What is the difference between physics and chemistry. Physics and chemistry - what is the difference between these sciences? History of physical chemistry[

... to get worn out general theme words "physics" and "chemistry".

Isn't it surprising that both words are related to bodybuilding? "Physics" is muscles, "chemistry" - well, there is no need to explain it.

In general, the science of chemistry is, in principle, the same physics: about the phenomena occurring in nature. When Galileo threw balls from the Leaning Tower of Pisa, and Newton created his own laws, it was on a scale commensurate with man - this was and is physics. Ordinary physics deals with objects that are made up of substances. Chemistry (alchemy) was and is engaged in the transformation of substances into each other - this molecular level. It turns out that the difference between physics and chemistry is in the scale of objects? Nothing! Here the quantum physics deals with what atoms are made of - this is the submolecular level. Quantum physics deals with the objects inside the atom, which gives power over atomic energy and puts philosophical questions. It turns out that chemistry is a narrow strip on the scale of physical scales, although it is clearly delimited by the level of the atomic-molecular structure of a substance.

I think that the bad flat (linear) infinity* does not apply to the surrounding world. Everything is looped or closed in a sphere. The universe is spherical. If we dig further into the structure of elementary particles (quarks and Higgs bosons), then sooner or later the found particles will close with the maximum scale - with the Universe, that is, sooner or later we will see our Universe from a bird's eye view in a microscope.

Now let's see if scale ranges apply to bodybuilding. It looks like yes. “Physics” (training with iron and on simulators) deals with iron objects and muscles as solid objects: a scale commensurate with a person. "Chemistry" (like steroids) is, of course, a molecular level. It remains to figure out what “quantum physics” is in bodybuilding? Apparently, this is motivation, concentration, willpower, and so on - that is, the psyche. And the psyche is based not on a molecular basis, but on certain electric fields and states - their scale is below the atomic scale. So about (t) enough bodybuilding all scale ...

We read the article by Ph.D. Elena Gorokhovskaya(“Novaya Gazeta”, No. 55, May 24, 2013, p. 12 or on the Postnauka website) on the basics of biosemiotics:

What is living? (…) The main “watershed” runs between reductionist** and anti-reductionist approaches. Reductionists argue that life in all its specifics can be explained in terms of physical and chemical processes. Anti-reductionist approaches argue that everything cannot be reduced to physics and chemistry. The most difficult thing is to understand the integrity and expedient structure of a living organism, where everything is interconnected and everything is aimed at supporting its vital activity, reproduction and development. During individual development, and in general, something changes in the body every moment, while the regular course of these changes is ensured. It is often said that living organisms should be called not objects, but processes.
… In the 20th century, cybernetics became important for understanding the specifics of living things, since it rehabilitated the concept of purpose in biology. In addition, cybernetics has made very popular the idea of living organisms as information systems. Thus, in the science of the living, humanitarian ideas were actually introduced that were not directly related to the material organization.
In the 1960s, a new direction arose in understanding the specifics of the living and in the study biological systems- biosemiotics, which considers life and living organisms as sign processes and relationships. We can say that living organisms do not live in the world of things, but in the world of meanings.
...Molecular genetics has been formed to a large extent due to the inclusion in its conceptual scheme of such concepts as "genetic information" and "genetic code". Talking about opening genetic code, the famous biologist Martynas Ichas wrote: “The most difficult thing about the “problem of the code” was to understand that the code exists. It took a whole century."
Although the biosynthesis of proteins is carried out in the cell with the help of many chemical reactions, there is no direct chemical relationship between the structure of proteins and the structure of nucleic acids. This connection is inherently not chemical, but informational, semiotic in nature. The nucleotide sequences in the nucleic acids of DNA and RNA are information about the structure of proteins (about the amino acid sequences in them) only because there is a “reader” (aka “writer”) in the cell - in this case a complex system protein biosynthesis, which owns the "genetic language". (…) Thus, even at the very fundamental level the living turns out to be communication, text and "speech". Reading, writing, rewriting, creation of new texts and constant “conversation” in the language of the genetic code of macromolecules and their interactions are constantly taking place in each cell and in the body as a whole.

* * *

Let's replace a few words in the phrases from the first and last paragraphs:

Retrogrades argue that bodybuilding in all its specifics can be reduced to physical training and chemical exposure. The progressive approach asserts that one cannot reduce everything to "physics" and "chemistry". Although muscle mass growth is carried out through a variety of physical exercises and chemical (at least nutritional) influences, there is no direct relationship between muscle growth and the amount of exercise and the amount of "chemistry" does not exist. This connection is inherently not physical or chemical, but informational, semiotic in nature. Thus, even at the most fundamental level bodybuilding turns out to be communication, text and "speech"(this, of course, is not about vulgar chatter between approaches). Therefore, it can be said that bodybuilders should not be called objects, but informational processes.

Who would argue that you can’t build a muscle foolishly. You need a properly constructed and executed training, you need proper nutrition, that is, information is required. And if we foolishly stuff ourselves with chemistry, we will get an ambiguous result, if we get it at all. We need a properly constructed and executed course, that is, again, information is required. The most difficult thing about the problem of such information is to understand that it actually exists. And realizing this, one must learn to isolate it from that muddy pseudo-informational ocean that rolls on the shore of our brain in heavy waves, occasionally throwing pearl shells out of its depths.

True, to open the shells you need an oyster knife ...

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* bad infinity- a metaphysical understanding of the infinity of the world, involving the assumption of a monotonous, endlessly repeating alternation of the same specific properties, processes and laws of motion on any scale of space and time, without any limit. As applied to the structure of matter, it means the assumption of unlimited divisibility of matter, in which each smaller particle has the same properties and obeys the same specific laws of motion as macroscopic bodies. The term was introduced by Hegel, who, however, considered true infinity to be a property of the absolute spirit, but not of matter.
** reductionist approach- from the Latin reductio - return, restoration; in this case, the reduction of the phenomena of life to something else.

History of physical chemistry

M.V. Lomonosov, which in 1752

N.N. Beketov 1865

And Nernst.

M. S. VREVSKII

Molecules, ions, free radicals.

Atoms of elements can form three types of particles involved in chemical processes - molecules, ions and free radicals.

molecule called the smallest neutral particle of a substance that has its chemical properties and is capable of independent existence. There are monatomic and polyatomic molecules (two-, three-atomic, etc.). Under normal conditions, noble gases are composed of monatomic molecules; molecules of macromolecular compounds, on the contrary, contain many thousands of atoms.

And he- a charged particle, which is an atom or a group of chemically bonded atoms with an excess of electrons (anions) or a lack of them (cations). In matter, positive ions always exist together with negative ones. Since the electrostatic forces acting between the ions are large, it is impossible to create any significant excess of ions of the same sign in the substance.

free radical a particle is called that has unsaturated valences, i.e., a particle with unpaired electrons. Such particles are, for example ·CH 3 and ·NH 2 . Under normal conditions, free radicals, as a rule, cannot exist for a long time, since they are extremely reactive and easily react, forming inert particles. So, two methyl radicals CH3 are combined into a C 2 H 6 (ethane) molecule. The course of many reactions is impossible without the participation of free radicals. At very high temperatures (for example, in the atmosphere of the Sun), the only diatomic particles that can exist are free radicals (·CN, ·OH, ·CH and some others). Many free radicals are present in the flame.

Free radicals are known complex structure, which are relatively stable and can exist under normal conditions, for example, the triphenylmethyl radical (C 6 H 5) 3 C ⋅ (the study of free radicals began with its discovery). One of the reasons for its stability are spatial factors - the large size of the phenyl groups, which prevent the combination of radicals into a hexaphenylethane molecule.

covalent bond.

Each chemical bond in structural formulas is represented valence line , For example:

H−H (bond between two hydrogen atoms)

H 3 N−H + (bond between the nitrogen atom of the ammonia molecule and the hydrogen cation)

(K +) - (I -) (bond between potassium cation and iodide ion).

A chemical bond is formed by attraction of atomic nuclei to a pair of electrons(indicated by dots ), which in the electronic formulas of complex particles (molecules, complex ions) is represented by valence line−, unlike their own, lone pairs of electrons each atom, for example:

:::F−F:::

(F2);

H−Cl:::

(HCl);

.. H−N−H | H

(NH3)

The chemical bond is called covalent if it is formed by socialization of a pair of electrons both atoms.

Polarity of molecules

Molecules that are formed by atoms of the same element tend to be non-polar , as the bonds themselves are non-polar. So, the molecules H 2, F 2, N 2 are non-polar.

Molecules that are formed by atoms of different elements can be polar and non-polar . It depends on the geometric shape .
If the shape is symmetrical, then the molecule non-polar(BF 3, CH 4, CO 2, SO 3), if asymmetric (due to the presence of lone pairs or unpaired electrons), then the molecule polar(NH 3, H 2 O, SO 2, NO 2).

When replacing one of the side atoms in a symmetric molecule with an atom of another element, the geometric shape is also distorted and polarity appears, for example, in the chlorine derivatives of methane CH 3 Cl, CH 2 Cl 2 and CHCl 3 (methane CH 4 molecules are nonpolar).

Polarity asymmetric in shape of a molecule follows from polarity covalent bonds between the atoms of the elements with different electronegativity .
As noted above, there is a partial shift of the electron density along the bond axis to an atom of a more electronegative element, for example:

H δ+ → Cl δ−	B δ+ → F δ−
C δ− ← H δ+	N δ− ← H δ+

(here δ is a partial electric charge on atoms).

The more electronegativity difference elements, the higher the absolute value of the charge δ and the more polar there will be a covalent bond.

In molecules that are symmetrical in shape (for example, BF 3), the "centers of gravity" of the negative (δ−) and positive (δ+) charges coincide, and in asymmetric molecules (for example, NH 3) they do not coincide.
As a result, in asymmetric molecules, electric dipole - Opposite charges separated by some distance in space, for example, in a water molecule.

Hydrogen bond.

In the study of many substances, the so-called hydrogen bonds . For example, HF molecules in liquid hydrogen fluoride are interconnected by a hydrogen bond, H 2 O molecules in liquid water or in an ice crystal, as well as NH 3 and H 2 O molecules are similarly connected to each other in an intermolecular compound - ammonia hydrate NH 3 H 2 O.

Hydrogen bonds unstable and are destroyed quite easily (for example, when ice melts, water boils). However, some additional energy is expended on breaking these bonds, and therefore the melting and boiling points of substances with hydrogen bonds between molecules turn out to be much higher than those of similar substances, but without hydrogen bonds:

Valence. Donor-acceptor bonds. According to the theory molecular structure, atoms can form as many covalent bonds as they have orbitals occupied by one electron, but this is not always the case. [In the accepted AO filling scheme, first indicate the shell number, then the type of orbital, and then, if there is more than one electron in the orbital, their number (superscript). So, record (2 s) 2 means that on s-orbitals of the second shell are two electrons.] A carbon atom in the ground state (3 R) has an electronic configuration (1 s) 2 (2s) 2 (2p x)(2 p y), while two orbitals are not filled, i.e. contain one electron. However, divalent carbon compounds are very rare and have high chemical activity. Usually carbon is tetravalent, and this is due to the fact that for its transition to an excited 5 S-state (1 s) 2 (2s) (2p x)(2 p y)(2 p z) with four empty orbitals, very little energy is needed. Energy costs associated with transition 2 s-electron to free 2 R-orbital, are more than offset by the energy released during the formation of two additional bonds. For the formation of unfilled AO, it is necessary that this process be energetically favorable. Nitrogen atom with electronic configuration (1 s) 2 (2s) 2 (2p x)(2 p y)(2 p z) does not form pentavalent compounds, since the energy required for translation 2 s-electron by 3 d-orbital with the formation of a pentavalent configuration (1 s) 2 (2s)(2p x)(2 p y)(2 p z)(3 d) is too large. Similarly, boron atoms with the usual configuration (1 s) 2 (2s) 2 (2p) can form trivalent compounds while in an excited state (1 s) 2 (2s)(2p x)(2 p y) that occurs at the transition 2 s-electron by 2 R-AO, but does not form pentavalent compounds, since the transition to an excited state (1 s)(2s)(2p x)(2 p y)(2 p z) due to the translation of one of the 1 s-electrons to a higher level, requires too much energy. The interaction of atoms with the formation of a bond between them occurs only in the presence of orbitals with close energies, i.e. orbitals with the same principal quantum number. The relevant data for the first 10 elements of the periodic table are summarized below. The valence state of an atom is understood as the state in which it forms chemical bonds, for example, state 5 S for tetravalent carbon.

VALENCE STATES AND VALENCES OF THE FIRST TEN ELEMENTS OF THE PERIODIC TABLE
Element	Basic state	Normal valence state	Usual valence
H	(1s)	(1s)
He	(1s) 2	(1s) 2
Li	(1s) 2 (2s)	(1s) 2 (2s)
Be	(1s) 2 (2s) 2	(1s) 2 (2s)(2p)
B	(1s) 2 (2s) 2 (2p)	(1s) 2 (2s)(2p x)(2 p y)
C	(1s) 2 (2s) 2 (2p x)(2 p y)	(1s) 2 (2s)(2p x)(2 p y)(2 p z)
N	(1s) 2 (2s) 2 (2p x)(2 p y)(2 p z)	(1s) 2 (2s) 2 (2p x)(2 p y)(2 p z)
O	(1s) 2 (2s) 2 (2p x) 2 (2 p y)(2 p z)	(1s) 2 (2s) 2 (2p x) 2 (2 p y)(2 p z)
F	(1s) 2 (2s) 2 (2p x) 2 (2 p y) 2 (2 p z)	(1s) 2 (2s) 2 (2p x) 2 (2 p y) 2 (2 p z)
Ne	(1s) 2 (2s) 2 (2p x) 2 (2 p y) 2 (2 p z) 2	(1s) 2 (2s) 2 (2p x) 2 (2 p y) 2 (2 p z) 2

These patterns are shown in the following examples:

History of physical chemistry

The beginning of physical chemistry was laid in the middle of the 18th century. The term "Physical Chemistry" belongs to M.V. Lomonosov, which in 1752 In 1992, he first read to the students of St. Petersburg University the "Course of True Physical Chemistry". In this course, he himself gave this definition of this science: "Physical chemistry is a science that must, on the basis of the provisions and experiments of physical scientists, explain the reason for what happens through chemical operations in complex bodies."

This was followed by a break of more than a hundred years, and the next course in physical chemistry was read by Academician N.N. Beketov at Kharkiv University in 1865 year. Following N.N. Beketov began teaching physical chemistry at other universities in Russia. Flavitsky (Kazan, 1874), V. Ostwald (University in Tartu, 18807), I.A. Kablukov (Moscow University, 1886).

Recognition of physical chemistry as an independent science and academic discipline, expressed at the University of Leipzig (Germany) in 1887. The first department of physical chemistry, headed by W. Ostwald and at the base of the first scientific journal in physical chemistry. At the end of the 19th century, the University of Leipzig was the center for the development of physical chemistry, and the leading physical chemists were: W. Ostwald, J. van't Hoff, Arrhenius and Nernst.

The first in Russia Department of Physical Chemistry was opened in 1914 at the Faculty of Physics and Mathematics of St. practical training in physical chemistry M. S. VREVSKII

The difference between physical chemistry and chemical physics

Both of these sciences are at the interface between chemistry and physics, sometimes chemical physics is included in physical chemistry. It is not always possible to draw a clear line between these sciences. However, with a reasonable degree of accuracy, this difference can be determined as follows:

physical chemistry considers in total the processes occurring with the simultaneous participation sets particles;

chemical physics considers individual particles and the interaction between them, that is, specific atoms and molecules (thus, there is no place in it for the concept of " ideal gas which is widely used in physical chemistry).

Lecture 2 The structure of molecules and the nature of the chemical bond. Types of chemical bonds. The concept of the electronegativity of an element. Polarization. dipole moment. Atomic energy of the formation of molecules. Methods pilot study molecular structures.

The structure of the molecules(molecular structure), mutual arrangement atoms in molecules. In the course of chemical reactions, the atoms in the molecules of the reactants are rearranged and new compounds are formed. Therefore, one of the fundamental chemical problems is to elucidate the arrangement of atoms in the initial compounds and the nature of the changes during the formation of other compounds from them.

The first ideas about the structure of molecules were based on the analysis of the chemical behavior of matter. These ideas have become more complex as knowledge about chemical properties substances. The application of the basic laws of chemistry made it possible to determine the number and type of atoms that make up the molecule of a given compound; this information is contained in the chemical formula. Over time, chemists realized that one chemical formula is not enough to accurately characterize a molecule, since there are isomer molecules that have the same chemical formulas, but different properties. This fact led scientists to the idea that the atoms in a molecule must have a certain topology, stabilized by the bonds between them. This idea was first expressed in 1858 by the German chemist F. Kekule. According to his ideas, a molecule can be depicted using a structural formula, which indicates not only the atoms themselves, but also the bonds between them. Interatomic bonds must also correspond spatial arrangement atoms. The stages in the development of ideas about the structure of the methane molecule are shown in Figs. 1. Structure meets modern data G : the molecule has the shape of a regular tetrahedron, in the center of which is a carbon atom, and at the vertices are hydrogen atoms.

Such studies, however, did not say anything about the size of the molecules. This information became available only with the development of relevant physical methods. The most important of these was X-ray diffraction. From the patterns of X-ray scattering on crystals, it became possible to determine the exact position of atoms in a crystal, and for molecular crystals, it was possible to localize atoms in a single molecule. Other methods include the diffraction of electrons as they pass through gases or vapors and the analysis of the rotational spectra of molecules.

All this information is only general idea about the structure of the molecule. The nature of chemical bonds can be explored by modern quantum theory. And although it has not yet been possible to calculate the molecular structure with a sufficiently high accuracy, all known data on chemical bonds can be explained. The existence of new types of chemical bonds has even been predicted.

Often, from many people who discuss a particular process, you can hear the words: "This is physics!" or "It's chemistry!" Indeed, almost all phenomena in nature, in everyday life and in space, which a person encounters during his life, can be attributed to one of these sciences. It's interesting to figure out what physical phenomena different from chemicals.

science physics

Before answering the question of how physical phenomena differ from chemical ones, it is necessary to understand what objects and processes each of these sciences investigates. Let's start with physics.

science chemistry

Unlike physics, chemistry is a science that studies the structure, composition and properties of matter, as well as its change as a result of chemical reactions. That is, the object of study of chemistry is the chemical composition and its change during a certain process.

Chemistry, like physics, has many sections, each of which studies a certain class chemical substances, for example, organic and inorganic, bio- and electrochemistry. Research in medicine, biology, geology and even astronomy is based on the achievements of this science.

It is interesting to note that chemistry, as a science, was not recognized by ancient Greek philosophers because of its focus on experiment, as well as because of the pseudoscientific knowledge that surrounded it (recall that modern chemistry was "born" from alchemy). Only since the Renaissance, and largely thanks to the work of the English chemist, physicist and philosopher Robert Boyle, chemistry began to be perceived as a full-fledged science.

Examples of physical phenomena

There are a huge number of examples that obey physical laws. For example, every student knows already in the 5th grade a physical phenomenon - the movement of a car along the road. At the same time, it does not matter what this car consists of, where it takes energy from to move, the only important thing is that it moves in space (along the road) along a certain trajectory at a certain speed. Moreover, the processes of acceleration and deceleration of the car are also physical. Vehicle traffic and other solids deals with the section of physics "Mechanics".

I. ... AND IN GENERAL II. ABOUT SCIENCE III. ABOUT CHEMISTRY Is chemistry bad? Is medicine the mother of chemistry? world without analytical chemistry. Apocalypse? How many crimes will not be revealed without forensic chemistry? Where will we go without agrochemistry? Will astrochemistry reveal the secret of life? Why do we need biochemistry? What's in halurgy from chemistry? Is geochemistry the basis of raw materials "drug addiction"? Will hydrochemistry give us new "gold"? Why are the tissues of ... a person stained? Histochemistry and cytochemistry. Cancer, AIDS, flu... What science is really against? Immunochemistry Is it possible to calculate chemistry? quantum chemistry. How does jelly look like a person? colloidal chemistry. When does Catholicism recognize divorce? About cosmetic chemistry. Why do earthlings need cosmochemistry? Is the modern information field possible without crystal chemistry? How does Santa Claus help chemists and doctors? Cryochemistry and cryotherapy. Laser chemistry - what is it eaten with? Is it possible to fight without a forest? Forest chemistry. Is life possible inside a magnet? Magnetochemistry. What is the relationship between medicinal chemistry and pathochemistry? What in metallurgy from chemistry? Why do we need mechanochemistry? Where do we encounter microwave chemistry? Nanochemistry - the dimensional limit of chemistry? Who is leading us? Neurochemistry. Not organic chemistry: old or new science? Sell oil or products of its processing? Petrochemistry. You, me, he, she - together ... organic chemistry? Perhaps we will synthesize the soul someday? organic synthesis. Is a long life of a free particle possible in non-free matter? Physical organic chemistry. What is "pegnochemistry"? What is common between a disciple of Christ and petrochemistry? Will we return to the stone age? Petrurgia. Will we return to the stone age? Petrurgia. How often do we chemise in the kitchen? Food chemistry. Plasma chemistry for people or for God? Applied chemistry for war or peace? What color is the electronic? Radiation chemistry. Who discovered the phenomenon of radioactivity? How dangerous is radioactivity? Does dark energy exist? Radiochemistry. What is stereochemistry? Which is better a flood or a methane catastrophe? supramolecular chemistry. What D.I. Mendeleev in his doctoral thesis? Thermochemistry. Technical chemistry - is isolation justified? Topochemistry is surface chemistry? Maybe you shouldn't burn coal? Coal chemistry. What are we treating? Pharmacochemistry. Femtochemistry - is it something new? Is a blow to the head a criminal act or ... physical chemistry? Who were the first phytochemists? Where does oxygen come from on Earth and what is the nature of vision? Photochemistry. How is high energy chemistry different from conventional chemistry? Is it possible to live without acceleration? Chemical kinetics and catalysis. How is chemical physics different from physical chemistry? What is the scarecrow of the layman? Chemical Technology. What is the role of chemistry in wars? Chemical weapons. What are shopping bags, tires, and heredity agents made of? Chemistry of macromolecular compounds. Is it possible to synthesize tea? Chemistry of natural compounds. Why do we need silicate chemistry? How does solid state chemistry answer the question: Is hetero-normal? What is organoelement chemistry? Electrochemistry, why do we need it? What pushes the boundaries Periodic system? Nuclear chemistry. How to get to "chemistry" without a university? Which chemical element named after Russia? On the name of chemical elements.

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How is chemical physics different from physical chemistry?

Chemical physics studies the electronic structure of molecules and solids, molecular spectra, elementary acts of chemical reactions, combustion and explosion processes, that is, the physical aspects of chemical phenomena. The term was introduced by the German chemist A. Eiken in 1930.

Formed in the 1920s. in connection with the development quantum mechanics and the use of its representations in chemistry. The boundary between chemical physics and physical chemistry is conditional. Thing physical chemistry on the contrary: the chemical result of a physical impact (for example, the death of a person as a result of hitting him on the head with a brick). One of the achievements of chemical physics should be considered the theory branched chain reactions.

Founder of the Institute of Chemical Physics of the Russian Academy of Sciences N.N. Semenov conducted in-depth research chain reactions. They are a series of self-initiating steps in a chemical reaction that, once started, continues until the last step is completed. Despite the fact that the German chemist M. Bodenstein first suggested the possibility of such reactions back in 1913, there was no theory explaining the stages of a chain reaction and showing its speed. The key to the chain reaction is the initial stage of formation free radical- an atom or group of atoms that has an unpaired electron and, as a result, is extremely chemically active. Once formed, it interacts with the molecule in such a way that a new free radical is formed as one of the reaction products. The newly formed free radical can then interact with another molecule, and the reaction continues until something stops the free radicals from forming their own kind, i.e. until the circuit breaks.

A particularly important chain reaction is the branched chain reaction, discovered in 1923 by physicists G.A. Kramers and I.A. Christiansen. In this reaction, free radicals not only create active centers, but also multiply, creating new chains and speeding up the reaction. The actual course of the reaction depends on a number of external constraints, such as the size of the vessel in which it occurs. If the number of free radicals grows rapidly, then the reaction can lead to an explosion. In 1926 two students N.N. Semenov observed this phenomenon for the first time, studying the oxidation of phosphorus vapor with water vapor. This reaction did not proceed as it should have proceeded according to the laws of chemical kinetics of the time. Semenov saw the reason for this discrepancy in the fact that they were dealing with the result of a branched chain reaction. But such an explanation was rejected by M. Bodenstein, at that time a recognized authority on chemical kinetics. N.N. continued intensive study of this phenomenon for another two years. Semenov and S.N. Hinshelwood, who carried out his research in England independently, and after this period it became obvious that Semyonov was right.

N.N. Semenov published a monograph (Chain reactions. L., ONTI., 1934), in which he proved that many chemical reactions, including the polymerization reaction, are carried out using the mechanism of a chain or branched chain reaction. Later it was found that the fission reaction of uranium-235 nuclei by neutrons also has the character of a branched chain reaction.

In 1956, Semenov, together with Hinshelwood, was awarded Nobel Prize in Chemistry "for research into the mechanism of chemical reactions." In the Nobel lecture, Semenov stated: “The theory of a chain reaction opens up the possibility of approaching closer to the solution of the main problem of theoretical chemistry - the relationship between the reactivity and structure of the particles that enter into the reaction ... It is hardly possible to enrich chemical technology to any extent or even achieve a decisive success in biology without this knowledge…”.

The Institute of Chemical Physics of the Russian Academy of Sciences (Moscow), the Institute of Problems of Chemical Physics of the Russian Academy of Sciences (Chernogolovka) work. There is a journal "Chemical Physics". You can read: Buchachenko A.L. Modern chemical physics: Goals and ways of progress // Uspekhi khimii. - 1987. - T. 56. - No. 11.

Physics and chemistry are sciences that directly contribute to technological progress in the 21st century. Both disciplines study the laws of the functioning of the surrounding world, changes in the smallest particles of which it consists. All natural phenomena have a chemical or physical basis, this applies to everything: glow, burning, boiling, melting, any interaction of something with something.
Everyone at school studied the basics of chemistry and physics, biology and natural science, but not everyone connected their lives with these sciences, not everyone can determine the line between them now.

In order to understand what the main differences between physical science and chemical science are, you must first of all take a closer look at them and get acquainted with the main provisions of these disciplines.

About physics: movement and its laws

Physics deals direct study common properties the world around, simple and complex forms of motion of matter, natural phenomena that underlie all of these processes. Science explores the qualities of various material objects and manifestations of interactions between them. Also under the gun of physicists are general patterns for different types matter; these unifying principles are called physical laws.

Physics is in many ways a fundamental discipline because it considers material systems at different scales most widely. She is very close to everyone. natural sciences, the laws of physics determine both biological and geological phenomena to the same extent. There is a strong connection with mathematics, since all physical theories are formulated in the form of numbers and mathematical expressions. Roughly speaking, the discipline widely studies absolutely all phenomena of the surrounding world and the laws of their course, based on the laws of physics.

Chemistry: what does everything consist of?

Chemistry is primarily concerned with the study of properties and substances in conjunction with their various changes. chemical reactions are the results of mixing pure substances and creating new elements.

Science closely interacts with other natural disciplines such as biology, astronomy. Chemistry studies the internal composition of different types of matter, aspects of the interaction and transformation of the constituents of matter. Chemistry also uses its own laws and theories, regularities, scientific hypotheses.

What are the main differences between physics and chemistry?

Belonging to natural science unites these sciences in many ways, but there is much more difference between them than common:

The main difference between the two natural sciences is that physics studies elementary particles(microworld, this includes the atomic and nucleon levels) and different properties of substances that are in a certain state of aggregation. Chemistry, on the other hand, is engaged in the study of the very processes of “assembling” molecules from atoms, the ability of a substance to enter into certain reactions with a substance of another kind.
Like biology and astronomy, modern physics allows for many non-rational concepts in its methodological tools, mainly theories of the origin of life on Earth, the origin of the Universe, connection with philosophy in considering the concepts of the primary cause of "ideal" and "material". Chemistry, however, remained much closer to rational foundations exact sciences, moving away from both ancient alchemy and philosophy in general.
The chemical composition of bodies in physical phenomena remains unchanged, as well as their properties. Chemical phenomena provide for the transformation of a substance into another with the appearance of its new properties; this is the difference between the subjects studied by these disciplines.
A wide class of phenomena described by physics. Chemistry is much more highly specialized discipline, it focuses on the study of only the microcosm (molecular level), in contrast to physics (macrocosm and microcosm).
Physics deals with the study of material objects with their qualities and properties, while chemistry works with the composition of these objects, the smallest particles of which they are composed and which interact with each other.