Chemistry of antiquity.

Chemistry, the science of the composition of substances and their transformations, begins with the discovery by man of the ability of fire to change natural materials. Apparently, people knew how to smelt copper and bronze, fire clay products, and get glass as far back as 4000 BC. By the 7th c. BC. Egypt and Mesopotamia became centers of dye production; gold, silver and other metals were also obtained there in their pure form. From about 1500 to 350 BC distillation was used to produce dyes, and metals were smelted from ores by mixing them with charcoal and blowing air through the burning mixture. The very procedures for the transformation of natural materials were given a mystical meaning.

Greek natural philosophy.

These mythological ideas penetrated into Greece through Thales of Miletus, who raised the whole variety of phenomena and things to a single element - water. However, Greek philosophers were not interested in the methods of obtaining substances and their practical use, but mainly in the essence of the processes taking place in the world. Thus, the ancient Greek philosopher Anaximenes argued that the fundamental principle of the Universe is air: when rarefied, air turns into fire, and as it thickens, it becomes water, then earth and, finally, stone. Heraclitus of Ephesus tried to explain the phenomena of nature, postulating fire as the primary element.

Four primary elements.

These ideas were combined in the natural philosophy of Empedocles of Agrigent, the creator of the theory of the four principles of the universe. In various versions, his theory dominated the minds of people for more than two millennia. According to Empedocles, all material objects are formed when the eternal and unchanging elements-elements - water, air, earth and fire - are combined under the influence of the cosmic forces of love (attraction) and hatred (repulsion). The theory of the elements of Empedocles was accepted and developed first by Plato, who clarified that the immaterial forces of good and evil can turn these elements one into another, and then by Aristotle.

According to Aristotle, elements-elements are not material substances, but carriers of certain qualities - heat, cold, dryness and humidity. This view was transformed into the idea of ​​the four "juices" of Galen and dominated science until the 17th century. Another important question that occupied the Greek natural philosophers was the question of the divisibility of matter. The founders of the concept, which later received the name "atomistic", were Leucippus, his student Democritus and Epicurus. According to their teaching, only emptiness and atoms exist - indivisible material elements, eternal, indestructible, impenetrable, differing in shape, position in emptiness and size; all bodies are formed from their "whirlwind". The atomistic theory remained unpopular for two millennia after Democritus, but did not disappear completely. One of its adherents was the ancient Greek poet Titus Lucretius Car, who outlined the views of Democritus and Epicurus in the poem On the nature of things (De Rerum Natura).

Alchemy.

Alchemy is the art of improving matter through the transformation of metals into gold and the improvement of man by creating the elixir of life. In an effort to achieve the most attractive goal for them - the creation of incalculable wealth - alchemists solved many practical problems, discovered many new processes, observed various reactions, contributing to the formation of a new science - chemistry.

Hellenistic period.

Egypt was the cradle of alchemy. The Egyptians brilliantly mastered applied chemistry, which, however, was not singled out as an independent field of knowledge, but was included in the "sacred secret art" of the priests. As a separate field of knowledge, alchemy appeared at the turn of the 2nd and 3rd centuries. AD After the death of Alexander the Great, his empire collapsed, but the influence of the Greeks spread to the vast territories of the Near and Middle East. Alchemy reached a particularly rapid flowering in 100–300 AD. in Alexandria.

Around 300 AD Egyptian Zosima wrote an encyclopedia - 28 books covering all the knowledge on alchemy for the previous 5-6 centuries, in particular information about the mutual transformations (transmutations) of substances.

Alchemy in the Arab world.

Having conquered Egypt in the 7th century, the Arabs assimilated the Greco-Oriental culture, which was preserved for centuries by the Alexandrian school. Imitating the ancient rulers, the caliphs began to patronize the sciences, and in the 7th-9th centuries. the first chemists appeared.

The most talented and famous Arab alchemist was Jabir ibn Hayyan (late 8th century), who later became known in Europe under the name Geber. Jabir believed that sulfur and mercury are two opposite principles from which seven other metals are formed; gold is the most difficult to form: this requires a special substance, which the Greeks called xerion - “dry”, and the Arabs changed it to al-iksir (this is how the word “elixir” appeared). The elixir was supposed to have other miraculous properties: to cure all diseases and give immortality. Another Arab alchemist, al-Razi (c. 865–925) (known in Europe as Razes) also practiced medicine. So, he described the method of preparing plaster and the method of applying a bandage to the fracture site. However, the most famous doctor was Ibn Sina from Bukhara, also known as Avicenna. His writings served as a guide for physicians for many centuries.

Alchemy in Western Europe.

The scientific views of the Arabs penetrated medieval Europe in the 12th century. through North Africa, Sicily and Spain. The works of Arab alchemists were translated into Latin and then into other European languages. At first, alchemy in Europe relied on the work of such luminaries as Jabir, but three centuries later there was renewed interest in the teachings of Aristotle, especially in the writings of the German philosopher and Dominican theologian, who later became a bishop and professor at the University of Paris, Albert the Great and his student Thomas Aquinas. Convinced of the compatibility of Greek and Arabic science with Christian doctrine, Albertus Magnus encouraged their introduction into scholastic curricula. In 1250 Aristotle's philosophy was introduced into the teaching curriculum at the University of Paris. The English philosopher and naturalist, Franciscan monk Roger Bacon, who anticipated many later discoveries, was also interested in alchemical problems; he studied the properties of saltpeter and many other substances, found a way to make black powder. Other European alchemists include Arnaldo da Villanova (1235–1313), Raymond Lull (1235–1313), Basil Valentin (15th–16th century German monk).

Achievements of alchemy.

The development of crafts and trade, the rise of cities in Western Europe in the 12th–13th centuries. accompanied by the development of science and the emergence of industry. The recipes of alchemists were used in such technological processes like metal processing. During these years, systematic searches for methods for obtaining and identifying new substances began. There are recipes for the production of alcohol and improvements in the process of its distillation. The most important achievement was the discovery of strong acids - sulfuric, nitric. Now European chemists were able to carry out many new reactions and obtain substances such as salts of nitric acid, vitriol, alum, salts of sulfuric and hydrochloric acids. The services of alchemists, who were often skilled doctors, were used by the highest nobility. It was also believed that alchemists possessed the secret of transmuting ordinary metals into gold.

By the end of the 14th century the interest of alchemists in the transformation of some substances into others gave way to an interest in the production of copper, brass, vinegar, olive oil and various medicines. In the 15th-16th centuries. the experience of alchemists was increasingly used in mining and medicine.

THE ORIGIN OF MODERN CHEMISTRY

The end of the Middle Ages was marked by a gradual departure from the occult, a decline in interest in alchemy, and the spread of a mechanistic view of the structure of nature.

Iatrochemistry.

Paracelsus (1493-1541) held a completely different view of the goals of alchemy. Under such a name chosen by him (“superior to Celsus”), the Swiss doctor Philipp von Hohenheim went down in history. Paracelsus, like Avicenna, believed that the main task of alchemy was not the search for ways to obtain gold, but the manufacture of medicines. He borrowed from the alchemical tradition the doctrine that there are three main parts of matter - mercury, sulfur, salt, which correspond to the properties of volatility, combustibility and hardness. These three elements form the basis of the macrocosm (Universe) and are associated with the microcosm (man) formed by the spirit, soul and body. Turning to the definition of the causes of diseases, Paracelsus argued that fever and plague come from an excess of sulfur in the body, paralysis occurs with an excess of mercury, and so on. The principle that all iatrochemists adhered to was that medicine is a matter of chemistry, and everything depends on the ability of the doctor to isolate pure principles from impure substances. Under this scheme, all the functions of the body were reduced to chemical processes, and the task of the alchemist was to find and prepare chemicals for medical purposes.

The main representatives of the iatrochemical trend were Jan Helmont (1577–1644), a doctor by profession; Francis Silvius (1614-1672), who enjoyed great fame as a physician and eliminated "spiritual" principles from the iatrochemical doctrine; Andreas Libavius ​​(c. 1550–1616), physician from Rothenburg Their research contributed greatly to the formation of chemistry as an independent science.

mechanical philosophy.

With the diminishing influence of iatrochemistry, natural philosophers turned again to the teachings of the ancients about nature. Foreground in the 17th century. atomistic (corpuscular) views came out. One of the most prominent scientists - the authors of the corpuscular theory - was the philosopher and mathematician Rene Descartes. He outlined his views in 1637 in an essay Reasoning about method. Descartes believed that all bodies “consist of numerous small particles of various shapes and sizes, ... which are not so closely adjacent to each other that there are no gaps around them; these gaps are not empty, but filled with ... rarefied matter. Descartes did not consider his “small particles” to be atoms, i.e. indivisible; he stood on the point of view of the infinite divisibility of matter and denied the existence of emptiness. One of Descartes' most prominent opponents was the French physicist and philosopher Pierre Gassendi. Atomism Gassendi was essentially a retelling of the teachings of Epicurus, however, unlike the latter, Gassendi recognized the creation of atoms by God; he believed that God created a certain number of indivisible and impenetrable atoms, of which all bodies are composed; there must be an absolute void between the atoms. In the development of chemistry in the 17th century. a special role belongs to the Irish scientist Robert Boyle. Boyle did not accept the statements of the ancient philosophers, who believed that the elements of the universe can be established speculatively; This is reflected in the title of his book. Skeptic Chemist. As a supporter of an experimental approach to the definition chemical elements(which was eventually accepted), he did not know about the existence of real elements, although one of them - phosphorus - almost discovered himself. Boyle is usually credited with introducing the term "analysis" into chemistry. In his experiments on qualitative analysis, he used various indicators, introduced the concept of chemical affinity. Based on the works of Galileo Galilei Evangelista Torricelli, as well as Otto Guericke, who demonstrated the “Magdeburg hemispheres” in 1654, Boyle described the air pump he designed and experiments to determine the elasticity of air using a U-shaped tube. As a result of these experiments, the well-known law on the inverse proportionality of the volume and pressure of air was formulated. In 1668 Boyle became an active member of the newly organized Royal Society of London, and in 1680 he was elected its president.

Technical chemistry.

Scientific advances and discoveries could not but affect technical chemistry, elements of which can be found in the 15th-17th centuries. In the middle of the 15th century blower technology was developed. The needs of the military industry stimulated work to improve the technology of gunpowder production. During the 16th century the production of gold doubled and the production of silver increased ninefold. There are fundamental works on the production of metals and various materials used in construction, in the manufacture of glass, dyeing of fabrics, for the preservation of food products, and leather dressing. With the expansion of the consumption of alcoholic beverages, distillation methods are being improved, new distillation apparatuses are being designed. Numerous production laboratories appear, primarily metallurgical ones. Among the chemical technologists of that time, we can mention Vannoccio Biringuccio (1480–1539), whose classic work ABOUT pyrotechnics was printed in Venice in 1540 and contained 10 books dealing with mines, testing of minerals, preparation of metals, distillation, martial arts and fireworks. Another famous treatise About mining and metallurgy, was painted by Georg Agricola (1494–1555). Mention should also be made of Johann Glauber (1604–1670), a Dutch chemist, creator of Glauber's salt.

XVIII CENTURY

Chemistry as a scientific discipline.

From 1670 to 1800, chemistry received official status in the curricula of leading universities along with natural philosophy and medicine. A textbook by Nicolas Lemery (1645–1715) appeared in 1675. Chemistry course, which gained immense popularity, 13 of its French editions were published, and in addition, it was translated into Latin and many other European languages. In the 18th century scientific chemical societies and a large number of scientific institutes are being created in Europe; their research is closely related to the social and economic needs of society. Practicing chemists appear who are engaged in the manufacture of devices and the preparation of substances for industry.

Phlogiston theory.

In the writings of chemists of the second half of the 17th century. much attention was paid to interpretations of the combustion process. According to the ideas of the ancient Greeks, everything that is capable of burning contains the element of fire, which is released under appropriate conditions. In 1669, the German chemist Johann Joachim Becher tried to rationalize flammability. He suggested that solids consist of three types of "earth", and he took one of the types, which he called "fat earth", for the "principle of combustibility".

A follower of Becher, the German chemist and physician Georg Ernst Stahl transformed the concept of "fat earth" into a generalized doctrine of phlogiston - "the beginning of combustibility". According to Stahl, phlogiston is a certain substance contained in all combustible substances and released during combustion. Stahl argued that the rusting of metals is similar to the combustion of wood. Metals contain phlogiston, but rust (dross) no longer contains phlogiston. This gave an acceptable explanation for the process of transformation of ores into metals: ore, the content of phlogiston in which is negligible, is heated on charcoal rich in phlogiston, and the latter turns into ore. Coal turns into ash, and ore into a metal rich in phlogiston. By 1780, the phlogiston theory was almost universally accepted by chemists, although it did not answer a very important question: why does iron become heavier when it rusts, although phlogiston escapes from it? Chemists of the 18th century. this contradiction did not seem so important; the main thing, in their opinion, was to explain the reasons for the change in the appearance of substances.

In the 18th century many chemists have worked scientific activity does not fit into the usual schemes for considering the stages and directions of the development of science, and among them a special place belongs to the Russian scientist-encyclopedist, poet, champion of education Mikhail Vasilievich Lomonosov (1711-1765). With his discoveries, Lomonosov enriched almost all areas of knowledge, and many of his ideas were more than a hundred years ahead of the science of that time. In 1756, Lomonosov carried out the famous experiments on firing metals in a closed vessel, which provided indisputable evidence of the conservation of matter in chemical reactions and the role of air in combustion processes: even before Lavoisier, he explained the observed increase in weight during firing of metals by combining them with air. In contrast to the prevailing ideas about caloric, he argued that thermal phenomena are due to the mechanical movement of material particles. He explained the elasticity of gases by the movement of particles. Lomonosov distinguished between the concepts of "corpuscle" (molecule) and "element" (atom), which was generally recognized only in the middle of the 19th century. Lomonosov formulated the principle of the conservation of matter and motion, excluded phlogiston from the number of chemical agents, laid the foundations of physical chemistry, created a chemical laboratory at the St. Petersburg Academy of Sciences in 1748, in which not only scientific work but also practical training for students. He conducted extensive research in areas of knowledge adjacent to chemistry - physics, geology, etc.

Pneumatic chemistry.

The shortcomings of the phlogiston theory were most clearly revealed during the development of the so-called. pneumatic chemistry. The largest representative of this direction was R. Boyle: he not only discovered the gas law, which now bears his name, but also designed apparatus for collecting air. Chemists have received the most important tool for isolating, identifying and studying various "airs". An important step was the invention by the English chemist Stephen Hales (1677–1761) of the "pneumatic bath" in the early 18th century. - a device for trapping gases released when a substance is heated, into a vessel with water, lowered upside down into a bath of water. Later, Hales and Henry Cavendish established the existence of certain gases (“airs”) that differ in their properties from ordinary air. In 1766, Cavendish systematically studied the gas formed during the interaction of acids with certain metals, later called hydrogen. A great contribution to the study of gases was made by the Scottish chemist Joseph Black. He took up the study of gases released during the action of acids on alkalis. Black found that the mineral calcium carbonate, when heated, decomposes with the release of gas and forms lime (calcium oxide). The liberated gas (carbon dioxide - Black called it "bound air") could be recombined with lime to form calcium carbonate. Among other things, this discovery established the inseparability of bonds between solid and gaseous substances.

chemical revolution.

Great success in the evolution of gases and the study of their properties was achieved by Joseph Priestley, a Protestant priest who was passionately engaged in chemistry. Near Leeds (England), where he served, there was a brewery, from where it was possible to obtain "bound air" (now we know that it was carbon dioxide) in large quantities for experiments. Priestley discovered that gases could dissolve in water and tried to collect them not over water, but over mercury. So he managed to collect and study nitric oxide, ammonia, hydrogen chloride, sulfur dioxide (of course, these are their modern names). In 1774, Priestley made his most important discovery: he isolated a gas in which substances burned especially brightly. Being a supporter of the theory of phlogiston, he called this gas "dephlogisticated air". The gas discovered by Priestley seemed to be the opposite of "phlogisticated air" (nitrogen) isolated in 1772 by the English chemist Daniel Rutherford (1749–1819). In the "phlogisticated air" the mice died, while in the "dephlogisticated" they were very active. (It should be noted that the properties of the gas isolated by Priestley were described as early as 1771 by the Swedish chemist Carl Wilhelm Scheele, but his message, due to the negligence of the publisher, appeared in print only in 1777.) The great French chemist Antoine Laurent Lavoisier immediately appreciated the significance of Priestley's discovery. In 1775, he prepared an article where he argued that air is not a simple substance, but a mixture of two gases, one of them is Priestley's "dephlogisticated air", which combines with burning or rusting objects, passes from ores to charcoal and is necessary for life. Lavoisier called him oxygen, oxygen, i.e. "producer of acids". The second blow to the theory of elemental elements was dealt after it became clear that water is also not a simple substance, but a product of the combination of two gases: oxygen and hydrogen. All these discoveries and theories, having done away with the mysterious "elements", led to the rationalization of chemistry. Only those substances that can be weighed or whose quantity can be measured in some other way have come to the fore. During the 80s of the 18th century. Lavoisier, in collaboration with other French chemists - Antoine Francois de Fourcroix (1755-1809), Guiton de Morveau (1737-1816) and Claude Louis Berthollet - developed a logical system of chemical nomenclature; it described more than 30 simple substances with an indication of their properties. This labor Method of chemical nomenclature, was published in 1787.

The revolution in the theoretical views of chemists that took place at the end of the 18th century as a result of the rapid accumulation of experimental material under the dominance of the phlogiston theory (albeit independently of it), is usually called the "chemical revolution".

NINETEENTH CENTURY

Composition of substances and their classification.

Lavoisier's successes showed that the use of quantitative methods can help in determining the chemical composition of substances and elucidating the laws of their association.

Atomic theory.

The birth of physical chemistry.

By the end of the 19th century the first works appeared in which the physical properties of various substances (boiling and melting points, solubility, molecular weight) were systematically studied. Such studies were initiated by Gay-Lussac and van't Hoff, who showed that the solubility of salts depends on temperature and pressure. In 1867, the Norwegian chemists Peter Waage (1833–1900) and Kato Maximilian Guldberg (1836–1902) formulated the law of mass action, according to which the reaction rate depends on the concentrations of the reactants. The mathematical apparatus they used made it possible to find a very important quantity that characterizes any chemical reaction - the rate constant.

Chemical thermodynamics.

Meanwhile, chemists turned to the central question of physical chemistry, the effect of heat on chemical reactions. By the middle of the 19th century. physicists William Thomson (Lord Kelvin), Ludwig Boltzmann and James Maxwell developed new views on the nature of heat. Rejecting Lavoisier's caloric theory, they presented heat as the result of motion. Their ideas were developed by Rudolf Clausius. He developed kinetic theory, according to which such quantities as volume, pressure, temperature, viscosity and reaction rate can be considered based on the concept of the continuous movement of molecules and their collisions. Simultaneously with Thomson (1850), Clasius gave the first formulation of the second law of thermodynamics, introduced the concepts of entropy (1865), an ideal gas, and the free path of molecules.

The thermodynamic approach to chemical reactions was applied in his works by August Friedrich Gorstmann (1842–1929), who, based on the ideas of Clausius, tried to explain the dissociation of salts in solution. In 1874–1878 the American chemist Josiah Willard Gibbs undertook a systematic study of the thermodynamics of chemical reactions. He introduced the concept of free energy and chemical potential, explained the essence of the law of mass action, applied thermodynamic principles in studying the equilibrium between different phases at different temperatures, pressures and concentrations (the phase rule). Gibbs' work laid the foundation for modern chemical thermodynamics. The Swedish chemist Svante August Arrhenius created the theory of ionic dissociation, which explains many electrochemical phenomena, and introduced the concept of activation energy. He also developed an electrochemical method for measuring the molecular weight of solutes.

A major scientist, thanks to whom physical chemistry was recognized as an independent field of knowledge, was the German chemist Wilhelm Ostwald, who applied Gibbs' concepts in the study of catalysis. In 1886 he wrote the first textbook on physical chemistry, and in 1887 he founded (together with van't Hoff) the journal Physical Chemistry (Zeitschrift für physikalische Chemie).

THE TWENTIETH CENTURY

New structural theory.

With the development of physical theories about the structure of atoms and molecules, such old concepts as chemical affinity and transmutation were rethought. New ideas about the structure of matter arose.

Model of the atom.

In 1896, Antoine Henri Becquerel (1852–1908) discovered the phenomenon of radioactivity, discovering the spontaneous emission of subatomic particles by uranium salts, and two years later, the spouses Pierre Curie and Marie Skłodowska-Curie isolated two radioactive elements: polonium and radium. In subsequent years, it was found that radioactive substances emit three types of radiation: a-particles, b-particles and g-rays. Together with the discovery of Frederick Soddy, which showed that during radioactive decay, some substances are transformed into others, all this gave a new meaning to what the ancients called transmutation.

In 1897, Joseph John Thomson discovered the electron, the charge of which was measured with high accuracy in 1909 by Robert Milliken. In 1911, Ernst Rutherford, based on Thomson's electronic concept, proposed a model of the atom: a positively charged nucleus is located in the center of the atom, and negatively charged electrons revolve around it. In 1913, Niels Bohr, using the principles of quantum mechanics, showed that electrons can be located not in any, but in strictly defined orbits. The Rutherford-Bohr planetary quantum model of the atom forced scientists to take a new approach to explaining the structure and properties of chemical compounds. The German physicist Walter Kossel (1888-1956) suggested that the chemical properties of an atom are determined by the number of electrons in its outer shell, and the formation of chemical bonds is determined mainly by the forces of electrostatic interaction. American scientists Gilbert Newton Lewis and Irving Langmuir formulated the electronic theory of chemical bonding. In accordance with these ideas, the molecules of inorganic salts are stabilized by electrostatic interactions between their constituent ions, which are formed during the transition of electrons from one element to another (ionic bond), and the molecules of organic compounds are stabilized due to the socialization of electrons (covalent bond). These ideas underlie contemporary ideas about the chemical bond.

New research methods.

All new ideas about the structure of matter could be formed only as a result of the development in the 20th century. experimental technique and the emergence of new research methods. The discovery of X-rays in 1895 by Wilhelm Conrad Roentgen served as the basis for the subsequent creation of the X-ray crystallography method, which makes it possible to determine the structure of molecules from the X-ray diffraction pattern on crystals. Using this method, the structure of complex organic compounds was deciphered - insulin, deoxyribonucleic acid (DNA), hemoglobin, etc. With the creation of the atomic theory, new powerful spectroscopic methods appeared that provide information about the structure of atoms and molecules. Various biological processes, as well as the mechanism of chemical reactions, are studied using radioisotope labels; Radiation methods are also widely used in medicine.

Biochemistry.

This scientific discipline deals with the study chemical properties biological substances, at first was one of the sections of organic chemistry. It emerged as an independent region in the last decade of the 19th century. as a result of research on the chemical properties of substances of plant and animal origin. One of the first biochemists was the German scientist Emil Fischer. He synthesized substances such as caffeine, phenobarbital, glucose, many hydrocarbons, made a great contribution to the science of enzymes - protein catalysts, first isolated in 1878. The formation of biochemistry as a science was facilitated by the creation of new analytical methods. In 1923, the Swedish chemist Theodor Svedberg designed an ultracentrifuge and developed a sedimentation method for determining the molecular weight of macromolecules, mainly proteins. Svedberg's assistant Arne Tiselius (1902-1971) in the same year created the method of electrophoresis, a more advanced method for separating giant molecules, based on the difference in the speed of migration of charged molecules in an electric field. At the beginning of the 20th century Russian chemist Mikhail Semenovich Tsvet (1872–1919) described a method for separating plant pigments by passing their mixture through a tube filled with an adsorbent. The method was called chromatography. In 1944, the English chemists Archer Martin and Richard Sing proposed a new version of the method: they replaced the tube with the adsorbent with filter paper. This is how paper chromatography appeared - one of the most common analytical methods in chemistry, biology and medicine, with the help of which, in the late 1940s and early 1950s, it was possible to analyze mixtures of amino acids resulting from the breakdown of various proteins and determine the composition of proteins. As a result of painstaking research, the order of amino acids in the insulin molecule was established (Frederick Sanger), and by 1964 this protein was synthesized. Now many hormones, medicines, vitamins are obtained by biochemical synthesis methods.

Industrial chemistry.

Probably the most important stage in the development of modern chemistry was the creation in the 19th century of various research centers engaged, in addition to fundamental, also applied research. At the beginning of the 20th century a number of industrial corporations created the first industrial research laboratories. In the USA, the chemical laboratory DuPont was founded in 1903, and in 1925 the laboratory of the Bell firm. After the discovery and synthesis of penicillin in the 1940s, and then other antibiotics, large pharmaceutical companies appeared, employing professional chemists. Works in the field of the chemistry of macromolecular compounds were of great practical importance. One of its founders was the German chemist Hermann Staudinger (1881–1965), who developed the theory of the structure of polymers. An intensive search for ways to obtain linear polymers led in 1953 to the synthesis of polyethylene (Karl Ziegler,), and then other polymers with desired properties. Today, the production of polymers is the largest branch of the chemical industry.

Not all advances in chemistry have been good for man. In the 19th century in the production of paints, soaps, textiles, hydrochloric acid and sulfur were used, which posed a great danger to the environment. In the 20th century the production of many organic and inorganic materials has increased due to the recycling of used substances, as well as through the processing of chemical waste that poses a risk to human health and the environment.

Literature:

Figurovsky N.A. Outline of the general history of chemistry. M., 1969
Juah M. History of chemistry. M., 1975
Azimov A. Brief history of chemistry. M., 1983



Chemistry has gone through a difficult path of development. This is an ancient science that arose from the demands of practice.

Naturally, neither the time nor the place is known when a person first lit a fire, began to use it for cooking, in pottery, for metal processing. In any case, by the beginning of the historical era, chemical knowledge in these areas was at a high level. In ancient Egypt, for example, they knew how to smelt metals (iron, lead, copper, tin) from ores, obtain their alloys (for example, bronze), used gold, silver, produced glass and porcelain, pottery, paints and pigments, perfumes. Chemical production existed in ancient Mesopotamia, India and China.

The roots of chemistry as a science should be sought, first of all, in the era of antiquity. Ancient Greece and Rome had a huge impact on art, literature, political, philosophical and religious views of all the peoples of Europe.

The pinnacle of the development of ancient Greek philosophy was reached in the teachings of Aristotle. Developing the ideas of his predecessors - Empedocles, Plato, he created a coherent philosophical system in which he raised natural science knowledge to a qualitatively new level. He paid special attention to the transformations of substances. He considered each substance to be a certain combination of primary elements (atoms), determined on the basis of their sensory perception. Movements, connections and separations of elements (atoms) give rise to all visible diversity in the Universe.

This period of development of the science of nature is characterized by a complete separation of theory from practice. The ancient philosophers only observed nature and set themselves the task of explaining it.

Approximately in the 300s. n. e. The Panopolitan Greek Zosima wrote an encyclopedia of 28 books covering all knowledge of chemistry. This moment marks the beginning of the next stage in the development of chemistry - alchemy which lasted until the 16th century.

Observing the transformation of some substances into others and carrying them out through various effects on substances and their mixtures, alchemists saw no obstacles to the implementation of any transformations, including some metals into others and, in particular, into gold, obtaining a universal medical preparation - the elixir of youth and , ultimately, the manufacture of the "philosopher's stone", with the help of which these transformations can be carried out.

From the alchemists modern science inherited an extremely valuable method of work - an experiment that tests a hypothesis. Looking for " philosopher's stone”, providing transmutation, alchemists discovered a number of substances (ethyl alcohol, many salts, acetic acid, sulfuric and nitric acids, etc.) and chemical elements (phosphorus, antimony, arsenic, chlorine, etc.).

Third period - period of formation of chemistry- covers the XVI-XVIII centuries. The purpose of the study has changed - instead of experimentation, the study of the laws of the transformation of substances begins in order to use them in practical activities.

During this period, technical chemistry develops, scientific works appear devoted to the description of chemical processes in a generally accessible language; the development of gas chemistry begins - pneumatic chemistry, associated primarily with the name of R. Boyle. He introduced the first scientific definition of a chemical element as an integral part of a substance that cannot be decomposed into simpler parts; created a truly experimental method of research; laid the foundation for chemical analysis; wrote the first scientific treatise "The Skeptic Chemist" (1661), which became widely known, contributed to the formation of chemistry as an independent science.

At the turn of the XVII-XVIII centuries. the first general chemical theory appeared phlogiston theory(1697-1703 1 , G. E. Stahl), based on the position that the more the body contains phlogiston, the more it is capable of burning.

The time of the birth of chemistry as an exact science can conditionally be considered the middle of the 18th century, when M. V. Lomonosov formulated the law of conservation of the mass of substances in chemical processes and proved it experimentally. He was the first to express the idea that when heated, the metal combines with "particles of air." The merit of the final overthrow of the theory of phlogiston belongs to A. L. Lavoisier, who clarified and made obvious to everyone the role of oxygen in combustion processes, clarified the concepts of a chemical element, a simple and complex substance, and, independently of Lomonosov, experimentally established the law of conservation of mass. Lavoisier put chemical research on a quantitative basis. Beginning with Lavoisier, chemistry "spoke" in modern language.

The fourth stage in the development of chemistry - period of atomic and molecular science- covers the end of the XVIII - 60-70s of the XIX century. and is characterized by the discovery of stoichiometric (quantitative) laws of chemistry: the law of equivalents (1792–1802, I. V. Richter); the law of constancy of composition (1799–1806, J. L. Proust); the law of multiple ratios (1802–1808, J. Dalton); the law of volumetric relations (1805–1808, J. L. Gay-Lussac); the law of proportionality between the densities of gases or vapors and molecular weights (1811, A. Avogadro); the law of isomorphism (1818–1819, E. Mitcherlich); the law of specific heat capacities (1819, P. L. Dulong, A. T. Petit); laws of electrolysis (1834, M. Faraday); the law of constancy of quantities of heat (1840, G. I. Hess); definitions of the concepts "atom", "molecule" and the creation of a scale of atomic masses (1858, S. Cannizzaro).

The next stage in the development of chemistry is period of classical chemistry- begins with the discovery in 1869 of the periodic law by D. I. Mendeleev and ends with the development in 1913–1921. theory of the structure of the atom N. Bohr - A. Sommerfeld.

At this time, the concept of valence also developed (1852, E. Frankland), theories of the structure of organic compounds appeared (1861–1864, A. M. Butlerov), aromatic compounds (1865, F. A. Kekule) , complex compounds (1893, A. Werner); the law of mass action (1864–1867, K. M. Guldberg, P. Waage); thermochemistry; the theory of electrolytic dissociation (1884, S. A. Arrhenius); the principle of displacement of chemical equilibrium (1884, A. L. Le Chatelier); phase rule (1876, J. W. Gibbs), etc.

The sixth period of the development of chemistry - modern.

Advances in chemistry in the 20th century associated with the progress of analytical chemistry and physical methods for studying substances and the impact on them, penetration into the mechanisms of reactions, with the synthesis of new classes of substances and new materials, the differentiation of chemical disciplines and the integration of chemistry with other sciences, with the satisfaction of the needs of modern industry, engineering and technology, medicine , construction, agriculture and other areas of human activity in new chemical knowledge, processes and products. The successful application of new physical methods of influence led to the formation of new important areas of chemistry, for example, radiation chemistry, plasma chemistry. Together with low temperature chemistry (cryochemistry) and high pressure chemistry, sonochemistry (the science that studies the chemical and physicochemical effects that occur in sound fields), laser chemistry, etc., they began to form a new area - the chemistry of extreme effects, which plays a large role in obtaining new materials (for example, for electronics) or old valuable materials in a relatively cheap synthetic way (for example, diamonds or metal nitrides).

One of the first places in chemistry is the problem of predicting the functional properties of a substance based on knowledge of its structure and determining the structure of a substance (and its synthesis), based on its functional purpose. The solution of these problems is associated with the development of computational quantum chemical methods and new theoretical approaches, with advances in inorganic and organic synthesis. Work is underway on genetic engineering and on the synthesis of compounds with unusual structures and properties (for example, high-temperature superconductors, fullerenes). Methods based on matrix synthesis, as well as using the ideas of planar technology, are increasingly being used. Methods simulating biochemical reactions are being further developed. Advances in spectroscopy (including scanning tunneling spectroscopy) opened up prospects for the "design" of substances at the molecular level, led to the creation of a new direction in chemistry - nanotechnology. To control chemical processes, both in the laboratory and on an industrial scale, the principles of molecular and supramolecular organization of ensembles of reacting molecules (including approaches based on the thermodynamics of hierarchical systems) are beginning to be used.

Development chemical science can be summarized in the form of a diagram (Fig. 1.1), which shows the emergence at certain stages of new conceptual systems (relatively closed systems of theories, united by some common concept), which determine further progress.

Rice. 1.1.Model of the development process of chemistry

The doctrine of chemical elements and their compounds, which is constantly developing, enriching, changing, starting from the works of R. Boyle to the present day. Even in our time, in some areas of chemistry, the categories "composition" and "properties" remain fundamental. This doctrine derives the properties of a substance based on its composition (Fig. 1.2).

System of structural theories, structural chemistry arose with the advent of the atomic-molecular concept. Now the properties of substances (their reactivity) are described not only on the basis of the composition, but also on the basis of the structure of the substance. Thus, just as “structure” deepens the concept of “composition,” so the concept of “function” (reactivity) deepens the concept of “property” (Fig. 1.2).

Theories of chemical kinetics and chemical thermodynamics, the doctrine of chemical processes. The emergence of this conceptual system is associated with the establishment of the role of the conditions for conducting chemical processes in their course. These conditions are not only external factors (temperature, pressure, etc.), but also concentrations of reagents, the presence of foreign substances (catalysts, inhibitors, etc.), etc. In other words, these theories describe the behavior of a system of substances based on the organization of chemical process (Fig. 1.2).

Biological chemistry and the doctrine of evolutionary catalysis- The theory of self-development (self-organization) of chemical systems (A. P. Rudenko). This theory is based on the idea of ​​a catalyst changing during a chemical reaction.

Rice. 1.2.Stages of evolution chemical knowledge

History of the development of chemistry. About two hundred years ago, the first historical and scientific research was undertaken and the first books on the history of chemistry were written. It was a time of leaps and bounds in the development of science itself. More than a thousand years of accumulation of natural science knowledge ended in the 18th century. formation of chemistry as an independent scientific discipline, a new learning system and terminology was created. Chemical research was aimed at solving urgent problems of understanding nature and at using the achievements of chemistry in industry.

The results of observations of practicing chemists of the Middle Ages at that time began to be forgotten, since in the 18th century. many new, much more accurate, experimental data were obtained. But the leading chemists of the XVIII century. understood the enormous significance of the work of their predecessors. Therefore, they put a lot of effort into publishing numerous collections of chemical "operations" carried out in the Middle Ages.

The first historians of chemistry - Thorbern Bergman, Johann Christian Wiegleb and Johann Friedrich Gmelin - were very impressed by the abundance of accumulated research results. So they tried to collect all these observations and describe them in chronological order.

Their followers - Johann Bartholomew Trommsdorf, Jean Baptiste Dumas, Justus Liebig, Hermann Kopp, Friedrich Höfer - have already made attempts to analyze historical facts from a certain point of view. Most of all, Hermann Kopp succeeded in this. He came to the conclusion that the nature of the work being carried out was determined mainly by the tasks set by chemists for themselves. So, for example, over a fairly long historical period (from the 300s to the 1600s), they sought to obtain gold from base metals. Therefore, Kopp called this period the alchemical period. Then, of course, there was no genuine scientific chemistry, although in ancient times people used many chemical transformations. But Kopp considered the methods of chemists of those times as purely empirical and found by chance. The historical period that followed, Kopp called the period of iatrochemistry (medical chemistry), since the main direction of chemical knowledge until the 1700s. was receiving medication. Following the period of iatrochemistry, Kopp singled out two more periods in the development of chemical knowledge: the periods of phlogiston and quantitative chemistry. Kopp named the period of phlogiston chemistry after the dominant in the 18th century. "phlogiston theory". The term "phlogiston" is derived from the ancient Greek word "phlogistos", which means "flammable", "combustible"; “phlogiston” is a special “substance” that allegedly determines the mechanism of combustion processes.

At the end of the XIX century. the German scientist Albert Ladenburg accepted the history of chemistry as the main principle of science (The ideas of his compatriot Wilhelm Ostwald: without analyzing the progress of the chemical experiment and the development of the chemical industry, one cannot understand general patterns development of chemistry as a science.

Disputes around the problem often break out among scientists: starting from what historical moment can we talk about the emergence of chemistry as a science? Some researchers defended the point of view that chemical science arose only after scientists were able to explain the causes and features of reactions. According to others, the emergence of scientific chemistry should be dated to the time when scientists set themselves research tasks. Kopp, for example, considered scientific even the tasks of alchemy, although, as it became clear in the 20th century, the tasks of alchemists were unrealistic and, in general, anti-scientific.

The development of chemistry has always gone in several directions, but different research tasks have come to the fore in different periods. The difference lies in the nature of the underlying scientific idea or theory at one time or another. The specificity of the use of the chemical transformation of substances is determined by what purpose it pursues - obtaining a product or the accumulation of new knowledge. Indeed, both of these tasks always face humanity, as they are inextricably linked with the purposeful use of chemical transformations.

However, if the significance of only one direction in the development of chemistry is absolute, then, undoubtedly, one cannot avoid the difficulties that Kopp encountered. He considered these difficulties, analyzed them from different angles, but failed to find a satisfactory way to overcome them.

The question arises: is it right to single out different stages (or periods) of development in the history of chemistry? No one denies that there is an enormous difference between ancient chemical practice and theory, on the one hand, and today, on the other. The difference (although somewhat smaller) is also clearly noticeable when comparing the chemical knowledge of other, more recent historical periods. In order to carry out a periodization of the development of chemistry, it is necessary to find the correct criteria for distinguishing historical stages. These criteria can be obtained as a consequence of the law of accumulation of knowledge and its highest development. According to this law, the gradual accumulation of practical and theoretical knowledge leads them to a new quality, which in turn can serve as the basis for the further development of science. The gradual accumulation of knowledge over a long historical period leads eventually to the emergence of a "revolutionary phase", during which the highest level of development in theory or practice, or both in theory and practice, is reached.

The intensive development of theory and practice in the history of chemistry did not always take place simultaneously. The phase of the highest development of knowledge is revealed when analyzing not only the general development of chemistry, but also when considering the evolution of its individual areas. And of course, these phases of the highest development of knowledge differ in certain periods and for different directions in the development of chemistry. If, for example, we divide the real material of the history of chemistry into two historical epochs, then with such an analysis, the most profound process of transformation of the phase of the highest accumulation of knowledge in chemistry from the end of the 18th century becomes obvious. Since that time, theory in chemistry has become increasingly important as an indispensable condition for the purposeful implementation of various transformations of substances. Until the end of the 18th century, on the contrary, especially importance for the progress of chemistry had not so much theoretical foundations as the practical implementation of various chemical "operations".

The division of the history of chemistry into empirical and theoretical eras cannot be taken literally: as if the first were devoted mainly to practical work, and the second to only theoretical ones. In history in general (and in the history of chemistry in particular) there are no frozen boundaries between historical periods: both in the “era of practice” theoretical research was carried out, and in the “theoretical era” practice has always been of considerable importance for the development of chemistry. Therefore, such an unambiguous name of the era does not reflect its content. It characterizes only the direction of work, which determines the specifics of the development of chemical knowledge within a significant historical period.

The considered approaches to periodization can also be used as the basis for identifying the historical periods of the formation of chemistry in accordance with the law of accumulation and the highest development of knowledge.

The question that the historian of science must constantly answer is how to methodologically approach the analysis of the subject - belongs to the field of the history of logic. To solve it, it is necessary to find out what significance the most important events in the history of science had for the development of society. In this case, the phase of the highest development of knowledge will be most fully manifested. However, we must not forget that the development of science did not take place in all countries and parts of the world. In addition, understanding the contribution of scientists from different countries to the development of chemical knowledge depends on the level of our knowledge of the fundamental chemical research carried out in different historical eras. The information known to historians of science about the development of chemical knowledge and skills in ancient India, China, medieval Arabia, and also in medieval Europe is fairly reliable.

The name "chemistry" comes, according to scientists, from the ancient Greek word "hemeya" (as Egypt was called); another alleged, also ancient Greek word, from which the term "chemistry" was formed, is "hyumeia" (from "hyum"), which means "casting" of metals.

From the very beginning of the use of chemical transformations by mankind, certain knowledge about the features of their implementation began to accumulate. Later, on the basis of such observations, the first hypotheses about the composition and properties of substances arose. At the same time (largely under the influence of the needs of handicraft practice), an opinion was formed that for the development of mankind, practical methods for obtaining large quantities of various substances are much more important than chemical theories. It is impossible not to note the limitations of any one-dimensional point of view. In fact, the theoretical and practical aspects of the study of the nature of substances developed in close relationship; the knowledge and skills acquired at the same time subsequently led to the emergence of scientific natural science. Although the relationship between the natural sciences and production that exists today was formed only in the 19th century, the prerequisites for scientific natural science were created in antiquity. However, for a long time the development natural science ideas was determined mainly by the results of observations obtained in handicraft practice during various processes. Therefore, in order to correctly understand the existence in antiquity and in the Middle Ages of the relationship between handicraft (and later industrial) practice and the development of ideas about the nature of substances, one should not evaluate these relationships only from the point of view of modern interconnections between natural science and industry.

To a large extent, such considerations also apply to the development of chemical science and the chemical industry. Chemistry as an independent science in the modern sense of the word arose only in the 18th century. Prior to this, chemical knowledge was accumulated mainly in the process of developing chemical crafts. Among them in the XVI-XVII centuries. The preparation of medicines played a very important role. The development of pharmacy in the first place, as well as the improvement of other chemical crafts, determined the progress of chemical knowledge at that time. The term "knowledge" is used here not in a narrow sense, describing only the development of theoretical concepts, but in a much broader sense - as a historical category.

In his work "The Role of Labor in the Process of the Transformation of Apes into Man", Friedrich Engels singled out the various stages of the "development of society". He put labor at the basis of such a division, which he considered not as the mechanical execution of operations, but as an activity precisely defined by Karl Marx in Capital. Marx defined labor as physical, mental and intellectual capabilities that are realized only in a complex "process of purposeful, expedient communication of people with each other." In the simplest case, labor is understood - consciously or unconsciously - as experience, which is the starting point of any further development: certain methods of influencing substances associated with specific operations lead to certain expected results. The repetition of this process leads to the accumulation of practical skills and knowledge, which are improved during the transition from generation to generation. Practical skills are understood not only as a mechanical sequence of operations, but also as the improvement of applied knowledge. The concept of “knowledge” used here is not an a priori given concept, but a historically understood category. So, for example, for people of the Stone Age, understanding the influence of various conditions on plant growth had the same great importance for progress in the development of skills and knowledge, as the discovery of the importance of applying fertilizers to increase crop yields, made in the 19th century. Justus Liebig.

History of chemistry is divided into several stages, ranging from the ancient world to the present.

Chemistry is one of the natural sciences, i.e. sciences about the surrounding world, nature and the phenomena occurring in it, the transformations of substances.

Even in ancient times, man noticed that substances are capable of changing, turning into others with new properties.

Bonfire became the first human chemical laboratory. After firing the clay in the fire, it became strong, it was possible to make simple dishes from it. On fire, man learned to cook food from the meat of dead animals, the fruits of the plant world. Here, a person accidentally received the first metals - copper, tin, pigs, as well as glass products from seemingly ordinary stones.

Thus, the first, as we now say, chemical crafts appeared - pottery and metallurgical. Approximately 7,000 years ago, man learned to smelt copper and make various products from it - tools, household items, weapons. This period in history ancient civilization called the Copper Age.

By 4000 B.C. a new stage in the history of the emergence of chemistry began, people learned how to smelt bronze - an alloy of copper and tin, which was much harder than copper. Bronze immediately began to be used for the manufacture of swords, arrowheads and spears, and shields. The Bronze Age has arrived.

In the last millennium before new era man mastered the method of obtaining iron from ores. This was a turning point both in the history of metallurgy and in the history of society. So the time of the Iron Age came, which actually lasted for many hundreds of years.

In those ancient times, people could receive not only metals. Faience glass, mineral and vegetable paints, inks, cosmetics and medicines - this is not a complete list of products that a person could make even then with the help of various chemical transformations.

At the turn of the old and new era, the very concept of "chemistry" was born. There are several versions of the manifestation of this term. According to one of them, this is due to the ancient name of Egypt "Khem" and its derivative "chemi" - Egyptian art. According to another version, it is believed that the word "himeya" - the secretion of juices, and then the smelting of metals, comes from the ancient Greek "himos", i.e. juice, casting.

In the middle of the first millennium of the new era, after the fall ancient rome, the center of civilization moved to the Middle East. It was there that the Arabs transformed the word "himeya" into "alchemy". This word meant all the knowledge related to the transformation of substances, both practical and theoretical.

And the main theoretical idea of ​​alchemy for almost one and a half thousand years was the transformation of base metals into noble ones (gold and silver) under the influence of the so-called philosopher's stone. With the help of this mythical "elixir" they also hoped to cure all diseases and even make a person immortal. The followers of this idea in the Arab East, and then in Europe, began to be called alchemists. Almost all scientists of the Middle Ages, monks, healers and even kings were alchemists.

All their efforts to get cheap gold were, of course, fruitless. However, a number of practical achievements of both alchemists and artisan practitioners left a noticeable mark on the history of the emergence of chemistry. Many new substances were obtained, primarily the most important acids (sulphuric, hydrochloric, nitric), various instruments and devices were invented, which have since become widely used in chemistry.

Chemistry gradually became an increasingly practical field of activity, the main task of which was to meet the growing needs of society: obtaining metals from ores, gunpowder, glass, paints, soap and many other substances no less necessary for life. The first books appeared on practical methods for producing metals and processing various substances. The search for the elixir of longevity led to the development of a medical field - iatrochemistry, which since the beginning of the 16th century. became the main activity of chemists, gradually replacing the previous ones - attempts to obtain noble metals from base metals.

The scientific principle, the desire to know the elemental nature of substances, the reasons for their ability to turn into other substances, more and more penetrated into alchemy. Scientists tried to give reasonable explanations for such important processes for practice as combustion, the recovery of metals from ores, and the oxidation of metals.

In the work of the English chemist and physicist Robert Boyle, a scientific definition of the concept of a chemical element was first given, and the beginning of chemical analysis was laid. Boyle's experimental studies were the beginning of chemistry as a real science. It was Boyle who dropped the prefix “al” from the name “alchemy”, thereby, as it were, opening a new period in the life of the history of the emergence of chemistry.

The transformation of chemistry into a real science in the 18th century. many scientists contributed, including the Russian scientist M. V. Lomonosov and the French scientist A. Lavoisier. Based on numerous experiments on the study of the processes of combustion and oxidation of metals, they independently came to the formulation of one of the most important laws of chemistry - the law of conservation of the mass of substances in chemical reactions.

In the XVIII century. many new elements were discovered, including oxygen, hydrogen, nitrogen. It was proved that air is a mixture of gases, and water is a complex substance.

At the beginning of the XIX century. the English scientist D. Dalton laid the foundations of chemical atomism, compiled the first table of atomic weights, and the Italian A. Avogardo introduced the concept of a molecule. Atomic-molecular theory became the main chemical theory. A particularly important role in its development at the beginning of the XIX century. belongs to the most prominent Swedish chemist J. Berzelius. On the basis of Dalton's theory, he carried out a reform of chemistry: he developed a system of symbols for elements, with the help of which they began to write down formulas and equations. He built a scale of atomic masses close to the modern one, introduced many terms and concepts that we still use today.

In the middle of the XIX century. Russian scientist A. M. Butlerov laid the foundations for the theory of the structure of organic compounds. In 1869, another Russian scientist D. I. Mendeleev discovered the periodic law of chemical elements. These two scientific ideas, together with atomic and molecular theory, became the basis of modern chemistry.

Chemistry became such a big science that it was divided into separate branches, such as organic, inorganic, analytical chemistry, and later - physical chemistry, biochemistry, agricultural chemistry, solid state chemistry, etc.

At present, chemistry has become not only one of the most important areas of human knowledge, but also a field practical activities many people - scientists, engineers, workers, etc. Life is impossible without chemistry modern society. It plays a key role in providing people with food, clothing, energy, thousands of various substances, many of which simply do not exist in nature.

Chemistry is a science that is constantly changing the world around us. Together with other natural sciences, it helps to better understand the secrets of nature and the laws of its development, to make life on Earth better for every person.

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Chemistry is one of the most ancient sciences. Man has always observed changes around him, when some substances give life to others or suddenly change their shape, color, smell.

Long before the advent of a new era, people already knew how to extract metals from ores, dye fabrics, and burn clay; related to chemistry.

Origins of chemistry. Alchemy

The first chemists were the Egyptian priests. They owned many hitherto unsolved chemical secrets. These, for example, include techniques for embalming the bodies of dead pharaohs and noble Egyptians, as well as methods for obtaining some paints. Thus, the blue and blue colors of the vessels found during excavations, made by ancient Egyptian craftsmen, continue to be bright, although several thousand years have passed since their manufacture.

Some chemical industries existed in antiquity in Greece, Mesopotamia, India, and China.

In the III century BC, significant material was already collected and described. For example, in the famous Library of Alexandria, which was considered one of the seven wonders of the world and consisted of 700 thousand handwritten books, many works on chemistry were also kept. They described such processes as calcination, sublimation, distillation, filtration, etc. Individual chemical information accumulated over many centuries made it possible to make some generalizations about the nature of substances and phenomena.

For example, the Greek philosopher Democritus, who lived in the 5th century BC, first expressed the idea that all bodies consist of the smallest, invisible, indivisible and eternally moving solid particles of matter, which he called atoms. Aristotle in the 4th century BC believed that the basis of the surrounding nature is the eternal primary matter, which is characterized by four main qualities: heat and cold, dryness and humidity. These four qualities, in his opinion, could be separated from the first matter or added to it in any quantity.

The teaching of Aristotle was the ideological basis for the development of a separate era in the history of chemistry, the era of the so-called alchemy.

Alchemy (late Latin Alchemia, alchimia, alchymia), a pre-scientific direction in chemistry, originated in the III-IV centuries BC. Its name goes back through Arabic to Greek shemeia from cheo - pour, pour, which indicates the connection of alchemy with the art of melting and casting metals. Another interpretation is from the Egyptian hieroglyph hmi, meaning black (fertile) land, as opposed to barren sands. This hieroglyph denoted Egypt, the place where alchemy, which was often called "Egyptian art", may have originated. The Arabs provided this word with their Arabic prefix "al", and thus the word alchemy was formed. For the first time the term "alchemy" is found in the manuscript of Julius Firmicus, an astrologer of the 4th century.

The alchemists considered the most important task to be the transformation (transmutation) of base metals into noble (valuable) ones, which, in fact, was the main task of chemistry until the 16th century. This idea was based on the ideas of Greek philosophy that the material world consists of one or more "primary elements" that, under certain conditions, can transform into each other. The spread of alchemy falls on the 4th-16th centuries, the time of the development of not only "speculative" alchemy, but also practical chemistry. There is no doubt that these two branches of knowledge influenced each other. No wonder the famous German chemist Liebig wrote about alchemy that it "never was nothing but chemistry."

Thus alchemy is to modern chemistry what astrology is to astronomy. The task of medieval alchemists was to prepare two mysterious substances with which one could achieve the desired refinement of metals. The most important of these two drugs, which was supposed to have the property of turning into gold not only silver, but also such metals as lead, mercury, etc., was called the philosopher's stone, the red lion, the great elixir. It has also been called the philosophical egg, the red tincture, the panacea, and the elixir of life. This remedy was supposed not only to ennoble metals, but also to serve as a universal medicine, its solution, the so-called golden drink, was supposed to heal all diseases, rejuvenate the old body and lengthen life.

Another mysterious remedy, already secondary in its properties, called the white lion, white tincture, was limited to the ability to turn all base metals into silver.

Ancient Egypt is considered the birthplace of alchemy. The alchemists themselves began their science from Hermes Trismegistus (aka the Egyptian god Thoth), and therefore the art of making gold was called hermetic. The alchemists sealed their vessels with a seal with the image of Hermes - hence the expression "hermetically sealed."

There was a legend that the angels taught earthly women with whom they married the art of turning "simple" metals into gold, as described in the Book of Genesis and the Book of the Prophet Enoch in the Bible. This art was expounded in a book called Hema. The Arab scholar al-Nadim (10th century) believed that the founder of alchemy was Hermes the Great, originally from Babylon, who settled in Egypt after the Babylonian pandemonium.

There were Greco-Egyptian, Arabic and Western European schools of alchemy. The Roman Emperor Diocletian ordered in 296 that all Egyptian manuscripts relating to the art of making gold should be burned (probably, it was about gilding and the art of making fake jewelry). In the 4th century AD, the task of turning metals into gold was explored by the Alexandrian school of scientists. The writer, who spoke under the pseudonym of Democrat, belonged to the Alexandrian scientists, with his work "Physics and Mysticism" laid the foundation for a long series of alchemical manuals. In order to ensure success, such works appeared under the names of famous philosophers (Plato, Pythagoras, etc.), but due to the general obscurity of the style, they are little understood, since the alchemists kept most of their achievements in secret, encrypted descriptions of the substances obtained and conducted experiments.

The largest collection of alchemical manuscripts is kept in the Library of Saint Mark in Venice.

The Greeks were the teachers of the Arabs, who gave alchemy its name. The West adopted alchemy from the Arabs in the 10th century. In the period from the 10th to the 16th century, well-known scientists who left their mark on European science were engaged in alchemy. For example, Albert the Great, the creator of the work "On Metals and Minerals", and Roger Bacon, who left to posterity the works "The Power of Alchemy" and "The Mirror of Alchemy", were also the most famous alchemists of their time. Arnoldo de Villanova, an eminent physician who died in 1314, he published more than 20 alchemical works.

Raymond Lull, the most famous scientist of the 13th and 14th centuries, was the author of 500 works of alchemical content, the main of which has the title "Testament setting forth in two books the universal chemical art." (Many experts believe, however, that Lull, known for his piety, did not write these works, and they are only attributed to him.)

In the 15th-17th centuries, many crowned persons were zealously engaged in alchemy. Such, for example, is the English King Henry VI, during whose reign the country was flooded with counterfeit gold and counterfeit coins. The metal that played the role of gold in this case was in all probability a copper amalgam. Charles VII of France acted in a similar way, along with the well-known swindler Jacques le Coeur.

Emperor Rudolf II was the patron of itinerant alchemists, and his residence represented the center of alchemical science of the time. The emperor was called the Germanic Hermes Trismegistus.

Elector August of Saxony and his wife Anna of Denmark made experiments: the first - in his Dresden "Golden Palace", and his wife - in a luxuriously arranged laboratory at her dacha "Pheasant Garden". Dresden long remained the capital of sovereigns patronizing alchemy, especially at a time when the rivalry for the Polish crown required significant financial outlays. At the Saxon court, the alchemist I. Betger, who failed to make gold, discovered porcelain for the first time in Europe.

One of the last adepts of alchemy was Caetan, called Count Ruggiero, a Neapolitan by birth, the son of a peasant. He acted at the Munich, Vienna and Berlin courts until he ended his days in 1709 in Berlin on a gallows decorated with tinsel gold.

But even after the spread of chemistry itself, alchemy aroused the interest of many, in particular I.V. Goethe spent several years studying the works of alchemists.

From the alchemical texts that have come down to us, it can be seen that alchemists discovered or improved methods for obtaining valuable compounds and mixtures, such as mineral and vegetable paints, glasses, enamels, salts, acids, alkalis, alloys, and medicines. They used these tricks laboratory work like distillation, sublimation, filtering. Alchemists invented furnaces for long-term heating, stills.

The achievements of the alchemists of China and India remained unknown in Europe. In Russia, alchemy was not widespread, although the treatises of alchemists were known, and some were even translated into Church Slavonic. Moreover, the German alchemist Van Geyden offered the Moscow court his services in preparing the philosopher's stone, but Tsar Mikhail Fedorovich, after "questioning", rejected these proposals.

The fact that alchemy did not become widespread in Russia is explained by the fact that money and gold in Russia began to be widely used later in comparison with Western countries, since here there was a transition from quitrent to cash rent later. In addition, mysticism, the vagueness of the goals and the unreality of the methods of alchemy were contrary to the common sense and efficiency of the Russian people. Almost all Russian alchemists (the most famous of them, J. Bruce) are of foreign origin.

Chemistry in the Middle Ages

Since the Renaissance, chemical research has increasingly been used for practical purposes (metallurgy, glassmaking, ceramics, paints). At the beginning of the VI century, alchemists began to use the knowledge gained for the needs of industry and medicine. The reformer in the field of mining and metallurgy was Agricola, and in the field of medicine - Paracelsus, who pointed out that "the purpose of chemistry is not to make gold and silver, but to make medicines." In the 16-18 centuries, a special medical direction of alchemy also arose - iatrochemistry (iatrochemistry), whose representatives considered the processes occurring in the body as chemical phenomena, diseases - as a result of chemical imbalance and set the task of finding chemical means of their treatment.

The desire of researchers to understand the true causes of inexplicable processes, to reveal the secrets of the great, but accidental achievements of practice, became more and more insistent. The number of experiments multiplied, the first scientific hypotheses appeared. In the Middle Ages, man began to actively and consciously compete with Nature in obtaining useful substances and materials. Gradually, chemical science was created, and already in the Middle Ages, chemical production appeared.

In Russia, chemistry developed mainly in its own way. In Kievan Rus, metals were smelted, glass, salts, paints, fabrics were produced. Under Ivan the Terrible, a pharmacy was opened in Moscow in 1581. Under Peter I, vitriol and alum factories were built, the first chemical manufactories, and there were already eight pharmacies in Moscow. The further development of chemistry in Russia is associated with the works of M.V. Lomonosov.

More than two hundred years ago, our famous compatriot Mikhail Vasilyevich Lomonosov spoke at a public meeting of the St. Petersburg Academy of Sciences. In a report that has been preserved in the history of science under the eloquent title “A Word on the Benefits of Chemistry”, we read the prophetic lines: “Chemistry spreads its hands widely in human affairs ... Wherever we look, wherever we look, everywhere we turn our eyes to the successes of its diligence ".

Profound and original research of Mikhail Vasilyevich contributed to the development of not only the theory of chemistry, but also chemical practice. He managed to develop a simple technology for staining glass, he made bright artificial mosaic tiles that surpassed natural colored stones in richness and variety of shades, plates from which for many centuries were used to make mosaics that adorned buildings. M.V. Lomonosov established, in modern terms, their industrial production. This was one of the first victories in the history of chemistry of a new material synthesized by man over a substance created by Nature. Good luck still came too rarely. The most insightful scientists of the 18th century, and among them M.N. Lomonosov, understood that scientific foundations chemistry is just being laid. One cannot always follow the endless path of countless experiments and repeat the same mistakes. For the further progress of chemistry, new theories were vital to explain experimental data and predict how materials and substances will behave when the conditions in which they are located change.

In the 2nd half of the 17th century, R. Boyle gave the first scientific definition of the concept of "chemical element". The period of transformation of chemistry into a genuine science ended in the 2nd half of the 18th century, when M.V. Lomonosov was discovered (1748) and A. Lavoisier (1789) formulated in general terms the law of conservation of mass in chemical reactions. At present, this law is formulated as follows: the sum of the mass of the substance of the system and the mass equivalent to the energy received or given away by the same system is constant. At nuclear reactions the law of conservation of mass should be applied in the modern formulation.

At the beginning of the 19th century, J. Dalton laid the foundations of chemical atomism, A. Avogadro introduced the concept of "molecule" (New Latin molecula, diminutive of Latin moles - mass). In the modern sense, it is a microparticle formed from atoms and capable of independent existence. It has a constant composition of its constituent atomic nuclei and a fixed number of electrons and has a set of properties that make it possible to distinguish molecules of one type from molecules of another. The number of atoms in a molecule can be different: from two to hundreds of thousands (for example, in a protein molecule); composition and arrangement of atoms in a molecule conveys chemical formula. Molecular structure substances are determined by X-ray diffraction analysis, electron diffraction, mass spectrometry, electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR) and other methods.

These atomic and molecular ideas were established only in the 60s of the 19th century. Then A.M. Butlerov created the theory of the structure of chemical compounds, and D.I. Mendeleev (1869) discovered the periodic law, which is natural system chemical elements. The modern formulation of this law sounds like this: the properties of elements are in a periodic dependence on the charge of their atomic nuclei. The nuclear charge Z is equal to the atomic (serial) number of the element in the system. Elements arranged in ascending Z (H, He, Li, Be...) form 7 periods. In the 1st - 2 elements, in the 2nd and 3rd - 8 each, in the 4th and 5th - 18 each, in the 6th - 32. In the 7th period (for 1990) 23 elements are known. In periods, the properties of the elements naturally change during the transition from alkali metals to noble gases. Vertical columns - groups of elements with similar properties. Within the groups, the properties of the elements also change regularly (for example, in alkali metals, when going from Li to Fr, the chemical activity increases). Elements with Z = 58-71, as well as with Z = 90-103, which are especially similar in properties, form 2 families - lanthanides and actinides, respectively. The periodicity of the properties of elements is due to the periodic repetition of the configuration of the outer electron shells of atoms. The position of an element in a system is associated with its chemical and many physical properties. Heavy nuclei are unstable, therefore, for example, americium (Z = 95) and subsequent elements are not found in nature; they are obtained artificially in nuclear reactions.

Mendeleev's law and system underlie the modern theory of the structure of matter, play a paramount role in the study of the entire variety of chemical substances and in the synthesis of new elements.

Mendeleev's periodic system of elements received a complete scientific explanation on the basis of quantum mechanics. Quantum mechanics for the first time made it possible to describe the structure of atoms and understand their spectra, establish the nature of the chemical bond, explain the periodic system of elements, etc. Since the properties of macroscopic bodies are determined by the motion and interaction of the particles that form them, the laws of quantum mechanics underlie the understanding of most macroscopic phenomena. Thus, quantum mechanics made it possible to understand many properties of solids, to explain the phenomena of superconductivity, ferromagnetism, superfluidity, and much more; quantum mechanical laws underlie nuclear energy, quantum electronics, etc. Unlike classical theory, all particles act in quantum mechanics as carriers of both corpuscular and wave properties, which do not exclude, but complement each other.

From the end of the 19th to the beginning of the 20th centuries, the study of the regularities of chemical processes became the most important direction in chemistry.

Modern development of chemistry

What are chemical compounds made of? How are the smallest particles of matter arranged? How are they located in space? What unites these particles? Why do some substances react with each other, while others do not? Can chemical reactions be accelerated? Probably more than any other science, chemistry required an understanding of the fundamentals, a knowledge of the root causes. And chemists successfully applied in their reasoning the basic provisions of the atomic-molecular theory long before the appearance of accurate experimental evidence of the real existence of atoms and molecules. The history of chemical science included the theoretical generalizations of A.L. Lavoisier, D.W. Gibbs, D.I. Mendeleev and other prominent scientists. The periodic law and the periodic system of elements, the laws of chemical equilibrium and the theory of chemical structure are now inseparable from new ideas about chemistry.

A significant contribution to the development of chemistry was made by the outstanding Russian scientist A.M. Butlerov. In 1861, he created a theory of the structure of organic compounds, which made it possible to bring into the system a huge number of organic substances and without which modern successes in the creation of new polymeric materials would not be conceivable.

Theories of chemical bonding, created in the 20th century, make it possible to describe all the subtleties of the relationship between the particles that make up a substance. The laws governing the course of chemical processes have been discovered. Now experimenters and technologists have the opportunity to choose the simplest and most effective way to carry out any chemical reaction. Chemistry had a solid foundation, born in union with mathematics and physics. Chemistry has become an exact science. Unusual successes in practical chemistry, based on a deep theoretical understanding of chemical phenomena, were achieved in a relatively short time separating us from the era of Lomonosov. For example, various stages of the chemical process that allowed Nature to turn organic substances into useful oil and gas for us today have been unraveled. This reaction, important for modern industry, took place with the participation of microorganisms and lasted for many hundreds and thousands of years. It was possible not only to understand, but also to recreate this process. Scientists at Moscow University have developed an installation in which, under the beneficial influence of lamp light in a shallow pool with a nutrient solution containing organic substances and microorganisms, artificial oil and gas are produced at an accelerated rate - over several days and months.

The chemistry of our day is capable of more unexpected transformations. An industrial chemical apparatus has been developed - a high cylinder, into the upper part of which crushed green grassy mass is fed. Inside the column, special biological compounds - enzymes that accelerate chemical reactions, according to the program set by scientists, convert the continuously incoming mass into ... milk. We got used to these "miracles" as quickly as to space flights. There is probably no sphere of human activity where products from materials that were born thanks to the talent and painstaking work of several generations of chemists would not be used. In their properties, they often surpass the chemical creations of Nature. These materials have imperceptibly and firmly entered our everyday life, but the surprise of people who saw them for the first time is quite understandable. At the beginning of the seventies of our century, inquisitive and ubiquitous tourists discovered in a remote corner of the endless Siberian forests a family that had lived far from cities and villages for several decades. What struck the hermits most of all among the things brought by tourists? Transparent plastic film! “Glass, but crumpled,” the gray-bearded head of the family said admiringly, feeling and looking at the light plastic film - one of the many synthetic materials invented by chemists to facilitate and improve our household and life. Materials that have become a useful and inconspicuous part of people's daily lives. Chemistry is now able to obtain substances with predetermined properties: frost-resistant and heat-resistant, hard and soft, rigid and elastic, moisture-loving and moisture-proof, solid and porous, sensitive to the smallest traces of foreign impurities or inert to the strongest chemical influences.

The appearance inside a semiconductor of one foreign impurity atom per million atoms of the main substance changes its properties beyond recognition: the semiconductor begins to feel light and conduct electricity. Chemists have developed methods for the complete purification of semiconductors from impurities, created methods for introducing a small amount of impurities into their composition, and invented devices that signal the appearance of “foreign” atoms in a substance. Scientists are able to synthesize materials that are stable and unchanged even with prolonged exposure sunlight and heat, cold and moisture.

Chemical discoveries take place in laboratories around the world, where new complex compounds are born. The famous French chemist M. Berthelot proudly pointed out the inner commonality of chemistry and art, which is rooted in their creative nature. Chemistry, like art, itself creates objects for study and its further research. And this feature, according to M. Berthelot, distinguishes chemistry from other natural and human sciences. Without a deep understanding of chemical laws, it is impossible to fully and comprehensively explain the phenomena studied by biologists and physicists, archaeologists and botanists, geologists and zoologists.

In modern chemistry, its individual areas - inorganic chemistry, organic chemistry, physical chemistry, analytical chemistry, polymer chemistry - have become largely independent sciences. At the intersection of chemistry and other fields of knowledge, such subsidiary, related sciences arose as:

biochemistry - a science that studies the chemicals that make up organisms, their structure, distribution, transformations and functions. The first information on biochemistry is associated with human economic activity (processing of plant and animal raw materials, the use of various types of fermentation, etc.) and medicine. Of fundamental importance for the development of biochemistry was the first synthesis of a natural substance - urea (F. Wöhler, 1828), which undermined the idea of ​​\u200b\u200bthe "life force" allegedly involved in the synthesis of various substances by the body. Using the achievements of general, analytical and organic chemistry, biochemistry in the 19th century was formed into an independent science. The introduction of the ideas and methods of physics and chemistry into biology and the desire to explain such biological phenomena as heredity, variability, muscle contraction, etc., by the structure and properties of biopolymers led in the middle of the 20th century to the separation of molecular biology from biochemistry. Needs National economy in the receipt, storage and processing of various types of raw materials led to the development of technical biochemistry. As well as molecular biology, biophysics, bioorganic chemistry, biochemistry is included in the complex of sciences - physical and chemical biology;

agrochemistry - the science of chemical processes in soil and plants, mineral nutrition of plants, the use of fertilizers and means of chemical soil reclamation; the basis of chemicalization of agriculture. Formed in the 2nd half of the 19th century. The formation of agrochemistry is associated with the names of A. Thayer, Yu. Liebig, D. I. Mendeleev, D. N. Pryanishnikov, and others. It develops on the basis of the achievements of agronomy and chemistry;

geochemistry - a science that studies the chemical composition of the Earth, the abundance of chemical elements and their stable isotopes in it, the patterns of distribution of chemical elements in various geospheres, the laws of behavior, combination and migration (concentration and dispersion) of elements in natural processes. The term "geochemistry" was introduced by K. F. Shenbein in 1838. The founders of geochemistry are V. I. Vernadsky, V. M. Goldshmidt, A. E. Fersman; the first major summary of geochemistry (1908) belongs to F. W. Clark (USA). Geochemistry includes: analytical geochemistry, physical geochemistry, lithosphere geochemistry, process geochemistry, regional geochemistry, hydrogeochemistry, radiogeochemistry, isotope geochemistry, radiogeochronology, biogeochemistry, organic geochemistry, landscape geochemistry, lithogenesis geochemistry. Geochemistry is one of the theoretical foundations of mineral exploration; and others. Such technical sciences as chemical technology and metallurgy are based on the laws of chemistry.

Surrounded by sister sciences and daughter sciences, chemistry continues to evolve. It helps us to understand ourselves, allows us to comprehend many complex processes taking place in the world.

Chemistry and environmental protection

Increasingly, a completely different problem arises: to quickly and without a trace dissolve or disassemble into separate simple elements materials that have already become unnecessary for a person. Some persistent chemicals, especially artificial polymers formed by very large molecules, remain in the earth for decades or hundreds of years without breaking down. Chemists are now developing synthetic fabrics, films, fibers, and plastics from lab-created polymers like starch or fiber found in plants. At the end of their useful life, these polymers will degrade quickly and easily without polluting the environment. Chemistry every day makes fuller and more diverse use of the wealth of the Earth, although it is high time to start saving them. Scientists all the time need to remember the warning of the ancient Roman philosopher Seneca: “As our ancestors believed, it’s too late to be thrifty when left on the bottom. And besides, not only little, but also the worst remains there. We must protect our Earth, we owe so much to it ...

Scientists began to pay more attention to the purity of the air that all life on Earth breathes. The Earth's atmosphere is not just a mechanical mixture of gases. Rapid chemical reactions take place in the gas envelope surrounding the Earth, and some industrial emissions into the atmosphere can lead to irreversible and undesirable changes in the delicate balance of heterogeneous, but very important for us, air components. The Soviet scientist V. L. Talroze once rightly noted how negligible the masses of substances that form the gaseous shell of the Earth vital for plants, animals and humans: “A layer of matter that creates a pressure of only one kilogram per square centimeter is the environment in which we live and work, which conducts sounds to our ear, transmits the light of the Sun. Ten milligrams of carbon dioxide from every kilogram of this substance, interacting with sunlight, continuously support life on Earth, 300 micrograms of ozone protect this life from harmful ultraviolet radiation, a millionth microgram of electrons makes it possible to communicate by radio. This environment, which allows us to fly to each other, which we breathe, finally, it also lives, lives physically: it is not only a stormy air ocean, but also a gas chemical reactor.” Chemists learned how to create new substances and even managed to overtake Nature, having obtained materials in which the incompatible was combined. Now scientists are investigating the ability and ability of Nature to maintain a wise balance between opposing processes: taking away its mineral wealth from the Earth, they try to preserve the purity of rivers, lakes, seas, the transparency of the air and the fragrant smell of herbs.

alchemy chemistry laboratory natural

Conclusion

Chemistry was at the center of important and complex physical processes. Chemical reactions occur not only in the world around us, but also in tissues, cells, vessels of the human body. Scientists of the 20th century discovered that it is chemistry that helps a person to distinguish between smells and colors, allows you to quickly respond to the subtle changes taking place in Nature. The visual pigment rhodopsin captures light rays, and we see a variety of colors around. Fragrant herbs and plants send volatile organic molecules in all directions, falling on the sensitive centers in the organs of smell of living creatures, transmitting the subtlest smells of Nature. In response to any external irritation, the human brain sends a signal of alarm or joy, action or calmness along the nerve fibers. In the human body, the nerve fibers that guide our movement and the muscles that carry it out are separated by a gap no more than 50 nanometers wide. This distance is 1000 times less than the thickness of a human hair. The endings of nerve fibers release an organic substance - acetylcholine, which transmits a chemical signal to the muscles of any organ, making a jump through the space that separates the fibers from the muscles.

Stormy chemical processes flow inside distant stars and in thermonuclear reactors created by scientists. There is a continuous chemical interaction of atoms and molecules in plants and in the bowels of the Earth, on the surface of water expanses and in the thickness of mountain ranges. Nature entrusted much to chemistry and was not mistaken: chemistry turned out to be her faithful ally and industrious assistant.

None of the areas of modern natural sciences can exist and develop without chemistry.

Ahead of chemistry - and the joys of accomplishments, and the difficulties of overcoming.

The chemistry is ready for them. On this distant, interesting trip, she sets off together with best friend- irrepressible, restless, searching human thought.

Bibliography

1. Gabrielyan O. S. Chemistry. Grade 8: Proc. for general education Proc. Institutions. - 4th ed., stereotype. - M.: Bustard, 2000. - 208 p.: ill.

2. Koltun M. M. The world of chemistry: Scientific and artistic literature / Format. B. Chuprygin. - M.: Det. lit., 1988.- 303 p.: ill., fotoil.

3. Concepts of modern natural science: Ser. "Textbooks and teaching aids" / Ed. S. I. Samygina. - Rostov n / a: "Phoenix", 1997. - 448 p.

4. Modern multimedia encyclopedia "Big Encyclopedia of Cyril and Methodius 2004" / © "Cyril and Methodius" 2002, 2003, with changes and additions, © "MultiTrade", 2004.

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