blue to red. We can do this with several crystals of cobalt (II) chloride - first heat the salt in a test tube and then place it in moist air.

Adsorbed water In a water molecule, the bonds going from the center of the oxygen atom to both hydrogen atoms form an angle of about 104±.

As is known, atoms in compounds tend to form filled electron shells. In our case (with water) this means that both hydrogen bonding electrons are attracted to oxygen, which is more electronegative. But here we are not talking about complete ionization, but about a displacement of the center of gravity of the charge, when a compound of a partially ionic nature is formed. As a result, water molecules acquire the properties of an electric dipole with a negative end on the oxygen atom and a positive end on the hydrogen atoms. This feature is of great practical importance, since many of the unusual properties of water, compared to other liquids, are due to the nature of the dipole. Thus, water molecules easily form a tetrahedral structure. This ordering, which increases below 4± C, explains why water has a minimum density at 4± C, and the porosity of the molecular structure of ice is about 10% greater than that of liquid water. Large external pressure does not prevent the volume from increasing during freezing - drivers are convinced of this with annoyance by looking at a defrosted engine or radiator. Let's reproduce this process: fill the medicine bottle to the brim with water, close it tightly with a screw cap and put it in the cold or in the freezer.

The connection of water molecules can be imagined as the attraction of oppositely charged ends of dipoles. The hydrogen atoms are connected to two much larger oxygen atoms by a specific ionic bond called a bridging hydrogen bond. Due to their dipole nature, water molecules are particularly capable of adsorption (attachment) at interfaces. Most solids in humid air are covered only by a monomolecular adsorption layer of water. On glasses, due to the addition of water molecules by alkali metal silicates, surface films are formed in which water is quite firmly bound. Let's make sure of this. Put several crystals of dehydrated cobalt (II) chloride into a round-bottomed flask and cover the flask with a piece of cotton wool. When heated on a wire mesh in the flame of a Bunsen burner to a temperature above 150 0C, a significant amount of adsorbed water will be released, which, upon cooling, will be partially absorbed by cobalt (II) chloride and change its color from blue to red. The effect will appear even more clearly if we place a little crushed glass or glass wool into the flask. With further heating to temperatures above 300 ± C, water is released from the glass again, so the glass parts of high-vacuum equipment are annealed to the softening temperature.

AIR IS AN INEXHAUSTABLE RAW MATERIAL Today we know very well the earth's atmosphere, the thickness of which is more than 1000 km.

Balloons with and without people, airplanes and rockets rose to great heights

open windows (due to the resulting sulfur oxides). We will save the resulting sodium nitrite for subsequent experiments.

The process proceeds as follows: heating

2KNO3 -? 2KNO2+ O2

You can get oxygen by other methods. Potassium permanganate KMnO4 (potassium salt of manganese acid) gives up oxygen when heated and turns into manganese (IV) oxide: 4KMnO4 - 4MnO2 +2K2O+3O2

(It would be more correct to depict this reaction as follows: 2КМnO4 ? МnO2 + К2МnО4 + O2. Ed.)

From 10 g of potassium permanganate you can get about a liter of oxygen, which means two grams is enough to fill five normal-sized test tubes with oxygen. Potassium permanganate can be purchased at any pharmacy if it is not in your home medicine cabinet.

We heat a certain amount of potassium permanganate in a refractory test tube and catch the released oxygen in the test tubes using a pneumatic bath. When the crystals crack, they are destroyed, and often a certain amount of dusty permanganate is entrained along with the gas. In this case, the water in the pneumatic bath and the outlet pipe will turn red. After completing the experiment, we clean the bath and tube with a solution of sodium thiosulfate (hyposulfite) - a photographic fixer, which we slightly acidify with dilute hydrochloric acid.

Oxygen can also be obtained in large quantities from hydrogen peroxide H2O2. Let's buy a three percent disinfectant solution or a preparation for treating wounds at the pharmacy. Hydrogen peroxide is not very stable. Already when standing in air, it decomposes into oxygen and water:

2Н2O2 ? 2H2O + O2

Decomposition can be significantly accelerated by adding a little manganese dioxide MnO2 (pyrolusite), activated carbon, metal powder, blood (coagulated or fresh), and saliva to the peroxide. These substances act as catalysts.

We can verify this if we place approximately 1 ml of hydrogen peroxide with one of the named substances in a small test tube, and determine the presence of released oxygen using a splinter test. If an equal amount of animal blood is added to 5 ml of a three percent hydrogen peroxide solution in a beaker, the mixture will foam strongly, the foam will harden and swell as a result of the release of oxygen bubbles.

Then we will test the catalytic effect of a 10% solution of copper (II) sulfate with and without the addition of potassium hydroxide (caustic potash), a solution of iron (II) sulfate, a solution of iron (III) chloride (with and without the addition of iron powder), carbonate sodium, sodium chloride and organic substances (milk, sugar, crushed green plant leaves, etc.). Now we have experienced that various substances catalytically accelerate the decomposition of hydrogen peroxide.

Catalysts increase the reaction rate of a chemical process without being consumed. They ultimately reduce the activation energy required to initiate a reaction. But there are also substances that act in the opposite way. They are called negative catalysts, anticatalysts, stabilizers or inhibitors. For example, phosphoric acid prevents the decomposition of hydrogen peroxide. Therefore, commercial hydrogen peroxide solution is usually stabilized with phosphoric or uric acid.

Catalysts are necessary for many chemical engineering processes. But even in living nature, so-called biocatalysts (enzymes, enzymes, hormones) participate in many processes. Since catalysts are not consumed in reactions, they can act in small quantities. One gram of rennet is enough to ensure the coagulation of 400-800 kg of milk protein.

Of particular importance for the operation of catalysts is the size of their surface. To increase the surface, porous substances riddled with cracks with a developed internal surface are used; compact substances or metals are sprayed onto the so-called carriers. For example, 100 g of supported platinum catalyst contains only about 200 mg of platinum; 1 g of compact nickel has a surface area of ​​0.8 cm2, and 1 g of nickel powder has a surface area of ​​10 m2. This corresponds to a ratio of 1:100,000; 1 g of active alumina has a surface area of ​​200 to 200 m2; for 1 g of active carbon this value is even 1000 m2. In some installations, the catalyst is worth several million marks. Thus, a gasoline contact furnace in Belem, 18 m high, contains 9-10 tons of catalyst.

Let's burn the iron. Let's use the collected oxygen for oxidation experiments. Let's add them to the oxygen-filled

small test tubes, if possible finely ground, samples of lead, copper, aluminum, zinc and

tin and loosely cover the test tubes with cotton wool. When heated, metals will burn with a bright flame; oxides will remain in the test tubes.

IN Thin iron wire will also burn in pure oxygen. Let's give it a spiral shape

And We will attach it to one of the ends of a piece of wood soaked in paraffin, which we will set on fire. As soon as possible, place the wire into a wide beaker filled with oxygen. To prevent the glass from cracking Due to falling hot particles, it is necessary to immerse the bottom of the glass in a layer of sand or water. The wire will burn with the appearance of bright flying sparks, resulting in the formation of iron oxide (II, III), the so-called scale:

3Fe + 2O2 ? Fe3O4

Oxygen is a colorless, odorless and tasteless gas, partially soluble in water; 1 liter of oxygen at 0 ± C and 760 mm Hg. Art. weighs 1.429 g. Therefore, oxygen is heavier than air (1 liter of air under the same conditions weighs 1.293 g). Oxygen forms oxides with almost all metals and non-metals.

Atomic oxygen

IN In nature, oxygen occurs in the form of diatomic molecules. Atomic oxygen O has an extremely strong oxidizing ability. It is obtained by the decomposition of ozone, the molecule of which contains three oxygen atoms:

If a little finely sprayed potassium permanganate is poured onto concentrated sulfuric acid poured into a porcelain cup, ozone is formed. (Wear safety glasses! Explosive!) We will hold over the cup: a) a piece of starch paper soaked in potassium iodide, b) a strip of litmus paper. Potassium iodide will release iodine, which will color the starch paper blue (iodine-starch reaction); The litmus paper will become discolored. Finally, immerse a little cotton wool soaked in alcohol or turpentine on a glass rod in a mixture of sulfuric acid and permanganate. The cotton wool will burn with an explosion.

In high (30-45 km) layers of air, in the so-called ozonosphere, ozone appears under the influence of ultraviolet rays or during a thunderstorm, and in technology it is most often obtained as a result of a quiet electrical discharge in an ozonator. It is used for disinfection and ozonation of indoor air (hospitals, refrigerators), as well as for the disinfection of drinking water.

LEINA WOULD SMOKE WITHOUT NITROGEN If, at the beginning of our century, a geography teacher in a German gymnasium had asked his student about

Leine, he would hardly have received a satisfactory answer. At that time, Leina was a village in the state district of Merseburg and had about three hundred inhabitants. The geographical book of 1899 says that there are deposits of brown coal, which can be used to produce pressed peat, mountain wax (paraffin) and oil - “solar oil”.

A current student will answer the same question from a teacher without much difficulty in answering that Leina lies on the Merseburg-Grosskorbet railway section and the largest chemical enterprise in the republic is located there. Leina became famous in last years. The history of Leina's company is also part of German history. It began during the First World War and seemed destined to end during the Second.

IN In 1908, the head of the Institute of Physical Chemistry and Electrochemistry at the Technical High School in Karlsruhe, Dr. Haber, invited Karl Bosch as an employee, who then headed the nitrogen production department at the Baden aniline and soda factory. Together with Dr. Mittash

And Engineer Lappe, from 1909 to 1912, conducted more than 10,000 experiments in a specially equipped laboratory with the aim of combining atmospheric nitrogen with hydrogen in the presence of a catalyst. As a result of this reaction, ammonia is formed - the starting product for many types of explosives and artificial fertilizers. This is how the Haber-Bosch method was developed.

One of the first ammonia productions was organized at the Leina factories using the reaction: N2 + 3H2 = 2NH3. This reaction is reversible and shifts towards the formation of NH3 only at high pressures. The implementation of a technological method for the synthesis of ammonia was the final stage of many years of work by many scientists to solve the problem of fixed nitrogen. In the process of studying this reaction, in addition to the practically important result, it was possible to clarify many of the most important issues related to the theory of chemical reactions (equilibrium shift under the influence of temperature and pressure, the action of a catalyst, etc.) - Approx. ed.

Carl Bosch chose the site for a large ammonia synthesis plant. On May 28, 1916, construction of an ammonia plant began in Merseburg. At this time, battles raged with unabated force on the western front. Eleven months after the first blow with a shovel, 27

April 1917, the company shipped the first tanks of ammonia - a new raw material for the deadly war.

The workers of Leina, organizing mass strikes, led a decisive struggle against the war.

The Leina plant was continuously expanded. Ammonia was no longer the only product. Two years after the start-up, the production of ammonium sulfate began, in 1923 the production of methanol, and from 1927 - gasoline. In 1945, it seemed that the huge enterprise was dead forever - 10,000 bombs dropped during 23 raids destroyed 80% of it. Thanks to Soviet help, it was revived again, first as an enterprise of the Soviet state joint stock company upon receipt mineral fertilizers. In 1954 it became a national property, and since then its capacity, thanks to the rationalization and expansion of production, has steadily increased.

The plant's installations occupy an area of ​​4 km2. More than 32 thousand workers arrive daily at two railway stations located 1.7 km from each other. 13 giant chimneys, cooling towers and distillation columns, long hangars and bunkers define the silhouette of the plant.

Along with such important raw materials as brown coal, the role of oil is increasingly increasing. This important raw material is supplied to the chemical centers of the republic via the Druzhba oil pipeline, which stretches from Soviet Union through Poland to the GDR.

Thousands of tons of more than 400 types of basic and intermediate chemicals, from fuels to plastic feedstocks, are produced from oil, air and water. Petroleum refining also releases many inorganic chemicals. Ammonia and nitric acid are used to produce fertilizers and other products.

WITH On February 1, 1966, Leina acquired special significance. The installations of the first stage of Leina II, the first petrochemical base of the GDR, began to produce products. On an area of ​​200 hectares, approximately 2,000 operating plants were built, serving 2,100 workers. Ethene, high-density polyethylene, caprolactam, and phenol are produced here. Gasoline cracking is also carried out here. The Leipa II plant operates at high productivity. Each worker at this plant produces 6 times more products than his colleague at the Leina 1 plant.

The company contributed enormously to the GDR's achievement of world-class petrochemicals. EXPERIMENTS WITH AMMONIA AND NITRIC ACID Using the Haber-Bosch method from air, water vapor and brown coal (or brown coal coke) or

Using the gasification of petroleum residue oils, a mixture of nitrogen and hydrogen is obtained. After cleaning (removal of sulfur, oxide and carbon dioxide) on a mixed catalyst at a pressure of 240 kgf/cm2 and a temperature of 420-610 ± C, the mixture turns into ammonia:

N2+ 3H2 = 2NH3 + Q

Largest economic effect provides use for the synthesis of waste from oil refining processes.

Ammonia fountain Ammonia is a colorless gas. It irritates the respiratory tract and is toxic in high concentrations.

Ammonia is lighter than air; 1 liter of gas weighs 0.7709 g. It dissolves extremely well in water, and we will now verify this experimentally.

From a commercial 25% solution of ammonia (ammonium hydroxide, NH4OH, ammonia), we extract ammonia when heated, which we collect in a dry round-bottomed flask. (Never use a flat-bottomed or Erlenmeyer flask! These vessels cannot withstand a vacuum

And explode. For this experiment, it is also convenient to use the lower parts of flasks for washing gases.) Then we close the flask with a rubber stopper, into the hole of which a glass tube drawn at the end is inserted. Fill a large beaker with water with a few drops of phenolphthalein. Repeatedly immersing the neck of the flask in this solution, we will try to introduce a few drops of water into the flask through the tube. Due to the high solubility of ammonia (702 volumes of ammonia dissolve in 1 volume of water at 20 0C), most of the gas will dissolve. A vacuum will arise in the flask, and the external air pressure will eject from great strength water from the beaker into the flask. The red color of the indicator in the flask indicates the presence of a basic medium there.

Let's get nitric acid

WITH Using catalytic oxidation (Ostwald method), ammonia can be converted to nitric acid. At the Bitterfeld chemical plant, a mixture of ammonia and air is passed over platinum-cobalt catalyst. The resulting colorless monoxide

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Name: Chemistry for the curious - Basics of chemistry and entertaining experiments. 1985.

The book presents the basics of inorganic and organic chemistry in a popular and entertaining way. The experiments described in it, which can be done in a chemistry circle and even at home, will help to actively master the material and awaken interest in chemistry. The uniqueness of the book lies in the fact that it is accessible for independent study, and the choice of experiments is determined not so much by their external effect as by their cognitive value.
The purpose of the book is to captivate the young reader with chemistry and prepare him for practical work in a laboratory or enterprise.

Content
Chapter 1. WATER AND AIR - THE CHEAPEST RAW MATERIALS
WATER IS THE NUMBER ONE SUBSTANCE
EXPERIMENTS WITH WATER
Let's break down the water
Magnesium - active, but protected
Electrolytic decomposition of water
Let's experiment with gases
WATER IN CRYSTALS
Detecting water of crystallization
Adsorbed water
AIR IS AN INEXHAUSTABLE RAW MATERIAL
INTERESTING MIX
EXPERIMENTS WITH OXYGEN
Obtaining oxygen in simple ways
Let's burn the iron
Atomic oxygen
LEINA WOULD Suffocate Without Nitrogen
EXPERIMENTS WITH AMMONIA AND NITRIC ACID
Ammonia fountain
Let's get nitric acid
NOT ALL ICE IS FROM WATER
Let's get carbon dioxide
Experiments with carbon dioxide
Chapter 2. SALT = BASE + ACID
ALKALI METAL CHLORIDES - RAW MATERIALS FOR OBTAINING BASES AND ACIDS
HOW ALKALI AND ACIDS ARE PRODUCED IN BITTERFELD
ELECTROCHEMICAL PLANT ON THE LABORATORY DESK Mercury method
Diaphragm made from a eaten egg
TITRATION BASICS
EXPERIMENTS WITH CHLORINE
Let's get chlorine
Simple experiments with chlorine
Hydrogen chloride synthesis
HOW IS SODA MADE?
Getting soda
BLOOD CHEMISTRY
SULFUR AND ITS COMPOUNDS
Dissolving sulfur
Carefully! I!
We obtain sulfides
Hydrogen sulfide combustion
TWO METHODS FOR ONE PRODUCT
Experiments with "sulfurous acid"
Chamber method
Contact method
Acid from gypsum
Let's get xylolite
VALUABLE SILICATES
Isolation of silicic acid from liquid glass
Filled cement produces concrete
Chapter 3. METALS - THE BASIS OF TECHNOLOGY
METALS AND THEIR COMPOUNDS
CLASSIFICATION OF METALS
ALKALI METALS (MAIN SUBGROUP OF GROUP I)
Detection of potassium and sodium
METALS OF SUB-GROUP I GROUP
Oxidation and reduction of copper
Detection of copper in alloys
Experiments with silver
Basic Photography Process
Assay art
ALKALINE EARTH METALS (MAIN SUBGROUP OF GROUP II)
Properties and detection of magnesium
Calcium detection
METALS OF SUB-GROUP II GROUP
Experiments with zinc
METALS OF THE MAIN SUBGROUP III GROUP
Aluminum is the most important light metal
CARBON GROUP (MAIN SUBGROUP OF GROUP IV)
Tin is a necessary but rare element
NITROGEN GROUP (MAIN SUBGROUP OF GROUP V)
METALS OF SUB-GROUP VI GROUP
Colored deposits with chromium
Detection of molybdenum and tungsten
METALS OF SUB-GROUP VII GROUP
GROUP VIII TRANSITION METALS
Iron is the most commonly used metal
Cobalt is a magnet component
Nickel meets the most stringent requirements
ANALYTICS - A TOUCHSTONE FOR A YOUNG CHEMIST
LET'S GET METALS
WASHING AND Roasting of ores
Ore beneficiation
Ore roasting
Smelting COPPER AND LEAD IN A LABORATORY CRUCCILE
Reduction of copper oxide
Lead from lead litharge
METAL FROM PYROLUSITE
Let's get manganese
PRODUCTION OF MAGNESIUM BY ELECTROLYSIS OF THE MELT
Magnesium from carnallite
IRON AND NICKEL IN UNUSUAL FORM
Let's get iron dust
Nickel according to the same recipe
FROM METALLURGICAL RECIPES
Lead alloys
Steel hardening
SMALL COURSE IN ELECTROCHEMISTRY OF METALS
METALS STRESS SERIES
Metal coatings, "trees" and "ice patterns" without current
LET'S LOOK BEHIND THE SCENES
The essence of a galvanic cell
APPLICATION OF GALVANIC COATINGS
Metal is deposited by current
Chapter 4. CHEMISTRY OF CARBON
LET'S LOOK INTO THE PAST
MARSH GAS
Let's get swamp gas
BASIC CONCEPTS OF ORGANIC CHEMISTRY
ETHENE - UNSATURATED HYDROCARBONS
DETECTION OF ELEMENTS IN ORGANIC SUBSTANCES
Nitrogen detection
Halogen detection
Sulfur detection
COAL - COKE - RESIN - GAS
WE WILL BUILD A SEMI-COKING PLANT
Dry distillation of wood
Semi-coking of brown coal
CARBIDE IS STILL NEEDED
Preparation of calcium carbide
Ethyn research
SOME OF THE 800,000 CONNECTIONS
WINE ALCOHOL AND ITS RELATIVES
Methanol research
Experiments with methanal
We study methanoic acid
Experiments with ethanol
Obtaining ethanal
Experiments with ethanal
SOLVENTS IN HOUSEHOLD AND TECHNOLOGY
Carbon tetrachloride is a non-flammable solvent
Propanone dissolves fat
And finally, the broadcast
BENZENE DERIVATIVES
Nitrobenzene from benzene
Aniline - the founder of dyes
Other representatives of the aromatic series
Let's get furfural from bran
Chapter 5. MATERIALS FOR EVERY TASTE: PLASTICS OF YESTERDAY, TODAY AND TOMORROW
SUBSTITUTE
GIANTS AMONG MOLECULES
WE EXPLORE PLASTICS
Determination of density
Melting test
Softening point
Pour point
Combustion test
Study of decomposition products
Chemical resistance
HOW NATURAL MATERIALS IMPROVE
IF YOU TAKE CELLULOSE, ACID AND CAMPHORA
Preparation of cellulose nitrates
Further processing of cellulose dinitrate
Experiments with cellulose trinitrate
WOOD AND PLASTICS
Let's make parchment paper
FROM SWITCH TO CAR BODY
35,000 tons of phenolics per year
Let's make transparent phenol-formaldehyde resin
Phenol-formaldehyde varnishes and adhesives
WITH FILLING YOU GET MORE AND... BETTER
Production of press material
Manufacturing of laminated plastic
13 TIMES LIGHTER THAN A CORK
Thermal insulation
Making foam plastic
Production of urea-formaldehyde resin
Let's prepare urea glue
PLATES FOR BEGINNER JULGLERS
FAMILY OF THERMOPLASTS
LET'S ASSEMBLE AND DISASSEMBLE POLYSTYRENE MOLECULES
Depolymerization of polystyrene
Obtaining polystyrene
POLYVINYL CHLORIDE IS AN IMPORTANT PLASTIC
Experiments with polyvinyl chloride
ORGANIC GLASS
CHEMISTRY DRESSES US MORE BEAUTIFUL AND BETTER
FIBER UNDER A MAGNIFYING GLASS
We study fibers
SILK AND WOOL FROM WOOD
Lignin detection
Making Chardonnay silk
Making acetate silk
Making copper-ammonia silk
Making viscose
CHEMISTRY OPENS NEW PATHWAYS
Chapter 6. BRIEFLY ABOUT THE CHEMISTRY OF DYES
WOLFEN DYES
THE SECRET OF COLOR
WE SYNTHESIS DYES FROM ANILINE
Mauveine in vitro
Synthesizing Aniline Yellow
Aniline black - dye for cotton
LET'S GET PHTHALEIN DYES
Phthalic anhydride from phthalic acid
Preparation of phenolphthalein indicator
How to color bath water
Beautiful as the dawn
CHEMISTRY IN THE FIGHT OF DISEASES
SIMPLE DISINFECTANT
Let's make a medicine
AROUND SALICYLIC ACID
Experiments with salicylic acid
FRAGRANCES, COSMETICS AND DETERGENTS
FRAGRANT RETORT
Let's get essential oils
SCENTED ESTERS
Let's get esters
Preparative preparation of ester
Scented soap alkanals
Fruit essence and isovaleric acid from isoamyl alcohol
The aroma of lilac from... turpentine!
PERFUME
Let's make perfume
BEAUTY - WITH THE HELP OF CHEMISTRY
Let's do cosmetics
HEALTHY FOAM
Secrets of soap making
COAL SOAP
Let's oxidize paraffin
Making soap from synthetic fatty acids
How do detergents work?
Chapter 7. CHEMISTRY OF LIFE
FOOD AS CHEMICAL COMPOUNDS
EXPERIMENTS WITH SUGAR
Does sugar burn?
What does sugar consist of?
Let's make artificial honey
Reactions of monosaccharides
Sugaring of potatoes and wood
Let's get milk sugar
Let's saccharify cotton wool
FATS - FUEL FOR THE BODY
Fat detection
Curing fats is not that easy!
PROTEIN IS NOT ONLY IN EGGS
How to recognize a protein?
Let's prepare soup concentrate
WHAT IS TURNING INTO WHAT?
METABOLISM
Detection of hemin using the Teichmann reaction
Blood detection using benzidine
Action of bile
"Artificial stomach"
Detection of cholesterol in egg yolk
CHEMICAL PLANT IN PLANTS
Separation of green leaf dye by adsorption column chromatography
Separation of dyes from plants using paper chromatography
Starch in leaves and margarine
Detection of starch in margarine
Detection of starch in lilac leaf
AGRONOMIST AS CHEMIST
FOLLOWING LIEBICH
ANALYSIS OF MINERAL FERTILIZERS
Detection of cations
Anion detection
CHEMISTRY HELPES AGRICULTURE
Let's make insecticide
Chapter 8. ARSENAL OF A YOUNG CHEMIST
WHAT DO WE NEED?
WORKPLACE
How to set up a laboratory bench
What you should always have on hand
SIMPLE LABORATORY EQUIPMENT
Simple glassware
China
Measuring utensils
Burners, electric stoves and accessories
Glass containers
Accessories
Chemical glassware for special purposes
Instruments for experiments in electrochemistry
Experiments with electric arc
GLASS PROCESSING
Burner
Tube cutting
Tube bending
Tube stretching
Additional Tips
BASIC CHEMICAL REAGENTS
MAIN INORGANIC ACIDS
IMPORTANT FOUNDATIONS.

Detection of potassium and sodium.
We will keep the magnesia sticks in the non-luminous flame of a Bunsen burner until the initial color of the flame disappears. Then apply a little table salt to the stick and again place it in the flame, which will turn bright yellow. Since the color is very intense, and sodium is an almost indispensable impurity in salts, one should always ascertain, by comparing the resulting color of the flame with the color of the flame of a pure sodium compound, whether the element is in the form of an impurity or in the form of a main component.

Potassium colors the flame red-violet. To get rid of the interfering yellow color, which is colored by sodium present in the flame, we use a blue filter (cobalt glass). This way you can check the potassium content of some salts.
In the presence of a small amount of lithium salts, this element can be observed to color the flame a wonderful red color.

Grosse Ernst

German ethnographer, sociologist and art critic. Born in the city of Stendal. He studied at the University of Halle, where in 1887 he received his Ph.D. From 1889 he taught at the University of Freiburg; At the same time he held the position of curator of the Freiburg municipal art collection (until 1902). One of the first in Europe to study Japanese art; repeatedly came to China and Japan as an art expert accompanying delegations involved in the acquisition of works of art for German museums. Since 1920 - Professor of Ethnology and History of East Asian Art at the University of Freiburg.

In his research, Ernst Grosse mainly dealt with the problem of the emergence of art and family forms. His main works, “The Origin of Art” (1894; Russian translation, 1899) and “Forms of the Family and Forms of Economy” (1896; Russian translation, 1898) contain enormous factual ethnographic and archaeological material. Grosse associated types of family, as well as the origin and early forms of art, with “forms of economy,” by which he understood only the forms of using the tools of production. In his opinion, as social evolution progresses, art is completely divorced from practical needs people and develops only as a result of the inherent sense of beauty and the desire for aesthetic pleasure. He sought to prove that the source of the origin of art were the games of primitive peoples, which, on the one hand, served practical purposes, and on the other, were a manifestation of “pure activity of the spirit.” Grosse's works influenced the well-known concept of the sociology of art by Academician of the USSR Academy of Sciences V. M. Fritsche.

Grosse E., Weissmantel H.
Chemistry for the curious. Basics of chemistry and entertaining experiments.
The book presents the basics of inorganic and organic chemistry in a popular and entertaining way. Active mastery of the material,
The experiments described in it, which can be done in a chemistry circle and even at home, will help awaken interest in chemistry. The uniqueness of the book lies in the fact that it is accessible for independent study, and the choice of experiments is determined not so much by their external effect,
how much cognition.

Read the book Chemistry for the Curious online

FROM THE PUBLISHER

When releasing the first Russian edition of this book in 1978, we tested

Some concern - after all, the book is intended for German schoolchildren, in

She often mentions industrial enterprises of the GDR, giving examples

From life and everyday life, close to a young citizen of this country... Will they not obscure

Are these details the main content of the book? But the reader's keen interest

Manifested both in letters and in discussions, and most importantly, in the speed with which

Which "Chemistry for the Curious" disappeared from book shelves, convinced

Us in the opposite.

Over the years, the first readers became adults, and the books, naturally,

Worn out. And now we are pleased to offer a new generation of readers

Second (mass) edition.

Not only to captivate the young reader with science, not only to instill in him

Practical skills needed to work in a laboratory or industrial environment

Vodka, but also to help him seriously, in an adult way, decide whether he wants and can

Connecting your destiny with chemistry is the goal of this book.

As for the details of the economic geography of the GDR, some

Details of everyday life, organization of production and

Etc., then they themselves represent considerable educational value.

I WANT TO BECOME A CHEMIST

I want to become a chemist! - this is how the high school student Justus Liebig answered (he was born

Il in 1803) to the question of the director of the Darmstadt gymnasium about the choice

Future profession. This caused laughter from those present during the conversation.

Teachers and schoolchildren. The fact is that at the beginning of the last century in

Germany and most other countries did not belong to such a profession

Seriously. Chemistry was considered as an applied part of natural science, and

Although theoretical ideas about substances have been developed,

The experiment was most often not given due importance.

But Liebig, while still studying at the gymnasium, was engaged in experimental chemistry.

His passion for chemical experiments helped him in further research.

Dovator's work. Already at the age of 21, Liebig became a professor in Giessen

And he organizes a one-of-a-kind chemical school that will

It attracted young adherents of this science from different countries. She served

The prototype of modern special educational institutions. Innovation in learning

The main thing was that the students paid a lot of attention

Experiences. It was only thanks to Liebig that the center of gravity of the chemistry course was shifted

From the classroom to the laboratory.

Nowadays, the desire to become a chemist will not make anyone laugh; on the contrary,

The chemical industry is constantly in need of people who have

Extensive knowledge and experimental skills are combined with a love of chemistry.

This book should help young chemists delve deeper into modern

Problems of chemistry. The experiments discussed here are borrowed for the most part

From practice. We will try to reproduce the complex processes of chemical technology

Produce using simple aids.

Anyone who has ever been to a chemical plant has seen huge machines there,

High pressure boilers, electric and combustion furnaces, pipeline network

Waters - all this makes up the appearance of modern chemical production.

But any chemical technological process begins in the laboratory.

Several test tubes, glass tubes and flasks are often the first

A functioning model of a modern process plant. Certainly,

A modern researcher also needs complex and expensive instruments:

Analytical balances, special ovens, thermostats, autoclaves, spectro-

Graphs, electron microscopes. But when the experimental chemist enters

An uncharted area, he cannot rely only on instruments and app-

Paratha, he must improvise and, using simple equipment,

Carry out more and more new experiments. Only the one who can collect

Current installations, who will work with unflagging tenacity on

Each experiment will overcome the obstacles that lie in wait for every experimenter.

Failure will become a good chemist.

The experiments described here do not use dangerous poisons or explosives.

The awns are harmless. Chemistry constantly uses such irreplaceable

Reagents, such as some acids and alkalis. Before

To begin experiments, you must carefully study the last chapter, where

The use of individual drugs and devices is commented on. Certainly,

Guided by the book, you can conduct many experiments, but much more important

Prepare thoroughly, carefully assemble the equipment and carefully

Monitor the progress of the process. Preliminary preparations, sketch of app-

Parameters, all observations and experimental results - all this is necessary

Put it into the protocol.

I would like to object in advance to those parents who believe that

Chemical experiments are a frivolous game with health. To avoid

Hazards, all specified precautions must be observed and not

Experiment with hazardous substances at your own risk.

Frivolity is unacceptable in any case - whether this applies to

Chemical experiments, behavior on the street or sports.

We hope that our reader will first of all thoroughly study the school

A comprehensive course in chemistry, reads special literature (recommendation

The list is given at the end of the book). The purpose of this book is to complement the basic

Systematized representations. Experiments are necessary for

Practical consolidation and creative development of theoretical knowledge.

The proposed experiments cover various areas of chemistry. Therefore our

The book is useful not only for future chemists, but also for those who will build

Spruces, metallurgists, agronomists, textile workers... The role of chemistry in various

The important fields of technology and agriculture are constantly increasing - in

This is the chemicalization of the national economy. Without numerous

Chemicals and materials could not be increased in capacity

Mechanisms and vehicles, expand the production of items

Consumption and increase productivity.

The chemical and pharmaceutical industry produces a variety of

Medicines that improve health and prolong human life.

Now in the chemical industry of the GDR at such plants as,

For example, Leina, Schwedt, Schkopau, Bitterfeld, Wolfen, Guben and others,

More than three hundred thousand people are employed.

For the further development of the chemical industry, information is very useful.

Emigration within the framework of the socialist community (for example, oil from the USSR

Supplied via oil pipeline to the GDR, Poland and Czechoslovakia). In accordance with

The comprehensive program of socialist economic integration built

There are already many giant chemical enterprises, for example a huge

Pulp mill in Eastern Siberia, installation for obtaining

High pressure liethylene, etc.

To improve well-being and better satisfy needs

The workers need qualified workers, engineers and

Scientists. And for sure many of our young readers will take part in

Implementation of this program.

1. WATER AND AIR ARE THE CHEAPEST RAW MATERIALS

WATER SUBSTANCE No. 1

Water is found almost everywhere on Earth, 70% of the earth's surface

Occupies the world's oceans; more than 1.5 trillion tons of water are contained in this

A giant reservoir. Under the influence of solar heat, part of the sea water