SUBSTANCE
SUBSTANCE
type of matter, which, unlike physical. field, has a rest mass. Ultimately, the universe is made up of elementary particles whose rest is not zero. (mainly from electrons, protons, neutrons). In classic physics V. and physical. zero were absolutely opposed to each other as two types of matter, the first of which is discrete, and the second is continuous. Quantum, which introduced the idea of dualities. The particle-wave nature of any micro-object led to the leveling of this opposition. The discovery of the close relationship between energy and field led to a deepening of ideas about the structure of matter. On this basis, V. and matter were strictly delimited throughout pl. centuries identified with both philosophy and science, and Philosopher the meaning remained with the category of matter, and V. retained the scientific one in physics and chemistry. Under terrestrial conditions, energy is found in four states: gases, liquids, solids, and plasma. It is stated that V. can also exist in a special, super-dense (e.g. in neutron) condition.
Vavilov S.I., Development of the idea of matter, Collection. Op., T. 3, M., 1956, With.-41-62; Structure and forms of matter. [Sat. Art.], M., 1967.
I. S. Alekseev.
Philosophical encyclopedic dictionary. - M.: Soviet Encyclopedia. Ch. editor: L. F. Ilyichev, P. N. Fedoseev, S. M. Kovalev, V. G. Panov. 1983 .
SUBSTANCE
its meaning is close to the concept matter, but not completely equivalent to it. While the word “” is predominantly associated with ideas about rough, inert, dead reality, in which exclusively mechanical laws dominate, substance is a “material” that, thanks to the receipt of form, evokes design, vitality, and ennoblement. Cm. Gestalt weaving.
Philosophical Encyclopedic Dictionary. 2010 .
SUBSTANCE
one of the basic forms of matter. V. includes macroscopic. bodies in all states of aggregation (gases, liquids, crystals, etc.) and the particles that form them, which have their own mass (“rest mass”). There are many types of V particles known: “elementary” particles (electrons, protons, neutrons, mesons, positrons, etc.), atomic nuclei, atoms, molecules, ions, free radicals, colloidal particles, macromolecules, etc. (see . Elementary particles of matter).
Lit.: Engels F., Dialectics of Nature, M., 1955; his, Anti-Dühring, M., 1957; Lenin V.I., Materialism and empirio-criticism, Works, 4th ed., vol. 14; Vavilov S.I., Development of the idea of matter, Collection. soch., vol. 3, M., 1956; his, Lenin and modern, ibid.; him, Lenin and the philosophical problems of modern physics, ibid.; Goldansky V., Leikin E., Transformations of atomic nuclei, M., 1958; Kondratiev V.N., Structure and chemical properties of molecules, M., 1953; "Advances in Physical Sciences", 1952, v. 48, no. 2 (dedicated to the problem of mass and energy); Ovchinnikov N.F., Concepts of mass and energy..., M., 1957; Kedrov B. M., Evolution of the concept of an element in chemistry, M., 1956; Novozhilov Yu. V., Elementary particles, M., 1959.
Philosophical Encyclopedia. In 5 volumes - M.: Soviet Encyclopedia. Edited by F. V. Konstantinov. 1960-1970 .
Synonyms:
The concept of matter is studied by several sciences at once. We will analyze the question of what substances are from two points of view - from the position of chemical science and from the position of physics.
Substance in chemistry and physics
Chemists understand matter as a physical substance with a certain set of chemical elements. In modern physics, matter is considered as a type of matter that consists of fermions or a type of matter that contains fermions, bosons, and has a rest mass. As usual, matter should consist of particles, mostly electrons, protons and neutrons. Protons and neutrons form atomic nuclei, and together these elements form atoms (atomic matter).
Properties of matter
Almost each substance has its own unique set of properties. Properties are understood as characteristics that indicate the individuality of a substance, which in turn demonstrates its differences from all other substances. Characteristic physical and chemical properties are constants - density, various types of temperatures, thermodynamics, indicators of crystal structure.
Chemical classification of substances
In chemistry, substances are divided into compounds and their mixtures. In addition, it should be said that organic substances. A compound is a set of atoms that are connected to each other, taking into account certain patterns. It should be noted that the boundary between a compound and a mixture of substances is quite difficult to clearly define. This is due to the fact that science knows substances of variable composition. It is impossible to create an exact formula for them. In addition, a compound is largely an abstraction, since in a practical sense only the final purity of the substance being studied can be achieved. Any sample that exists in real life is a mixture of substances, but with a predominance of one substance from the entire group. In addition, it should be said what organic substances are. This group of complex substances contains carbon (proteins, carbohydrates).
Simple and complex substances
Simple substances (O2, O3, H2, Cl2) are those substances that consist only of atoms of one chemical element. These substances are a form of existence of elements in free form. In other words, these chemical elements, which are not combined with other elements, form simple substances. Science knows more than 400 varieties of such substances. Simple substances are classified according to the type of bond between atoms. Thus, simple substances are divided into metals (Na, Mg, Al, Bi, etc.) and non-metals (H 2, N 2, Br 2, Si, etc.).
Complex substances are chemical compounds that consist of atoms of two or more elements bound together. Simple substances also have the right to be called chemical compounds if their molecules consist of atoms connected by a covalent bond (nitrogen, oxygen, bromine, fluorine). But it would be a mistake to call inert (noble) gases and atomic hydrogen chemical compounds.
Physical classification of substances
From the point of view of physics, substances exist in several states of aggregation - body, liquid and gas. What solid substances, for example, are visible to the naked eye. The same can be said about another state of aggregation. We know from school what liquid substances exist in nature. It is noteworthy that a substance such as water can exist in three states at once - as ice, liquid water and steam. The three aggregate states of a substance are not considered individual characteristics of substances, but correspond to different ones, depending on the external conditions of existence of substances. In the transition from states of aggregate states to real states of a chemical substance, a number of intermediate types can be identified, which in science are called amorphous or glassy states, as well as liquid crystal states and polymer states. In this regard, scientists often use the concept of “phase”.
Among others, physics also considers the fourth state of aggregation of a chemical substance. This is a plasma, that is, a state that is completely or partially ionized, and the density of positive and negative charges in this state is the same, in other words, the plasma is electrically neutral. In general, there are many substances in nature, but now you know what substances there are, and this is much more important.
All chemical substances can be divided into two types: pure substances and mixtures (Fig. 4.3).
Pure substances have a constant composition and well-defined chemical and physical properties. They are always homogeneous (uniform) in composition (see below). Pure substances, in turn, are divided into simple substances (free elements) and compounds.
A simple substance (free element) is a pure substance that cannot be divided into simpler pure substances. Elements are usually divided into metals and non-metals (see Chapter 11).
A compound is a pure substance consisting of two or more elements related to each other in constant and definite relationships. For example, the compound carbon dioxide (CO2) consists of two elements - carbon and oxygen. Carbon dioxide invariably contains 27.37% carbon and 72.73% oxygen by mass. This statement applies equally to carbon dioxide samples obtained at the North Pole, South Pole, Sahara Desert or on the Moon. Thus, in carbon dioxide, carbon and oxygen are always combined in a constant and strictly defined ratio.
Rice. 4.3. Classification of chemicals
Mixtures are substances consisting of two or more pure substances. They have a random composition. In some cases, mixtures consist of one phase and are then called homogeneous (homogeneous). An example of a homogeneous mixture is solutions. In other cases, mixtures consist of two or more phases. Then they are called heterogeneous (heterogeneous). An example of heterogeneous mixtures is soil.
Particle types. All chemical substances - simple substances (elements), compounds or mixtures - consist of particles of one of three types, which we have already become acquainted with in previous chapters. These particles are:
- atoms (an atom is made up of electrons, neutrons and protons, see Chapter 1; the atom of each element is characterized by a certain number of protons in its nucleus, and this number is called the atomic number of the corresponding element);
- molecules (a molecule consists of two or more atoms connected to each other in an integer ratio);
- ions (an ion is an electrically charged atom or group of atoms; the charge of an ion is due to the gain or loss of electrons).
Elementary chemical particles. An elementary chemical particle is any chemically or isotopically individual atom, molecule, ion, radical, complex, etc., identifiable as a separate species unit. A collection of identical elementary chemical particles forms a chemical species. Chemical names, formulas and reaction equations can refer, depending on the context, to either elementary particles or chemical species*. The concept of a chemical substance introduced above refers to a chemical species that can be obtained in sufficient quantities to allow detection of its chemical properties.
Man has always sought to find materials that leave no chance for his competitors. Since ancient times, scientists have been looking for the hardest materials in the world, the lightest and the heaviest. The thirst for discovery led to the discovery of an ideal gas and an ideal black body. We present to you the most amazing substances in the world.
1. The blackest substance
The blackest substance in the world is called Vantablack and consists of a collection of carbon nanotubes (see carbon and its allotropes). Simply put, the material consists of countless “hairs”, once caught in them, the light bounces from one tube to another. In this way, about 99.965% of the light flux is absorbed and only a tiny fraction is reflected back out.
The discovery of Vantablack opens up broad prospects for the use of this material in astronomy, electronics and optics.
2. The most flammable substance
Chlorine trifluoride is the most flammable substance ever known to mankind. It is a strong oxidizing agent and reacts with almost all chemical elements. Chlorine trifluoride can burn concrete and easily ignite glass! The use of chlorine trifluoride is practically impossible due to its phenomenal flammability and the impossibility of ensuring safe use.
3. The most poisonous substance
The most powerful poison is botulinum toxin. We know it under the name Botox, which is what it is called in cosmetology, where it has found its main application. Botulinum toxin is a chemical produced by the bacteria Clostridium botulinum. In addition to the fact that botulinum toxin is the most toxic substance, it also has the largest molecular weight among proteins. The phenomenal toxicity of the substance is evidenced by the fact that only 0.00002 mg min/l of botulinum toxin is enough to make the affected area deadly to humans for half a day.
4. The hottest substance
This is the so-called quark-gluon plasma. The substance was created by colliding gold atoms at near light speed. Quark-gluon plasma has a temperature of 4 trillion degrees Celsius. For comparison, this figure is 250,000 times higher than the temperature of the Sun! Unfortunately, the lifetime of matter is limited to a trillionth of one trillionth of a second.
5. The most caustic acid
In this nomination, the champion is fluoride-antimony acid H. Fluoride-antimony acid is 2×10 16 (two hundred quintillion) times more caustic than sulfuric acid. It is a very active substance and can explode if a small amount of water is added. The fumes of this acid are deadly poisonous.
6. The most explosive substance
The most explosive substance is heptanitrocubane. It is very expensive and is used only for scientific research. But the slightly less explosive octogen is successfully used in military affairs and in geology when drilling wells.
7. The most radioactive substance
Polonium-210 is an isotope of polonium that does not exist in nature, but is manufactured by humans. Used to create miniature, but at the same time, very powerful energy sources. It has a very short half-life and is therefore capable of causing severe radiation sickness.
8. The heaviest substance
This is, of course, fullerite. Its hardness is almost 2 times higher than that of natural diamonds. You can read more about fullerite in our article The Hardest Materials in the World.
9. The strongest magnet
The strongest magnet in the world is made of iron and nitrogen. At present, details about this substance are not available to the general public, but it is already known that the new super-magnet is 18% more powerful than the strongest magnets currently in use - neodymium. Neodymium magnets are made from neodymium, iron and boron.
10. The most fluid substance
Superfluid Helium II has almost no viscosity at temperatures close to absolute zero. This property is due to its unique property of leaking and pouring out of a vessel made of any solid material. Helium II has prospects for use as an ideal thermal conductor in which heat does not dissipate.
Difference between matter and field
The field, unlike substances, is characterized by continuity; electromagnetic and gravitational fields, the field of nuclear forces, and the wave fields of various elementary particles are known.
Modern natural science eliminates the difference between matter and field, considering that both matter and fields consist of various particles that have a particle-wave (dual) nature. The identification of the close relationship between field and matter led to a deepening of ideas about the unity of all forms and structure of the material world.
A homogeneous substance is characterized by density - the ratio of the mass of a substance to its volume:
Where ρ - density of the substance, m- mass of substance, V- volume of the substance.
Physical fields do not have such density.
Properties of matter
Each substance has a set of specific properties - objective characteristics that determine the individuality of a particular substance and thereby make it possible to distinguish it from all other substances. The most characteristic physical and chemical properties include constants - density, melting point, boiling point, thermodynamic characteristics, crystal structure parameters. The main characteristics of a substance include its chemical properties.
Variety of substances
The number of substances is in principle unlimited; To a certain number of substances, new substances are constantly being added, both discovered in nature and synthesized artificially.
Individual substances and mixtures
Aggregate states
All substances, in principle, can exist in three states of aggregation - solid, liquid and gaseous. Thus, ice, liquid water and water vapor are solid, liquid and gaseous states of the same substance - water H 2 O. Solid, liquid and gaseous forms are not individual characteristics of substances, but correspond only to different ones, depending on external physical conditions states of existence of substances. Therefore, it is impossible to attribute to water only a sign of a liquid, oxygen - a sign of a gas, and sodium chloride - a sign of a solid state. Each of these (and all other substances), when conditions change, can transform into any other of the three states of aggregation.
During the transition from ideal models of solid, liquid and gaseous states to real states of matter, several borderline intermediate types are discovered, the well-known of which are the amorphous (glassy) state, the liquid crystal state and the highly elastic (polymer) state. In this regard, the broader concept of “phase” is often used.
In physics, the fourth aggregate state of matter is considered - plasma, a partially or completely ionized state in which the density of positive and negative charges is the same (plasma is electrically neutral).
Crystals
Crystals are solid substances that have a natural external shape of regular symmetrical polyhedra, based on their internal structure, that is, on one of several specific regular arrangements of the particles that make up the substance (atoms, molecules, ions). Crystal structure, being individual for each substance, refers to the basic physical and chemical properties. The constituent particles of this solid form a crystal lattice. If crystal lattices are stereometrically (spatially) identical or similar (have the same symmetry), then the geometric difference between them lies, in particular, in different distances between the particles occupying lattice sites. The distances between particles themselves are called lattice parameters. The lattice parameters, as well as the angles of geometric polyhedra, are determined by physical methods of structural analysis, for example, methods of X-ray structural analysis.
Often solids form (depending on conditions) more than one form of crystal lattice; such forms are called polymorphic modifications. For example, among simple substances, rhombic and monoclinic sulfur, graphite and diamond, which are hexagonal and cubic modifications of carbon, are known; among complex substances, quartz, tridymite and cristobalite are various modifications of silicon dioxide.
Organic matter
Literature
- Chemistry: Reference. ed./ W. Schröter, K.-H. Lautenschläger, H. Bibrak et al.: Trans. with him. - M.: Chemistry, 1989
see also
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