History of the development of chemistry table. Historical overview of the main stages in the development of chemistry
The origin of the science of substances can be attributed to the era of antiquity. The ancient Greeks knew seven metals and several more alloys. Gold, silver, copper, tin, lead, iron and mercury were the substances that were known at that time. The history of chemistry began with practical knowledge. Their theoretical understanding was first undertaken by various scientists and philosophers - Aristotle, Plato and Empedocles. The first of them believed that each of these substances can be transformed into another. He explained this by the existence of primordial matter, which served as the beginning of all beginnings.
Ancient philosophy
It was also widely believed that every substance in the world was based on a combination of four elements - water, fire, earth and air. It is these forces of nature that are responsible for At the same time, in the 5th century. BC e. The theory of atomism appeared, the founders of which were Leucippus and his student Democritus. This doctrine stated that all objects consist of tiny particles. They were called atoms. And although this theory did not find scientific confirmation in antiquity, it was this teaching that became a help to modern chemistry in
Egyptian alchemy
Around the 2nd century BC. e. Egyptian Alexandria became the new center of science. Alchemy also originated there. This discipline originated as a synthesis of the theoretical ideas of Plato and the practical knowledge of the Hellenes. The history of chemistry of this period is characterized by increased interest in metals. A classical designation was invented for them in the form of the then known planets and celestial bodies. For example, silver was depicted as the Moon, and iron as Mars. Since science at that time was inseparable from religion, alchemy, like any other scientific discipline, had its own patron god (Thoth).
One of the most significant researchers of that time was Bolos of Mendes, who wrote the treatise “Physics and Mysticism”. In it he described metals and precious stones (their properties and value). Another alchemist Zosimus Panopolite in his works explored artificial methods of obtaining gold. In general, the history of the emergence of chemistry began with the search for this noble metal. Alchemists tried to obtain gold through experiments or magic.
Egyptian alchemists studied not only the metals themselves, but also the ores from which they were mined. This is how amalgam was discovered. This is a type of alloy of metals with mercury, which occupied a special place in the worldview of alchemists. Some considered it the primordial substance. The discovery of a method for purifying gold using lead and saltpeter can be attributed to the same period.
Arabian discoveries
If the history of chemistry began in the Hellenistic countries, it continued several centuries later during the Arab Golden Age, when scientists of the young Islamic religion were at the forefront of human science. These researchers discovered many new substances, such as antimony and phosphorus. Much of the unique knowledge was used in medicine and pharmacy to develop drugs and potions. It is impossible to sketch the history of the development of chemistry without mentioning the philosopher's stone - a mythical substance that allows you to turn any substance into gold.
Around 815, the Arab alchemist Jabir ibn Hayyan formulated the mercury-sulfur theory. She explained the origin of metals in a new way. These principles became fundamental for alchemy not only of the Arab, but also of the European school.
European alchemists of the Middle Ages
Thanks to the Crusades and greater contact between the West and the East, Christian scientists finally became aware of the discoveries of the Muslims. Since the 13th century, it was the Europeans who took a confident leadership position in the research of substances. The history of chemistry in the Middle Ages owes much to Roger Bacon, Albertus Magnus, Raymond Lull, etc.
Unlike Arab science, European research was imbued with the spirit of Christian mythology and religion. Monasteries became the main centers for the study of substances. One of the first serious achievements of the monks was the discovery of ammonia. It was received by the famous theologian Bonaventure. The discoveries of alchemists had little impact on society until Roger Bacon described gunpowder in 1249. Over time, this substance revolutionized the battlefields and ammunition of armies.
In the 16th century, alchemy gained momentum as a medical discipline. The works of Paralces, who discovered many medicines, are best known.
New time
The Reformation and the advent of the New Age could not but affect chemistry. It increasingly got rid of religious overtones, becoming an empirical and experimental science. The pioneer of this direction was who set a specific goal for chemistry - to find as many chemical elements as possible, as well as to study their composition and properties.
In 1777, Antoine Lavoisier formulated the oxygen theory of combustion. It became the foundation for the creation of a new scientific nomenclature. The history of chemistry, briefly described in his textbook “Elementary Course in Chemistry,” took a leap. Lavoisier compiled a new table of the simplest elements based on the law of conservation of mass. Ideas and concepts about the nature of substances have changed. Now chemistry has become an independent rational science, based only on experiments and real evidence.
19th century
At the beginning of the 19th century, he formulated the atomic theory of the structure of substances. In fact, he repeated and deepened the teachings of the ancient philosopher Democritus. A term such as atomic mass has come into use.
With the discovery of new laws, the history of the development of chemistry received a new impetus. Briefly speaking, at the turn of the 18th and 19th centuries. mathematical and physical theories appeared that easily and logically explained the diversity of substances on the planet. Dalton's discovery was confirmed when Swedish scientist Jens Jakob Berzelius related atoms to the polarity of electricity. He also introduced the now familiar designations of substances in the form of Latin letters.
Atomic mass
In 1860, chemists around the world at a congress in Krlsruhe recognized the fundamental atomic-molecular theory proposed by Stanislao Cannizzaro. With its help, the relative mass of oxygen was calculated. So the history of chemistry (it is very difficult to describe it briefly) has come a long way in several decades.
Relative atomic mass made it possible to systematize all elements. In the 19th century, many options were proposed on how to do this in the most convenient and practical way. But the Russian scientist Dmitry Mendeleev succeeded best of all. Its elements, proposed in 1869, became the foundation for modern chemistry.
Modern chemistry
A few decades later there was a phenomenon of radioactivity. This confirmed long-held assumptions about the divisibility of the atom. In addition, these discoveries gave impetus to the development of a border discipline between chemistry and physics. Models of the structure of the atom appeared.
A brief outline of the history of the development of chemistry cannot do without mentioning quantum mechanics. This discipline influenced ideas about connections within matter. New methods for analyzing scientific knowledge and theories have emerged. These were various variations of spectroscopy and the use of X-rays.
In recent years, the history of the development of chemistry, briefly described above, has been marked by great results in connection with biology and medicine. New substances are actively used in modern medicines, etc. The structure of proteins, DNA and other important elements inside living organisms has been studied. A brief outline of the history of the development of chemistry can be completed with the discovery of more and more new substances in the periodic table, which are obtained experimentally.
Chemistry is the science of the composition, structure and properties of substances. Chemistry studies the process of transformation of these substances, as well as the laws according to which these transformations occur.
Man began to engage in chemical activities long before our era. This happened at a time when people learned to obtain metals. Then the production of ceramics, glass, leather tanning, fabric dyeing, the creation of medicines, and the production of cosmetics began.
Back in 300 BC, the Egyptian Zosima created an encyclopedia that consisted of 28 volumes. These volumes collected knowledge on the mutual transformations of substances over the past 500-600 years.
Alchemy
The emergence of alchemy can be considered the initial stage in the development of chemistry. Alchemy was based on the ideas of the ancient Greek philosophers Empedocles, Plato and Aristotle about the elements of nature and their mutual transformation. It was believed that there were four principles: earth, water, air and fire. And they are capable of transforming into each other, since each of them is one of the states of a single primary matter. And all substances are formed as a result of the combination of these principles.
Alchemists transformed one substance into another. They believed that metals could undergo similar transformations. Many scientists were busy searching for the “philosopher’s stone,” which was supposed to turn base metals into gold. And during these searches in their laboratories, alchemists learned to obtain alkalis, many salts, sulfuric and nitric acids, ethanol. With the help of these substances they could influence other substances. In the middle of the 13th century, European alchemists obtained gunpowder.
It should be said that alchemy was banned in Europe. The practice of alchemy was prohibited by both the church and secular authorities. But despite this, alchemy was popular until the beginning of the 16th century.
Development of chemistry as a science
In the 16th century, the Irish scientist Boyle freed chemistry from alchemy. He suggested that all substances consist of chemical elements that cannot be broken down into simpler parts. We can say that from that time on, chemistry became a separate science.
At the end of the 17th - beginning of the 18th centuries, the theory of the German chemist E.G. Stahl, explaining the phenomena of combustion, oxidation and reduction of metals. But this theory was recognized as erroneous in the middle of the 18th century by the French physicist Lavoisier, who established the role of oxygen in these processes. M.V. Lomonosov discovered the law of conservation of mass of matter in chemical processes.
From the end of the 18th to the middle of the 19th century, a whole series of stoichiometric laws were discovered that established quantitative relationships (mass and volume) between reacting substances and reaction products. Avogadro's law, the laws of conservation of mass, equivalents, constancy of composition, volumetric ratios, multiple ratios are the laws underlying stoichiometry. These laws made it possible to create rules for compiling chemical equations and formulas. It was after the experimental confirmation of these laws that chemistry was formed as a science. The atomic-molecular concept of the structure of matter was established, confirmed by the theory of the structure of chemical compounds created by A.M. Butlerov. D.M. Mendeleev discovered the periodic law.
After in late XIX century, electrons and radioactivity were discovered; at the beginning of the twentieth century, the theory of heteropolar (ionic) bonding and the theory of homeopolar (covalent) bonding were developed. In 1927, the development of the quantum mechanical theory of chemical bonding began. Mendeleev's doctrine of the periodicity of chemical elements was confirmed. It has become possible to predict the properties of substances. Physico-mathematical methods have become widely used for a variety of calculations in the field of chemistry. New physicochemical methods of analysis have appeared: electronic and vibrational spectrometry, magnetochemistry, etc.
In the twentieth century, thanks to the achievements of chemical science, it became possible to obtain substances with desired properties: synthetic antibiotics, synthetic polymers, plastics, all kinds of building materials, fabrics, etc.
Modern chemistry works closely with other sciences. As a result, completely new branches of chemistry appeared: biochemistry, geochemistry, colloidal chemistry, crystal chemistry, electrochemistry, chemistry of macromolecular compounds, etc.
An important direction of modern chemistry is the production of cheap fuel, creating an alternative to the main modern energy sources - oil and gas.
Precision modern instruments and computers have greatly simplified research and mathematical calculations in the field of chemistry, increased their accuracy, speed and reduced cost.
Chemistry (the science of the substances that make up the material world) dates back to ancient alchemy. But alchemy, closely associated with magic and witchcraft, was not a science in the true sense of the word. The beginning of the history of the development of chemistry lies in the production processes of processing and preparation of medicines. Thanks to constant experiments, chemistry became a real science.
Study of chemical reactions
In 1756, Scottish researcher Joseph Black (1728-1799) made an important discovery in the field of chemical reactions (changes leading to the formation of new substances). Black discovered that when magnesium carbonate is heated, its weight decreases. He found that this was due to the release of gas when heated. Black called this gas "trapped air." We know him as carbon dioxide.
New gas
Joseph Priestley (1733-1804) was born in Yorkshire (England). He wanted to become a priest, but became interested in scientific research. His works brought him wide fame, but political persecution forced him to emigrate to the United States in 1791. Priestley made his most significant discovery in 1774. He noticed that when mercury oxide is heated, gas is released. If you bring a candle to it, the flame flares up brighter. In those days, scientists believed that when substances burn, they lose a special substance - phlogiston(from the Greek "flame"). Priestley called the gas he discovered “dephlogisticated air.” He thought that when heated, it loses phlogiston. In fact, Priestley discovered a gas that we call oxygen.
Founder of modern chemistry
Antoine Lavoisier (1743-1794) was born in Paris. He studied law, but then became interested in science and worked as a tax collector in order to have funds for scientific research. Tax collectors aroused particular ire among the leaders, and Lavoisier shared the fate of many French executed during the Reign of Terror.
Oxygen
Lavoisier conducted a number of experiments to study the combustion process. He heated various substances in the air, carefully weighing them before and after heating. It turned out that some substances become heavier after heating. Lavoisier suggested that they absorb something from the air, and proved that this “something” is the same gas that Priestley discovered. Lavoisier called the gas oxygen. Lavoisier's discovery provided a scientific explanation for the observations of various scientists and allowed the phlogiston theory, which had been held for a century, to be rejected. His definition of combustion as the reaction of a substance with oxygen is still used today. Lavoisier was the first to prove that oxygen is necessary for all types of combustion, as well as for the respiration of animals and plants. His works helped to abandon many outdated views dating back to alchemy.
Building blocks
In 1789, Lavoisier published Methods of Naming Chemical Elements, based on the work of Robert Boyle. In it, he outlined the theory (of substances that cannot be further decomposed) as the building blocks of chemistry. Lavoisier identified 33 elements, arranging them to show how they interact with each other. The book also contained a new system for naming elements based on their chemical composition. Previously, many elements had confusing names given to them by alchemists.
Modern atomic theory
John Dalton (1766-1844) was born in a small village in the north of England and devoted his entire life to science. His ideas made it possible to penetrate into the essence of a fundamental chemical process - the formation of compounds. In 1808, he published the book “A New System of Chemical Philosophy,” which contains two important points. One of them says that everything is the result of combination or division. It is also important to state that atoms of different elements have different weights.
Relationship between elements
Dmitri Mendeleev (1834-1907) was born and raised in Siberia, Russia. He was the youngest of 14 children in the family. Mendeleev brilliantly graduated from St. Petersburg University and soon became a professor of chemistry there. He studied the relationship between various elements. In those days, very few people understood the proximity of certain elements to each other, as expressed in their atomic weight. The atomic weight of an element is the weight of one atom of it compared to the weight of an atom. Mendeleev published his Periodic Table of the Elements in 1869. It groups elements into “families” according to their atomic weights.
The lightest is hydrogen, the heaviest is lead. The periodic table shows how elements are related to each other. In his table, Periodic also provided free cells corresponding to elements that actually exist, but were not yet discovered. And he was right. 4 years later, the first such element was discovered - gallium. In total, more than 100 elements have already been added to the table.
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Chemistry is one of the most ancient sciences. Man has always observed changes around him, when some substances gave life to others or unexpectedly changed their shape, color, and smell.
Long before the advent of the new era, people already knew how to extract metals from ores, dye fabrics, burn clay, the restless minds of thinkers of the past tried to explain the chemical transformations continuously occurring in Nature, inquisitive eyes noticed new phenomena in the surrounding world, skillful hands mastered complex crafts - invariably related to chemistry.
Origins of chemistry. Alchemy
The first chemist scientists were Egyptian priests. They possessed many chemical secrets that had not yet been solved. These, for example, include techniques for embalming the bodies of deceased pharaohs and noble Egyptians, as well as methods for obtaining certain paints. Thus, the blue and blue paints of vessels found during excavations, made by ancient Egyptian craftsmen, continue to remain bright, although several thousand years have passed since their manufacture.
Some chemical production existed in ancient times in Greece, Mesopotamia, India, and China.
In the 3rd century BC, significant material had already been collected and described. For example, in the famous Library of Alexandria, which was considered one of the seven wonders of the world and contained 700 thousand handwritten books, many works on chemistry were also kept. They described processes such 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 tiny, invisible, indivisible and ever-moving solid particles of matter, which he called atoms. Aristotle in the 4th century BC believed that the basis of the surrounding nature is eternal primordial matter, which is characterized by four main qualities: heat and cold, dryness and moisture. These four qualities, in his opinion, could be separated from primordial matter or added to it in any quantity.
Aristotle's teaching was the ideological basis for the development of a separate era in the history of chemistry, the era of so-called alchemy.
Alchemy (Late Latin Alchemia, alchimia, alchymia), a pre-scientific direction in chemistry, originated in the 3rd-4th centuries BC. Its name goes back through Arabic to the Greek сhemeia from cheo - pour, cast, which indicates the connection of alchemy with the art of smelting and casting metals. Another interpretation is from the Egyptian hieroglyph "khmi", meaning black (fertile) land, as opposed to barren sands. This hieroglyph represented Egypt, the place where alchemy, often called the "Egyptian art," may have originated. The Arabs added their Arabic prefix “al” to this word, and thus the word alchemy was formed. The term “alchemy” first appears in the manuscript of Julius Firmicus, a 4th century astrologer.
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 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”, which under certain conditions can transform into each other. The spread of alchemy dates back to the 4th-16th centuries, a time of 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 “has never been anything other than chemistry.”
Thus, alchemy is to modern chemistry as astrology is to astronomy. The task of medieval alchemists was to prepare two mysterious substances with the help of which the desired refinement of metals could be achieved. The most important of these two drugs, which was supposed to have the property of turning not only silver into gold, 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 philosopher's egg, red tincture, panacea and elixir of life. This remedy was supposed to not only refine metals, but also serve as a universal medicine; its solution, the so-called golden drink, was supposed to heal all diseases, rejuvenate the old body and prolong life.
Another mysterious remedy, already secondary in its properties, called the white lion, white tincture, was limited to the ability to transform all base metals into silver.
Ancient Egypt is considered the birthplace of alchemy. The alchemists themselves traced the beginning of their science to Hermes Trismegistus (aka the Egyptian god Thoth), and therefore the art of making gold was called hermetic. Alchemists sealed their vessels with a seal with the image of Hermes - hence the expression “hermetically sealed.”
There was a legend that angels taught the art of turning “simple” metals into gold to earthly women with whom they married, 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 scientist 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 concerning the art of making gold (they were probably talking about gilding and the art of making counterfeit jewelry) should be burned. In the 4th century AD, the problem of turning metals into gold was studied by the Alexandrian school of scientists. The writer, who spoke under the pseudonym Democrat and belonged to the Alexandrian scientists, laid the foundation for a long series of alchemical manuals with his essay “Physics and Mysticism”. 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 accessible to understanding, since alchemists kept most of their achievements secret, encrypted descriptions of the substances obtained and experiments performed.
The largest collection of alchemical manuscripts is kept in the Library of St. 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 centuries, famous scientists studied alchemy and left their mark on European science. For example, Albertus Magnus, 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 outstanding 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 one of which is entitled “Testament expounding in two books the general art of chemistry.” (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 heads zealously practiced 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 likelihood, copper amalgam. Charles VII acted in a similar way in France, together with the famous swindler Jacques le Coeur.
Emperor Rudolf II was the patron of traveling alchemists, and his residence represented the center of alchemical science of that time. The emperor was called the German Hermes Trismegistus.
Elector Augustus of Saxony and his wife Anna of Denmark carried out experiments: the first in his Dresden “Golden Palace”, and his wife in a luxuriously arranged laboratory at their dacha “Pheasant Garden”. Dresden long remained the capital of sovereigns who patronized alchemy, especially at a time when competition for the Polish crown required significant financial expenditures. At the Saxon court, the alchemist I. Betger, who was unable to make gold, discovered porcelain for the first time in Europe.
One of the last adepts of alchemy was Cajetan, 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 devoted several years to studying the works of alchemists.
From the alchemical texts that have come down to us, it is clear that alchemists were responsible for the discovery or improvement of methods for obtaining valuable compounds and mixtures, such as mineral and vegetable paints, glasses, enamels, salts, acids, alkalis, alloys, medications. They used laboratory techniques such as distillation, sublimation, and filtration. Alchemists invented furnaces for long-term heating and alembics.
The achievements of the alchemists of China and India remained unknown in Europe. Alchemy was not widespread in Russia, although the treatises of alchemists were known, and some were even translated into Church Slavonic. Moreover, the German alchemist Van Heyden offered his services to prepare the philosopher’s stone to the Moscow court, but Tsar Mikhail Fedorovich, after “questioning,” rejected these offers.
The fact that alchemy did not become widespread in Rus' is explained by the fact that money and gold in Rus' began to be widely used later compared to Western countries, since the transition from quitrent to cash rent took place here later. In addition, mysticism, the vagueness of goals and the unreality of alchemy methods contradicted the common sense and efficiency of the Russian people. Almost all Russian alchemists (the most famous of them is 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, production of ceramics, paints). At the beginning of the 6th century, alchemists began to use the acquired knowledge 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 16th-18th 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 an imbalance in the chemical balance, and set the task of finding chemical means of treating them.
The desire of researchers to understand the true causes of inexplicable processes and to reveal the secrets of great but random achievements of practice became more and more insistent. The number of experiments increased, and the first scientific hypotheses appeared. In the Middle Ages, man began to actively and consciously compete with Nature in obtaining useful substances and materials. Chemical science was gradually created, and already in the Middle Ages chemical production appeared.
In Rus', chemistry developed primarily in an original way. In Kievan Rus they smelted metals and produced glass, salts, paints, and fabrics. Under Ivan the Terrible, a pharmacy was opened in Moscow in 1581. Under Peter I, vitriol and alum factories and the first chemical manufactories were built, and there were already eight pharmacies in Moscow. The further development of chemistry in Russia is connected 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 the report, 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 into human affairs... Wherever we look, wherever we look, the successes of its diligence turn before our eyes. "
Mikhail Vasilyevich’s in-depth and original research contributed to the development of not only the theory of chemistry, but also chemical practice. He managed to develop a simple technology for coloring glass; he made bright artificial mosaic tiles that were superior in richness and variety of shades to natural colored stones, plates of which were used for many centuries to make mosaics that decorated 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 and manufactured by man over a substance created by Nature. Success still came too rarely. The most insightful scientists of the 18th century, and among them M.N. Lomonosov, understood that the scientific foundations of chemistry were just being laid. You can’t always follow the endless path of countless experiments and repeat the same mistakes. For the further progress of chemistry, new theories were vitally needed to explain experimental data and predict how materials and substances would behave when the conditions in which they were found changed.
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 the law of conservation of mass in chemical reactions was discovered by M. V. Lomonosov (1748) and formulated in general form by A. Lavoisier (1789). Currently, this law is formulated as follows: the sum of the mass of the substance of a system and the mass equivalent to the energy received or given off by the same system is constant. In nuclear reactions, the law of conservation of mass should be applied in its 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 molecule, diminutive from the Latin moles - mass). In the modern understanding, it is a microparticle formed from atoms and capable of independent existence. It has a constant composition of the atomic nuclei included in it 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 vary: from two to hundreds of thousands (for example, in a protein molecule); The composition and arrangement of atoms in a molecule is conveyed by a chemical formula. The molecular structure of a substance is determined by X-ray diffraction analysis, electron diffraction, mass spectrometry, electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR) and other methods.
These atomic-molecular concepts 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 a natural system of chemical elements. The modern formulation of this law is as follows: the properties of elements periodically depend on the charge of their atomic nuclei. The nuclear charge Z is equal to the atomic (ordinal) number of the element in the system. Elements arranged in ascending order of 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, in the 6th - 32. In the 7th period (as of 1990) 23 elements are known. In periods, the properties of elements naturally change during the transition from alkali metals to noble gases. Vertical columns are groups of elements with similar properties. Within groups, the properties of elements also change naturally (for example, in alkali metals, when moving from Li to Fr, chemical activity increases). Elements with Z = 58-71, as well as with Z = 90-103, 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 produced artificially through nuclear reactions.
Mendeleev's law and system underlie the modern doctrine of the structure of matter and play a primary 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 chemical bonds, explain the periodic system of elements, etc. Since the properties of macroscopic bodies are determined by the movement 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 solids, 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 late 19th to early 20th centuries, the most important area of chemistry was the study of the laws of chemical processes.
Modern development of chemistry
What are chemical compounds made of? How are the smallest particles of matter structured? How are they located in space? What unites these particles? Why do some substances react with each other, while others do not? Is it possible to speed up chemical reactions? Probably more than any other science, chemistry required an understanding of the fundamental principles, a knowledge of the root causes. And chemists successfully applied the basic principles of the atomic-molecular theory in their reasoning long before the appearance of accurate experimental evidence of the real existence of atoms and molecules. The history of chemical science includes the theoretical generalizations of A.L. Lavoisier, D.W. Gibbs, D.I. Mendeleev and other outstanding 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.
The outstanding Russian scientist A.M. made a significant contribution to the development of chemistry. Butlerov. In 1861, he created a theory of the structure of organic compounds, which made it possible to bring a huge number of organic substances into the system and without which modern successes in the creation of new polymer materials would be unthinkable.
The theories of chemical bonding, created in the 20th century, make it possible to describe all the subtleties of the relationships between the particles that make up a substance. The laws governing the flow of chemical processes were discovered. Now experimenters and technologists have the opportunity to choose the simplest and most effective method carrying out any chemical reaction. Chemistry has a solid foundation, born in alliance with mathematics and physics. Chemistry has become an exact science. Extraordinary 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, the various stages of the chemical process that allowed Nature to transform organic substances into oil and gas that are useful to us today have been unraveled. This reaction, important for modern industry, occurred 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 from 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 rapidly - within several days and months.
The chemistry of our days is capable of more unexpected transformations. An industrial chemical apparatus has been developed - a tall cylinder, into the upper part of which chopped green herbal mass is fed. Inside the column, special biological compounds - enzymes that accelerate chemical reactions, according to a 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 made 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 quietly and firmly entered our everyday life, but the surprise of people who saw them for the first time is quite understandable. In the early seventies of our century, curious and ubiquitous tourists discovered in a remote corner of the endless Siberian forests a family who had lived far from cities and villages for several decades. What struck the hermits most among the things brought by tourists? Transparent plastic film! “Glass, but it crumples,” said the gray-bearded head of the family admiringly, touching and looking at the light of plastic film - one of the many synthetic materials invented by chemists to facilitate and improve our economy and life. Materials that have become a useful and invisible part Everyday life of people. Chemistry is now capable of producing substances with predetermined properties: frost-resistant and heat-resistant, hard and soft, hard and elastic, moisture-loving and moisture-proof, solid and porous, sensitive to the slightest 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 sense light and conduct electric current. Chemists have developed methods for completely purifying semiconductors from impurities, created methods for introducing small amounts of impurities into their composition, and came up with devices that signal the appearance of “foreign” atoms in a substance. Scientists are able to synthesize materials that are stable and unchanged even after prolonged exposure to sunlight and heat, cold and moisture.
Chemical discoveries occur in laboratories around the world, where new complex compounds are born. The famous French chemist M. Berthelot proudly pointed out the internal commonality of chemistry and art, which is rooted in their creative nature. Chemistry, like art, itself creates objects for study and its own 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 comprehensively and completely 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 is a science that studies the chemical substances that make up organisms, their structure, distribution, transformations and functions. The first information on biochemistry is associated with economic activity human (processing of plant and animal raw materials, use of various types of fermentation, etc.) and medicine. The first synthesis of a natural substance - urea (F. Wöhler, 1828) was of fundamental importance for the development of biochemistry, which undermined the idea of the “vital force” supposedly involved in the synthesis of various substances by the body. Using the achievements of general, analytical and organic chemistry, biochemistry in the 19th century emerged as an independent science. The introduction of 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 mid-20th century to the separation of molecular biology from biochemistry. The needs of the national economy for obtaining, storing and processing various types of raw materials led to the development of technical biochemistry. Along with molecular biology, biophysics, and 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 chemical soil reclamation agents; 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 is a science that studies the chemical composition of the Earth, the prevalence 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. Technical sciences such as chemical technology and metallurgy are based on the laws of chemistry.
Surrounded by sister sciences and daughter sciences, chemistry continues to develop. It helps us understand ourselves, allows us to comprehend many complex processes occurring in the world.
Chemistry and environmental protection
Increasingly, a completely different problem arises: to quickly and completely dissolve or separate into separate simple elements materials that have become unnecessary to humans. Some persistent chemicals, especially man-made polymers formed by very large molecules, remain in the ground for tens or hundreds of years without breaking down. Chemists are now developing synthetic fabrics, films, fibers, and plastics from laboratory-created polymers similar to starch or fiber produced in plants. At the end of their useful life, these polymers will degrade quickly and easily without contaminating environment. Chemistry uses the Earth's riches more fully and variably every day, although it is high time to start saving them. Scientists always need to remember the warning of the ancient Roman philosopher Seneca: “As our ancestors believed, it is too late to be thrifty when there is nothing left. And besides, not only little remains there, but also the worst.” We must take care of our Earth, we owe it so much...
Scientists began to pay more attention to the purity of the air that all living things on Earth breathe. The Earth's atmosphere is not just a mechanical mixture of gases. Rapid chemical reactions occur in the gaseous 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, components of the air. The Soviet scientist V.L. Talrose 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 substance 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 ears, 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 creates the ability 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 ocean of air, but also a gas chemical reactor.” Chemists learned to create new substances and even managed to overtake Nature by obtaining materials that combined the incompatible. Now scientists are exploring Nature’s ability and ability to maintain a wise balance between opposing processes: by robbing the Earth of its mineral wealth, they are trying 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 found itself at the center of important and complex physical processes. Chemical reactions occur not only in the world around us, but also in the tissues, cells, and vessels of the human body. Scientists of the 20th century discovered that it is chemistry that helps people distinguish between smells and colors and allows them to quickly respond to subtle changes occurring in Nature. The visual pigment rhodopsin captures light rays, and we see a variety of colors around. Scented herbs and plants send volatile organic molecules in all directions, falling on the sensitive centers in the olfactory organs of living beings, transmitting the subtlest odors of Nature. In response to any external irritation, the human brain sends a signal of alarm or joy, action or calm 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 the nerve fibers release an organic substance - acetylcholine, which transmits a chemical signal to the muscles of any organ, jumping through the space separating the fibers from the muscles.
Violent chemical processes take place inside distant stars and in thermonuclear reactors created by scientists. There is a continuous chemical interaction between atoms and molecules in plants and in the bowels of the Earth, on the surface of water spaces and in the depths of mountain ranges. Nature entrusted a lot to chemistry and was not mistaken: chemistry turned out to be its faithful ally and hardworking assistant.
None of the areas of modern natural sciences can exist and develop without chemistry.
Chemistry has both the joys of accomplishment and the difficulties of overcoming ahead.
The chemistry is ready for them. She goes on this long, interesting journey together with best friend- irrepressible, restless, searching human thought.
Bibliography
1. Gabrielyan O. S. Chemistry. 8th grade: Educational. for general education Textbook Establishments. - 4th ed., stereotype. - M.: Bustard, 2000. - 208 p.: ill.
2. Koltun M. M. World of chemistry: Scientific and artistic literature / Design. B. Chuprygin. - M.: Det. lit., 1988.- 303 pp.: ill., photo.
3. Concepts of modern natural science: Ser. "Textbooks and teaching aids"/Ed. S. I. Samygina. - Rostov n/d: “Phoenix”, 1997. - 448 p.
4. Modern multimedia encyclopedia " Great encyclopedia Cyril and Methodius 2004" / © "Cyril and Methodius" 2002, 2003, with amendments and additions, © "MultiTrade", 2004.
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Chemistry, as one of the sciences that studies natural phenomena, originated in Ancient Egypt before our era, one of the most technically developed countries in those days. People received the first information about chemical transformations while engaged in various crafts, when they dyed fabrics, smelted metal, and made glass. Then certain techniques and recipes appeared, but chemistry was not yet a science. Even then, humanity needed chemistry mainly in order to obtain from nature all the materials necessary for human life - metals, ceramics, lime, cement, glass, dyes, medicines, precious metals, etc. Since ancient times, the main task of chemistry has been to obtain substances with the necessary properties.
In Ancient Egypt, chemistry was considered a divine science and its secrets were carefully guarded by the priests. Despite this, some information leaked outside the country and reached Europe through Byzantium.
In the 8th century, in European countries conquered by the Arabs, this science spread under the name “alchemy”. It should be noted that in the history of the development of chemistry as a science, alchemy characterizes an entire era. The main task of alchemists was to find the “philosopher’s stone”, which supposedly turns any metal into gold. Despite the extensive knowledge gained from experiments, the theoretical views of alchemists lagged behind for several centuries. But as they carried out various experiments, they were able to make several important practical inventions. Furnaces, retors, flasks, and devices for distilling liquids began to be used. Alchemists prepared the most important acids, salts and oxides, and described methods for the decomposition of ores and minerals. As a theory, alchemists used the teachings of Aristotle (384-322 BC) about the four principles of nature (cold, heat, dryness and moisture) and the four elements (earth, fire, air and water), subsequently adding solubility (salt) to them ), flammability (sulfur) and metallicity (mercury).
At the beginning of the 16th century, a new era began in alchemy. Its emergence and development is associated with the teachings of Paracelsus (1493-1541) and Agricola (1494-1555). Paracelsus argued that the main purpose of chemistry was to make medicines, not gold and silver. Paracelsus had great success by proposing the treatment of certain diseases using simple inorganic compounds instead of organic extracts. This prompted many doctors to join his school and become interested in chemistry, which served as a powerful impetus for its development. Agricola studied mining and metallurgy. His work “On Metals” was a textbook on mining for more than 200 years.
In the 17th century, the theory of alchemy no longer met the requirements of practice. In 1661, Boyle opposed the prevailing ideas in chemistry and severely criticized the theory of alchemists. He first identified the central object of chemistry research: he tried to define a chemical element. Boyle believed that an element is the limit of decomposition of a substance into its constituent parts. By decomposing natural substances into their components, researchers made many important observations and discovered new elements and compounds. The chemist began to study what is what.
In 1700, Stahl developed the phlogiston theory, according to which all bodies capable of burning and oxidizing contain the substance phlogiston. During combustion or oxidation, phlogiston leaves the body, which is the essence of these processes. During the almost century-long dominance of the phlogiston theory, many gases were discovered, various metals, oxides, and salts were studied. However, the inconsistency of this theory hampered the further development of chemistry.
In 1772-1777, Lavoisier, as a result of his experiments, proved that the combustion process is a reaction between air oxygen and a burning substance. Thus, the phlogiston theory was refuted.
In the 18th century, chemistry began to develop as an exact science. At the beginning of the 19th century. Englishman J. Dalton introduced the concept of atomic weight. Each chemical element received its most important characteristics. Atomic-molecular science became the basis of theoretical chemistry. Thanks to this teaching, D.I. Mendeleev discovered the periodic law, named after him, and compiled the periodic table of elements. In the 19th century Two main branches of chemistry were clearly defined: organic and inorganic. At the end of the century, physical chemistry became an independent branch. The results of chemical research began to be increasingly used in practice, and this led to the development of chemical technology.