Preface Everywhere, wherever we turn our eyes, we are surrounded by objects and products made from substances and materials obtained in chemical plants and factories. In addition, in everyday life, without knowing it, every person carries out chemical reactions. For example, washing with soap, washing with detergents, etc. When a piece of lemon is dropped into a glass of hot tea, the color weakens - tea here acts as an acid indicator, similar to litmus. A similar acid-base interaction occurs when chopped blue cabbage is soaked in vinegar. Housewives know that cabbage turns pink. By lighting a match, mixing sand and cement with water, or extinguishing lime with water, or burning a brick, we carry out real and sometimes quite complex chemical reactions. Explaining these and other widespread chemical processes in human life is the job of specialists.

Table salt We can say with confidence that at least one chemical compound is present in a fairly pure form in every home, in every family. This is table salt or, as chemists call it, sodium chloride NaCl. It is known that, when leaving a taiga shelter, hunters certainly leave matches and salt for random travelers. Table salt is absolutely necessary for the functioning of the human and animal bodies. A lack of this salt leads to functional and organic disorders: spasms of smooth muscles may occur, and sometimes the centers of the nervous system are affected. Prolonged salt starvation can lead to the death of the body. The daily requirement for table salt for an adult is g. In hot climates, the need for salt increases to g. This is due to the fact that sodium chloride is excreted from the body through sweat and more salt must be introduced into the body to restore losses.

Matches Man has long been familiar with the miraculous properties of fire, spontaneously arising as a result of a lightning strike. Therefore, the search for ways to make fire was undertaken by primitive man. Vigorous rubbing of two pieces of wood is one such method. Wood spontaneously ignites at temperatures above 300°C. It is clear what kind of muscular effort must be made to locally heat the wood to such a temperature. And yet, at one time, mastering this method was the greatest achievement, since the use of fire allowed man to significantly remove his dependence on the climate, and therefore expand the space for existence. Creating sparks when a stone hits a piece of FeS2 pyrite and igniting charred pieces of wood or plant fibers with them was another way for humans to produce fire.

Paper and pencils Without exaggeration, we can say that every person uses paper or products made from it every day and in large quantities. The role of paper in the history of culture is invaluable. The written history of mankind dates back about six thousand years and began before the invention of paper. At first, a clay plate and stone served for this purpose. However, without paper it is unlikely that writing, the most important means of human communication, would have developed as much as it did. Writing, being a sign system for recording speech, allows it to be stored in time and transmitted over distances. Even with the widest distribution of radio, television and tape recordings, as well as the memory of electronic computers, paper as a means of storing information and cultural values ​​of mankind continues to this day to play its invaluable role.

Glass The main consumer of glass today is the construction industry. More than half of all glass produced is window glass for glazing buildings and vehicles: cars, railway cars, trams, trolleybuses. In addition, glass is used as a walling and finishing material in the form of hollow bricks, foam glass blocks, and facing tiles. Approximately a third of the glass produced is used to make vessels of various types and purposes. This is primarily glass containers - bottles and jars. Glass is used in large quantities to make tableware. Glass is still indispensable for the production of chemical glassware. Quite a lot of glass is used to make wool, fiber and fabrics for thermal and electrical insulation.

Ceramics Ceramics are widely represented in everyday life and construction. The word ceramics has become so firmly established in the Russian language that we are surprised when we learn that it is of foreign origin. In fact, the word ceramics originates from Greece. The Greek word keramos means earthenware. Since ancient times, ceramic products have been produced by firing clays or their mixtures with certain mineral additives. Excavations show that ceramic products have been produced by humans since the Neolithic era (8...3 thousand years BC). Since clays are very common in nature, the craft of pottery developed widely and often independently in different parts of the world, and was relatively easily adopted and spread.

Cement Cement is the collective name for various powdery binders that, when mixed with water, can form a plastic mass that acquires a stone-like state over time. Most cements are hydraulic, i.e. binders, which, having begun to harden in air, continue to harden under water. The first cement was discovered during the Roman Empire. Residents of the town of Puzzoli, located at the foot of the Vesuvius volcano, noticed that when volcanic ash (pozzolans) was added to lime, an effective binding agent was formed. Lime itself, as is known, exhibits binding properties, but when combined it is unstable to water.

Adhesives Currently, a very large number of different adhesives are used in everyday life and industry. They can be divided into mineral, plant, animal and synthetic. Mineral adhesives sometimes include binders such as lime and gypsum, but they lack one of the main properties of adhesives - stickiness. Silicate glue or, what is the same, liquid glass fully satisfies all the properties inherent in glue.

Chemical bleaches When washing fabrics, it is necessary not only to remove dirt, but also to destroy colored compounds. Often they are natural dyes from berries or wines. This function is performed by chemical bleaches. The most common bleach is sodium perborate. Its chemical formula is conventionally written as NaBO2·H2O2·3H2О. The formula shows that the bleaching agent is hydrogen peroxide, which is formed as a result of the hydrolysis of perborate. This chemical bleach is effective at 70°C and above.

Mineral fertilizers Mineral fertilizers began to be used in the world relatively recently. The initiator and active advocate of their use in agriculture was the German chemist Justus Liebig. In 1840, he published the book “Chemistry as applied to agriculture.” In 1841, on his initiative, the first superphosphate plant was built in England. Potash fertilizers began to be produced in the 70s of the last century. Mineral nitrogen at that time was supplied to the soil with Chilean nitrate. It should be noted that currently it is considered rational to apply phosphorus, potassium and nitrogen fertilizers to the soil in a nutrient ratio of approximately 1:1.5:3. The demand for mineral fertilizers is rapidly increasing so that their global consumption has doubled every ten years since the beginning of this century. Fortunately, the reserves of the main fertilizer elements on Earth are large and their depletion is not yet expected.

Corrosion of Metals The word corrosion comes from the Latin corrodere, which means to corrode. Although corrosion is most often associated with metals, it also affects stones, plastics and other polymeric materials, and wood. For example, we are currently witnessing great concern among broad sections of people due to the fact that monuments (buildings and sculptures) made of limestone or marble are catastrophically suffering from acid rain.

Noble metals Noble metals usually include gold, silver and platinum. However, their list is far from exhausted by these metals. In science and technology, these also include platinum's satellites - the platinum metals: palladium, ruthenium, rhodium, osmium and iridium. Noble metals are characterized by low chemical activity and corrosion resistance to atmospheric influences and mineral acids. Products made from precious metals have a beautiful appearance (nobility).

Conclusion In everyday life, people constantly use products and substances obtained through chemical transformations. Moreover, without knowing it, in everyday life a person himself often carries out chemical reactions. The book is structured in the form of individual stories about common substances, materials and chemical processes used by humans every day.

Introduction. 2

Paper and pencils. eleven

Glass. 13

Soaps and detergents. 17

Chemical hygiene and cosmetic products. 20

Chemistry in agriculture. 24

Candle and light bulb. 26

Chemical elements in the human body. 29

References. 33

Introduction

Everywhere, wherever we turn our gaze, we are surrounded by objects and products made from substances and materials obtained in chemical plants and factories. In addition, in everyday life, without knowing it, every person carries out chemical reactions. For example, washing with soap, washing with detergents, etc. When a piece of lemon is dropped into a glass of hot tea, the color weakens - tea here acts as an acid indicator, similar to litmus. A similar acid-base interaction occurs when chopped blue cabbage is soaked in vinegar. Housewives know that cabbage turns pink. By lighting a match, mixing sand and cement with water, or extinguishing lime with water, or burning a brick, we carry out real and sometimes quite complex chemical reactions. Explanation of these and other chemical processes widespread in human life is the task of specialists.

Cooking is also a chemical process. It’s not for nothing that they say that women chemists are often very good cooks. Indeed, cooking in the kitchen can sometimes feel like performing organic synthesis in a laboratory. Only instead of flasks and retorts in the kitchen they use pots and pans, but sometimes also autoclaves in the form of pressure cookers. There is no need to further list the chemical processes that a person carries out in everyday life. It is only necessary to note that in any living organism various chemical reactions take place in huge quantities. The processes of assimilation of food, breathing of animals and humans are based on chemical reactions. The growth of a small blade of grass and a mighty tree is also based on chemical reactions.

Chemistry is a science, an important part of natural science. Strictly speaking, science cannot surround a person. He may be surrounded by the results of the practical application of science. This clarification is very significant. Nowadays, you can often hear the words: “chemistry has spoiled nature,” “chemistry has polluted the reservoir and made it unsuitable for use,” etc. In fact, the science of chemistry has nothing to do with it. People, using the results of science, poorly incorporated them into a technological process, treated the requirements of safety rules and environmentally acceptable standards for industrial discharges irresponsibly, ineptly and excessively used fertilizers on agricultural land and plant protection products from weeds and plant pests. Any science, especially natural science, cannot be good or bad. Science is the accumulation and systematization of knowledge. How and for what purposes this knowledge is used is another matter. However, this already depends on the culture, qualifications, moral responsibility and morality of people who do not obtain, but use knowledge.

Modern man cannot do without the products of the chemical industry, just as he cannot do without electricity. The same situation applies to chemical industry products. We need to protest not against some chemical industries, but against their low culture.

Human culture is a complex and diverse concept, in which such categories arise as a person’s ability to behave in society, speak their native language correctly, monitor the neatness of their clothes and appearance, etc. However, we often talk and hear about the culture of construction, culture of production, culture of agriculture, etc. Indeed, when it comes to the culture of Ancient Greece or even earlier civilizations, we first of all remember the crafts that people of that era mastered, what tools they used, what they knew how to build, how knew how to decorate buildings and individual objects.

Many chemical processes important to humans were discovered long before chemistry became a science. A significant number of chemical discoveries were made by observant and inquisitive artisans. These discoveries became family or clan secrets, and not all of them have reached us. Some of them were lost to humanity. It was and is necessary to expend enormous work, create laboratories, and sometimes even institutes to reveal the secrets of ancient masters and their scientific interpretation.

Many people do not know how a TV works, but they use it successfully. However, knowing how a TV works will never prevent anyone from using it correctly. Same with chemistry. Understanding the essence of the chemical processes that we encounter in everyday life can only benefit a person.

Water

Water on a planetary scale. Humanity has long paid great attention to water, since it was well known that where there is no water, there is no life. In dry soil, grain can lie for many years and germinate only in the presence of moisture. Despite the fact that water is the most common substance, it is distributed very unevenly on Earth. On the African continent and Asia there are vast areas devoid of water - deserts. An entire country - Algeria - lives on imported water. Water is delivered by ship to some coastal areas and islands of Greece. Sometimes water costs more than wine there. According to the United Nations, in 1985, 2.5 billion of the world's population lacked clean drinking water.

The surface of the globe is 3/4 covered with water - these are oceans, seas; lakes, glaciers. Water is found in fairly large quantities in the atmosphere, as well as in the earth's crust. The total reserves of free water on Earth are 1.4 billion km3. The main amount of water is contained in the oceans (about 97.6%), in the form of ice on our planet there is 2.14 %. The water of rivers and lakes is only 0.29 % and atmospheric water - 0.0005 %.

Thus, water is in constant motion on Earth. The average time of its stay in the atmosphere is estimated at 10 days, although it varies with the latitude of the area. For polar latitudes it can reach 15, and in middle latitudes - 7 days. Water changes in rivers occur on average 30 times a year, i.e. every 12 days. The moisture contained in the soil is renewed within 1 year. The waters of flowing lakes are exchanged over tens of years, and in non-flowing lakes, over 200-300 years. The waters of the World Ocean are renewed on average every 3000 years. From these figures you can get an idea of ​​how long it takes to self-clean reservoirs. You just need to keep in mind that if a river flows out of a polluted lake, then the time of its self-cleaning is determined by the time of self-cleaning of the lake.

Water in the human body. It is not very easy to imagine that a person is approximately 65% ​​water. With age, the water content in the human body decreases. The embryo consists of 97% water, the body of a newborn contains 75%, and an adult contains about 60% %.

In a healthy adult body, a state of water equilibrium or water balance is observed. It lies in the fact that the amount of water consumed by a person is equal to the amount of water removed from the body. Water metabolism is an important component of the general metabolism of living organisms, including humans. Water metabolism includes the processes of absorption of water that enters the stomach when drinking and with food, its distribution in the body, excretion through the kidneys, urinary tract, lungs, skin and intestines. It should be noted that water is also formed in the body due to the oxidation of fats, carbohydrates and proteins taken with food. This type of water is called metabolic water. The word metabolism comes from Greek, which means change, transformation. In medicine and biological science, metabolism refers to the processes of transformation of substances and energy that underlie the life of organisms. Proteins, fats and carbohydrates are oxidized in the body to form water H2 O and carbon dioxide (carbon dioxide) CO2. The oxidation of 100 g of fat produces 107 g of water, and the oxidation of 100 g of carbohydrates produces 55.5 g of water. Some organisms make do with only metabolic water and do not consume it from the outside. An example is carpet moths. In natural conditions, jerboas, which are found in Europe and Asia, and the American kangaroo rat do not require water. Many people know that in an exceptionally hot and dry climate, the camel has a phenomenal ability to go without food and water for a long time. For example, with a mass of 450 kg during an eight-day trek through the desert, a camel can lose 100 kg in weight, A then restore them without consequences for the body. It has been established that his body uses water contained in the fluids of tissues and ligaments, and not blood, as happens with a person. In addition, the camel's humps contain fat, which serves as both a food store and a source of metabolic water.

The total volume of water consumed by a person per day when drinking and eating is 2-2.5 liters. Thanks to the water balance, the same amount of water is removed from the body. About 50-60 are removed through the kidneys and urinary tract. % water. When the human body loses 6-8 % moisture above the normal norm, the body temperature rises, the skin turns red, the heartbeat and breathing quicken, muscle weakness and dizziness appear, and a headache begins. A loss of 10% of water can lead to irreversible changes in the body, and a loss of 15-20% leads to death, since the blood becomes so thick that the heart cannot cope with pumping it. The heart has to pump about 10,000 liters of blood per day. A person can live without food for about a month, but without water - only a few days. The body's reaction to a lack of water is thirst. In this case, the feeling of thirst is explained by irritation of the mucous membrane of the mouth and pharynx due to a large decrease in humidity. There is another point of view on the mechanism of formation of this sensation. In accordance with it, a signal about a decrease in the concentration of water in the blood is sent to the cells of the cerebral cortex by the nerve centers embedded in the blood vessels.

Water metabolism in the human body is regulated by the central nervous system and hormones. Dysfunction of these regulatory systems causes disruption of water metabolism, which can lead to body edema. Of course, different tissues of the human body contain different amounts of water. The richest tissue in water is the vitreous body of the eye, containing 99%. The poorest is tooth enamel. It contains only 0.2% water. There is a lot of water in the brain matter.

An important function of the oceans and seas is to regulate the content of carbon dioxide (carbon dioxide) in the atmosphere. Its relative content in the atmosphere is small and amounts to only 0.03-0.04 %, However, the total mass contained in the atmosphere is very large - 2000-2500 billion tons. In connection with the development of energy, industry and transport, huge amounts of coal and petroleum products are burned. The main product of their oxidation is CO2. Scientists have found that atmospheric CO2 has the ability to delay, i.e. not allow the Earth’s thermal radiation to pass into outer space (“greenhouse effect”). The more CO2 in the atmosphere, the warmer the Earth's climate. General climate warming can lead to catastrophic consequences. As a result of warming, the melting of ice at the planet's poles and in mountainous regions will increase, which will lead to rising sea levels and flooding of vast areas of land. It is estimated that if all the glaciers of Greenland and Antarctica melt, the sea level will rise by almost 60 m. It is not difficult to guess that then St. Petersburg and many coastal cities will find themselves under water. An important content regulator CO2 in the atmosphere is the vegetation cover of the Earth. As a result of photosynthesis, plants convert CO2 into fiber and release oxygen:

CO2 + 6 H2 O-> C6 H12 O6+6 O2

It is appropriate to note that plants are the main suppliers of atmospheric oxygen, and its source, directly or indirectly, is water. The annual production of oxygen by the planet's terrestrial vegetation is 300 billion tons.

Main role in content regulation CO2 Oceans play in the atmosphere. An equilibrium is established between the oceans and the Earth's atmosphere: carbon dioxide CO2 dissolves in water, turning into carbonic acid H2 CO3, and then turns into bottom carbonate sediments. The fact is that sea water contains calcium and magnesium ions, which, together with carbonate ions, can be converted into slightly soluble calcium carbonate CaCO3 and magnesium MgCO3. Many marine organisms extract the first salt from seawater and build shells from it. When these organisms die over long periods of time, huge accumulations of shells form at the bottom. This is how chalk deposits are formed, and as a result of secondary geological transformations - limestone deposits, often in the form of rubble slabs. Both chalk and rubble stone are widely used in construction.

It is impossible for the Earth's green cover to cope with the task of maintaining approximately the same level of content CO2 in the atmosphere. It is estimated that land plants annually consume 20 billion tons from the atmosphere to build their bodies. CO2, and the inhabitants of the oceans and seas extract 155 billion tons from the water in terms of CO2 .

No less important substance in creating the “greenhouse effect” than CO2, is atmospheric water. It also intercepts and absorbs thermal radiation from the Earth. However, there is much more of it in the atmosphere than carbon dioxide. Atmospheric moisture, especially in the form of clouds, is sometimes compared to a "blanket" of the planet. Many have noticed that with a clear and cloudless sky, the nights can be colder than in cloudy weather.

The main consumers of fresh water include: agriculture (70%), industry, including energy (20 %) and utilities (~10%). In industrial production, the most water-intensive industries are the chemical, pulp and paper and metallurgical industries. Thus, for the production of 1 ton of synthetic fiber, 2500-5000 m3 of water are consumed, plastic - 500-1000, paper - 400-800, steel and cast iron - 160-200 m3 of water. Experience shows that a resident of a well-maintained city spends 200-300 liters of water per day for household needs. The distribution of water consumption on average is as follows: only 5% is spent on cooking and drinking, in the toilet flush cistern - 43, for baths and showers - 34, for washing dishes - 6, for laundry - 4, for cleaning the room - 3 %.

Natural water can be used for cooking and drinking if it does not contain harmful microorganisms, as well as harmful mineral and organic impurities, if it is transparent, colorless and has no taste or odor. In accordance with the State Standard, the content of mineral impurities should not exceed 1 g/l. The acidity of water in pH units should be in the range of 6.5-9.5. The concentration of nitrate ion should not exceed 50 mg/l. Naturally, it must also meet bacteriological requirements and have acceptable levels for toxic chemical compounds. These requirements are most often met by well and spring water. However, it is difficult to find water in large quantities that meets the State standard. Therefore, it has to be cleaned at special stations. The main stages of purification are filtration (through a layer of sand) and treatment with oxidizing agents (chlorine or ozone). In some cases, coagulation has to be used. For this purpose, aluminum sulfate A12 (SO4)3 is used. In the slightly alkaline environment created by calcium carbonates, under the influence of water this salt is hydrolyzed and from it a flocculent precipitate of aluminum hydroxide Al(OH)3 is obtained, as well as calcium sulfate CaSO4 according to equation

Al2 ( SO4)3 + ZCa (НСО3)2 = 2 AI (OH) 3 ↓ + 3 CaSO4 ↓ + 6СО2

Aluminum hydroxide A1(OH)3 initially formed in the form of small colloidal particles, which eventually combine into larger ones. This process is called coagulation. When coagulating flakes A1(OH)3 capture suspended impurities and sorb organic and mineral substances on their developed surface.

Since ancient times, simple boiling was used to sterilize drinking water, and the ancient Greeks added dry wine to the water, which created an acidic environment in which many pathogenic microbes died.

Drinking water should contain small amounts of dissolved salts and gases. Depending on them, water tastes different in different places. Ions are considered macrocomponents of the chemical composition of surface and some groundwaters. Na+, K+, Mg2+, Ca2+, SO4, C l, NO3. Ions Fe2+, Fe3+, Al3+ are found in noticeable quantities only in local groundwater, characterized by an acidic environment. Silicic acid H2 SiO3 is the predominant component in some types of ground and surface waters with very low mineralization, as well as in thermal waters. The boundary between fresh and mineral water is considered to be the content of mineral chemical compounds in an amount of 1 g/l.

Natural waters containing salts, dissolved gases, and organic substances in higher concentrations than drinking water are called mineral waters. Some of the mineral waters contain biologically active components: CO2, H2 S, some salts (for example, sodium and magnesium sulfates), arsenic compounds, radioactive elements (for example, radon), etc. Therefore, mineral waters have been used for a long time as a remedy. Currently, mineral waters are divided into medicinal, medicinal-table and table.

Healing mineral waters exhibit their effects in some cases when used externally, and in others when used internally. Of course, waters suitable for internal use sometimes turn out to be useful for external use. Hydrogen sulfide waters are widely known as medicinal waters (for example, waters in the Matsesta resort area), Borjomi is best known as medicinal table water, and Narzan and Essentuki No. 20 are best known as table waters. In different regions of our country, various local mineral waters are widely used as canteens; for example, Polustrovo water is known in St. Petersburg. Before bottling, table mineral waters are usually additionally saturated with carbon dioxide to a concentration of 3-4 %.

Distilled water obtained by condensation of steam contains practically no salts and dissolved gases and therefore tastes unpleasant. In addition, with prolonged use it is even harmful to the body. This is due to the leaching of the salts and trace elements they contain from the tissue cells of the stomach and intestines, which are necessary for the normal functioning of the body.

Since water is a very good solvent, in nature it always contains dissolved substances, since there are no absolutely insoluble substances. Their number and nature depend on the composition of the rocks with which the water was in contact.

The least amount of impurities and dissolved substances is found in rainwater. However, even it contains dissolved gases, salts and solid particles. The salts contained in rainwater originate from the oceans and seas. Bursting bubbles on the surface of the oceans release quite a large amount of salts into the atmosphere. They are captured by air currents (especially in stormy weather) and distributed in the atmosphere. The solid residue that is formed when rainwater evaporates is dust particles captured by raindrops. From 30 liters of rainwater, approximately 1 g of dry residue remains upon evaporation. Dissolved gases are both the main components of the air and the pollutants found in the area. The composition of rainfall over the sea is consistent with the rule that it is identical to what is obtained by adding 1.5 ml of sea water to 1 liter of distilled water.

Obtaining high-purity water is a very difficult task. Since it is stored in some kind of vessel, it must contain impurities of the material of that vessel (be it glass or metal). For precision scientific research, the purest water is obtained by rectification (distillation) of distilled water in fluoroplastic columns.

The main reserves of fresh water on Earth are concentrated in glaciers.

Air humidity.

An important characteristic of the state of the atmosphere is air humidity or, what is the same, the degree of saturation of the air with water vapor. It is expressed by the ratio of the content of water vapor in the air to its content when the air is saturated at a given temperature. Therefore, it is more correct to talk not just about humidity, but about relative humidity. When the air is saturated with water vapor, the water in it no longer evaporates. The most favorable air humidity for humans is 50%. Humidity, like many other things, is subject to the following rule: too much and too little are equally bad. Indeed, with increased humidity, a person feels low temperatures more acutely. Many could see that severe frosts with low air humidity are more easily tolerated than less severe frosts with high humidity. The fact is that water vapor, like liquid water, has a much greater heat capacity than air. Therefore, in humid air the body gives off more heat to the surrounding space than in dry air. In hot weather, high humidity again causes discomfort. Under these conditions, the evaporation of moisture from the surface of the body decreases (a person sweats), which means that the body cools less well and, therefore, overheats. In very dry air, the body loses too much moisture and, if it cannot be replenished, this affects a person’s well-being.

There is practically no absolutely dry air.

In 1913, the English chemist Baker found that liquids dried for nine years in sealed ampoules boil at much higher temperatures than indicated in reference books. For example, benzene begins to boil at a temperature 26° higher than usual, and ethyl alcohol - at 60, bromine - at 59, and mercury - almost 100°. The freezing point of these liquids has increased. The influence of traces of water on these physical characteristics has not yet been satisfactorily explained. It is now known that thoroughly dried gases NH3 And HG1 do not form ammonium chloride, and dry NH4 C1 in the gas phase does not dissociate into NH3 And NS1 when heated. Acidic sulfur trioxide does not react with basic oxides under dry conditions SaO, BaO, CuO, and alkali metals do not react with either anhydrous sulfuric acid or anhydrous halogens.

In well-dried oxygen, coal, sulfur, and phosphorus burn at a temperature much higher than their combustion temperature in undrained air. Moisture is believed to play a catalytic role in these chemical reactions.

A very rare property of water is manifested when it transforms from a liquid to a solid state. This transition is associated with an increase in volume and, consequently, a decrease in density.

Scientists have proven that solid water has an openwork structure with cavities and voids. When melting, they are filled with water molecules, so the density of liquid water is higher than the density of solid water. Since ice is lighter than water, it floats on it rather than sinking to the bottom. This plays a very important role in nature. If the density of ice were higher than water, then, having appeared on the surface due to cooling of the water by cold air, it would sink to the bottom and, as a result, the entire reservoir would freeze. This would have a catastrophic effect on the lives of many organisms in water bodies.

It is interesting that if high pressure is created over water and then cooled until it freezes, then the resulting ice under conditions of increased fission melts not at 00C, but at a higher temperature. Thus, ice obtained by freezing water, which is under a pressure of 20,000 atm, under normal conditions melts only at 800C.
Salt

Salt starvation can lead to the death of the body. The daily need for table salt for an adult is 10-15 g. In hot climates, the need for salt increases to 25-30 g.

Sodium chloride is needed by the human or animal body not only for the formation of hydrochloric acid in gastric juice. This salt is included in tissue fluids and blood. In the latter, its concentration is 0.5-0.6 %.

Aqueous solutions NaCI in medicine they are used as blood-substituting fluids after bleeding and in cases of shock. Content reduction NaCI in the blood plasma leads to metabolic disorders in the body.

Not receiving NaCI from the outside, the body releases it from the blood and tissues.

Sodium chloride promotes water retention in the body, which in turn leads to increased blood pressure. Therefore, for hypertension, obesity, and edema, doctors recommend reducing the daily intake of table salt. Excess in the body NaCI can cause acute poisoning and lead to paralysis of the nervous system.

The human body quickly reacts to salt imbalance with the appearance of muscle weakness, rapid fatigue, loss of appetite, and the development of unquenchable thirst.

Table salt has, although weak, antiseptic properties. The development of putrefactive bacteria stops only when its content is 10-45 %. This property is widely used in the food industry and for preserving food at home.

When seawater evaporates at temperatures of 20-35 °C, the least soluble salts are released first - calcium carbonates, magnesium carbonates and calcium sulfate. Then more soluble salts precipitate - sodium and magnesium sulfates, sodium, potassium, magnesium chlorides and after them potassium and magnesium sulfates. The order of crystallization of salts and the composition of the resulting precipitation may vary somewhat depending on temperature, evaporation rate and other conditions.

Table salt exposed to humid air becomes damp. Pure sodium chloride is a non-hygroscopic substance, that is, it does not attract moisture. Magnesium and calcium chlorides are hygroscopic. Their impurities are almost always contained in table salt and thanks to them, moisture is absorbed.

Rock salt layers are quite common in the earth's crust. Table salt is the most important raw material of the chemical industry. Soda, chlorine, hydrochloric acid, sodium hydroxide, and metallic sodium are obtained from it.

When studying the properties of soils, scientists found that, being saturated with sodium chloride, they do not allow water to pass through. This discovery was used in the construction of irrigation canals and reservoirs. If the bottom of a reservoir is covered with a layer of earth soaked NaCl, then no water leakage occurs. For this purpose, of course, technical salt is used. Builders use sodium chloride to prevent the ground from freezing in winter and turning it into hard stone. To do this, areas of soil that are planned to be removed are sprinkled thickly in the fall. NaCl. In this case, during severe frosts, these areas of the ground remain soft.

Chemists are well aware that mixing finely ground ice with table salt can create an effective cooling mixture. For example, a mixture of 30 g NaCl per 100 g of ice is cooled to a temperature of -20 C, this occurs because an aqueous solution of salt freezes at subzero temperatures. Consequently, ice, which has a temperature of about 0°C, will melt in such a solution, removing heat from the environment. This property of a mixture of ice and table salt can also be successfully used by housewives.

Matches

Creating sparks when a stone hits a piece of pyrite FeS2 and setting fire to charred pieces of wood or plant fibers with them was man's way of producing fire.

Since the methods of producing fire were imperfect and labor-intensive, a person had to constantly maintain a burning source of fire. To carry fire in ancient Rome, they used wooden sticks dipped in molten sulfur.

Devices for producing fire, based on chemical reactions, began to be made at the end of the 18th century. At first these were wood splinters, on the tip of which potassium chlorate (Berthollet salt) was fixed in the form of a head KS1Oz) and sulfur. The head was immersed in sulfuric acid, a flash occurred and the splinter caught fire. The person was forced to store and handle unsafe sulfuric acid, which was extremely inconvenient. Nevertheless, this chemical “flint” can be considered as the progenitor of modern matches.

At the beginning of the 19th century. The German chemist Debereiner invented a more advanced, but also more complex flint. He found that a jet of hydrogen directed at spongy platinum ignites in air.

Spongy platinum plays the role of a catalyst. To use this product to create fire in everyday life, he created a small glass device (similar to the device previously invented by Kipp, which bears his name). Hydrogen was obtained by casting V contact of zinc metal and sulfuric acid. Thus, obtaining a flame and extinguishing it was ensured by turning the tap, bringing into contact (or separating) sulfuric acid and zinc. The Döbereiner flint can be considered the progenitor of the modern gas or gasoline lighter.

In a modern lighter, fuel is ignited under the action of a spark resulting from the combustion of the smallest particle of “flint” cut off by a gear wheel. “Flint” is a mixture of rare earth metals (lanthanides). In a finely divided state, this mixture is pyrophoric, that is, it spontaneously ignites in air, forming a spark.

However, an earlier pyrophor was made from a mixture of potash K2 CO3 and dried alum K2 SO4∙ Al2 ( SO4)3.K finely dispersed coal or soot was added to it and heated to a glow without access to air. The powder was cooled and placed in a hermetically sealed vessel, from where it could be removed as needed. To start a fire, the powder was poured onto tinder, cotton wool or rags and ignited in the air. It is believed that during calcination, finely dispersed metallic potassium is formed on the remaining coal particles, which, oxidizing in air, serves as an ignition initiator.

The most important step on the way to modern matches was the introduction of white phosphorus into the composition of the match head (1833). Such matches were easily lit by friction against a rough surface. However, when burned, they created an unpleasant odor and, most importantly, their production was very harmful to workers. White phosphorus vapors led to a severe disease - phosphorus necrosis of bones. First of all, the bones of people's jaws were subjected to necrosis, since phosphorus penetrated through carious teeth.

In 1847, it was found that white phosphorus, when heated in a closed vessel without air access, turns into another modification - red phosphorus. It is much less volatile and practically non-toxic. Soon the white phosphorus in match heads was replaced with red. Such matches were lit only by friction against a special surface made of red phosphorus, glue and other substances. These matches were called safe or Swedish, since they were first manufactured in Sweden in 1867-1869.

There are several varieties of modern matches. According to their intended purpose, they distinguish between matches that light under normal conditions, moisture-resistant (designed to ignite after storage in humid conditions, for example in the tropics), wind matches (lighted in the wind), etc.

Since the last century, mainly aspen and less commonly linden have been used as the main raw material for making match straws. To do this, the tape is removed in a spiral from a round block of bark, cleared of bark, using a special knife, which is then chopped into matchsticks. When a match burns, it is necessary to obtain a non-smoldering ember from the straw and to hold on it the hot slag from the burnt head. The need for the latter is determined by the desire to protect the consumer from burns to clothing when exposed to hot slag. A smoldering ember from a straw naturally poses a fire hazard. To eliminate the smoldering of the straw and secure the slag from the head, the straw is impregnated with substances that form a film on its surface during combustion. Thanks to this film, the combustion of coal stops. It also secures the slag from the head. Phosphoric acid and its salt are used as antismoldering agents. ( NH4)2 HPO4 .

Over a period of more than 150 years, a large number of formulations of incendiary masses from which match heads are made have been used. They are complex multicomponent systems. These include: oxidizing agents (KS1O3, KrCr2 O7, MnO2), providing oxygen necessary for combustion; flammable substances (sulfur, animal and vegetable glues, phosphorus sulfide P4 S3); fillers - substances that prevent the explosive nature of combustion of the head (crushed glass, Fe2 Oz); adhesives (glues), which are also flammable; acidity stabilizers ( ZnO, CaCO3 and etc.); substances that color the match mass in a certain color (organic and inorganic dyes).

In terms of the amount of oxygen released per part by mass, chromium peak K2 Cr2 O7 is inferior to Berthollet salt KS lO3, but incendiary compositions containing the first oxidizer ignite much more easily. In addition, chromium improves the quality of the slag.

Pyrolusite MnO2 plays a dual role: a catalyst for the decomposition of Berthollet salt and a source of oxygen. Iron(III) oxide Fe2 O3 also performs two functions. It is a mineral paint (rust color) and significantly reduces the burning rate of the mass, making combustion more calm.

The combustion temperature of match heads reaches 1500 0C, and their ignition temperature lies in the range of 180 – 200 0C.

Phosphorus (grating) mass is also

Paper and pencils

Documents have survived indicating that in 105 AD. e. The minister of the Chinese emperor organized the production of paper from plants with rag additives. Around 800 such paper became widespread in China, as well as in the Middle East. The acquaintance of Europeans with paper is associated with the crusades in the Middle East - in Syria, Palestine, North Africa, organized by Western European feudal lords and the Catholic Church (the first campaign took place in 1096-1099). In the early Middle Ages (before the start of the Crusades), papyrus was mainly used for writing in Europe. In Italy it was used back in the 12th century.

Writing was known in Egypt and Mesopotamia from the end of the 4th and beginning of the 3rd millennium BC. e., i.e. long before the invention of paper. As already noted, the main predecessors of paper as a material on which writing was applied were papyrus and parchment.

Papyrus plant ( Cyperus papyrus) grows in Egypt in swampy areas near the Nile River. The stem of the plant was cleared of bark and bast, and thin strips were cut from the snow-white material. They were laid in layers lengthwise and crosswise, and then the plant juice was squeezed out of them using mechanical pressure. This juice itself has the ability to glue strips of papyrus. Later, glue made from raw hides or flour was used to hold the strips together. After drying in the sun, the resulting sheets were sanded with stone or leather. Papyrus for writing began to be made about 4,000 years ago. It is believed that the name of the paper ( papiera) comes from the word papyrus.

Parchment is untreated, but freed from hair and treated with lime, animal, sheep or goat skin. Just like papyrus, parchment is a strong and durable material. Although paper is less strong and durable, it is cheaper and therefore more widely available.

Cellulose fibers in wood are bound together by lignin. To remove lignin and release cellulose from it, wood is boiled. A common cooking method is sulfite. It was developed in the USA in 1866, and the first plant using this technology was built in Sweden in 1874. The method received wide industrial significance in 1890. According to this method, to separate lignin and some other substances contained in wood, the latter is boiled in sulfite liquor, which consists of Ca(H SOz)2, H2 SO3 And SO2.

Binders are required to ensure a strong bond between the pigment particles and the base paper. Often their role is played by substances that provide paper sizing. Kaolin is widely used as mineral pigments - an earthy mass similar in composition to clays, but compared to the latter, characterized by reduced plasticity and increased whiteness. One of the oldest fillers is calcium carbonate (chalk), which is why such papers are called coated. Known pigments also include titanium dioxide T iO2 and calcium hydroxide mixture Ca(OH)2(slaked lime) and aluminum sulfate A12 (SO4)3. The latter is essentially a mixture of calcium sulfate CaSO4 and aluminum hydroxide A1(OH)z, which are obtained as a result of an exchange reaction.

To make the working part of a graphite pencil, prepare a mixture of graphite and clay with the addition of a small amount of hydrogenated sunflower oil. Depending on the ratio of graphite and clay, lead of varying softness is obtained - the more graphite, the softer the lead. The mixture is stirred in a ball mill in the presence of water for 100 hours. The prepared mass is passed through filter presses and slabs are obtained. They are dried, and then a rod is squeezed out of them using a syringe press, which is cut into pieces of a certain length. The rods are dried in special devices and the resulting curvature is corrected. Then they are fired at a temperature of 1000-1100°C in mine crucibles.

The composition of colored pencil leads includes kaolin, talc, stearin (known to a wide range of people as a material for making candles) and calcium stearate (calcium soap). Stearine and calcium stearate are plasticizers. Carboxymethylcellulose is used as a binding material. This is an adhesive used for wallpapering. Here it is also pre-filled with water to swell. In addition, appropriate dyes are introduced into the leads; as a rule, these are organic substances. This mixture is mixed (rolled on special machines) and obtained in the form of thin foil. It is crushed and the resulting powder is filled into a gun, from which the mixture is syringed in the form of rods, which are cut into pieces of a certain length and then dried. To color the surface of colored pencils, the same pigments and varnishes are used that are usually used to color children's toys. The preparation of wooden equipment and its processing is carried out in the same way as for graphite pencils.

Glass

The history of glass goes back to ancient times. It is known that in Egypt and Mesopotamia they knew how to make it already 6000 years ago. Probably, glass began to be produced later than the first ceramic products, since its production required higher temperatures than for firing clay. If for the simplest ceramic products only clay was sufficient, then glass requires at least three components.

In glassmaking, only the purest varieties of quartz sand are used, in which the total amount of impurities does not exceed 2-3%. The presence of iron is especially undesirable, since even in tiny quantities (tenths of a percent) it colors the glass greenish. If you add soda to sand Na2 CO3, then it is possible to weld glass at a lower temperature (200-300°). Such a melt will be less viscous (bubbles are easier to remove during cooking, and products are easier to shape). But! Such glass is soluble in water, and products made from it are subject to destruction under the influence of atmospheric influences. To make the glass insoluble in water, a third component is introduced into it - lime, limestone, chalk. All of them are characterized by the same chemical formula - CaCO3.

Glass, the initial components of the charge being quartz sand, soda and lime, is called sodium-calcium. It makes up about 90% of the glass produced in the world. When cooked, sodium carbonate and calcium carbonate decompose according to the equations:

Na2 CO3 → Na2 O + CO2

CaCO3 → CaO + CO 2

As a result, the glass contains SiO2 oxides, Na2 O And Sao. They form complex compounds - silicates, which are sodium and calcium salts of silicic acid.

In glass instead Na2 O you can successfully enter K2 O, A Sao can be replaced MgO, PbO, ZnO, BaO. Part of the silica can be replaced with boron oxide or phosphorus oxide (by introducing boric or phosphoric acid compounds). Each glass contains a small amount of alumina Al2 O3, which comes from the walls of the glass melting vessel. Sometimes it is added on purpose. Each of the listed oxides provides glass with specific properties. Therefore, by varying these oxides and their amounts, glasses with desired properties are obtained. For example, boric acid oxide B2 O3 leads to a decrease in the coefficient of thermal expansion of glass, which means it makes it more resistant to sudden temperature changes. Lead greatly increases the refractive index of glass. Alkali metal oxides increase the solubility of glass in water, so glass with a low content of them is used for chemical glassware.

Glass is colored by introducing oxides of certain metals into it or by forming colloidal particles of certain elements. Thus, gold and copper, when distributed colloidally, color glass red. Such glass is called gold and copper ruby, respectively. Silver in a colloidal state turns glass yellow. Selenium is a good dye. In the colloidal state it colors glass pink, and in the form of a compound CdS 3CdSe - red. This glass is called selenium ruby. When painting with metal oxides, the color of the glass depends on its composition and the amount of dye oxide. For example, cobalt(II) oxide produces blue glass in small quantities, and violet-blue with a reddish tint in large quantities. Copper(II) oxide in soda-lime glass gives a blue color, and in potassium-zinc glass it gives a green color. Manganese (II) oxide in soda-lime glass gives a red-violet color, and in potassium-zinc glass it gives a blue-violet color. Lead(II) oxide enhances the color of glass and gives the color vibrant shades.

There are chemical and physical ways to discolor glass. In the chemical method, they strive to convert all the contained iron into Fe3+. To do this, oxidizing agents are introduced into the charge - alkali metal nitrates, cerium dioxide CeO2, as well as arsenic(III) oxide AS2 O3 and antimony(III) oxide Sb2 O3. Chemically bleached glass is only slightly colored (due to ions Fe3+) in a yellowish-greenish color, but has good light transmission. During physical bleaching, “dyes” are introduced into the glass, i.e., ions that color it in additional tones to the color created by iron ions - these are oxides of nickel, cobalt, rare earth elements, and also selenium. Manganese dioxide MnO2 It has both chemical and physical bleaching properties. As a result of double absorption of light, the glass becomes colorless, but its light transmittance decreases. Thus, it is necessary to distinguish between translucent and discolored glasses, since these concepts are different.

In some palaces, state buildings and religious buildings in Europe, mica plates were inserted into small cells in window openings, which were very valuable. In the homes of ordinary people, an ox bladder and oiled paper or cloth were used for this purpose. In the middle of the 16th century. Even in the palaces of the French kings, windows were covered with oiled linen or paper. Only in the middle of the 17th century. under Louis XIV, glass appeared in the windows of his palace in the form of small squares inserted into lead binding. For a long time they were not able to obtain sheet glass of a large area. Therefore, even in the 18th century. the glazed windows had small frames. Pay attention to restored buildings from the Peter I era, such as the Menshikov Palace in St. Petersburg. However, let's return to the origins of window glass production.

At the end of the medieval period, the “lunar” method of producing sheet glass began to be widely used in Europe. It was also based on the blowing method. With this method, a ball was first blown out, then it was flattened, an axle was soldered to its bottom, and the workpiece was cut off near the blowing tube. The result was something like a vase with a soldered axle leg. The red-hot “vase” rotated at high speed around its axis and, under the influence of centrifugal force, turned into a flat disk. The thickness of such a disk was 2-3 mm, and the diameter reached 1.5 m. Next, the disk was separated from the axis and annealed. This glass was smooth and transparent. Its characteristic feature is the presence of a thickening in the center of the disc, which experts call the “navel.” The lunar production method made sheet glass accessible to the population. However, it was replaced already at the beginning of the 18th century. Another more advanced “free” method came along, which was used all over the world for almost two centuries. Essentially, it was an improvement on the medieval method of blowing, which resulted in a cylinder. A “freebie” was the name given to the formed mass of glass at the end of the blowing tube. It reached 15-20 kg and eventually produced sheets of glass with an area of ​​up to 2-2.5 m2.

Small glass items are made matte by treatment with hydrofluoric acid. The latter reacts with silicon dioxide located on the surface to form volatile silicon tetrafluoride SiF4 according to equation

SiO2 + 4 HF = SiF4+2 H2 O

Photochromic glasses change color under the influence of radiation. Currently, glasses with lenses that darken when illuminated, and in the absence of intense lighting, become colorless again, have become widespread. Such glass is used to protect heavily glazed buildings from the sun and to maintain constant illumination in rooms, as well as in transport. Photochromic glasses contain boron oxide B2 O3, and the photosensitive component is silver chloride AgCl in the presence of copper(I) oxide Cu2 O. When illuminated, a process occurs

The release of atomic silver causes the glass to darken. In the dark, the reaction proceeds in the opposite direction. Copper(I) oxide plays the role of a kind of catalyst.

Crystal, crystal glass is silicate glass containing varying amounts of lead oxide. Product labeling often indicates lead content. The greater the quantity, the higher the quality of the crystal. Crystal is characterized by high transparency, good shine and high density. You can feel the weight of crystal products in your hand.

Lead-potassium glass is strictly called crystal. Crystal glass, in which part KgO replaced by Na2 O, and part R bО replaced by CaO, MgO, BaO or ZnO, called half-crystal.

It is believed that crystal was discovered in England in the 17th century.

Quartz glass. It is obtained by melting pure quartz sand or rock crystal having the composition SiO2. The production of quartz glass requires very high temperatures (above 1700 °C).

Molten quartz is highly viscous and air bubbles are difficult to remove. Therefore, quartz glass is often easily recognized by its V no bubbles. The most important property of quartz glass is its ability to withstand any temperature changes. For example, quartz pipes with a diameter of 10-30 mm can withstand repeated heating to 800-900 ° C and cooling in water. Quartz glass bars, cooled on one side, retain a temperature of 1500 °C on the opposite side and are therefore used as refractories. Thin-walled quartz glass products can withstand sudden cooling in air from temperatures above 1300 °C and are therefore successfully used for high-intensity light sources. Quartz glass is the most transparent of all glasses to ultraviolet rays. This transparency is negatively affected by impurities of metal oxides and especially iron. Therefore, for the production of quartz glass used in products for working with ultraviolet radiation, particularly stringent requirements are imposed on the purity of raw materials. In especially critical cases, silica is purified by converting it into silicon tetrafluoride SiF4(by the action of hydrofluoric acid) followed by decomposition by water into silicon dioxide SiO2 and hydrogen fluoride HF .

Quartz glass is transparent in the infrared region.

Sitalls- glass-crystalline materials obtained by controlled crystallization of glass. Glass, as is known, is a solid amorphous material. Its spontaneous crystallization has caused production losses in the past. Typically, glass melt is quite stable and does not crystallize. However, when the glass product is reheated to a certain temperature, the stability of the glass mass decreases and it turns into a fine-grained crystalline material. Technologists have learned to carry out the crystallization process of glass, eliminating cracking.

Citales have high mechanical strength and heat resistance, are waterproof and gas-tight, and are characterized by a low expansion coefficient, high dielectric constant and low dielectric losses. They are used for the manufacture of pipelines, chemical reactors, pump parts, dies for spinning synthetic fibers, as linings for electrolysis baths and material for infrared optics, in the electrical and electronics industry.

Strength, lightness and fire resistance determined the use of glass ceramics in residential and industrial construction. They are used to make hinged self-supporting panels of external walls of buildings, partitions, slabs and blocks for internal cladding of walls, paving roads and sidewalks, window frames, balcony railings, flights of stairs, corrugated roofing, sanitary equipment. In everyday life, glass ceramics are more often found in the form of white, opaque, heat-resistant kitchenware. It has been established that glass ceramics can withstand about 600 sudden thermal changes. Products made from glass ceramic do not scratch or burn through. They can be removed from the stove while red-hot and plunged into ice water, removed from the refrigerator and placed over an open flame without fear of cracking or breaking.

Sitalls are one of the types of glass-crystalline materials that date back only to the 50s of the current century, when the first patent was issued for them.

Foam glass- a porous material, which is a glass mass penetrated by numerous

voids. It has heat and sound insulation properties, low density (about 10 times lighter than brick) and high strength comparable to concrete. Foam glass does not sink in water and is therefore used to make pontoon bridges and rescue accessories. However, its main area of ​​application is construction. Foam glass is an extremely effective material for filling the internal and external walls of buildings. It is easy to machine: sawing, cutting, drilling and turning on a lathe.

Glass wool and fiber. When heated, the glass softens and easily stretches into thin and long threads. Thin glass threads show no signs of fragility. Their characteristic property is extremely high tensile strength. A thread with a diameter of 3-5 microns has a tensile strength of 200-400 kg/mm2, i.e., this characteristic is close to mild steel. Glass wool, glass fiber and fiberglass are made from threads. It is not difficult to guess the areas of use of these materials. Glass wool has excellent heat and sound insulation properties. Fabrics made from glass fiber have extremely high chemical resistance. Therefore, they are used in the chemical industry as filters for acids, alkalis and chemically active gases. Due to their good fire resistance, fiberglass fabrics are used for sewing clothing for firefighters and electric welders, theater curtains, draperies, carpets, etc. In addition to fire resistance and chemical resistance, fiberglass fabrics also have high electrical insulation properties

Glassware. The quality of the glassware depends on the composition of the glass, the method of its production and the nature of the decorative processing. The cheapest glass is

calcium-sodium. For tableware of improved quality, calcium-sodium-potassium glass is used, and for high-grade tableware, calcium-potassium glass is used. The best types of tableware are made from crystal.

Tableware is produced by blowing or pressing. Blowing, in turn, can be done by machine or by hand. The production method, naturally, affects the quality of the dishes. Products that are complex in shape and artistic are made only by hand. Pressed products are easily distinguished from blown products by characteristic small irregularities on the surface, including on the inside. They are absent on blown products.

Soaps and detergents

Soap was known to man before the new era. Scientists do not have information about the beginning of soap making in Arab countries and China. The earliest written mention of soap in European countries is found in the Roman writer and scientist Pliny the Elder (23-79). In his treatise “Natural History” (in 37 volumes), which was essentially an encyclopedia of natural scientific knowledge of antiquity, Pliny wrote about methods for making soap by saponifying fats. Moreover, he wrote about hard and soft soap made using soda and potash, respectively. Previously, lye obtained from treating ash with water was used to wash clothes. Most likely this was before it became known that ash from burning plant fuels contained potash.

Despite the fact that at the end of the Middle Ages there was a fairly developed soap industry in different countries, the chemical essence of the processes, of course, was not clear. Only at the turn of the 18th and 19th centuries. The chemical nature of fats was clarified and clarity was brought into the reaction of their saponification. In 1779, the Swedish chemist Scheele showed that the reaction of olive oil with lead oxide and water produced a sweet and water-soluble substance. A decisive step towards studying the chemical nature of fats was taken by the French chemist Chevrel. He discovered stearic, palmitic and oleic acids as products of the decomposition of fats when they are saponified with water and alkalis. The sweet substance obtained by Scheele was named glycerin by Chevreul. Forty years later, Berthelot established the nature of glycerol and explained the chemical structure of fats. Glycerin is a trihydric alcohol. Fats - glycerol esters (glycerides) of heavy monobasic carboxylic acids, mainly palmitic CH3(CH2)14 COOH, stearic CH3 (CH2)16 COOH and oleic CH3 (CH2)7 CH=CH(CH2)7 COOH. Their formula and hydrolysis reaction can be described as follows:

CH2 OOCR1 R1 COONa CH2 OH

CHOOCR2 + 3NaOH→R2 COONa + CHOH

CH2 OOCR3 R3 COONa CH2 OH

fat-glyce-

acidrin

Various fats contain palmitic, stearic, oleic and other acids in varying proportions. In vegetable (liquid) fats, unsaturated acids (containing ethylene bonds) predominate, and in animal (solid) fats, saturated acids predominate, i.e., those that do not contain double bonds. The requirement for solid animal fats is greater than for vegetable fats. Therefore, liquid vegetable fats are converted into solid fats by catalytic hydrogenation. In this process, the residues of unsaturated acids in glycerides are converted (by the addition of hydrogen) into residues of saturated acids. For example,

This is how cooking fats, frying oils, salad oils, and fats used in the production of margarine are obtained. Hydrogenated fats are called lard (fat from oil).

If we try to give a definition, then washing can be called cleaning a contaminated surface with a liquid containing a detergent or a system of detergents. Water is mainly used as a liquid in everyday life. A good cleaning system should perform a dual function: remove dirt from the surface being cleaned and transfer it into an aqueous solution. This means that the detergent must also have a dual function: the ability to interact with the pollutant and transfer it into water or an aqueous solution. Therefore, a detergent molecule must have hydrophobic and hydrophilic parts. Phobospo in Greek means fear, fear. So, hydrophobic means afraid, avoiding water. Phileo - in Greek - love, and hydrophilicity - loving, holding water. The hydrophobic part of the detergent molecule has the ability to interact with the surface of the hydrophobic contaminant. The hydrophilic part of the detergent interacts with water, penetrates into the water and carries with it a particle of pollutant attached to the hydrophobic end.

In the production of soap, rosin has long been used, which is obtained by processing the resin of coniferous trees. Rosin consists of a mixture of resin acids containing about 20 carbon atoms in the chain. In the formulation of laundry soap, 12-15% of rosin by weight of fatty acids is usually added, and in the formulation of toilet soaps - no more than 10 %. The introduction of rosin in large quantities makes the soap soft and sticky.

The soap making process consists of chemical and mechanical stages. At the first stage (soap cooking), an aqueous solution of sodium salts (less often potassium) of fatty acids or their substitutes (naphthenic, resin) is obtained. At the second stage, mechanical processing of these salts is carried out - cooling, drying, mixing with various additives, finishing and packaging.

Soap cooking is completed by treating the soap solution (soap glue) with an excess of alkali ( NaOH) or solution NaCl. As a result, a concentrated layer of soap, called a core, floats to the surface of the solution. The soap obtained in this way is called sound soap, and the process of isolating it from the solution is called salting out or salting out. When salting out, the concentration of soap increases and it is purified from protein, coloring and mechanical impurities - this is how laundry soap is obtained.

A special place among fillers is occupied by saponin, obtained by leaching of certain plants and, above all, soap root. It dissolves well in water and its solutions foam strongly. Therefore, saponin is used to improve foaming and is used for expensive soaps.

In addition to using soap as a detergent, it is widely used in finishing fabrics, in the production of cosmetics, for the manufacture of polishing compounds and water-based paints. There is also a less harmless use for it. Aluminum soap (aluminum salts of a mixture of fatty and naphthenic acids) is used in the USA to produce some types of napalm - a self-igniting composition used in flamethrowers and incendiary bombs. The word napalm itself comes from the initial syllables of naphthenic and palmitic acids. The composition of napalm is quite simple - it is gasoline thickened with aluminum soap.

Currently, the chemical industry produces a large number of different synthetic detergents (washing powders). Of greatest practical importance are compounds containing a saturated hydrocarbon chain of 10-15 carbon atoms, one way or another associated with a sulfate or sulfonate group, for example

The production of synthetic detergents is based on cheap raw materials, or more precisely on oil and gas products. As a rule, they do not form calcium and magnesium salts that are poorly soluble in water.

Consequently, many synthetic detergents clean equally well in both soft and hard water. Some products are even suitable for washing in sea water. Synthetic detergents act not only in hot water, as is typical for laundry soap, but also in water at relatively low temperatures, which is important when washing fabrics made from artificial fibers. Finally, the concentration of synthetic detergents, even in soft water, can be much lower than soap derived from fats. Synthetic detergents usually have a rather complex composition, since they contain various additives: optical brighteners, chemical bleaches, enzymes, foaming agents, softeners.

Chemical hygiene and cosmetic products

The word hygiene comes from the Greek. hygienos, which means healing, bringing health, and cosmetics - from Greek, meaning the art of decorating.

One way to prevent caries is by brushing your teeth and rinsing your mouth after eating. This leads to the prevention of the formation of soft plaque and tartar.

It is difficult to say when people started brushing their teeth, but there is evidence that one of the oldest preparations for cleaning teeth was tobacco ash.

The most important means of dental care are toothpastes. They have a lower abrasive ability compared to powders, are more convenient to use and are characterized by higher efficiency. Toothpastes are multi-component compositions. They are divided into hygienic and therapeutic and prophylactic. The former only have a cleansing and refreshing effect, while the latter, in addition, serve to prevent diseases and contribute to the treatment of teeth and oral cavity.

The main components of toothpaste are as follows: abrasives, binders, thickeners, foaming agents. Abrasive substances provide mechanical cleaning of the tooth from plaque and polishing it. Chemically deposited chalk is most often used as abrasives. CaCO3. It has been established that the components of toothpaste can affect the mineral component of the tooth and, in particular, the enamel. Therefore, calcium phosphates began to be used as abrasives: CaHRO4, Ca3 (PO4)2, Ca2 P2 O7, as well as poorly soluble polymeric sodium meta-phosphate ( NaPOz). In addition, aluminum oxide and hydroxide, silicon dioxide, zirconium silicate, as well as some organic polymer substances, such as sodium methyl methacrylate, are used as abrasives in various types of pastes. In practice, not one abrasive substance is often used, but a mixture of them.

Of the synthetic substances, fiber derivatives (cotton and wood) - sodium carboxymethylcellulose, ethoxylated ethyl and methyl cellulose ethers, or simply ethyl and methyl cellulose ethers - have found widespread use.

The fight against caries with the help of therapeutic and prophylactic toothpastes is carried out in two directions: 1) strengthening the mineral tissue of the tooth; 2) prevention of plaque formation. The first is achieved by introducing fluorine compounds into the pastes: sodium monofluorophosphate, the formula of which can be conventionally written in the form of a double salt NaF∙ NaPO3, as well as sodium fluoride NaF and tin(II) fluoride SnF2. There are two points of view on the effect of fluoride ions on strengthening tooth enamel. 1. Ions F translate enamel hydroxydapatite CaOH(PO4)3 in fluoro-rapatite, which is less soluble in acids Ca5 F( PO4)h. 2. As a result of the exchange reaction, the paste forms CaF2, which is adsorbed on hydroxydapatite and protects it from exposure to acids. It is also known that fluoride compounds help suppress the activity of bacteria that cause the formation of organic acids in the oral cavity. Currently, enzymes are widely used in anti-caries pastes, and sometimes antibiotics are introduced into them.

Deodorants and the ozone “shield” of the planet.

Deodorants are products that eliminate the unpleasant odor of sweat. What is their action based on? Sweat is secreted by special glands located V skin at a depth of 1-3 mm. In healthy people, it consists of 98-99% water. With sweat, metabolic products are excreted from the body: urea, uric acid, ammonia, some amino acids, fatty acids, cholesterol, trace amounts of proteins, steroid hormones, etc. Mineral components in sweat include sodium, calcium, magnesium, copper, manganese ions , iron, as well as chloride and iodide anions. The unpleasant odor of sweat is associated with bacterial breakdown of its components or with their oxidation by atmospheric oxygen. Deodorants (anti-sweat cosmetics) come in two types. Some inhibit the decomposition of metabolic products excreted in sweat by inactivating microorganisms or preventing the oxidation of sweat products. The action of the second group of deodorants is based on partial suppression of sweating processes. Such products are called antiperspirans. These properties are possessed by salts of aluminum, zinc, zirconium, lead, chromium, iron, bismuth, as well as formaldehyde, tannins, and ethyl alcohol. In practice, aluminum compounds are most often used among salts as antiperspirans. The listed substances interact with the components of sweat, forming insoluble compounds that close the channels of the sweat glands and thereby reduce sweating. Both types of deodorants contain fragrances.

The concentration of ozone in the atmosphere depends on the content of nitrogen oxides and fluorochloromethanes. Nitrogen oxides are constantly present in low concentrations as a result of the photochemical interaction of nitrogen and oxygen. Nitric oxide (II) destroys ozone, and nitric oxide (IV) binds atomic oxygen according to the equations

ABOUT 3 + NO → NO2 + O 2

NO2+ O → NO + O2

Oz + About → 2 ABOUT 2

Thus, nitrogen oxides play the role of catalysts in the decomposition of ozone.

Over the 4.6 billion years of our planet’s existence, equilibrium was established, and life on Earth arose and developed under a certain equilibrium composition of the atmosphere. However, the intensive development of supersonic aviation is beginning to influence the balance created in the atmosphere. Since supersonic aircraft are designed to fly in the stratosphere, the upper limit of which approaches the “ozone” layer, there is a danger of supersonic technology influencing this layer. When fuel burns in aircraft engines, nitrogen oxides are formed in fairly large quantities.

Another source of danger to the ozone layer are fluorochloromethanes (mainly CF2 CI2 And CFCl3). These substances are widely used in aerosol cans, and also as refrigerants in industrial and household refrigerators.

Cosmetical tools.

In the world, it is believed that among the most profitable industries, cosmetics is one of the first places. Observations show that if necessary, women can deny themselves many things, but not what will make them at least a little more beautiful.

The art of cosmetics goes back a long way. Thus, during excavations, Egyptian mummies were found whose nails were painted. In the tombs of the Egyptian pyramids, natural paints and cosmetic tools, various tiles for preparing a mixture of paints and blush, and vessels for storing ointments and oils were discovered. A written document was found - the Ebers papyrus, which sets out cosmetic rules and recipes. Its writing dates back to the fifth millennium BC.

Ancient manuscripts testify that thousands of years ago women of the East tinted their eyelids blue with the finest pollen from crushed turquoise. Turquoise is a natural mineral with the composition WITH uA16 (PO4)4 (OH)8 ∙4H2 O .

Since time immemorial, a soft natural mineral - antimony shine - has been used to tint eyebrows. Sb2 S3. In Russian there was an expression “to make eyebrows”. Antimony glitter was supplied to various countries by the Arabs, who called it stibi. From this name came the Latin stibium, which in ancient times meant not a chemical element, but its sulfide Sb2 S3. Natural antimony luster ranges in color from gray to black with a blue or iridescent tarnish.

It is reliably known that in Russia cosmetic paints were used at the end of the 16th century and especially widely in the 17th century.

The industry produces pearlescent lipsticks and creams, as well as shampoos with pearlescent glosses. The pearlescent effect in cosmetics is created by bismuthyl salts IN iOS l And BiO( NO3) or titanated mica - pearlescent powder containing about 40 % T iO2. Pearl or Spanish white has long been known. Their main component is BiO( NO3)2 , formed when bismuth nitrate dissolves Bi( NO3)z in water. In cosmetics, this white is used to prepare white makeup.

Zinc oxide is used to create special cosmetics (make-ups) ZnO obtained by calcination of basic carbonate ( ZnOH)2 CO3. In medicine, it is used in powders (as an astringent, drying agent, disinfectant) and for the manufacture of ointments.

Cosmetic decorative powders are multicomponent mixtures. They include: talc, kaolin, ZnO, TiO2, MgCO3, starch, zinc and magnesium salts of stearic acid, as well as organic and inorganic pigments, in particular Fe2 O3. Talc gives the powder flowability and a sliding effect. Its disadvantage is the ability to be absorbed into the skin and give an oily shine. However, it is included in powders in amounts up to 50-80 %. Kaolin has high hiding power and the ability to absorb excess oil from the skin. Its increased hygroscopicity contributes to caking and uneven distribution of powder on the skin, so kaolin is administered no more than 25 %. Zinc and titanium oxides have good hiding power. In addition, zinc oxide has antiseptic properties and therefore simultaneously acts as a disinfectant additive. These oxides are added to powders up to 15 %. In large quantities they lead to dry skin. Starch gives the skin a velvety feel, and thanks to zinc and magnesium stearates, the powder adheres well to the skin and makes it smooth.

Compact powder, unlike loose powder, contains binding additives: sodium carboxymethylcellulose, higher fatty acids, waxes, polyhydric alcohols and their esters, mineral and vegetable oils. They make it possible to obtain briquettes of a certain shape by pressing, which retain their strength during long-term use.

In everyday life, solutions (3, 6, 10%) of hydrogen peroxide are widely used as a disinfectant and bleaching agent. A more concentrated solution - a 30% solution of hydrogen peroxide - is called perhydrol. Hydrogen peroxide is an unstable (especially in light) chemical compound. It decomposes into water and oxygen:

2H2 O2 = 2H2 O + O2

At the moment of formation, oxygen is in the atomic state and only then turns into a molecular state:

2O = O2

Atomic oxygen has a particularly strong oxidizing property. Thanks to it, hydrogen peroxide solutions destroy dyes and bleach cotton and wool fabrics, silk, feathers, and hair. The ability of hydrogen peroxide to bleach hair is used in cosmetics. It is based on the interaction of atomic oxygen with the hair dye melanin - a mixture of complex organic substances. When oxidized, melanin becomes a colorless compound. It should be remembered that perhydrol causes burns to the skin and mucous membranes.

Currently, there is a wide range of different organic dyes available for hair coloring.

Sometimes salts of silver, copper, nickel, cobalt, and iron are used for this purpose. In this case, hair dyeing is carried out using two solutions. One of them contains salts of these metals: nitrates, citrates, sulfates or chlorides, and the second contains reducing agents: pyrogallol, tannin, etc. When these solutions are mixed, metal ions are reduced to atoms, which are deposited on the surface of the hair.

The most common nail polish is a solution of nitrocellulose in organic solvents. Nitrocellulose is obtained by nitration of cellulose (cotton or wood) with a mixture of nitric and sulfuric acids. It is an ester of nitric acid and is characterized by the general formula [C6 H7 O2 (OH)3- X (O NO2) X ] N. Amyl ester of acetic acid, acetone, various alcohols, ethyl ether, and mixtures thereof are used as solvents. Plasticizers are added to the varnish - castor oil or other extracts, which prevent nails from degreasing and prevent their fragility.

Chemistry in agriculture

The Earth as a planet in the solar system has existed for about 4.6 billion years. It is believed that life arose on it 800-1000 thousand years ago. Scientists have discovered traces of the activity of primitive man, the age of which is estimated at 600-700 thousand years. The era of agriculture dates back only 17 thousand years.

Over many millions of years, water, air, and then living organisms destroyed and crushed the rocks of the earth's crust. When living organisms died, they formed humus or, as scientists call it, humus. It mixed with crushed rock, glued and cemented it. This is how the soil on our planet was born. The first soil served as the basis for the development of subsequent larger plants, which, in turn, contributed to a new accelerated formation of humus. The process of soil formation began to proceed with even greater acceleration with the appearance of animals, especially those inhabiting the soil layer. Various types of bacteria contributed to the transformation of organic matter into humus. The formation and breakdown of organic matter in soil is considered the main cause of soil formation.

Thus, the soil consists of mineral and organic (humus) parts. The mineral part makes up from 90 to 99% or more of the total mass of the soil. It includes almost all elements of D. I. Mendeleev’s periodic table

The soil, as an ion exchanger of cations, is “charged” mainly with calcium ions Ca2+, to a lesser extent - magnesium Mg2+ and even to a lesser extent ammonium ions NH, sodium Na+ and potassium K+. Calcium ions Ca2+ and magnesium Mg2+ help maintain a strong soil structure. By soil structure, agricultural workers understand its ability to break up into separate lumps. Ions K+ or N.H. and especially Na+, on the contrary, contribute to the destruction of structural soil aggregates and increase the leaching of humus and minerals. When wet, such soil becomes sticky, and when dry, it turns into blocks that cannot be processed (salone lick). The water flowing from such soil has the color of tea infusion, which indicates a loss of humus.

The chemical binding of anions of certain acids by the soil is important. Nitrate NO and chloride WITH l anions do not produce poorly soluble compounds with cations usually found in soil.

On the contrary, the anions of phosphoric, carbonic, and sulfuric acids form poorly soluble compounds with calcium ions. This determines the chemical absorption capacity of soils.

Manure.

On average, manure contains 0.5% nitrogen bound into chemical compounds, 0.25 % phosphorus and 0.6 % potassium The content of these nutrients depends on the type of livestock, the nature of the feed being fed, the type of bedding and other factors. In addition to nitrogen, phosphorus and potassium, manure contains all the elements, including microelements, necessary for plant life. Straw and sawdust are used as bedding, but peat is considered the best. Litter allows for better retention of nutrients in the manure.

Mineral fertilizers.

Mineral fertilizers began to be used in the world relatively recently. The initiator and active advocate of their use in agriculture was the German chemist Justus Liebig. In 1840, he published the book “Chemistry as applied to agriculture.” In 1841 At his initiative, the first superphosphate plant was built in England. Potash fertilizers began to be produced in the 70s of the last century. Mineral nitrogen at that time was supplied to the soil with Chilean nitrate. It should be noted that currently it is considered rational to apply phosphorus, potassium and nitrogen fertilizers to the soil in a nutrient ratio of approximately 1:1.5:3.

Nitrogen-containing mineral fertilizers are divided into ammonia, nitrate and amide. The first group includes ammonia itself NНз(anhydrous and aqueous solutions) and its salts - primarily sulfate ( NH4)2 SO4 and ammonium chloride NH4 CI. To the second group of nitrate: sodium NaNO3, potassium KNO3 and calcium Ca( NO3)2. The industry also produces ammonium nitrate fertilizers, for example ammonium nitrate NH4 NO3. Amide fertilizers include calcium cyanamide SaS N2 and urea (urea) NH2 CONH2. To reduce dusting of calcium cyanamide, up to 3% petroleum oils are often added to it. As a result, this fertilizer has the smell of kerosene. When hydrolyzed, calcium cyanamide produces ammonia and calcium carbonate:

SaS N2 + 3H2 O = CaCO3 + 2NH3

Nature has created many storehouses of phosphorus raw materials, including in our country. These storehouses consist of apatites and phosphorites. In the group of minerals under the general name apatites, the most common phosphates of the composition Ca5 X(PO4)3, Where X = F, Cl, OH . The corresponding minerals are called fluorapatite, chlorapatite, hydroxydapatite. The most common is fluorapatite. Apatites are part of igneous igneous rocks. Sedimentary rocks that contain apatite with inclusions of particles of foreign minerals (quartz, calcite, clay, etc.) are called phosphorites.

In the body of plants, potassium regulates the respiration process, promotes the absorption of nitrogen and increases the accumulation of proteins and sugars in plants. For grain crops, potassium increases the strength of straw, and in flax and hemp it increases the strength of the fiber. Potassium increases the resistance of winter grains to frost and overwintering, and of vegetable crops to early autumn frosts. Potassium deficiency in plants manifests itself on the leaves. Their edges become yellow and dark brown with red speckles.

Other macronutrients included in nutrients.

As already noted, soils are most quickly depleted of nitrogen, phosphorus and potassium. In addition to them, plants also need other chemical elements in fairly large quantities: calcium, magnesium, sulfur, iron. Their content in soils is often close to the needs of plants and their removal with commercial products is relatively low.

Microfertilizers.

Microfertilizers are nutrients that contain chemical elements consumed by plants in very small quantities. Currently, the biological role of boron, copper, manganese, molybdenum, etc. in the life of plant and animal organisms has been identified. Fertilizers containing these microelements have received appropriate names.

Candle and light bulb

Nowadays, buying a candle is available to everyone almost in the same way as matches. However, this was not always the case. At the beginning of the last century in Rus', candles were highly valued and in the homes of ordinary people a torch or lamp with oil was usually lit. Kerosene lamps appeared later. People's generosity was judged by the size of the candle a person lit when attending church.

In the last century, candle production was a developed industry. There were descriptions of production technologies and their chemical essence. In particular, such work in 1851. was written by a teacher at the St. Petersburg Institute of Technology N. Witt.

From his book we learn that the candles were wax, tallow, stearic, spermaceti and very expensive paraffin. The materials from which the candles were made will be discussed below. However, not immediately about this. One cannot help but recall that in the middle of the last century, the great English scientist Michael Faraday gave a lecture on the topic. "The Story of a Candle" It was an inspired hymn to the creation of man and nature. The lecture was translated into Russian and part of it was published. The author recommends that anyone interested in physics and chemistry read this outstanding work.

Probably the first candles were wax. Beeswax is a gift from nature and a candle from it could be made in the most primitive way. Much later, the wax began to be cleaned. The technology was again very simple. This was achieved by melting the wax and filtering the molten state through a cloth. To bleach the wax, depending on the capabilities, bone charcoal, sulfur dioxide or chlorine were used.

It should be noted that vegetable wax was imported from the American continents to Europe. It was used to make candles instead of bees, but it was much more expensive and therefore could not compete.

The candle threads were boiled for several hours in lye made from potash and burnt lime. This was followed by washing with water and bleaching with bleach.

Stearin was originally understood as two different products extracted from beef and lamb lard. One of them was obtained by removing liquids from lard by pressing. The solid residue was called stearin. Another product was obtained by chemically treating lard first with lime and then with sulfuric acid. Essentially, this was the hydrolysis of fats (glycerides) followed by the release of a mixture of acids: stearic, palmitic and a small amount of unsaturated acids.

Stearic acid CH3 (CH2)16 COOH was opened in salo in 1816. French chemist Chevrel. Together with Gay-Lussac in 1825. he took the privilege of making stearin candles in England.

Stearin candles turned out to be cheaper than wax candles. However, the Russian Church for a long time did not agree to replace wax candles with stearin ones. One of the reasons was that wax candles emitted a pleasant smell when burned.

Tallow candles were made from rendered lard, which was then purified mechanically (by straining through a cloth) or chemically (with alumina or tannins) and bleached in the same way as wax. When burning, tallow candles produced a lot of smoke.

Spermaceti for spermaceti suppositories was extracted from cavities located in the heads of whales. It was freed from accompanying liquid oils by cold or hot pressing. If necessary, cleaning was carried out using soap lye. Candles made from spermaceti were white and translucent. However, they also had a drawback. When burning, they floated over time.

In the current century, before the extermination of whales, the scarce spermaceti was used mainly as a base for creams and various ointments, and also as a high-quality lubricating oil for precision instruments.

Paraffin candles were initially quite expensive, since paraffin was extracted by distilling the tar of plant substances. Then in England they began to extract it from peat. However, in both cases it was obtained only in small quantities. A fundamental change occurred with the establishment of large-scale oil refining. Now it is one of the most accessible petrochemical products. Paraffin - a mixture of saturated hydrocarbons C18 -C35. Mixture of saturated hydrocarbons C36 -C55 called ceresin. Modern candles consist of a mixture of paraffin and ceresin.

The light bulb consists of a glass container into which the spiral holders are inserted, and the spiral itself. The spiral is made of tungsten - one of the most refractory metals. Its melting point is 3410 °C. In addition to high refractoriness, tungsten has another very important property - high ductility. From 1 kg. With tungsten, you can stretch a wire 3.5 km long, which is enough to make 23 thousand 60-watt light bulbs. The holder is made of molybdenum, an element analogous to tungsten. In the periodic table of D.I. Mendeleev, these two elements are in the same subgroup. The most important property of molybdenum is its low linear expansion coefficient. When heated, it expands in size in the same way as glass. Since molybdenum and glass change sizes synchronously when heated and cooled, the latter does not crack and therefore the seal is not broken.

It is known that the intensity of radiation of a body increases in proportion to the fourth power of absolute temperature. This follows from the Stefan-Boltzmann law. Consequently, an increase in the temperature of the tungsten filament of an electric light bulb by only 100° from 24001 to 2500 °C leads to an increase in luminous flux by 16%. In addition, with increasing temperature, the proportion of visible light in the total radiation flux increases. This phenomenon is reflected by Wien's law, i.e. As the temperature of the filament increases, the light output increases, which means the efficiency of the light bulb increases. The temperature rise is prevented by the heating of the glass container and the evaporation of the filament. You can reduce the heating of the cylinder by creating a vacuum in it. These" by reducing the thermal conductivity from the filament to the glass. However, in a vacuum, the evaporation of the filament will increase. This will lead to its thinning and, eventually, the thread will burn out. Filling the cylinder with an inert gas, for example nitrogen, prevents the evaporation of the filament, and the heavier the molecules of the filling gas, the more so. Tungsten atoms separated from the filament will hit gas molecules, their path to the walls of the balloon will be lengthened, and some atoms may return to the filament. The heavier the fill gas molecules are, the more they will hinder the evaporation of the filament. Thus, partial replacement of nitrogen with argon makes it possible to increase the temperature of the tungsten filament to 2600-2700 °C. It is impossible to completely replace nitrogen with argon, since the latter has a relatively high electrical conductivity and there is a danger of an electric arc between the molybdenum holders. Heavier noble gases - krypton and xenon - protect the tungsten filament from destruction even better. They allow you to raise the filament temperature to 2800 °C and reduce the volume of the gas cylinder. Filling lamps with them instead of argon allows you to get 15% more light output, double the life of the filament and reduce the volume of the cylinder by 50%.

To increase the service life of incandescent electric lamps, a small amount of iodine is added to the cylinder. He acts as a dog guarding a flock of sheep. In a zone with a temperature of approximately 1600 °C, iodine interacts with tungsten atoms detached from the filament, transforming them into a compound Wl2. With chaotic movement, sooner or later the tungsten (II) iodide molecule enters the region of higher temperatures, where it dissociates in accordance with the equation

WI2 → W+2 l

Thus, iodine returns tungsten atoms to the area surrounding the filament and, therefore, prevents its evaporation. In iodine lamps, there are no traces of dark deposits of metal tungsten on the walls of the glass bottle. For this reason, the light output of such lamps does not decrease over time, and their service life increases.

Chemical elements in the human body

All living organisms on Earth, including humans, are in close contact with the environment. Food and drinking water contribute to the entry of almost all chemical elements into the body. They are introduced into and removed from the body every day. Analyzes have shown that the number of individual chemical elements and their ratio in the healthy body of different people is approximately the same.

The opinion that almost all elements of D.I. Mendeleev’s periodic system can be found in the human body is becoming commonplace. However, scientists' assumptions go further - not only are all chemical elements present in a living organism, but each of them performs some kind of biological function. It is quite possible that this hypothesis will not be confirmed. However, as research in this direction develops, the biological role of an increasing number of chemical elements is revealed. Undoubtedly, the time and work of scientists will shed light on this issue.

Bioactivity of individual chemical elements. It has been experimentally established that metals make up about 3% (by weight) in the human body. That's a lot. If we take the mass of a person as 70 kg, then the share of metals is 2.1 kg. The mass is distributed among individual metals as follows: calcium (1700 g), potassium (250 g), sodium (70 g), magnesium (42 g), iron (5 g), zinc (3 g). The rest comes from microelements. If the concentration of an element in the body exceeds 102%, then it is considered a macroelement. Microelements are found in the body in concentrations of 103 -105 %. If the concentration of an element is below 105%, then it is considered an ultramicroelement. Inorganic substances in a living organism are found in various forms. Most metal ions form compounds with biological objects. It has already been established that many enzymes (biological catalysts) contain metal ions. For example, manganese is included in 12 different enzymes, iron - in 70, copper - in 30, and zinc - in more than 100. Naturally, the lack of these elements should affect the content of the corresponding enzymes, and therefore the normal functioning of the body. Thus, metal salts are absolutely necessary for the normal functioning of living organisms. This was also confirmed by experiments on a salt-free diet, which was used to feed experimental animals. For this purpose, salts were removed from food by repeated washing with water. It turned out that eating such food led to the death of animals

Six elements whose atoms are part of proteins and nucleic acids: carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur. Next, we should highlight twelve elements, the role and importance of which for the life of organisms is known: chlorine, iodine, sodium, potassium, magnesium, calcium, manganese, iron, cobalt, copper, zinc, molybdenum. In the literature there are indications of the manifestation of biological activity by vanadium, chromium, nickel and cadmium

There are a large number of elements that are poisons for a living organism, for example, mercury, thallium, pigs, etc. They have an adverse biological effect, but the body can function without them. There is an opinion that the reason for the action of these poisons is associated with the blocking of certain groups in protein molecules or with the displacement of copper and zinc from certain enzymes. There are elements that are poisonous in relatively large quantities, but in low concentrations have a beneficial effect on the body. For example, arsenic is a strong poison that disrupts the cardiovascular system and affects the liver and kidneys, but in small doses it is prescribed by doctors to improve a person’s appetite. Scientists believe that microdoses of arsenic increase the body's resistance to harmful microbes. Mustard gas is a widely known strong toxic substance. S(CH2 CH2 C1)2. However, diluted 20,000 thousand times with petroleum jelly under the name “Psoriasin”, it is used against scaly lichen. Modern pharmacotherapy cannot yet do without a significant number of drugs that contain toxic metals. How can one not recall the saying that in small quantities it heals, but in large quantities it cripples.

Interestingly, sodium chloride (table salt) in a tenfold excess in the body compared to normal levels is poisonous. Oxygen, which a person needs for breathing, has a toxic effect in high concentrations and especially under pressure. From these examples it is clear that the concentration of an element in the body sometimes plays a very significant, and sometimes catastrophic, role.

Iron is part of blood hemoglobin, or more precisely in red blood pigments, which reversibly bind molecular oxygen. An adult's blood contains about 2.6 g of iron. In the process of life, the body constantly breaks down and synthesizes hemoglobin. To restore iron lost with the breakdown of hemoglobin, a person needs a daily intake of about 25 mg. Lack of iron in the body leads to a disease - anemia. However, excess iron in the body is also harmful. It is associated with siderosis of the eyes and lungs, a disease caused by the deposition of iron compounds in the tissues of these organs. Lack of copper in the body causes destruction of blood vessels. In addition, it is believed that its deficiency causes cancer. In some cases, doctors associate lung cancer in older people with an age-related decrease in copper in the body. However, excess copper leads to mental disorders and paralysis of some organs (Wilson's disease). Only large amounts of copper compounds cause harm to humans. In small doses, they are used in medicine as an astringent and bacteriostasis (inhibiting the growth and reproduction of bacteria). For example, copper (II) sulfate CuSO4 used in the treatment of conjunctivitis in the form of eye drops (0.25% solution), as well as for cauterization for trachoma in the form of eye pencils (an alloy of copper (II) sulfate, potassium nitrate, alum and camphor). In case of burns of the skin with phosphorus, it is copiously moistened with a 5% solution of copper (II) sulfate.

The bactericidal (causing the death of various bacteria) property of silver and its salts has long been noticed. For example, in medicine, a solution of colloidal silver (collargol) is used to wash purulent wounds, the bladder for chronic cystitis and urethritis, as well as in the form of eye drops for purulent conjunctivitis and blennorrhea. Silver nitrate AgNO3 in the form of pencils, it is used to cauterize warts, granulations, etc. In diluted solutions (0.1-0.25%) it is used as an astringent and antimicrobial agent for lotions, and also as eye drops. Scientists believe that the cauterizing effect of silver nitrate is associated with its interaction with tissue proteins, which leads to the formation of protein salts of silver - albuminates.

At present, it has undoubtedly been established that all living organisms are characterized by the phenomenon of ion asymmetry - the uneven distribution of ions inside and outside the cell. For example, inside the cells of muscle fibers, heart, liver, and kidneys there is an increased content of potassium ions compared to the extracellular content. The concentration of sodium ions, on the contrary, is higher outside the cell than inside it. The presence of a concentration gradient of potassium and sodium is an experimentally established fact. Researchers are concerned about the mystery of the nature of the potassium-sodium pump and its functioning. The efforts of many teams of scientists, both in our country and abroad, are aimed at resolving this issue. Interestingly, as the body ages, the concentration gradient of potassium and sodium ions at the cell boundary decreases. When death occurs, the concentration of potassium and sodium inside and outside the cell immediately equalizes.

The biological function of lithium and rubidium ions in a healthy body is not yet clear. However, there is evidence that by introducing them into the body it is possible to treat one of the forms of manic-depressive psychosis.

Biologists and doctors are well aware that glycosides play an important role in the human body. Some natural glycosides (extracted from plants) actively act on the heart muscle, enhancing contractile functions and slowing the heart rate. If a large amount of cardiac glycoside enters the body, complete cardiac arrest can occur. Some metal ions affect the action of glycosides. For example, when magnesium ions are introduced into the blood, the effect of glycosides on the heart muscle is weakened. Calcium ions, on the contrary, enhance the effect of cardiac glycosides

Some mercury compounds are also extremely poisonous. It is known that mercury (II) ions are able to bind strongly to proteins. Poisonous effect of mercuric chloride (II) HgCl2(sublimate) manifests itself primarily in necrosis (death) of the kidneys and intestinal mucosa. As a result of mercury poisoning, the kidneys lose their ability to excrete waste products from the blood.

Interestingly, mercuric(I) chloride Hg2 Cl2(ancient name calomel) is harmless to the human body. This is probably due to the extremely low solubility of salt, as a result of which mercury ions do not enter the body in noticeable quantities.

Potassium cyanide (Potassium cyanide) KCN- hydrocyanic acid salt HCN. Both compounds are fast-acting and powerful poisons

In acute poisoning with hydrocyanic acid and its salts, consciousness is lost, respiratory and cardiac paralysis occurs. At the initial stage of poisoning, a person experiences dizziness, a feeling of pressure in the forehead, acute headache, rapid breathing, and palpitations. First aid for poisoning with hydrocyanic acid and its salts is fresh air, oxygen breathing, heat. Antidotes are sodium nitrite NaNO2 and organic nitro compounds: amyl nitrite C5 H11 ONO and propyl nitrite C3 H7 ONO. It is believed that the effect of sodium nitrite is reduced to the conversion of hemoglobin into meta-hemoglobin. The latter firmly binds cyanide ions into cyanmetagemoglobin. In this way, respiratory enzymes are freed from cyanide ions, which leads to the restoration of the respiratory function of cells and tissues.

Sulfur-containing compounds are widely used as antidotes to hydrocyanic acid: colloidal sulfur, sodium thiosulfate Na2 S2 O3, sodium tetrathionate Na2 S4 O6, as well as sulfur-containing organic compounds, in particular amino acids - glutathione, cysteine, cystine. Hydrocyanic acid and its salts, when reacting with sulfur, are converted into thiocyanates in accordance with the equation

HCN+ S → HNCS

Thiocyanates are completely harmless to the human body.

Since ancient times, in case of danger of cyanide poisoning, it has been recommended to keep a piece of sugar under the cheek. In 1915 German chemists Rupp and Golze showed that glucose reacts with hydrocyanic acid and some cyanides to form the non-toxic compound glucose cyanohydrin:

OH OH OH OH N OH OHON OH OH N

| | | | | | | | | | | |

CH2 -CH-CH-CH-CH-C = O + HCN → CH2 -CH-CH-CH-CH-C-OH

glucose cyanohydrin glucose

Lead and its compounds are quite strong poisons. In the human body, lead accumulates in the bones, liver and kidneys.

Compounds of the chemical element thallium, which is considered rare, are very toxic.

It should be pointed out that all non-ferrous and especially heavy (located at the end of the periodic table) metals are poisonous in quantities higher than permissible.

Carbon dioxide is found in large quantities in the human body and therefore cannot be poisonous. In 1 hour, an adult exhales approximately 20 liters (about 40 g) of this gas. During physical work, the amount of exhaled carbon dioxide increases to 35 liters. It is formed as a result of the combustion of carbohydrates and fats in the body. However, with high content CO2 suffocation occurs in the air due to lack of oxygen. Maximum duration of a person's stay in a room with concentration CO2 up to 20% (by volume) should not exceed 2 hours. In Italy there is a well-known cave (“Dog Cave”), in which a person can stand for a long time, and a dog that runs into it suffocates and dies. The fact is that the cave is filled with heavy (compared to nitrogen and oxygen) carbon dioxide up to a person’s waist. Since the person’s head is in the air layer, he does not feel any discomfort. As the dog grows, it finds itself in an atmosphere of carbon dioxide and therefore suffocates.

Doctors and biologists have found that when carbohydrates are oxidized in the body to water and carbon dioxide, one molecule of oxygen is released per molecule of oxygen consumed. CO2. Thus, the ratio of the selected CO2 to absorbed O2(the value of the respiratory coefficient) is equal to one. In the case of fat oxidation, the respiratory coefficient is approximately 0.7. Consequently, by determining the value of the respiratory coefficient, one can judge which substances are predominantly burned in the body. It has been experimentally established that during short-term but intense muscle loads, energy is obtained through the oxidation of carbohydrates, and during long-term exercises, energy is obtained mainly through the combustion of fats. It is believed that the body’s switch to fat oxidation is associated with the depletion of carbohydrate reserves, which is usually observed 5-20 minutes after the start of intense muscular work.

Antidotes.

Antidotes are substances that eliminate the effects of poisons on biological structures and inactivate poisons through chemical

Yellow blood salt K4 [ Fe( CN)6] forms poorly soluble compounds with ions of many heavy metals. This property is used in practice to treat poisoning with heavy metal salts.

A good antidote for poisoning with compounds of arsenic, mercury, lead, cadmium, nickel, chromium, cobalt and other metals is unithiol:

CH2 -CH- CH2 SO3 Na ∙ H2 O

SH SH

Milk is a universal antidote.

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Chemistry plays a huge role in the lives of each of us. Chemical processes surround people, filling human existence with meaning. Chemistry is around us in everything: from ordinary actions like cooking dinner to the most important processes that occur in the human body. Thanks to chemistry, the most important missions are carried out, such as salvation from death, thanks to the creation of vaccines and medicines. This science will not leave anyone indifferent, because it is full of interesting discoveries and experiments.

Everyday activities that we perform every day are not possible without chemical processes. Let's think about it. When you light a match, a complex chemistry process occurs. What products do you use for personal hygiene? Soap that creates foam after contact with water. Or laundry detergent, which gives the same reaction. Now, pour yourself some hot tea, add lemon and see what happens. The color of the tea will become weaker under the influence of the acid indicator. All these are chemical processes that a person does not think about, because he gets used to them from childhood and does not attach importance to how they occur. If certain processes had not occurred on earth that took place before the origin of life, then, naturally, humanity simply would not exist. The way we digest and process food and the way we breathe is built on chemical processes.

Chemistry plays a vital role in medicine. It can have both beneficial and destructive effects. Everyone knows that most medicines are developed thanks to chemistry. They help a person strengthen the immune system and cope with the disease. But also with the help of chemical processes toxic poisons are created that cause enormous harm to human health and life.

Since ancient times, a special interest in chemistry has been shown by curious people, as well as people who want to make money. The first category wanted discoveries, they were driven by a love of science, and the second category wanted to create valuable things that would bring them wealth.

One of the most expensive substances is gold. After it come the rest of the metals. The first and most relevant areas of development of chemistry today are the extraction and processing of ore in order to obtain valuable metals. Other ancient industries include oil refining and ceramics production. A huge number of substances are produced from oil and it shows the great importance of chemical processes. The paint and varnish industry has its foundation in chemistry. Also in construction, materials created using chemical processes are widely used. The quality is getting better and better, and thus chemistry is strengthening its position as a necessity for humans.

Chemistry is an ancient science that is a constant companion in human life. Look around and you will see how many chemical processes happen every day. Treat it with respect, because without chemistry our life would be impossible.

Report 2

Chemistry as a science originated in the 16th and 17th centuries. Early fundamental discoveries include the discovery of Oxygen by A. Lavoisier, the development of the atomic theory by D. Dalton, and the combination of atoms into molecules by A. Avogadro .

Chemistry is the science of simple and complex transformations of substances, their structure, changes under different conditions, patterns of reactions.

This knowledge provides great opportunities for improving many areas of human life, as well as knowledge of the world around us.

Chemistry in the human body. Every day we encounter chemical processes. Chemistry is not only around us, but also inside. The human body consists of organic and inorganic elements. Organic substances include carbohydrates, lipids, and proteins. Each of these substances is divided into molecules. Organic substances also include vitamins, hormones, amino acids and others.

Inorganic compounds are water and salts. Their main role is to accelerate chemical processes. The faster it is, the more benefits the body receives. More than 60% of a person is water. All reactions occur in an aqueous environment. It dissolves incoming minerals well and delivers them to the organs.

The role of chemistry in the life of society. Understanding chemical compounds allowed society to form a new understanding of the world. In combination with other sciences, such as physics, biology, chemistry, it makes a big leap in development and gives a new level to the quality of life.

Many centuries ago, people could not imagine that this science would change the environment globally. With the help of chemistry, humanity has acquired:

• The most important chemical products: acids, alkalis, salts.
• Energy chemical reaction for use in the energy sector.
• Development of industrial sectors: metallurgy, mechanical engineering.
• Development of the pharmaceutical industry.
• Improvement of agriculture.
• The emergence of related sciences: biochemistry, geochemistry, agrochemistry.

Harm from chemicals. Chemistry is an undoubted achievement of civilization, but insufficient knowledge in the field of chemistry leads to devastating consequences.

Household and cosmetic products that people use every day certainly make it easier for us to take care of ourselves and our home. But their excessive or improper use can lead to illness. For example: allergies, damage to mucous membranes, central nervous system.

Global harm from chemical processes is the pollution of soil, atmospheric layer and water by industrial plants. Currently, programs are being developed to save our planet. This will become possible with the introduction of processing technologies.

Introduction. 2

Paper and pencils. eleven

Glass. 13

Soaps and detergents. 17

Chemical hygiene and cosmetic products. 20

Chemistry in agriculture. 24

Candle and light bulb. 26

Chemical elements in the human body. 29

References. 33

Introduction

Everywhere, wherever we turn our gaze, we are surrounded by objects and products made from substances and materials obtained in chemical plants and factories. In addition, in everyday life, without knowing it, every person carries out chemical reactions. For example, washing with soap, washing with detergents, etc. When a piece of lemon is dropped into a glass of hot tea, the color weakens - tea here acts as an acid indicator, similar to litmus. A similar acid-base interaction occurs when chopped blue cabbage is soaked in vinegar. Housewives know that cabbage turns pink. By lighting a match, mixing sand and cement with water, or extinguishing lime with water, or burning a brick, we carry out real and sometimes quite complex chemical reactions. Explanation of these and other chemical processes widespread in human life is the task of specialists.

Cooking is also a chemical process. It’s not for nothing that they say that women chemists are often very good cooks. Indeed, cooking in the kitchen can sometimes feel like performing organic synthesis in a laboratory. Only instead of flasks and retorts in the kitchen they use pots and pans, but sometimes also autoclaves in the form of pressure cookers. There is no need to further list the chemical processes that a person carries out in everyday life. It is only necessary to note that in any living organism various chemical reactions take place in huge quantities. The processes of assimilation of food, breathing of animals and humans are based on chemical reactions. The growth of a small blade of grass and a mighty tree is also based on chemical reactions.

Chemistry is a science, an important part of natural science. Strictly speaking, science cannot surround a person. He may be surrounded by the results of the practical application of science. This clarification is very significant. Nowadays, you can often hear the words: “chemistry has spoiled nature,” “chemistry has polluted the reservoir and made it unsuitable for use,” etc. In fact, the science of chemistry has nothing to do with it. People, using the results of science, poorly incorporated them into a technological process, treated the requirements of safety rules and environmentally acceptable standards for industrial discharges irresponsibly, ineptly and excessively used fertilizers on agricultural land and plant protection products from weeds and plant pests. Any science, especially natural science, cannot be good or bad. Science is the accumulation and systematization of knowledge. How and for what purposes this knowledge is used is another matter. However, this already depends on the culture, qualifications, moral responsibility and morality of people who do not obtain, but use knowledge.

Modern man cannot do without the products of the chemical industry, just as he cannot do without electricity. The same situation applies to chemical industry products. We need to protest not against some chemical industries, but against their low culture.

Human culture is a complex and diverse concept, in which such categories arise as a person’s ability to behave in society, speak their native language correctly, monitor the neatness of their clothes and appearance, etc. However, we often talk and hear about the culture of construction, culture of production, culture of agriculture, etc. Indeed, when it comes to the culture of Ancient Greece or even earlier civilizations, we first of all remember the crafts that people of that era mastered, what tools they used, what they knew how to build, how knew how to decorate buildings and individual objects.

Many chemical processes important to humans were discovered long before chemistry became a science. A significant number of chemical discoveries were made by observant and inquisitive artisans. These discoveries became family or clan secrets, and not all of them have reached us. Some of them were lost to humanity. It was and is necessary to expend enormous work, create laboratories, and sometimes even institutes to reveal the secrets of ancient masters and their scientific interpretation.

Many people do not know how a TV works, but they use it successfully. However, knowing how a TV works will never prevent anyone from using it correctly. Same with chemistry. Understanding the essence of the chemical processes that we encounter in everyday life can only benefit a person.

Water

Water on a planetary scale. Humanity has long paid great attention to water, since it was well known that where there is no water, there is no life. In dry soil, grain can lie for many years and germinate only in the presence of moisture. Despite the fact that water is the most common substance, it is distributed very unevenly on Earth. On the African continent and Asia there are vast areas devoid of water - deserts. An entire country - Algeria - lives on imported water. Water is delivered by ship to some coastal areas and islands of Greece. Sometimes water costs more than wine there. According to the United Nations, in 1985, 2.5 billion of the world's population lacked clean drinking water.

The surface of the globe is 3/4 covered with water - these are oceans, seas; lakes, glaciers. Water is found in fairly large quantities in the atmosphere, as well as in the earth's crust. The total reserves of free water on Earth are 1.4 billion km 3 . The main amount of water is contained in the oceans (about 97.6%), in the form of ice on our planet there is 2.14 %. The water of rivers and lakes is only 0.29 % and atmospheric water - 0.0005 %.

Thus, water is in constant motion on Earth. The average time of its stay in the atmosphere is estimated at 10 days, although it varies with the latitude of the area. For polar latitudes it can reach 15, and in middle latitudes - 7 days. Water changes in rivers occur on average 30 times a year, i.e. every 12 days. The moisture contained in the soil is renewed within 1 year. The waters of flowing lakes are exchanged over tens of years, and in non-flowing lakes, over 200-300 years. The waters of the World Ocean are renewed on average every 3000 years. From these figures you can get an idea of ​​how long it takes to self-clean reservoirs. You just need to keep in mind that if a river flows out of a polluted lake, then the time of its self-cleaning is determined by the time of self-cleaning of the lake.

Water in the human body. It is not very easy to imagine that a person is approximately 65% ​​water. With age, the water content in the human body decreases. The embryo consists of 97% water, the body of a newborn contains 75%, and an adult contains about 60% %.

In a healthy adult body, a state of water equilibrium or water balance is observed. It lies in the fact that the amount of water consumed by a person is equal to the amount of water removed from the body. Water metabolism is an important component of the general metabolism of living organisms, including humans. Water metabolism includes the processes of absorption of water that enters the stomach when drinking and with food, its distribution in the body, excretion through the kidneys, urinary tract, lungs, skin and intestines. It should be noted that water is also formed in the body due to the oxidation of fats, carbohydrates and proteins taken with food. This type of water is called metabolic water. The word metabolism comes from Greek, which means change, transformation. In medicine and biological science, metabolism refers to the processes of transformation of substances and energy that underlie the life of organisms. Proteins, fats and carbohydrates are oxidized in the body to form water H 2 O and carbon dioxide (carbon dioxide) CO 2. The oxidation of 100 g of fat produces 107 g of water, and the oxidation of 100 g of carbohydrates produces 55.5 g of water. Some organisms make do with only metabolic water and do not consume it from the outside. An example is carpet moths. In natural conditions, jerboas, which are found in Europe and Asia, and the American kangaroo rat do not require water. Many people know that in an exceptionally hot and dry climate, the camel has a phenomenal ability to go without food and water for a long time. For example, with a mass of 450 kg during an eight-day trek through the desert, a camel can lose 100 kg in weight, A then restore them without consequences for the body. It has been established that his body uses water contained in the fluids of tissues and ligaments, and not blood, as happens with a person. In addition, the camel's humps contain fat, which serves as both a food store and a source of metabolic water.

The total volume of water consumed by a person per day when drinking and eating is 2-2.5 liters. Thanks to the water balance, the same amount of water is removed from the body. About 50-60 are removed through the kidneys and urinary tract. % water. When the human body loses 6-8 % moisture above the normal norm, the body temperature rises, the skin turns red, the heartbeat and breathing quicken, muscle weakness and dizziness appear, and a headache begins. A loss of 10% of water can lead to irreversible changes in the body, and a loss of 15-20% leads to death, since the blood becomes so thick that the heart cannot cope with pumping it. The heart has to pump about 10,000 liters of blood per day. A person can live without food for about a month, but without water - only a few days. The body's reaction to a lack of water is thirst. In this case, the feeling of thirst is explained by irritation of the mucous membrane of the mouth and pharynx due to a large decrease in humidity. There is another point of view on the mechanism of formation of this sensation. In accordance with it, a signal about a decrease in the concentration of water in the blood is sent to the cells of the cerebral cortex by the nerve centers embedded in the blood vessels.

Chekalina Olesya

This work is addressed to those who are just beginning to get acquainted with the interesting world of chemistry. The work is made in the form of a computer presentation; it is recommended to show it to students who have just started studying chemistry or are already studying this subject. This gives an idea of ​​the chemicals that surround us in everyday life. The work expands the understanding of the use of various (synthetic or natural) substances and increases the importance of the science of chemistry. It is recommended to show the presentation in lessons, elective courses, clubs and electives in chemistry.

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Substances around us. Completed by Olesya Chekalina Teacher: Elena Vladimirovna Karmaza Ivangorod Secondary School No. 1

Every day we deal with various types of household chemicals, ranging from ordinary soap to dyes for cars, as well as dozens of types, hundreds of names of chemical industry products designed to perform all possible household tasks. Chemistry in the kitchen; Chemistry in the bathroom; Chemistry in the garden; Chemistry in cosmetics and hygiene; Chemistry in the home medicine cabinet. Here are some of them:

Chemistry in the kitchen Chemistry in the kitchen is necessary, first of all, for human health because... It is in the kitchen that we spend half our lives. Everything in the kitchen needs to be kept clean and tidy, because unsanitary conditions can cause skin diseases and even lead to poisoning. In order for the kitchen not to be a vulnerable place for human health, it is necessary to constantly clean it up: · The kitchen table must be wiped before and after each meal; · It is best to wipe the table surface with a rag previously soaked in soapy water with the addition of acetic acid (this is a very effective method); · For washing dishes, the most effective are liquid SMP (dishwashing detergents, such as AOS, Sorti, etc.), which are highly soapy; · Cleaning of glass surfaces is carried out using spray-like substances.

Chemistry in the bathroom Chemistry in the bathroom also implies cleanliness because... In the bath we improve body hygiene. In order to clean the bathroom, it is necessary to use chlorine-containing substances and cleaning powders (“Pemo-lux”, “Soda effect”, etc.). In order to maintain body hygiene, a person uses many chemicals - all kinds of shampoos, shower gels, soaps, body creams, all kinds of lotions, etc.

Chemistry in the garden and vegetable garden Fruits, berries, vegetables, cereals - all this grows in the garden and vegetable garden, and in order for the harvest to be good, people add various chemicals to accelerate plant growth, pesticides, herbicides. All this, to varying degrees, is harmful to health, primarily to the consumer of these fruit and berry crops. To avoid the harmful effects of these substances, you need to use natural fertilizers of animal origin. Chemicals in the garden are used mainly to protect against pests and plant diseases: fruit crops, berries, vegetables, flowers. Mineral fertilizers containing nitrogen, potassium, phosphorus and microelements are also used. They help increase plant productivity. Insecticides, fungicides, repellents - involve the fight against harmful insects, garden fungi, etc.

Chemistry in cosmetics and hygiene Cosmetics are mostly used by the female half of humanity. Hygiene products include soap, shampoos, deodorants, and creams. Cosmetic products include lipsticks, powders, eye shadows, mascara and eyebrows, eyeliner pencils, lip liners, foundation and much more. Nowadays, there are no cosmetics that are not of chemical origin, with the exception of creams and masks prepared on the basis of plants. To protect yourself from low-quality cosmetics, you need to monitor their expiration dates. After all, the substances from which they are made are exposed to the environment.

Chemistry in the home medicine cabinet “There is a potion for every illness” (Russian proverb) In ancient times there were no pharmacies: doctors made up their own medicines. They bought raw materials for the production of medicinal potions from “plant root diggers” and stored them in a warehouse - a pharmacy. The word “pharmacy” itself comes from the Greek “warehouse”. In Russia, under Tsar Mikhail Fedorovich (1613-1645), pharmacies already had the position of “alchemist” (laboratory chemist) who prepared medicines. Many famous scientists who went down in history as chemists were pharmacists and pharmacists in their main position. It goes without saying that every family should have a home first aid kit. And this is the most “chemical” place in the apartment.

Pharmacy old-timers “The older, the righter. The younger, the more expensive” (Russian proverb) There are ancient medicines that have not lost their significance to this day. This is potassium permanganate - "potassium permanganate", hydrogen peroxide (peroxide), iodine, ammonia, table salt, Epsom salt (magnesium sulfate), baking soda (sodium bicarbonate), alum, lapis (silver nitrate) "lead sugar" - lead acetate , boric acid, acetylsalicylic acid (aspirin) is a common antipyretic.

Nature heals Nature is an inexhaustible storehouse of healing agents that has not yet been fully explored by people. Among them, a place of honor is occupied by: · honey, · propolis, · kombucha. They contain natural chemicals.

HONEY "Bird of honey, God's bee, You, queen of forest flowers! Go and bring honey, Taking from flower cups, From fragrant blades of grass, So that I can soothe the pain, Quench the suffering of my son..." (Karelian epic "Kalevala") Bee honey in ointments helps the formation of glutathione, a substance that plays an important role in the redox processes of the body and accelerates the growth and division of cells. Therefore, under the influence of honey, wounds heal faster. An ointment made from equal amounts of honey and sea buckthorn oil is especially powerful.

Propolis Propolis (“bee glue”) is a resinous substance that bees use to seal the cracks of their homes. It is obtained during the primary digestion of flower pollen by bees and contains about 59% resins and balms, 10% essential oils and 30% wax.

Kombucha "Rising from the silver shackles, a sweet and salty pool will be born, populated with an unknown breath and a fresh crush of bubbles." (B. Akhmadulina) Undeservedly forgotten kombucha helps to create a small “factory” of soft drinks right at home, producing tasty and, importantly, healthy products that can quench your thirst in the summer heat.

Disease of the 21st century - allergies