FEDERAL EDUCATION AGENCY
STATE EDUCATIONAL INSTITUTION
HIGHER PROFESSIONAL EDUCATION
"ALTAI STATE UNIVERSITY"
Chemical faculty
Department of Life Safety

Chemical, physical and biological
picture of the world.
(Abstract)

Performed:
5th year student
Kosinskaya K.A.
Checked:
Teacher
Belova O.V.
Signature________

Barnaul, 2011
Content
Introduction……………………………………………………………………..3

Chemical picture of the world……………………………………………..5

2. Physical picture of the world……………..…………………………….7
2.1 Mechanical picture of the world…………… …………………….…….8
2.2 Electromagnetic picture of the world…………………………….…….10
3. Biological picture of the world…………………………………….....13
Conclusion………………………………………………… ………………….17
References……………………………………………………………19

INTRODUCTION
It has always been human nature to describe the world around us, study and imagine its structure, and talk about our ideas about the world around us to other people.
Natural scientific picture of the world is called part of the general scientific picture of the world, which includes ideas about nature.
The creation of a unified natural-scientific picture of the world presupposes the establishment of connections between sciences. In the structure of specific sciences, their main components express their own holistic picture of nature, which is called a special (or local) picture of the world. These pictures are, to some extent, fragments of the surrounding world, which are studied using the methods of this science (for example, the biological picture of the world, the chemical picture of the world, the physical picture of the world). Such pictures are often considered as relatively independent fragments of a single scientific picture of the world.
Scientific knowledge is a huge mass of interacting elements of knowledge. There are a variety of forms for describing this interaction of layers of scientific knowledge.
Within the framework of pictures of the world, the knowledge of the corresponding science (or group of sciences) is systematized; they are a visual embodiment of the system of interacting elements of knowledge - theories (fundamental and applied), which are developed systems of scientific concepts and connections between them.
Well-known scientific facts fit into the framework of pictures of the world. Pictures of the world ensure the integrity of the scientific field (science), form the methods of scientific knowledge for us and determine the strategy of scientific research, set the tasks of empirical and theoretical research, and clearly display their results.
Before others, the physical picture of the world arose as a general theoretical basis for all sciences about inanimate nature.
The biological picture of the world as a theoretical basis for the sciences of living nature arose only in the 19th century. Biological sciences have long been extremely isolated from each other, less interconnected than the group of physical and chemical sciences. The unification of the biological sciences occurred with the introduction by Charles Darwin of the basic concepts of modern biology (adaptation, heredity and variability, natural selection, struggle for existence, evolution, etc.). On their basis, a unified picture of biological phenomena is built, connecting all natural sciences into one field of science and making it possible to construct complete biological theories.
The core of a unified natural-scientific picture of the world as a whole is the physical picture of the world, since physics is the fundamental basis of the modern worldview. The centuries-old development of physics has led to the creation of a holistic natural-scientific picture of our world and its development.

1. Chemical picture of the world.
The lack of theoretical foundations in chemistry that would allow one to accurately predict and calculate the course of chemical reactions did not allow it to be placed on a par with the sciences that substantiate existence itself. Therefore, the statement of D.I. Mendeleev’s ideas about the chemical understanding of the world ether were not only not in demand at the beginning of the 20th century, but also turned out to be undeservedly completely forgotten for a whole century. Whether this is connected with the then revolutionary revolution in physics, which captured and captivated most minds in the 20th century in the study of quantum concepts and the theory of relativity, is no longer so important. It’s only a pity that the conclusions of the brilliant scientist, who was also recognized at that time, did not awaken qualitatively different philosophical and methodological principles, different from the philosophical principles that, by the way, figured in abundance in the reasoning of physicists.
The explanation for this unwanted oblivion is most likely due to the spread of reductionist currents caused by the exaltation of physics. It was the reduction of chemical processes to a set of physical ones that seemed to directly indicate the uselessness of chemical views in the analysis of the fundamental principles of existence. By the way, when chemists tried to defend the specifics of their science with arguments about the statistical nature of chemical interactions, in contrast to most interactions in physics, determined by dynamic laws, physicists immediately pointed to statistical physics, which supposedly more fully describes such processes.
The specificity of chemistry was lost, although the presence of a strict geometry of bonds of interacting particles in chemical processes introduced an informational aspect specific to chemistry into statistical consideration.
Analysis of the essence of the information-phase state of material systems sharply emphasizes the informational nature of chemical interactions. Water as a chemical medium, being the first example of the information-phase state of material systems, combines two states: liquid and information-phase precisely because of the proximity of chemical interactions to information ones.
Vacuum as an electromagnetic environment of physical space, which has demonstrated the properties of an information-phase state, is most likely closer to the environment in which processes that resemble chemical ones occur. Therefore, the chemical understanding of the world ether by D.I. Mendeleev becomes extremely relevant. A long-noticed terminological coincidence in describing the corresponding processes of particle transformation in chemistry and in elementary particle physics as reactions further emphasizes the role of chemical concepts in physics.
The supposed relationship between the information-phase states of the aquatic environment and the electromagnetic environment of the physical vacuum indicates changes in the physical vacuum accompanying chemical processes, which was probably felt by D.I. Mendeleev in his experiments.
Consequently, in the question of the nature of the world ether, chemistry at some points even acts as a determining factor in relation to the physical view.
Therefore, it is probably not worth talking about the priority of physical or chemical concepts in developing a scientific picture of the world.

2. Physical picture of the world.
The history of science shows that natural science, which arose during the scientific revolution of the 16th–17th centuries, was associated for a long time with the development of physics. It was physics that was and remains the most developed and the concepts and arguments that largely determined this picture. The degree of development of physics was so great that it could create its own physical picture of the world, unlike other natural sciences, which only in the 20th century. were able to set themselves this task (creating a chemical and biological picture of the world). Therefore, when starting a conversation about specific achievements of natural science, we will start it with physics, with the picture of the world created by this science.
The concept of “physical picture of the world” has been used for a long time, but only recently has it begun to be considered not only as a result of the development of physical knowledge, but also as a special independent type of knowledge - the most general theoretical knowledge in physics (a system of concepts, principles and hypotheses), which serves as the initial basis for building theories. The physical picture of the world, on the one hand, generalizes all previously acquired knowledge about nature, and on the other, introduces into physics new philosophical ideas and the concepts, principles and hypotheses determined by them, which did not exist before and which radically change the foundations of physical theoretical knowledge: old physical concepts and principles break down, new ones arise, the picture of the world changes. The key concept in the physical picture of the world is the concept of “matter”, which addresses the most important problems of physical science. Therefore, a change in the physical picture of the world is associated with a change in ideas about matter. This has happened twice in the history of physics. First, a transition was made from atomistic, corpuscular concepts of matter to field - continual ones. Then, in the 20th century, continuum concepts were replaced by modern quantum ones. Therefore, we can talk about three successively replacing each other physical pictures of the world.
One of the first to emerge was the mechanistic picture of the world, since the study of nature began with the analysis of the simplest form of movement of matter - the mechanical movement of bodies.

2.1. Mechanistic picture of the world.
It develops as a result of the scientific revolution of the 16th-17th centuries. based on the work of Galileo Galilei, who established the laws of motion of freely falling bodies and formulated the mechanical principle of relativity. But Galileo's main merit is that he was the first to use the experimental method to study nature, together with measurements of the quantities under study and mathematical processing of measurement results. If experiments had been carried out before, it was Galileo who first began to systematically apply their mathematical analysis.
The fundamental difference between the new method of studying nature and the previously existing natural philosophical method was, therefore, that in it hypotheses were systematically tested by experience. The experiment can be seen as a question addressed to nature. To get a definite answer to it, it is necessary to formulate the question in such a way as to obtain a completely unambiguous and definite answer to it. To do this, the experiment should be structured in such a way as to isolate as much as possible from the influence of extraneous factors that interfere with the observation of the phenomenon being studied in its “pure form.” In turn, a hypothesis, which is a question to nature, must allow empirical verification of certain consequences derived from it. For these purposes, starting with Galileo, mathematics began to be widely used to quantify the results of experiments.
Thus, the new experimental natural science, in contrast to the natural philosophical guesses and speculations of the past, began to develop in close interaction between theory and experience, when each hypothesis or theoretical assumption is systematically tested by experience and measurements.
The key concept of the mechanistic picture of the world was the concept of movement. It was the laws of motion that Newton considered the fundamental laws of the universe. Bodies have an internal innate property to move uniformly and rectilinearly, and deviations from this movement are associated with the action of an external force (inertia) on the body. The measure of inertia is mass, another important concept of classical mechanics. A universal property of bodies is gravity.
Newton, like his predecessors, attached great importance to observations and experiment, seeing them as the most important criterion for separating false hypotheses from true ones. Therefore, he sharply opposed the so-called hidden qualities, with the help of which Aristotle's followers tried to explain many phenomena and processes of nature.
Newton puts forward a completely new principle of the study of nature, according to which to deduce two or three general principles of motion from a phenomenon and then set out how the properties and actions of all corporeal things follow from these obvious principles would be a very important step in philosophy, although the causes of these started and were not yet open.
These principles of motion represent the basic laws of mechanics, which Newton precisely formulated in his main work, “The Mathematical Principles of Natural Philosophy,” published in 1687.
The discovery of the principles of mechanics really means a truly revolutionary revolution, which is associated with the transition from natural philosophical guesses and hypotheses about “hidden” qualities and speculative fabrications to precise experimental natural science, in which all assumptions, hypotheses and theoretical constructions were tested by observations and experience. Since mechanics is abstracted from qualitative changes in bodies, for its analysis it was possible to widely use mathematical abstractions and the analysis of infinitesimals created by Newton himself and at the same time by Leibniz (1646-1716). Thanks to this, the study of mechanical processes was reduced to their exact mathematical description.
Based on the mechanistic picture of the world in the 18th and early 19th centuries. terrestrial, celestial and molecular mechanics were developed. Technology was developing at a rapid pace. This led to the absolutization of the mechanistic picture of the world, to the fact that it began to be considered as universal.
At the same time, empirical data began to accumulate in physics that contradicted the mechanistic picture of the world. Thus, along with the consideration of a system of material points that fully corresponded to corpuscular ideas about matter, it was necessary to introduce the concept of a continuous medium, which in essence is no longer associated with corpuscular, but with continuum ideas about matter. Thus, to explain light phenomena, the concept of ether was introduced - a special subtle and absolutely continuous light matter.
These facts, which do not fit into the mechanistic picture of the world, indicated that the contradictions between the established system of views and the data of experience turned out to be irreconcilable. Physics needed a significant change in ideas about matter, a change in the physical picture of the world.

2.2. Electromagnetic picture of the world.
In the process of lengthy reflections on the essence of electrical and magnetic phenomena, M. Faraday came to the idea of ​​​​the need to replace corpuscular ideas about matter with continual, continuous ones. He concluded that the electromagnetic field is completely continuous, the charges in it are point centers of force. Thus, the question of constructing a mechanistic model of the ether, the discrepancy between mechanistic ideas about the ether and real experimental data on the properties of light, electricity and magnetism, disappeared.
Maxwell (1831-1879) was one of the first to appreciate Faraday's ideas. At the same time, he emphasized that Faraday put forward new philosophical views on matter, space, time and forces, which largely changed the previous mechanistic picture of the world.
Views on matter changed radically: the totality of indivisible atoms ceased to be the final limit of the divisibility of matter; a single absolutely continuous infinite field with force point centers - electric charges and wave movements in it - was accepted as such.
etc.................

(structural levels of organization of matter from the point of view of chemistry).

Chemistry is one of the branches of natural science, the subject of study of which is chemical elements (atoms), the simple and complex substances (molecules) they form, their transformations and the laws to which these transformations are subject. By definition D.I. Mendeleev (1871), “chemistry in its modern state can be called the study of elements.” The origin of the word "chemistry" is not completely clear. Many researchers believe that it comes from the ancient name of Egypt - Chemia (Greek Chemía, found in Plutarch), which is derived from "hem" or "hame" - black and means "science of the black earth" (Egypt), "Egyptian science" .

Modern chemistry is closely connected both with other sciences and with all branches of the national economy. The qualitative feature of the chemical form of motion of matter and its transitions into other forms of motion determines the versatility of chemical science and its connections with areas of knowledge that study both lower and higher forms of motion. Knowledge of the chemical form of the movement of matter enriches the general teaching about the development of nature, the evolution of matter in the Universe, and contributes to the formation of a holistic materialistic picture of the world. The contact of chemistry with other sciences gives rise to specific areas of their mutual penetration. Thus, the areas of transition between chemistry and physics are represented by physical chemistry and chemical physics. Between chemistry and biology, chemistry and geology, special border areas arose - geochemistry, biochemistry, biogeochemistry, molecular biology. The most important laws of chemistry are formulated in mathematical language, and theoretical chemistry also cannot develop without mathematics. Chemistry has had and continues to influence the development of philosophy and has itself been and is being influenced by it. Historically, two main branches of chemistry have developed: inorganic chemistry, which studies primarily chemical elements and the simple and complex substances they form (except for carbon compounds), and organic chemistry, the subject of which is the study of carbon compounds with other elements (organic substances). Until the end of the 18th century. the terms “inorganic chemistry” and “organic chemistry” indicated only from which “kingdom” of nature (mineral, plant or animal) certain compounds were obtained. Since the 19th century. these terms came to indicate the presence or absence of carbon in a given substance. Then they acquired a new, broader meaning. Inorganic chemistry comes into contact primarily with geochemistry and then with mineralogy and geology, i.e. with the sciences of inorganic nature. Organic chemistry is a branch of chemistry that studies a variety of carbon compounds up to the most complex biopolymer substances; through organic and bioorganic chemistry Chemistry borders on biochemistry and then on biology, i.e. with the totality of sciences about living nature. At the interface between inorganic and organic chemistry is the field of organoelement compounds. In chemistry, ideas about the structural levels of organization of matter gradually formed. The complication of a substance, starting from the lowest, atomic, goes through the stages of molecular, macromolecular, or high-molecular compounds (polymer), then intermolecular (complex, clathrate, catenane), finally, diverse macrostructures (crystal, micelle) up to indefinite non-stoichiometric formations. Gradually, corresponding disciplines emerged and became isolated: chemistry of complex compounds, polymers, crystal chemistry, studies of dispersed systems and surface phenomena, alloys, etc.

The study of chemical objects and phenomena by physical methods, the establishment of patterns of chemical transformations, based on the general principles of physics, lies at the basis of physical chemistry. This area of ​​chemistry includes a number of largely independent disciplines: chemical thermodynamics, chemical kinetics, electrochemistry, colloidal chemistry, quantum chemistry and the study of the structure and properties of molecules, ions, radicals, radiation chemistry, photochemistry, studies of catalysis, chemical equilibria, solutions etc. Analytical chemistry has acquired an independent character, the methods of which are widely used in all areas of chemistry and the chemical industry. In the areas of practical application of chemistry, such sciences and scientific disciplines as chemical technology with its many branches, metallurgy, agricultural chemistry, medicinal chemistry, forensic chemistry, etc. arose.

The external world, which exists independently of man and his consciousness, represents various types of movement of matter. Matter exists in perpetual motion, the measure of which is energy. The most studied forms of the existence of matter are matter and field. To a lesser extent, science has penetrated into the essence of vacuum and information as possible forms of existence of material objects.

Matter is understood as a stable collection of particles (atoms, molecules, etc.) with a rest mass. The field is considered as a material medium that ensures the interaction of particles. Modern science believes that the field is a stream of quanta that do not have a rest mass.

The material bodies surrounding humans consist of various substances. In this case, bodies are called objects of the real world that have a rest mass and occupy a certain volume of space.

Each body has its own physical parameters and properties. And the substances from which they consist have chemical and physical properties. Physical properties include the aggregate states of a substance, density, solubility, temperature, color, taste, smell, etc.

There are solid, liquid, gaseous and plasma states of matter. Under normal conditions (temperature 20 degrees Celsius, pressure 1 atmosphere), various substances are in different states of aggregation. For example: sucrose, sodium chloride (salt), sulfur are solids; water, benzene, sulfuric acid – liquids; oxygen, carbon dioxide, methane are gases.

The main task of chemistry as a science is to identify and describe those properties of a substance that make it possible to transform one substance into another based on chemical reactions.

Chemical transformations are a special form of movement of matter, which is caused by the interaction of atoms, leading to the formation of molecules, associates and aggregates.

From the point of view of chemical organization, the atom is the starting level in the overall structure of matter.

Chemistry, therefore, studies a special “chemical” form of motion of matter, a characteristic feature of which is the qualitative transformation of matter.

Chemistry is a science that studies the transformation of some substances into others, accompanied by changes in their composition and structure, and also studies the mutual transitions between these processes.

The term "natural science" means knowledge about nature or natural history. The study of nature began with natural philosophy (“natural science” translated from German “naturphilosophie”; and translated from Latin – “natura” - nature, “Sophia” - wisdom).

In the course of the development of each science, including chemistry, the mathematical apparatus and conceptual apparatus of theories developed, and the experimental base and experimental technique were improved. As a result, complete differentiation arose in the subjects of study of various natural sciences. Chemistry mainly studies the atomic and molecular level of organization of matter, which is presented in Fig. 8.1.

Rice. 8.1. Levels of matter studied by chemical science

Basic concepts and laws of chemistry

The basis of modern natural science is the principle of conservation of matter, motion and energy. Formulated by M.V. Lomonosov in 1748. This principle has become firmly established in chemical science. In 1756 M.V. Lomonosov, studying chemical processes, discovered the constancy of the total mass of substances participating in a chemical reaction. This discovery became the most important law of chemistry - the law of conservation and relationship between mass and energy. In the modern interpretation, it is formulated as follows: the mass of substances that entered into a chemical reaction is equal to the mass of substances formed as a result of the reaction.

In 1774, the famous French chemist A. Lavoisier supplemented the law of conservation of mass with ideas about the invariability of the masses of each substance participating in the reaction.

In 1760 M.V. Lomonosov formulated the law of conservation of energy: energy does not arise from nothing and does not disappear without a trace, it transforms from one type to another. The German scientist R. Mayer experimentally confirmed this law in 1842. And the English scientist Joule established the equivalence of various types of energy and work (1 cal = 4.2 J). For chemical reactions, this law is formulated as follows: the energy of the system, including the substances that entered into the reaction, is equal to the energy of the system, including the substances formed as a result of the reaction.

The law of constancy of composition was discovered by the French scientist J. Proust (1801): every chemically pure individual substance always has the same quantitative composition, regardless of the method of its preparation. In other words, no matter how you get water - during the combustion of hydrogen or during the decomposition of calcium hydroxide (Ca (OH)2), the ratio of the masses of hydrogen and oxygen in it is 1:8.

In 1803 J. Dalton (English physicist and chemist) discovered the law of multiple ratios, according to which, if two elements form several compounds with each other, then the masses of one of the elements per one and the same mass of the other are related to each other as small integers. This law is a confirmation of atomistic ideas about the structure of matter. If elements combine in multiple ratios, then the chemical compounds are distinguished by whole atoms, which represent the smallest amount of the element that entered the connection.

The most important discovery of chemistry in the 19th century is Avogadro's law. As a result of quantitative studies of reactions between gases, the French physicist J.L. Gay-Lussac established that the volumes of reacting gases relate to each other and to the volumes of the resulting gaseous products as small integers. An explanation for this fact is given by Avogadro's law (discovered by the Italian chemist A. Avogadro in 1811): equal volumes of any gases taken at the same temperature and pressure contain the same number of molecules.

The law of equivalents is often used in chemical calculations. From the law of constancy of composition it follows that the interaction of elements with each other occurs in strictly defined (equivalent) ratios. Therefore, the term equivalent has established itself as a basic one in chemical science. The equivalent of an element is the amount of it that combines with one mole of hydrogen or replaces the same number of hydrogen atoms in chemical reactions. The mass of one equivalent of a chemical element is called its equivalent mass. The concepts of equivalents and equivalent masses are also applicable to complex substances. An equivalent of a complex substance is the amount of it that reacts without a residue with one equivalent of hydrogen or with one equivalent of any other substance. The formulation of the law of equivalents was given by Richter at the end of the 18th century: all substances react with each other in quantities proportional to their equivalents. Another formulation of this law states: the masses (volumes) of substances reacting with each other are proportional to their equivalent masses (volumes). The mathematical notation of this law has the form: m 1: m 2 = E 1: E 2, where m 1 and m 2 are the masses of interacting substances, E 1 and E 2 are the equivalent masses of these substances, expressed in kg/mol.

The periodic law of D.I. plays an important role. Mendeleev, whose modern interpretation states that the order of arrangement and chemical properties of elements are determined by the charge of the nucleus.

Slide 2

questions

1. Chemistry as a science. 2. Alchemy as the prehistory of chemistry. 3. 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 "hemi", which meant Egypt and also "black". Historians of science translate this term as "Egyptian art". chemistry means the art of producing necessary substances, including the art of transforming ordinary metals into gold and silver or their alloys

Slide 4

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

Slide 5

Chemistry is 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 studies the properties of chemical elements and their simple compounds: alkalis, acids, salts. studies complex carbon-based compounds - polymers, including those created by man: gases, alcohols, fats, sugars

Slide 6

Main periods of development of chemistry

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

Slide 7

3. The first sixty years of the 19th century. 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 19th century to the present day. The periodic classification of elements, the theory of aromatic compounds and stereochemistry, the electronic theory of matter, etc. were developed. The range of constituent parts 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 that is understood as "the juice of plants." 3 types: Greco-Egyptian, Arabic, Western European

Slide 9

The birthplace of alchemy is Egypt.

Empedocles' philosophical theory of 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 search for the philosopher's stone was considered the most important problem of alchemy. Improved the process of refining gold through cupellation (heating gold-rich ore with lead and saltpeter). Isolation of silver by alloying ore with lead. The metallurgy of ordinary metals developed. The process for producing mercury is known.

Slide 10

ARABIC ALCHEMY

“khemi” in “al-chemistry” Jabir ibn Khayyam described ammonia, the technology for preparing white lead, and the method of distilling vinegar to obtain acetic acid; all seven basic 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

British philosopher of the 12th century. – 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 Raymond Lullia (1235-1313). attempts to obtain the philosopher's stone and gold (unsuccessfully), produced potassium bicarbonate. Italian alchemist Cardinal Giovanni Fidanza (1121-1274) - Bonaventura received a solution of ammonia in nitric acid. The most prominent alchemist was a Spaniard, lived in the 14th century - Geber. described sulfuric acid, described how nitric acid is formed, noted the property of aqua regia to affect 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, was one of the first to develop drugs to combat mental disorders, and is credited with the discovery of ether.

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Chemistry– the science of substances and their transformations, which are accompanied by changes in the composition and structure of the substance. These processes take place on the border between the micro and macro worlds.

Chemistry began to develop as an independent science from the middle of the 17th century. The scientific stage of development of chemistry was preceded by the period of alchemy. This cultural phenomenon is associated with attempts to obtain “perfect” metals - gold and silver - from “imperfect” metals using a hypothetical substance - the “philosopher’s stone” or elixir. Despite the obvious impossibility of carrying out this transformation, alchemy stimulated the development of chemical technologies (metallurgy, glassmaking, production of ceramics, paper, alcoholic beverages) and the discovery of ways to obtain new chemicals.

The scientific stage of development of chemistry is usually divided into four periods, in each of which a conceptual knowledge system is formed:

a) the doctrine of the composition of matter(mid 17th – mid 18th centuries) – studies the dependence of the properties of substances on the chemical composition (composition of the molecule);

b) the study of the structure of matter (structural chemistry)(mid 18th – mid 20th centuries) – studies the dependence of the properties of substances on the structure of the molecule;

c) the study of chemical processes(mid-20th century) – the mechanisms of chemical reactions, as well as the processes of their acceleration (catalysis), are studied;

d) evolutionary chemistry(last 25-30 years) - studies chemical processes in living nature, processes of self-organization of chemical systems.

3.1.1 The doctrine of the composition of matter

Classical chemistry is based on the concept of atomism, which was formulated in ancient philosophy by Leucipus, Democritus and Epicurus. On the basis of atomism, in the mid-19th century the basic principles of atomic-molecular teaching were formulated.

Substances are made up of molecules. A molecule is the smallest particle of a substance that has its chemical properties. Molecules differ in composition, size, physical and chemical properties.

Molecules are in continuous motion; there is mutual attraction and repulsion between them. The speed of movement of molecules depends on the state of aggregation of substances.

During physical phenomena, the composition of molecules remains unchanged, but during chemical reactions, others are formed from some molecules.

Molecules are made up of atoms. The properties of atoms of one element differ from the properties of atoms of other elements. Atoms are characterized by certain sizes and masses. The mass of an atom expressed in atomic mass units (amu) is called relative atomic mass.

1 amu = 1.667 10 -27 kg.

Atomic-molecular science made it possible to explain the basic concepts and laws of chemistry. The concept of “chemical element” was proposed by R. Boyle, and the designation of chemical elements by symbols was proposed in 1814 by J. Berzelius. X imical element- a certain type of atom with the same nuclear charge. The charge of the nucleus is numerically equal to the atomic number of the element in the periodic table. Currently, 118 chemical elements are known, of which 94 are found in nature, the remaining 24 are obtained artificially as a result of nuclear reactions.

Atom- the smallest particle of a chemical element that retains all its chemical properties. The chemical properties of an element are determined by the structure of its atom. This leads to a definition of an atom that corresponds to modern concepts: Atom is an electrically neutral particle consisting of a positively charged atomic nucleus and negatively charged electrons.

Isotopes- atoms of the same chemical element that have different masses and, accordingly, different numbers of neutrons in the nucleus. Isotopes can be stable, i.e. their nuclei are not subject to spontaneous decay, and are radioactive, which are capable of transforming into atoms of other elements until a stable isotope is formed (Uranium-238 Lead-206).

Allotropy– the ability of elements to exist in the form of various simple substances that differ in physical and chemical properties. Allotropy can result from the formation of molecules with different numbers of atoms (for example, atomic oxygen O, molecular oxygen O 2 and ozone O 3) or the formation of different crystalline forms (for example, graphite and diamond). As a result of allotropy, about 400 simple substances are formed from 118 elements.

Molecule - it is the smallest particle of a given substance that has its chemical properties. The concept of molecule was introduced by the Italian scientist A. Avogadro. In 1811, he proposed a molecular theory of the structure of matter.

The chemical properties of a molecule are determined by its composition and chemical structure. The sizes of molecules are determined by their mass and structure, and for large molecules they can reach 10 -5 cm. Currently, over 18 million types of molecules of different substances are known.

A chemical formula is a conventional recording of the composition of a substance using chemical symbols and indices. The chemical formula shows which atoms of which elements and in what ratio are connected to each other in a molecule.

Basic chimic laws.

Law of conservation of mass(M.V. Lomonosov, A.L. Lavoisier): the mass of substances that entered into the reaction is equal to the mass of substances formed as a result of the reaction. From the point of view of atomic-molecular science, as a result of chemical reactions, atoms do not disappear or appear, but they are rearranged (chemical transformation). Since the number of atoms before and after the reaction remains unchanged, their total mass should also not change. Based on the law of conservation of mass, it is possible to draw up equations of chemical reactions and make calculations using them. This law is the basis of quantitative chemical analysis.

At the beginning of the 20th century, the formulation of the law of conservation of mass was revised in connection with the advent of the theory of relativity (see section 2.4.1), according to which the mass of a body depends on its speed and, therefore, characterizes not only the amount of matter, but also its movement. Energy received by the body E is associated with an increase in its mass m by the ratio E= m c 2, where c is the speed of light. This ratio is not used in chemical reactions, because 1 kJ of energy corresponds to a change in mass of approximately 10 -11 g and m practically cannot be measured. However, in nuclear reactions, where the change in energy E is millions of times greater than in chemical reactions, m should be taken into account.

Law of constancy of the composition of matter:

According to the law of constancy of composition, any chemically pure substance has a constant qualitative and quantitative composition, regardless of the method of its preparation. The qualitative and quantitative composition of a substance is shown by the chemical formula. For example, no matter how the substance water (H 2 O) is obtained, it has a constant composition: two hydrogen atoms and one oxygen atom.

From the law of constancy of composition it follows that during the formation of a complex substance, elements combine with each other in certain mass ratios.

It has now been established that this law is always valid for compounds with a molecular structure. The composition of compounds with a non-molecular structure (with an atomic, ionic and metal crystal lattice) is not constant and depends on the conditions of preparation.

Law of multiple ratios (J. Dalton)- if two elements form several chemical compounds with each other, then the masses of the elements are related to each other as small integers.

For example: in nitrogen oxides N2O, N2O3, NO2 (N2O4), N2O5, the number of oxygen atoms per two nitrogen atoms is related as 1: 3: 4: 5.

Law of volumetric relations (Gay-Lussac) - the volumes of gases entering into chemical reactions and the volumes of gases formed as a result of the reaction are related to each other as small integers. Consequently, the stoichiometric coefficients in the equations of chemical reactions for molecules of gaseous substances indicate in what volume ratios gaseous substances react or are obtained. For example:

2CO+O 2
2CO 2

When two volumes of carbon (II) oxide are oxidized by one volume of oxygen, 2 volumes of carbon dioxide are formed, i.e. the volume of the initial reaction mixture is reduced by 1 volume.

Avogadro's law- equal volumes of any gases taken at the same temperature and at the same pressure contain the same number of molecules. According to this law:

the same number of molecules of different gases under the same conditions occupies the same volumes;

1 mole of any ideal gas under normal conditions (0°C = 273°K, 1 atm = 101.3 kPa) occupies the same volume of 22.4 liters.

French chemist A.L. Lavoisier was the first to try to systematize chemical elements according to their mass. The English chemist J. Dalton introduced the concept of atomic mass and was the creator of the theory of atomic structure. In 1804, he proposed a table of the relative atomic masses of hydrogen, nitrogen, carbon, sulfur and phosphorus, taking the atomic mass of hydrogen as one. Currently, atomic mass is measured relative to 1/12 the mass of an atom of the carbon isotope.

The work on studying the properties of atoms was continued by D.I. Mendeleev formulated the periodic law in 1869 and developed the Periodic Table of Chemical Elements. The periodic law was formulated as follows: “The properties of simple bodies, as well as the forms and properties of compounds of elements, are periodically dependent on the atomic weights of the elements.” D.I. Mendeleev used as a system-forming factor mass of a chemical element. In the Periodic System D.I. Mendeleev had 62 elements.

Quantum mechanics clarified that the properties of chemical elements and their compounds are determined by the charge of the atomic nucleus. Modern formulation of the periodic law of chemical elements: the properties of simple substances, as well as the forms and properties of compounds of elements, periodically depend on the magnitude of the charge of the atomic nucleus and are determined by periodically repeating similar electronic configurations of their atoms.

The reactivity of an atom of a chemical element is determined by the number of electrons in the outer shell of the atom.

Valence– properties of atoms of one element to form a certain number of bonds with atoms of other elements. Chemical bonds between atoms are carried out by electrons located on the outer shell and less tightly bound to the nucleus. They were named valence electrons. Valence (the number of valence electrons) can be determined using D.I. Mendeleev’s table, knowing the number of the group in which the chemical element is located.

Electronegativity– the property of an atom in a compound to attract valence electrons. The more an atom attracts electrons toward itself, the greater its electronegativity. Oxidation state- a conditional charge that is formed on an atom, taking into account that when a bond is formed, the electron goes completely to a more electronegative atom. The maximum oxidation state of an element is determined by the group number in the periodic table.

Atoms in molecules are interconnected by chemical bonds, which are formed due to the redistribution of valence electrons between atoms. When a chemical bond is formed, atoms tend to acquire a stable (complete) outer electron shell. Chemical bonding is a type of fundamental electromagnetic interaction. The formation of a chemical bond occurs due to the attraction of positive and negative charges that are formed on an atom when its electron is lost or displaced from a stationary orbit. Depending on the nature of the interaction of atoms, covalent, ionic, metallic and hydrogen chemical bonds are distinguished.

Covalent bond carried out due to the formation of shared electron pairs between two atoms. It can be polar and non-polar. Ionic bond is an electrostatic attraction between ions that are formed due to the complete displacement of an electron pair to one of the atoms. Metal connection - it is the connection between positive metal ions through a common electron cloud ("electron gas").

In addition to intramolecular bonds, intermolecular bonds are also formed. Intermolecular interactions are interactions between molecules that do not lead to the rupture or formation of intramolecular chemical bonds. The state of aggregation of a substance, structural, thermodynamic, thermophysical and other properties of substances depend on intermolecular interactions. An example of an intermolecular bond is a hydrogen bond.

A hydrogen bond is an intermolecular bond formed by the attraction of a more electronegative atom (F, O, N) and a hydrogen atom with a partial positive charge. For example, hydrogen bonds occur between molecules of water, alcohol, and organic acids. It affects the boiling point of a substance.

Hydrogen bonds can also form inside molecules. For example, intramolecular hydrogen bonds exist in molecules of nucleic acids, proteins, polypeptides, etc. and determine the structure of these macromolecules

Chemistry– the science of transformations of substances, accompanied by changes in their composition and structure.

Phenomena in which other substances are formed from one substance are called chemical. Naturally, on the one hand, in these phenomena can be detected purely physical changes, and, on the other hand, chemical phenomena are always present in all biological processes. Thus, it is obvious connection chemistry with physics and biology.

This connection, apparently, was one of the reasons why chemistry could not become an independent science for a long time. Although already Aristotle divided substances into simple and complex, pure and mixed, and tried to explain the possibility of some transformations and the impossibility of others, chemical he considered the phenomenon as a whole quality changes and therefore attributed to one of the genera movement. Chemistry Aristotle was part of him physicists– knowledge about nature ().

Another reason for the lack of independence of ancient chemistry is associated with theoreticality, the contemplation of all ancient Greek science as a whole. They looked for the unchangeable in things and phenomena - idea. Theory chemical phenomena led to element idea() as a certain beginning of nature or to idea of ​​the atom as an indivisible particle of matter. According to the atomistic concept, the peculiarities of the shapes of atoms in their many combinations determine the diversity of qualities of the bodies of the macrocosm.

Empirical experience belonged in Ancient Greece to the area arts And crafts. It also included practical knowledge about chemical processes: smelting metals from ores, dyeing fabrics, tanning leather.

Probably, from these ancient crafts, known back in Egypt and Babylon, the “secret” hermetic art of the Middle Ages arose - alchemy, most widespread in Europe in the 9th-16th centuries.

Originating in Egypt in the 3rd-4th centuries, this area of ​​practical chemistry was associated with magic and astrology. Its goal was to develop ways and means of transforming less noble substances into more noble ones in order to achieve real perfection, both material and spiritual. During the search universal By means of such transformations, Arab and European alchemists obtained many new and valuable products, and also improved laboratory technology.

1. The period of the birth of scientific chemistry(XVII - late XVIII century; Paracelsus, Boyle, Cavendish, Stahl, Lavoisier, Lomonosov). It is characterized by the fact that chemistry stands out from natural science as an independent science. Its goals are determined by the development of industry in modern times. However, theories of this period, as a rule, use either ancient or alchemical ideas about chemical phenomena. The period ended with the discovery of the law of conservation of mass in chemical reactions.

For example, iatrochemistry Paracelsus (XVI century) was devoted to the preparation of medicines and the treatment of diseases. Paracelsus explained the causes of disease by disruption of chemical processes in the body. Like the alchemists, he reduced the variety of substances to several elements - carriers of the basic properties of matter. Consequently, restoring their normal ratio by taking medications cures the disease.

Theory phlogiston Stahl (XVII-XVIII centuries) generalized many chemical oxidation reactions associated with combustion. Stahl suggested the existence of the element “phlogiston” in all substances - the beginning of flammability.

Then the combustion reaction looks like this: combustible body → residue + phlogiston; the reverse process is also possible: if the residue is saturated with phlogiston, i.e. mixed, for example, with coal, you can again get metal.

2. The period of discovery of the basic laws of chemistry(1800-1860; Dalton, Avogadro, Berzelius). The result of the period was the atomic-molecular theory:

a) all substances consist of molecules that are in continuous chaotic motion;

b) all molecules consist of atoms;

3. Modern period(started in 1860; Butlerov, Mendeleev, Arrhenius, Kekule, Semenov). It is characterized by the separation of branches of chemistry as independent sciences, as well as the development of related disciplines, for example, biochemistry. During this period, the periodic system of elements, theories of valence, aromatic compounds, electrochemical dissociation, stereochemistry, and the electronic theory of matter were proposed.

The modern chemical picture of the world looks like this:

1. Substances in the gaseous state consist of molecules. In the solid and liquid states, only substances with a molecular crystal lattice (CO 2, H 2 O) consist of molecules. Most solids have either an atomic or ionic structure and exist in the form of macroscopic bodies (NaCl, CaO, S).

2. A chemical element is a certain type of atom with the same nuclear charge. The chemical properties of an element are determined by the structure of its atom.

3. Simple substances are formed from atoms of one element (N 2, Fe). Complex substances or chemical compounds are formed by atoms of different elements (CuO, H 2 O).

4. Chemical phenomena or reactions are processes in which some substances are transformed into others in structure and properties without changing the composition of the nuclei of atoms.

5. The mass of substances entering into a reaction is equal to the mass of substances formed as a result of the reaction (law of conservation of mass).

6. Any pure substance, regardless of the method of preparation, always has a constant qualitative and quantitative composition (the law of constancy of composition).

The main task chemistry– obtaining substances with predetermined properties and identifying ways to control the properties of the substance.