Chemistry is usually divided into 5 sections: inorganic, organic, physical, analytical and macromolecular chemistry.

The most important features of modern chemistry include:

1. Differentiation of the main sections of chemistry into separate, largely independent scientific disciplines, which is based on the difference between objects and research methods.

2. Integration of chemistry with other sciences. As a result of this process, arose: biochemistry, bioorganic chemistry and molecular biology who study the chemical processes in living organisms. Both geochemistry and cosmochemistry arose at the intersection of disciplines.

3. The emergence of new physicochemical and physical methods research.

4. Formation of the theoretical foundation of chemistry based on the quantum wave concept.

With the development of chemistry to its modern level, four sets of approaches to solving the main problem have developed in it (the study of the origin of the properties of substances and the development on this basis of methods for obtaining substances with predetermined properties).

1. The doctrine of the composition, in which the properties of substances were associated exclusively with their composition. At this level, the content of chemistry was limited to its traditional definition - as the science of chemical elements and their compounds.

2. Structural chemistry. This concept combines theoretical concepts in chemistry that establish a connection between the properties of substances not only with the composition, but also with the structure of molecules. Within the framework of this approach, the concept of "reactivity" arose, including the idea of ​​the chemical activity of individual fragments of a molecule - its individual atoms or entire atomic groups. The structural concept made it possible to transform chemistry from a predominantly analytical to a synthetic science. This approach eventually made it possible to create industrial technologies for the synthesis of many organic substances.

3. The doctrine of chemical processes. Within the framework of this concept, using the methods of physical kinetics and thermodynamics, factors affecting the direction and speed of chemical transformations and their results were identified. Chemistry revealed the mechanisms of reaction control and suggested ways to change the properties of the resulting substances.

4. Evolutionary chemistry. The last stage of the conceptual development of chemistry is associated with the use in it of some principles implemented in the chemistry of living nature. Within the framework of evolutionary chemistry, a search is carried out for such conditions under which self-improvement of reaction catalysts occurs in the process of chemical transformations. In essence, we are talking about the self-organization of chemical processes occurring in the cells of living organisms.

Lecture 10Chemistry system.

1. The main problem of chemistry. Conceptual systems of chemistry.

2. The doctrine of the composition of matter. Solving the problems of a chemical element and a chemical compound. Periodic system of elements.

3. Structural chemistry.

4. Kinetic chemistry.

5. Evolutionary chemistry.

The main problem of chemistry as a science. Conceptual systems of chemistry. D. I. Mendeleev called chemistry "the science of chemical elements and their compounds." In some textbooks, chemistry is defined as "the science of substances and their transformations", in others - as "the science that studies the processes of qualitative transformation of substances", etc. All these definitions are good in their own way, but they do not take into account the fact that chemistry is not just a sum of knowledge about substances, but an ordered, constantly evolving system of knowledge, which has a certain social purpose and its place among other sciences.

The whole history of the development of chemistry is a natural process of changing the ways of solving its main problem. All chemical knowledge that has been acquired over the course of many centuries is subject to a single the main task of chemistry - the problem of obtaining substances with the necessary properties.

So, basic dual problem of chemistry- this is:

1. Obtaining substances with desired properties is a production task.

2. Revealing ways to control the properties of a substance is the task of scientific research.

As science developed, ideas about the organization of matter, the composition of substances, and the structure of molecules changed, new data were obtained on the chemical processes themselves, which, of course, radically changed both the methods for the synthesis of new compounds and the methods for studying their properties. There is only four ways to solve this problem , which are associated primarily with the presence of only four main natural factors on which the properties of the substances obtained depend:

1. The composition of the substance (elementary, molecular).

2. Structure of molecules.

3. Thermodynamic and kinetic conditions of the chemical reaction during which this substance is obtained.

4. The level of organization of matter.

The successive appearance first of the first, then the second, third and, finally, the fourth ways of solving the basic problem of chemistry leads to the sequential appearance and coexistence of four levels of development of chemical knowledge, or, as they are now commonly called, four conceptual systems , located in a hierarchy relationship, i.e., subordination. In the system of all chemistry they are subsystems, just as chemistry itself is a subsystem of all Natural Science as a whole. The existence of only four ways to solve the basic problem of chemistry is reflected in the division of the System of Chemistry into four subsystems.

Thus, in the development of chemistry, there is not a change, but a strictly natural, consistent appearance of conceptual systems. Moreover, each newly emerging system does not deny the previous one, but, on the contrary, relies on it and includes it in a transformed form.

Summing up some results, we can give the following definition: Chemistry system -a single integrity of all chemical knowledge that appears and exists not separately from each other, but in close interconnection, complement each other and are combined into conceptual systems of chemical knowledge that are hierarchical with each other.

Each of the four historical stages in the extraction of chemical knowledge had its own tasks that needed to be solved.

The first stage in the development of chemistry - the XVII century: The doctrine of the composition of matter. The main problems facing scientists at the very first stage - the stage studying the composition of matter :

1. The problem of a chemical element.

2. The problem of a chemical compound.

3. The problem of creating new materials, which include newly discovered chemical elements.

An effective way to solve a problem originproperties of matter appeared in the second half of the 17th century. in the works of the English scientist Robert Boyle. His research showed that the qualities and properties of bodies are not absolute and depend on what material elements these bodies are composed of.

Boyle thus contributed to the solution of the basic problem of chemistry by establishing the relationship:

COMPOSITION OF THE SUBSTANCE ---------> PROPERTIES OF THE SUBSTANCE

This method laid the foundation for the doctrine of the composition of substances, which was first level scientific chemical knowledge . Until the first half of the 19th century. the doctrine of the composition of substances represented the entire chemistry of that time.

Solving the problem of a chemical element. The historical roots of solving this problem go back to ancient times. AT Ancient Greece the first atomistic theories about the structure of the world appear and, in contrast to them, ideas about the elements; properties and elements, qualities taken up later by the false teachings of the alchemists.

R. Boyle laid the foundation for the modern idea of ​​a chemical element as a "simple" body or as the limit of the chemical decomposition of a substance. Chemists, trying to obtain "simple substances", used the most common method at that time - the calcination of "complex substances". Calcination also led to scale, which was taken as a new element. Accordingly, metals - iron, for example, were taken as complex bodies consisting of the corresponding element and the universal "weightless body" - phlogiston (phlogistos - Greek lit). The phlogiston theory (false in its essence) was the first scientific chemical theory and served as an impetus for many studies.

In 1680-1760. exact quantitative methods of analysis substances, and they, in turn, contributed to the discovery of true chemical elements. At this time they were open phosphorus, cobalt, nickel, hydrogen, fluorine, nitrogen, chlorine and manganese .

In 1772-1776. simultaneously opened in Sweden, England and France oxygen . In France, its discoverer was a remarkable chemist A.L. Lavoisier(1743-1794). He established the role of oxygen in the formation of acids, oxides and water, refuted the theory of phlogiston and created a fundamentally new theory of chemistry. He also owned the first attempt to systematize the chemical elements, which was later corrected by D. I. Mendeleev.

Periodic law and periodic system of chemical elements D.I. Mendeleev. The Russian chemist D. I. Mendeleev made this discovery in 1869, making a revolution in natural science, because. it not only established a relationship between the chemical and physical properties of individual elements, but also a mutual relationship between all chemical elements. Groups and series of the periodic system have become a reliable basis for identifying families of related elements.

N. B! The first practical application of the periodic law was to correct the valencies and atomic weights of certain elements, for which incorrect values ​​were assumed at that time. This applied, in particular, to indium, cerium, and other rare earth elements: thorium, uranium.

The basic principle on which Mendeleev built his table was to arrange the elements in ascending order of their atomic weights. Based on the valency and chemical properties of the elements, Mendeleev arranged all the elements into 8 groups, each of which contained elements with similar properties.

The reason for the periodic changes in the physical and chemical properties of elements lies inperiodicity of the structure of electron shells of atoms .

N. B! At the beginning of each period, the valence electrons are in the s-sublevels of the corresponding energy levels in the atoms. Then, in small periods, the s and p sublevels are filled with electrons, and in large periods, the d sublevels are also filled. In periods VI and VII, in addition, the filling of the f-sublevels is observed. Atoms of inert gases always contain outer electrons at fully formed s and p sublevels. Thus, the chemical elements of the same subgroups of the periodic system are characterized by a similar structure of the electron shells of the atom.

One of the most important properties of atoms related to the structure of their electron shells is the effective atomic and ionic radii. It turns out that they also change periodically depending on the value of the element's atomic number. For elements of the same period, as the serial number increases, first a decrease in atomic radii is observed, and then, towards the end of the period, their increase. This unusual physical property finds a simple explanation based on knowledge of the structure of the outer electron shell of atoms belonging to the same period: it's all about electrostatics.

But the most important thing was that the periodic table did not just explain the physical properties of the elements, but put them in line with their Chemical properties. The main postulate of the table was that valence chemical element is determined by the number of electrons in the outer electron shell(these electrons are called - valence electrons ).

An important role of the periodic law is that it establishes a connection between the structure of atoms and the influence of this structure on the physical and chemical properties of elements.

Solving the problem of a chemical compound. The beginning of the solution of this problem was laid thanks to the work of the French chemist J. Proust, which in 1801-1808. installed law of constancy of composition , Whereby any individual chemical compound has a strictly defined, unchanged composition - a strong attraction of its constituent parts (atoms) and thus differs from mixtures.

The theoretical justification for Proust's law was given by an Englishman J. Dalton, who is the author of another fundamental law in the doctrine of the composition of substances - law of multiple ratios . He showed that all substances consist of molecules, and all molecules, in turn, are made of atoms, and that the composition of any substance can be imagined as a simple formula like AB, AB2, A2 B3, etc., where the symbols A and B stands for the names of the two atoms that make up a molecule. According to this law of equivalents, the “components of a molecule” - atoms A and B can be replaced by other atoms - C and D, for example, according to the reactions:

AB + C --> AC + B or

A2B3 + 3D ---> A2D3 + 3B

Dalton's law of multiple ratios (1803) states: If a certain amount of one element enters into combination with another element in several weight ratios, then the quantities of the second element are related to each other as whole numbers.

The molecular theory of the structure of matter made it possible to take a fresh look at the processes occurring in the gas phase, and gave rise to a new science, standing at the intersection of chemistry and physics - molecular physics . The real sensation was the discovery Avogadro's law in 1811 Italian scientist Amadeo Avogadro(1776-1856) established that under the same physical conditions (pressure and temperature), equal volumes of different gases contain an equal number of molecules. In other words, this means that gram molecule Any gas at the same temperature and pressure occupies the same volume.

However, the development of chemistry and the study of an increasing number of compounds led chemists to the idea that, along with substances that have certain composition , there are also connections variable composition - and this was the reason for the revision of ideas about the molecule as a whole. A molecule, as before, continued to be called the smallest particle of a substance capable of determining its properties and existing independently, but now such unusual quantum mechanical systems, such as ionic, atomic and metallic single crystals , as well as polymers formed by hydrogen bonds.

As a result of the application of physical methods for the study of matter, it became clear that the properties of a real body are determined not so much by whether the composition of a chemical compound is constant or not, but rather the physical nature of chemistry, i.e. the nature of those forces that cause several atoms to combine into one molecule. So now under chemical compound understand a certain substance consisting of one or more chemical elements, the atoms of which, due to interaction with each other, are combined into a particle with a stable structure - a molecule, complex, single crystal or other aggregate. This is a broader concept than the concept of "complex substance". Indeed, after all, everyone knows chemical compounds that consist not of different, but of the same elements. These are molecules of hydrogen, oxygen, chlorine, graphite, diamond, etc.

A special position in the series of molecular particles is occupied by polymer macromolecules . They contain a large number of repeating, chemically related to each other structural units - fragments of monomeric molecules having the same chemical properties.

Further complication of the chemical organization of matter follows the path of formation of a more complex set of interacting atomic and molecular particles, the so-called molecular associates and aggregates , as well as their combinations. During the formation of aggregates, the phase state of the system changes, which does not occur during the formation of associates. F basic state -is the basic physical state in which any substance can exist(gas, liquid, solid).

The problem of creating new materials. Nature generously "scattered" its material resources throughout the planet. But what a strange pattern scientists have discovered: it turns out that most often in their activities a person uses those substances, the reserves of which are limited in nature.

Therefore, chemists currently face three tasks:

1. Bringing the practice of using chemical elements in production into line with their real resources in nature.

2. Successive replacement of metals by various types of ceramics.

3. Expansion of the production of organoelement compounds based on organic synthesis. Organoelement compounds I-these are compounds that include both organic elements (carbon, hydrogen, sulfur, nitrogen, oxygen) and derivatives of a number of other chemical elements: silicon, fluorine, magnesium, calcium, zinc, sodium, lithium, etc.

It is proposed to focus on increasing the use in the production of such elements as aluminum, magnesium, calcium, silicon. In nature, these elements are quite common, and their extraction is not difficult. In addition, the use of these substances, composed of the most commonly found natural elements, will lead to less environmental pollution with waste, a problem that is so acutely felt by everyone at the present time.

The increased need to replace metals with ceramics is due to the fact that the production of ceramics is easier and more economical, and, in addition, in some industries it simply cannot be replaced by metals. Chemists have learned how to obtain refractory, heat-resistant, chemically resistant, high-hard ceramics, as well as ceramics for electrical engineering. Recently, an amazing property of some ceramic products has been discovered to have high-temperature superconductivity, i.e. superconductivity at temperatures above the boiling point of nitrogen. The discovery of this unique physical property was facilitated by the work of chemists on the creation of new ceramics based on complexes with barium, lanthanum and copper, taken in a single complex.

The chemistry of organoelement materials with the use of silicon (organosilicon chemistry) underlies the creation of the production of many polymers that have valuable properties and are indispensable in aviation and energy. And organofluorine compounds are exceptionally stable (even in acids and alkalis) and have a special surface activity and therefore can carry, for example, oxygen like a hemoglobin molecule! Organofluorine compounds are actively used in medicine to create all kinds of coatings, etc.

The solution of practical problems facing chemists at the present time is associated with the synthesis of new substances and the analysis of their chemical composition. Therefore, as many years ago, the problem of the composition of substances remains relevant in chemistry.

The second stage in the development of chemistry as a science - XIX century: Structural chemistry.

In 1820 - 1830. the manufactory stage of production with its manual technique was replaced by the factory stage. New machines appeared in production, there was a need to search for new raw materials for use in industry. In chemical production, the processing of huge masses of substances of plant and animal origin began to prevail, the qualitative variety of which was amazingly great, and the composition was uniform: carbon, hydrogen, oxygen, sulfur, nitrogen, phosphorus. This means that the properties of substances are determined not only by the composition - the chemists concluded.

Chemists have found that the properties of substances, and hence their qualitative diversity, are determined not only by their composition, but also by the structure of molecules. If a knowledgecomposition of matter answers the question of what chemical elements the molecule of a given substance consists of, then knowledgestructure of matter gives an idea of ​​the spatial arrangement of atoms in this very molecule.

At the same time, it became clear that not all atoms that make up the molecule of a given substance interact equally well with atoms of other molecules. Each molecule can be conditionally subdivided into several so-called functional or reactive units, which include groups of atoms, just individual atoms, or even individual chemical bonds. Each of these structures has its own unique ability to enter into chemical reactions, i.e. hisreactivity .

The second level of development of chemical knowledge received the conditional name structural chemistry .The main achievement of this stage could be called the establishment of a relationship between the structure of the molecule and the functional activity of the compound:

STRUCTURE OF A MOLECULE ---> FUNCTION (REACTIVITY)

Thus, knowledge of the structure of molecules transferred chemistry to the second level of development of chemical knowledge and contributed to the transformation of chemistry from predominantly analytical science to science synthetic . There was also organic matter technology which did not exist before.

The evolution of the concept of "structure" in chemistry. According to the theory put forward J. Dalton, any chemical substance is a collection of molecules that have a strictly defined qualitative and quantitative composition, i.e., consisting of a certain number of atoms of one, two or three chemical elements. The theory of the structure of matter by J. Dalton answered the question: how to distinguish individual substances from mixtures of substances, but it did not answer many other questions: how do atoms combine into a molecule, is there any order in the arrangement of atoms in a molecule, or are they combined haphazardly, by chance?

The Swedish chemist tried to answer these questions AND I. Berzelius who lived in the first half of the 19th century. I. Ya. Berzelius believed that a molecule is not a simple heap of atoms, but a certain ordered structure of atoms interconnected by electrostatic forces. He proposed a new atom model as electric dipole . AND I. Berzelius put forward the hypothesis that all atoms of different chemical elements have different electronegativity and arranged them in a kind of row as it increases.

N. B! AND I. Berzelius, based on the determination of the percentage composition of many substances given by him and the search for elementary stoichiometric patterns, as well as studying the decomposition of complex substances in solution under the action of an electric current, asked the question: what affects the sign and magnitude of the electric charge of a particular substance? Why are there electropositive and electronegative substances? What is the difference in the structure of the molecules of an acid and an alkali, or an alkali and a neutral salt?

In 1840, in the works of the French scientist C. Gerard it was shown that the structures of I. Ya. Berzelius are not valid in all cases: there is a mass of substances whose molecules cannot be decomposed into individual atoms under the influence of an electric current, they represent, as it were, a single whole system and just such indivisible system of interconnected atoms C. Gerard and proposed to call molecule . He developed the theory of types of organic compounds.

In 1857 a German chemist A. Kekule published his observations on the properties of individual elements that can replace hydrogen atoms in a number of compounds. He came to the conclusion that some of them can replace three hydrogen atoms, while others - only two or even one. A. Kekule also found that "one carbon atom ... is equivalent to four hydrogen atoms." These were the fundamentals theories of valency of substances .

A. Kekule introduced a new chemical term affinity , which denoted the number of hydrogen atoms that a given chemical element can replace. He assigned three, two, or one unit of affinity to all elements, respectively. At the same time, carbon was in an unusual position - its atom had four units of affinity. The number of units of affinity inherent in a given chemical element, the scientist calledatom valency .

When atoms combine into a molecule, free affinity units are closed.

concept molecular structure with the light hand of A. Kekule, it was reduced to the construction of visual formula schemes that served as a guide for chemists in their practical work, a specific indication of which starting substances should be taken in order to obtain the necessary chemical product.

N. B! A. Kekule's schemes, however, could not always be implemented in practice: a well-thought-out (or invented) reaction did not want to proceed according to a beautiful scheme. This happened because formula schematism did not take into account the reactivity of substances that enter into chemical interaction with each other.

The answers to the questions that concern practical chemists were given by the theory of the chemical structure of the Russian scientist Alexander Mikhailovich Butlerov. Butlerov, like Kekule, recognized that the formation of molecules from atoms occurs due to the closure of free units of affinity, but at the same time he pointed out the importance of what “tension, greater or lesser energy (this affinity) binds substances together ".

The theory of A. M. Butlerov became a guide for chemists in their practical activities. Later, it found its confirmation and physical justification in quantum mechanics.

Chemical bond.A chemical bond is the interaction between the atoms of elements, causing their combination into molecules and crystals.

The type of bond is determined by the nature of the physical interaction of atomic-molecular particles with each other. The fundamental theory of chemical bonds was created in the 30s of the twentieth century by an American chemist Linus Pauling.

At present, the concept of "chemical bond" has become broader . Now under chemical bond understood as such a type of interaction not just between individual atoms, but sometimes between atomic and molecular particles, which is due to the joint use of their electrons. Here it is understood that such socialization of electrons by interacting particles can vary over a wide range. Exist covalent (polar, non-polar), hydrogen and ionic (ionic-covalent) bonds, as well as metallic bonds.

Ionic bond is formed when, uniting into one molecule, one of the atoms loses electrons from its outer shell (cation), and the other acquires them (anion), oppositely charged ions are attracted to each other, forming strong bonds. Ionic compounds are generally solids with a very high melting point (salts, alkalis, e.g. table salt).

covalent bond is formed as a result of an electron pair belonging simultaneously to both atoms that create a molecule of a substance. Since such molecules are held by weak forces, they are unstable and exist as liquids or gases with low melting and boiling points (oxygen, butane).

The hydrogen bond is due to the polarization of covalent bonds, when joint electrons most of the time are at the atom of the element associated with the hydrogen atom. As a result, such an atom receives a small negative charge, which makes compounds with hydrogen bonds stronger than other covalent compounds (water).

Metallic bonds are due to the free movement of electrons in the outer shells of metal atoms. Atoms in metals line up in precisely matched rows, held together by an electronic field.

Thanks to the development of structural representations in 1860-1880. the term appeared in chemistry organic synthesis , denoting not only actions to obtain new organic substances, but also a whole field of science, so named in contrast to the general enthusiasm for the analysis of natural substances.

So under valency of atomic particles understood them the property to enter into a chemical interaction, the quantitative measure of which is the total number of unpaired electrons, lone electron pairs and vacant orbitals involved in the formation of chemical bonds. The valency of an atomic particle is not a constant value and can vary from unity to a certain maximum value depending on the nature of the partner particles and the conditions for the formation of a chemical compound.

Under the concept structure understand stable ordering of a qualitatively unchanged system.

Under molecular structure understand a combination of a limited number of atoms that have a regular arrangement in space and are chemically bonded to each other using valence electrons. The molecular structure is divided into nuclear (geometric) and electronic .

In the first approximation under atomic structure should be understood a stable collection of the nucleus and the electrons surrounding it, which are in electromagnetic interaction with each other.

The third stage in the development of chemistry as a science - the first half of the XX century: The doctrine of chemical processes - kinetic chemistry.

In connection with the development of technology and precisely at this time, chemistry becomes a science not only and not so much about substances, but a science about the processes and mechanisms of change in substances.

The intensive development of the automotive industry, aviation, energy and instrumentation at the beginning of our century required quality fuel for the operation of motors. Special high-strength rubbers for car tires, plastics to lighten their weight, all kinds of polymers and semiconductors - all this had to be obtained in large quantities, but, alas, the development of chemical skills did not meet the demands of production.

The fact is that the chemical reaction itself is a rather capricious thing. The interaction of substances during the reaction leads to a change in the composition of the substance. To do this, one combination of atoms must be destroyed and another created. To destroy the old connection, it is necessary to expend energy. The formation of a new compound is usually accompanied by the release of energy.

Chemical reactions are described by equations based onlaw of conservation of matter . According to this law, the total mass of substances that have entered into a reaction must exactly correspond to the mass of the formed substances. For mass calculations, a counting unit is used - mol, contains the same number of particles (6 10 23, Avogadro's number)

The doctrine of chemical processes. Methods of chemical process control. The doctrine of chemical processes is such a field of science in which there is the deepest interpenetration of physics, chemistry and biology. At the heart of this doctrine are chemical thermodynamics and kinetics , therefore, all this doctrine of chemical processes applies equally to both chemistry and physics.

There are a large number of problems to be solved in connection with the creation of the doctrine of chemical processes. Their detailed description can be found in any modern textbook on physical chemistry. But, perhaps, one of the most basic problems was the task of creating methods to control chemical processes.

In the most general form, all control methods can be divided into two large groups: thermodynamic and kinetic. The first group - thermodynamic methods - this is methods affecting the shift of the chemical equilibrium of the reaction; second group - kinetic methods -These are methods that affect the rate of a reaction.

In 1884, a book by an outstanding Dutch chemist appeared I. van't Hoff, in which he substantiated the laws establishing the dependence of the direction of a chemical reaction on changes in temperature and the thermal effect of the reaction. In the same year, the French chemist A. Le Chatelier formulated his famous principle of moving balance , having armed chemists with methods of shifting the equilibrium towards the formation of reaction products. In this case, the main control levers were temperature, pressure and concentration reactants. Therefore, these control methods got their name - thermodynamic .

Remember that any chemical reaction is reversible. For example, a reaction like:

AB+CD<=>AC+BD

Reversibility of reactions serves as the basis for the balance between forward and reverse reactions. In practice, the balance shifts in one direction or another. In order for a chemical reaction to go in the direction of increasing the reaction products AC and BD, it is necessary either to increase the concentration of substances AB and CD, or to change the temperature or pressure.

But thermodynamic methods only allowed to control direction reactions, not their rates. speed controlchemical reactions depending on various factors, a special science is engaged - chemical kinetics . A lot of things can affect the rate of a chemical reaction, even the walls of the vessel in which the reaction takes place.

The third way to solve the main problem, taking into account the complexity of the organization of chemical processes and ensuring economically acceptable performance of these processes in chemical reactors, can be represented by the scheme:

CHEMICAL ORGANIZATION ---> PERFORMANCE

PROCESSES IN THE REACTOR REACTOR

Catalysis and chemistry of extreme states. In 1812, a Russian academician K.S. Kirchhoff phenomenon was discovered chemical catalysis .Catalysisis the most common and widespread way of carrying out chemical reactions, the peculiarity of which is the activation of reagent molecules upon contact with a catalyst. In this case, there is a kind of "relaxation" of chemical bonds in the original substance, "pulling" it into separate parts, which then more easily interact with each other.

Unsteady kinetics. Development of ideas about the evolution of systems. In the 1970s, many chemical systems were discovered that used catalysts, in which, over time, everything happened the other way around - the process did not stabilize as usual, but became non-stationary . Several types have been discovered self-oscillating chemical reactions , in which periodic changes in the yield of reaction products occur over time. In other words, the necessary product of a chemical reaction is either released in large quantities, or, on the contrary, the reaction almost does not proceed or even changes its direction, and then all this is repeated again. It turned out that in a number of cases the total amount of the substance obtained in the course of such unstable chemical reaction, even exceeds the amount of substance that would be released during the reaction if it took place stationary or, i.e. would have constant speed .

The study non-stationary kinetics started recently. But there are already practical results. With its help, some energetically coupled processes were investigated, i.e. such chemical processes in which several reactions take part at once, exchanging energy with each other. Non-stationary chemical processes have also been discovered in wildlife.

The fourth stage in the development of chemistry as a science - the second half of the XX century: Evolutionary chemistry. In 1960 - 1979, a new way to solve the basic problem of chemistry appeared, which was called evolutionary chemistry . This method is based on the principle of using in the processes of obtaining chemical products such conditions that lead to self-improvement of catalysts for chemical reactions, i.e. to the self-organization of chemical systems.

Thus, the fourth stage in the development of chemistry, which continues to the present, establishes a connection between the self-organization of a system of reagents and the behavior of this system:

SELF-ORGANIZING -----> REAGENT SYSTEM BEHAVIOR REAGENT SYSTEM

Evolutionary problems of chemistry. Start evolutionary chemistry associated with 1950-1960. Under evolutionary problems should be understood problems of synthesis of new complex, highly organized compounds without human intervention.

Theory chemical evolution and biogenesis A.P. Rudenko. In the 1960s, cases of self-improvement of some chemical catalysts during a chemical reaction were noted. Conventional catalysts eventually (like everything in the world) age and wear out. But chemists managed to find such catalysts that not only did not age, but, on the contrary, "rejuvenated" with each chemical reaction. The answer to this question was tried to be given by the theory of chemical evolution and biogenesis, proposed by scientists of the world in 1964 by a Russian professor A. P. Rudenko. The essence of this theory is that chemical evolution is self-development of catalytic systems . During the reaction, the selection of those catalytic centers that have the highest activity occurs (the main law of chemical evolution): Evolutionary changes in the catalyst occur in the direction where its maximum activity is manifested. Self-development of systems occurs due to the constant absorption by catalysts of the energy flow that is released during the chemical reaction itself, therefore catalytic systems with higher energy evolve. Such systems destroy the chemical equilibrium and, as a result, serve as a tool for selecting the most stable evolutionary changes in the catalyst.

The study of the structure and functioning of enzymes in wildlife is such a stage of chemical knowledge that will open up the creation of fundamentally new chemical technologies in the future.

Despite the fact that chemistry is currently still far from the perfection that the “laboratory of a living organism” possesses, the paths to this ideal are outlined. Today, chemists have come to the conclusion that using the same principles on which the chemistry of living organisms is built, in the future (without exactly repeating nature) it will be possible to “build” a fundamentally new chemistry, a new control of chemical processes - the way it happens in any living cell . Chemists hope to obtain a new generation of catalysts that would make it possible to create, for example, unusual solar light converters.

Scientists strive to create industrial analogues of chemical processes occurring in wildlife. They study the experience of biochemical catalysts and create such catalysts in the laboratory. The particular difficulty of working with biochemical catalysts - enzymes , is the fact that they are very unstable during storage and quickly deteriorate, losing their activity. Therefore, chemists have been working for a long time on the creation of enzyme stabilization, and as a result they have learned how to obtain the so-called immobilized enzymes - this is enzymes isolated from a living organism and attached to a solid surface by their adsorption. Such biocatalysts are very stable and stable in chemical reactions and can be used repeatedly. founder chemistry of immobilized systems is a Russian chemist I. V. Berezin.

Among the promising areas of chemistry of the XXI century, of particular interest are:

brain chemistry

Earth macrochemistry

coherent chemistry

Spin chemistry and chemical radiophysics

Chemistry of Extreme States

cold fusion

Physics of chemical reactions.

The origins of chemical knowledge lie in ancient times. They are based on the human need to obtain the necessary substances for their life. The origin of the term "chemistry" has not yet been clarified, although there are several versions on this issue. According to one of them, this name comes from the Egyptian word "chemi", which meant Egypt, and also "black". Historians of science also translate this term as "Egyptian art." Thus, in this version, the word chemistry means the art of producing the necessary substances, including the art of turning ordinary metals into gold and silver or their alloys.

However, another explanation is now more popular. The word "chemistry" comes from the Greek term "chymos", which can be translated as "plant juice". Therefore, "chemistry" means "the art of making juices," but the juice in question could also be molten metal. So chemistry can also mean "the art of metallurgy."

The history of chemistry shows that its development was uneven: periods of accumulation and systematization of data from empirical experiments and observations were replaced by periods of discovery and heated discussion of fundamental laws and theories. The successive alternation of such periods makes it possible to divide the history of chemical science into several stages.

The main periods in the development of chemistry

1. Alchemy Period- from antiquity to the 16th century. ad. It is characterized by the search philosopher's stone, elixir of longevity, alkagest (universal solvent). In addition, during the alchemical period, almost all cultures practiced the “transformation” of base metals into gold or silver, but all these “transformations” were carried out by each people in a variety of ways.

2. The period of the birth of scientific chemistry, which lasted during the XVI - XVIII centuries. At this stage, the theories of Paracelsus, the theories of gases by Boyle, Cavendish, and others, the theory of phlogiston by G. Stahl, and, finally, the theory of chemical elements by Lavoisier were created. During this period, applied chemistry was improved, associated with the development of metallurgy, the production of glass and porcelain, the art of distillation of liquids, etc. By the end of the 18th century, chemistry was consolidated as a science independent of other natural sciences.

3. Period of discovery of the basic laws of chemistry covers the first sixty years of the 19th century and is characterized by the emergence and development of Dalton's atomic theory, Avogadro's atomic-molecular theory, the establishment of the atomic weights of elements by Berzelius and the formation of the basic concepts of chemistry: atom, molecule, etc.

4. Modern period lasts from the 60s of the XIX century to the present day. This is the most fruitful period in the development of chemistry, since in a little over 100 years the periodic classification of elements, the theory of valency, the theory of aromatic compounds and stereochemistry, the Arrhenius theory of electrolytic dissociation, the electronic theory of matter, etc. have been developed.

At the same time, during this period, the range of chemical research was significantly expanded. Such components of chemistry as inorganic chemistry, organic chemistry, physical chemistry, pharmaceutical chemistry, food chemistry, agrochemistry, geochemistry, biochemistry, etc., have acquired the status of independent sciences and their own theoretical base.

Alchemy Period

Historically alchemy It was formed as a secret, mystical knowledge aimed at searching for the philosopher's stone, which turns metals into gold and silver, and the elixir of longevity. During its centuries-old history, alchemy solved many practical problems related to obtaining substances and laid the foundation for the creation of scientific chemistry.

Highest Development Alchemy has reached in three main types:

Greco-Egyptian

· Arabic;

Western European.

The birthplace of alchemy is Egypt. Even in ancient times, there were known methods for obtaining metals, alloys used for the production of coins, weapons, and jewelry. This knowledge was kept secret and was the property of a limited circle of priests. The growing demand for gold prompted metallurgists to look for ways to convert (transmute) base metals (iron, lead, copper, etc.) into gold. The alchemical nature of ancient metallurgy connected it with astrology and magic. Each metal had an astrological connection with the corresponding planet. The pursuit of the philosopher's stone made it possible to deepen and expand knowledge of chemical processes. Metallurgy was developed, and the processes for refining gold and silver were improved. However, during the reign of Emperor Diocletian in Ancient Rome alchemy began to be pursued. The possibility of obtaining cheap gold frightened the emperor and, on his orders, all works on alchemy were destroyed. A significant role in the prohibition of alchemy was played by Christianity, which considered it as a diabolical craft.

After the Arab conquest of Egypt in the 7th c. n. e. alchemy began to develop in Arab countries. The most famous Arab alchemist was Jabir ibn Khayyam, known in Europe as Geber. He described ammonia, the technology for preparing white lead, and the method of distilling vinegar to obtain acetic acid. Jabir's fundamental idea was the theory of the formation of all the then known seven metals from a mixture of mercury and sulfur as the two main components. This idea anticipated the division of simple substances into metals and non-metals.

The development of Arabic alchemy followed two parallel paths. Some alchemists were engaged in the transmutation of metals into gold, others were looking for the elixir of life, which gave immortality.

The emergence of alchemy in countries Western Europe made possible by the Crusades. Then the Europeans borrowed scientific and practical knowledge from the Arabs, among which was alchemy. European alchemy came under the protection of astrology and therefore acquired the character of a secret science. The name of the most prominent medieval Western European alchemist remained unknown, it is only known that he was a Spaniard and lived in the XIV century. He was the first to describe sulfuric acid, the process of formation of nitric acid, aqua regia. The undoubted merit of European alchemy was the study and production of mineral acids, salts, alcohol, phosphorus, etc. Alchemists created chemical equipment, developed various chemical operations: heating over direct fire, water bath, calcination, distillation, sublimation, evaporation, filtering, crystallization, etc. Thus, appropriate conditions were prepared for the development of chemical science.

2. The period of the birth of chemical science covers three centuries: from the 16th to the 19th centuries. The conditions for the formation of chemistry as a science were:

Ø renewal of European culture;

Ø the need for new types of industrial production;

Ø discovery of the New World;

Ø Expansion of trade relations.

Separated from the old alchemy, chemistry acquired greater freedom of research and established itself as a single independent science.

In the XVI century. alchemy was replaced by a new direction, which was engaged in the preparation of medicines. This direction is called iatrochemistry . The founder of iatrochemistry was a Swiss scientist Theophrastus Bombast von Hohenheim, known in science as Paracelsus.

Iatrochemistry expressed the desire to combine medicine with chemistry, overestimating the role of chemical transformations in the body and attributing to certain chemical compounds the ability to eliminate imbalances in the body. Paracelsus firmly believed that if the human body consists of special substances, then the changes occurring in them should cause diseases that can only be cured by the use of drugs that restore normal chemical balance. Before Paracelsus, medicines were predominantly herbal preparations, but he relied only on the effectiveness of medicines made from minerals, and therefore sought to create medicines of this type.

In his chemical research, Paracelsus borrowed from the alchemical tradition the doctrine of the three main constituents of matter - mercury, sulfur and salt, which correspond to the basic properties of matter: volatility, combustibility and hardness. These three elements form the basis of the macrocosm (universe), but they also refer to the microcosm (man), consisting of the spirit, soul and body. Determining the causes of diseases, Paracelsus argued that fever and plague come from an excess of sulfur in the body, with an excess of mercury, paralysis occurs, and an excess of salt can cause indigestion and dropsy. In the same way, he attributed the causes of many other diseases to an excess or deficiency of these three basic elements.

In preserving human health, Paracelsus gave great importance chemistry, since he proceeded from the observation that medicine rests on four pillars, namely philosophy, astrology, chemistry and virtue. Chemistry must develop in harmony with medicine, because this union will lead to the progress of both sciences.

Iatrochemistry brought significant benefits to chemistry, as it helped to free it from the influence of alchemy and significantly expanded knowledge about vital compounds, thereby having a beneficial effect on pharmacy. But at the same time, iatrochemistry was also an obstacle to the development of chemistry, because it narrowed the field of its research. For this reason, in the XVII and XVIII centuries. a number of researchers abandoned the principles of iatrochemistry and chose a different path for their research, introducing chemistry into life and putting it at the service of man.

It was these researchers who, with their discoveries, contributed to the creation of the first scientific chemical theories.

In the 17th century, in the age of the rapid development of mechanics, in connection with the invention of the steam engine, chemistry became interested in the combustion process. The result of these studies was phlogiston theory, the founder of which was a German chemist and physician Georg Stahl.

Phlogiston's theory

Long before the 18th century, Greek and Western alchemists tried to answer these questions: Why do some things burn while others don't? What is the combustion process?

According to the ideas of the ancient Greeks, everything that is capable of burning contains the element of fire, which, under appropriate conditions, can be released. Alchemists adhered to approximately the same point of view, but believed that substances capable of burning contain the element "sulphur". In 1669 German chemist Johann Becher tried to give a rational explanation for the phenomenon of flammability. He suggested that solids were composed of three kinds of "earth", and one of these kinds, which he called "fatty earth", served as a combustible substance. All these explanations did not answer the question about the essence of the combustion process, but they became the starting point for the creation of a unified theory, known as the theory of phlogiston.

Instead of Becher's concept of "fat earth", Stahl introduced the concept of "phlogiston" - from the Greek "phlogistos" - combustible, flammable. The term "phlogiston" became widespread due to the work of Stahl himself and because his theory combined numerous information about combustion and roasting.

The phlogiston theory is based on the belief that all combustible substances are rich in a special combustible substance - phlogiston, and the more phlogiston a given body contains, the more it is capable of burning. What remains after the completion of the combustion process does not contain phlogiston and therefore cannot burn. Stahl argues that the melting of metals is like burning wood. Metals, in his opinion, also contain phlogiston, but, losing it, they turn into lime, rust or scale. However, if phlogiston is again added to these residues, then again metals can be obtained. When these substances are heated with coal, the metal is "reborn".

This understanding of the melting process made it possible to give an acceptable explanation for the process of turning ores into metals - the first theoretical discovery in the field of chemistry.

Stahl's theory of phlogiston at first met with sharp criticism, but at the same time it quickly began to gain popularity in the second half of the 17th century. was accepted by chemists everywhere, as it allowed to give clear answers to many questions. However, neither Stahl nor his followers could resolve one issue. The fact is that most combustible substances (wood, paper, fat) largely disappeared during combustion. The remaining ash and soot were much lighter than the original substance. But the chemists of the XVIII century. this problem did not seem important, they did not yet realize the importance of accurate measurements, and they neglected the change in weight. The phlogiston theory explained the reasons for the change in the appearance and properties of substances, and changes in weight were unimportant.

The influence of the ideas of A.L. Lavoisier on development chemical knowledge

By the end of the XVIII century. in chemistry, a large amount of experimental data was accumulated, which needed to be systematized within the framework of a unified theory. The creator of such a theory was the French chemist Antoine-Laurent Lavoisier.

From the very beginning of his activity in the field of chemistry, Lavoisier understood the importance of accurately measuring the substances involved in chemical processes. The use of precise measurements in the study of chemical reactions allowed him to prove the inconsistency of the old theories that hindered the development of chemistry.

The question of the nature of the combustion process was of interest to all chemists of the 18th century, and Lavoisier also could not help being interested in it. His numerous experiments on heating various substances in closed vessels made it possible to establish that, regardless of the nature of chemical processes and their products, the total weight of all substances participating in the reaction remains unchanged.

This allowed him to put forward a new theory of the formation of metals and ores. According to this theory, the metal in the ore is combined with gas. When ore is heated on charcoal, the charcoal absorbs the gas from the ore and carbon dioxide and metal are formed.

Thus, unlike Stahl, who believed that the smelting of metal involved the transfer of phlogiston from charcoal to ore, Lavoisier imagines this process as the transfer of gas from ore to coal. Lavoisier's idea made it possible to explain the reasons for the change in the weight of substances as a result of combustion.

Considering the results of his experiments, Lavoisier came to the conclusion that if we take into account all the substances involved in the chemical reaction and all the products formed, then there will never be a change in weight. In other words, Lavoisier came to the conclusion that mass is never created or destroyed, but only passes from one substance to another. This conclusion, known today as the law of conservation of mass, became the basis for the entire development of chemistry in the 19th century.

However, Lavoisier himself was dissatisfied with the results obtained, because he did not understand why scale was formed when air was combined with metal, and gases were formed when combined with wood, and why not all air, but only about a fifth of it, participated in these interactions?

Again, as a result of numerous experiments and experiments, Lavoisier came to the conclusion that air is not a simple substance, but a mixture of two gases. One fifth of the air, according to Lavoisier, is "dephlogisticated air", which combines with burning and rusting objects, passes from ores to charcoal and is necessary for life. Lavoisier called this gas oxygen, that is, generating acids, since he mistakenly believed that oxygen is a component of all acids.

The second gas, which is four-fifths of the air ("phlogisticated air"), was recognized as a completely independent substance. This gas did not support combustion, and Lavoisier called it nitrogen - lifeless.

An important role in Lavoisier's research was played by the results of experiments English physics Cavendish, who proved that the gases formed during combustion condense into a liquid, which, as analyzes have shown, is just water.

The importance of this discovery was enormous, since it turned out that water is not a simple substance, but a product of the combination of two gases.

Lavoisier called the gas released during combustion hydrogen (“forming water”) and noted that hydrogen burns by combining with oxygen, and therefore water is a combination of hydrogen and oxygen.

Lavoisier's new theories brought about a complete rationalization of chemistry. It was finally finished with all the mysterious elements. Since that time, chemists have become interested only in those substances that can be weighed or measured in some other way.

The birth of chemistry, as well as of all European science, despite their long history of formation, is associated with the emergence of the idea of ​​the existence of laws of nature in modern times. The classical definition of chemistry is the definition according to which chemistry is the science of substances, their structure, properties, reactions and the laws that govern their transformations; one of the branches of natural science 1 . However, already in 1967, in the fundamental monograph “The Evolution of Ideas about the Basic Laws of Chemistry”, V. I. Kuznetsov concluded that the definition of chemistry as “the science of substances and their transformations” is outdated. The understanding of the structure of matter and the dynamics of chemical processes and, accordingly, the methodology of their study have changed. This led to the fruitful development of all the main areas of chemical research. New chemical compounds have been discovered. Thus, modern chemistry has more than 15 million chemical compounds and chemical reactions that exhibit unexpected properties and require the introduction of completely new concepts.

Yu. A. Zhdanov, referring to the problem of the specifics of the chemical form of motion, notes that, paradoxically, chemistry in the system of modern natural science occupies a somewhat ambiguous position: it is readily recognized as necessary scientific basis to understand biological, geological phenomena, to create technological processes, but often she is denied the status of a theoretical science, reducing it to quantum mechanics, static physics, thermodynamics. Zhdanov writes that there are many authoritative witnesses both from among philosophers and from among natural scientists who are ready to swear that chemistry as a science does not exist in principle, that the term “chemistry” hides a mixture of accurate, elegant physical theory and dirty, vulgar cuisine, which only out of compassion can be called a science. In such a situation, the question is valid, which raises in his research not only K). A. Zhdanov, but also many scientists and philosophers: if the theoretical side of chemistry is exhausted by physics, then only practical experimentation remains of chemistry, but who would dare to consider a field of activity devoid of its own theory as a science?

Although there are estimates state of the art of chemistry as the birth of a new chemistry, one of the problems that needs clarification is the question of the reduction of chemical knowledge to physical knowledge. This problem is a philosophical question, because, in essence, it is a question of how it is formulated.

V. Dekelman about whether chemistry has some own concept of being, or whether it is, by its very foundations, just a private area of ​​physics. The tradition of reducing chemical changes to physical ones has its origins in the idea that the atoms of fire, air and earth mechanically interact with each other and form "mixed bodies" (R. Descartes, R. Boyle, I. Newton). According to M. Volkenstein, there is no theoretical chemistry, except for physics. This understanding was established with the development, firstly, of classical mechanics (M. Faraday) and was shared by many chemists; for example, D. I. Mendeleev admitted that the brilliance of chemical discoveries made modern chemistry a completely special science, while noting that “the time must undoubtedly come when chemical affinity will be considered as a mechanical phenomenon” . Secondly, with the development of quantum mechanics, the principles and provisions of which are applicable to solving traditional problems of chemical science, which gives grounds for belief in the quantum mechanical nature of the fundamental foundations of chemistry.

Physical basis chemical knowledge are the following main postulates of quantum mechanics: 1) the concept of the wave function of an electron as a charge and spin (angular momentum) distributed in space and time; 2) the Pauli principle, which "organizes" electrons according to energy levels, spin states and their own orbitals (wave functions); 3) the E. Schrödinger equation as a quantum heir to the equations of classical mechanics.

In this regard, many physicists of the 20th century, for example, W. Heisenberg, P. Jordan, R. Feynman, developed the thesis about the possibility of reducing the laws of any chemical processes to fundamental physical laws. Moreover, physicists express their confidence that the moment will certainly come "when biology also completely merges with physics and chemistry, just as the current quantum mechanics has merged physics and chemistry together." Many representatives of Russian physics and philosophy also share this point of view. So, S. V. Vonsovsky writes that in all chemical processes we meet, first of all, with the atomism of the bodies of nature. Chemistry is understood by him as one of the most important natural science disciplines, primarily the science of the structure of molecules, as well as the processes of interaction of molecules and the behavior of substances during various chemical reactions.

The problem of reduction in the chemical picture of the world is an attempt to turn chemistry into the same exact science as theoretical physics. However, there is another basis of chemistry - mathematical, the expression of which was the establishment of many quantitative laws, exact laws (including the electronic periodicity of Mendeleev's law), the highest measuring level of determination of atomic-molecular, thermodynamic and kinetic constants characterizing matter and chemical process. Along with the fundamental physical and mathematical basis of chemistry, a large number of research areas of chemical knowledge itself have been formed today. Moreover, the trends in the development of interdisciplinary interactions both at the junctions of chemical disciplines and between all natural sciences have led to the action of feedbacks between disciplines.

The main thesis of the tradition that opposes the reduction of chemistry to physics: “In a chemical phenomenon there is always something more than just a physical phenomenon” (W. Ostwald, N. N. Semenov, Yu. A. Zhdanov, B. M. Kedrov, A. N. Nesmeyanov and others). This provision leads to the need to formulate the problem of the object basis of chemistry. The expression of this problem can be the question: do chemistry and physics deal with the same object of study?

As G. A. Krestov notes, chemistry studies the world by the united concept of matter, which exists in the form of matter and field, possessing mass, energy and characterized by the dialectical unity of corpuscular and wave properties.

However, physics operates with the concept of "field". V. M. Kedrov notes that atoms and molecules can be the final stage in the development of an object in relation to their original structural elements and be the object of study of physics, but they can also be the initial chemical unit in relation to the molecular structures arising from it, and in this case act as an object of study of chemistry 11 .

Proponents of reducing chemical bonds to physical ones postulate an understanding of chemical interaction as a special kind of more general electromagnetic interaction. If we take into account that an individual atom is not yet a chemical substance, then the periodic system of elements of D. I. Mendeleev is not a chemical concept. As V. A. Engelgardt rightly points out when analyzing the chemical process: “... a part that was previously independent ceases to exist as such, becomes a component of an internally united integral whole. Something new arises, something that did not exist before, with new qualities inherent in it.

The peculiarity of the chemical picture of the world is that the main objects of study are not just atoms or molecules, but very complex organization substances. It must be taken into account that the rearrangement of the electronic orbitals of the atom occurs inside the atom as a whole. That is, the rearrangement of electronic orbitals is due to the entire structure of the atom, and not only to the individual properties of electrons. Only within the framework of the whole can we say that this or that interaction is chemical. It must be taken into account that chemical compounds are not built from individual atoms, but from atomic nuclei(atomic cores) connected by a socialized electronic continuum. This causes the fact that the process of losing an electron by one atom and gaining it by another cannot reflect the essence of chemical interaction.

In this matter, such researchers as N. M. Cheremnykh and O. S. Sirotkin rightly believe that it is the presence of a chemical bond in a substance that is the criterion that it is an object of chemical research; neither elementary particle, neither the atom (sometimes considered a “legitimate” object of chemistry) satisfies this criterion, and therefore the elementary and atomic level models of the organization of matter cannot be extrapolated to the chemical level. A chemical system is a kind of integrity, therefore, a description of the individual elements on the basis of which it arose cannot give a complete picture of the chemical process, for example, the formation of glycogen from glucose, etc. It is fair to say that there is a difference between physics and chemistry, it is not reduced only to the difference between chemical and physical (electromagnetic) interactions. N. N. Semyonov identifies the basic principles from which all chemical laws that cannot be reduced to the laws of physics can be derived:

Principle electronic structure molecular systems; the doctrine of the relationship between the structure and properties of molecular

• - the doctrine of the reactivity of chemical compounds;
• - the concept of the unity of chemical phenomena.

Moreover, if we take into account the fact that, according to the authoritative opinion of the physicochemist N. N. Semenov, the essence of the chemical is the chemical process, considered in modern chemistry as a kinetic continuum of many substances, then it is the chemical process that forms the bridge between the objects of physics and the objects of biology.

• See: Chemical Encyclopedic Dictionary. M.: Soviet Encyclopedia, 1983.
• See: Kuznetsov V.I. Evolution of ideas about the basic laws of chemistry.M. : Nauka, 1967.
• See: Zhdanov Yu. A. Carbon and life. Rostov n / a: Publishing House of the Russian State University, 1968; Zhdanov Yu. A. Essays on the methodology of organic chemistry. M. : Vyssh. school, 1960.
• See: V. I. Kuznetsov. Dialectics of the development of chemistry. Moscow: Nauka, 1973; Solovyov Yu. I., Trifonov D. II., Shamin A. II. Development of the main directions of modern chemistry. Moscow: Education, 1978; Polit L. General chemistry. M. : Mir, 1974.

slide 2

questions

1. Chemistry as a science. 2. Alchemy as the prehistory of chemistry. 3. The evolution of chemical science. 4. Ideas of D. I. Mendeleev and A. M. Butlerov. 5. Anthropogenic chemistry and its impact on the environment.

slide 3

from the Egyptian word "chemi", which meant Egypt, as well as "black". Historians of science translate this term as "Egyptian art". chemistry means the art of producing the necessary substances, including the art of converting ordinary metals into gold and silver or their alloys

slide 4

The word "chemistry" comes from the Greek term "chymos", which can be translated as "plant juice". "chemistry" means "the art of making juices," but the juice in question could also be molten metal. Chemistry can mean "the art of metallurgy".

slide 5

Chemistry - a branch of natural science that studies the properties of matter and their transformations

The main problem of chemistry is obtaining substances with desired properties. inorganic organic chemistry explores the properties of chemical elements and their simple compounds: alkalis, acids, salts. studies complex compounds based on carbon - polymers, including those created by man: gases, alcohols, fats, sugars

slide 6

The main periods in the development of chemistry

1. The period of alchemy - from antiquity to the 16th century. ad. It is characterized by the search for the philosopher's stone, the elixir of longevity, alkahest (universal solvent). 2. Period during the XVI - XVIII centuries. The theories of Paracelsus, the theories of gases by Boyle, Cavendish, and others, the theory of phlogiston by G. Stahl, and the theory of chemical elements by Lavoisier were created. Applied chemistry was improved, connected with the development of metallurgy, the production of glass and porcelain, the art of distillation of liquids, etc. By the end of the 18th century, chemistry was consolidated as a science independent of other natural sciences.

Slide 7

3. The first sixty years of the XIX century. It is characterized by the emergence and development of Dalton's atomic theory, Avogadro's atomic-molecular theory and the formation of the basic concepts of chemistry: atom, molecule, etc. 4. From the 60s of the XIX century to the present day. The periodic classification of elements, the theory of aromatic compounds and stereochemistry, the electronic theory of matter, etc. have been developed. The range of constituents of chemistry has expanded, such as inorganic chemistry, organic chemistry, physical chemistry, pharmaceutical chemistry, food chemistry, agrochemistry, geochemistry, biochemistry, etc.

Slide 8

ALCHEMY

"Alchemy" is an Arabized Greek word, which is understood as "plant juice". 3 types: Greco-Egyptian, Arabic, Western European

Slide 9

The birthplace of alchemy is Egypt.

Philosophical theory of Empedocles about the four elements of the Earth (water, air, earth, fire). According to it, various substances on Earth differ only in the nature of the combination of these elements. These four elements can be mixed into homogeneous substances. The most important problem in alchemy was the search for the philosopher's stone. Improved the process of refining gold by cupellation (heating gold-rich ore with lead and saltpeter). Isolation of silver by alloying ore with lead. The metallurgy of ordinary metals was developed. Known for the production of mercury.

Slide 10

ARAB ALCHEMY

"chemi" in "al-chemistry" Jabir ibn Khayyam described ammonia, the technology for preparing white lead, a method for distilling vinegar to obtain acetic acid; all seven base metals are formed from a mixture of mercury and sulfur. and

slide 11

WESTERN EUROPEAN ALCHEMY

Dominican monk Albert von Bolstedt (1193-1280) - Albert the Great described in detail the properties of arsenic, expressed the opinion that metals consist of mercury, sulfur, arsenic and ammonia.

slide 12

12th century British philosopher - Roger Bacon (about 1214 - after 1294). possible inventor of gunpowder; wrote about the extinction of substances without access to air, wrote about the ability of saltpeter to explode with burning coal.

slide 13

Spanish physician Arnaldo de Villanova (1240-1313) and Raimund Lullia (1235-1313). attempts to get the philosopher's stone and gold (unsuccessfully), made potassium bicarbonate. Italian alchemist Cardinal Giovanni Fidanza (1121-1274) - Bonaventure received a solution of ammonia in nitric acid. The most prominent alchemist was a Spaniard, lived in the XIV century - Gebera. described sulfuric acid, described how nitric acid is formed, noted the property of aqua regia to act on gold, which until then was considered unchangeable.

Slide 14

Vasily Valentin (XIV century) discovered sulfuric ether, hydrochloric acid, many compounds of arsenic and antimony, described methods for obtaining antimony and its medical use

slide 15

Theophrastus von Hohenheim (Paracelsus) (1493-1541), founder of iatrochemistry - medicinal chemistry, achieved some success in the fight against syphilis, one of the first to develop drugs to combat mental disorders, he is credited with the discovery of ether.

View all slides