Are you here: Service sector

The properties and characteristics of any substance are determined by its chemical composition. In modern laboratories, chemical examinations are carried out to determine the qualitative and quantitative composition of almost any object, for example, soil or a food product.

Chemical bond, structure and properties of matter

Interactions that result in the combination of chemical particles into substances are usually divided into chemical and intermolecular bonds. The first group, in turn, is divided into ionic, covalent and metallic bonds.

An ionic bond is a bond between oppositely charged ions. This connection occurs due to electrostatic attraction. In order for an ionic bond to form, the ions must be of different sizes. This is because ions of certain sizes tend to give up electrons, while others tend to accept them.

A covalent bond occurs due to the formation of a shared pair of electrons. For it to occur, it is necessary that the radius of the atoms be the same or similar.

A metallic bond occurs due to the sharing of valence electrons. It is formed if the size of the atoms is large. Such atoms usually donate electrons.

According to the type of structure, all substances can be divided into molecular and non-molecular. Most organic substances belong to the first type. Based on the type of chemical bond, substances with covalent, ionic and metallic bonds are distinguished.

Basic principles of the theory of chemical structure of organic substances

Butlerov's theory is the scientific foundation of all organic chemistry. Based on its basic principles, Butlerov gave an explanation of isomerism, which subsequently helped him discover several isomers.

According to the theory of the chemical structure of organic substances, the combination of atoms in molecules is strictly ordered. It occurs in a certain sequence (depending on the valency of the atoms). The sequence of interatomic bonds is usually called the chemical structure of the molecule.

Another important point of this theory is the possibility of using various chemical methods to determine the structure of a substance.

Groups of atoms in a molecule are interconnected and influence each other. The basic properties of a substance, according to this theory, are determined by its chemical structure.

Chemical structure of organic substances

As is known, carbon is always present in organic matter. This distinguishes organic substances from inorganic ones. Organic substances are used in everyday life; they serve as a raw material base for the production of food and various food products.

Scientists have managed to synthesize many types of organic substances that do not exist in nature (various types of plastics, rubber and others). Organic substances differ from inorganic substances in their chemical structure. Carbon atoms form various chains and rings. This explains the huge variety of organic substances in nature.

Atomic bonds in such substances have a pronounced covalent character. When heated, organic substances completely decompose. This is explained by the low strength of interatomic bonds.

Among organic compounds, the phenomenon of isomerism is widespread.

Chemical research

The study of chemical substances is usually carried out in special laboratories and expert centers. This allows you to determine the exact quantitative and qualitative composition of the material under study.

If the chemical composition of a substance is completely unknown, laboratory staff use a whole range of analytical methods. Experts determine the exact content of certain chemical elements in samples.

The study of the chemical composition of a substance occurs in stages:

First, specialists determine the goals of their work;
then, the substance samples are classified;
Next comes quantitative and qualitative analysis.

Often, in laboratory conditions, various substances are tested for the content of toxic elements and industrial materials.

Chemical reactions

Chemical reactions are the transformation of some substances (initial reagents) into others. In this case, a redistribution of electrons occurs. Unlike nuclear reactions, chemical reactions do not affect the total number of atomic nuclei and do not change the isotopic composition of chemical elements.

The conditions for chemical reactions may vary. They can occur through physical contact of reagents, mixing, heating, as well as exposure to light, electric current, or ionizing radiation. Chemical reactions often occur under the influence of catalysts.

The rate of a chemical reaction depends on the concentration of active particles in the interacting substances and on the difference between the bond energy that is broken and the energy that is formed.

As a result of chemical processes, new substances are formed, the properties of which are different from the properties of the original reagents. However, during chemical reactions, atoms of new elements are not formed.

Russian Register of Chemical and Biological Substances

The Russian Register of Potentially Hazardous Chemical and Biological Substances conducts independent examinations of various products in order to establish their compliance with sanitary, epidemiological and hygienic requirements.

This agency labels chemicals according to generally accepted classifications. The purpose of the register is to provide information in the field of chemical safety, as well as to promote the integration of our country into the global economic community.

The Russian register annually publishes lists of chemical substances that pose a threat to human life, data on their transportation, disposal, toxicity and other parameters.

Lists of chemical substances that have passed state registration and a database of hazardous substances can be found in the public domain.

The Federal Register is the main information resource that ensures the implementation of many international treaties that our country has entered into regarding hazardous chemicals and pesticides.

Manufacturers and suppliers of industrial chemicals

Chemicals for various industries are manufactured at large plants and factories. The leader among manufacturers of such products is the company "RUSHIMTECH". She specializes in developing innovations in the field of organic chemistry.

Another company that specializes in the production of chemicals is the Sarsilika company. The company produces silicon dioxide for factories.

Among the large suppliers of chemical raw materials, one can note the company BIO-CHEM. The company supplies various chemicals to domestic plants and factories.

Production and receipt of chemicals and chemical products

The production of chemicals makes it possible to obtain synthetic materials that can replace natural ones. At one time, such a need was dictated by the shortage of natural materials or their cost, so humanity had to invent synthetic substitutes.

With the help of chemical reactions, it is possible to obtain much faster some natural substances that take a very long time to form naturally. In addition to saving natural raw materials, chemical production makes it possible to improve the physical and mechanical characteristics and chemical properties of the resulting materials.

To produce many chemicals, chemical reactions such as catalysis, hydrolysis, electrolysis, chemical decomposition and others are used.

Chemical properties used:

in metallurgy;
in the production of polyethylenes and plastics;
for the production of nitrogen and phosphorus fertilizers, medicines and other useful materials in almost any area of production and field of human activity.

Equipment for the production of chemicals

Considering the versatility of chemical production, equipment for different types of products differs significantly. But in general, production involves heating elements, special containers resistant to high temperatures and aggressive environments, and mixers. Any processing occurs on the principles of chemical reactions (for example, processing chemical fibers, applying protective layers to glass or metal).

Use of chemicals

Chemicals are used very widely due to the fact that synthetic substitutes now exist in almost all areas of industry.

Chemical substances:

are raw materials for food production;
serve as the basis for the creation of agricultural fertilizers;
used in paint and varnish production, metalworking;
necessary for glass production.

Chemicals in industry

There are two types of chemicals used in industry: organic and inorganic.

The first includes derivatives of natural oil and gas, the second:

weak and strong acids;
alkalis;
cyanides;
sulfur compounds;
heavy liquids (such as bromoform).

Manufacturers and suppliers of industrial chemicals

The largest representatives of the production and supply of raw materials for chemical production in Russia are the following companies:

Sibur Holding (Moscow) - petrochemical holding;
"Salavatnefteorgsintez" (Salavat, Bashkortostan) is a plant that includes a chemical plant, a petrochemical plant, an oil refinery plant, a petrochemical production plant, the Sintez and Monomer plants, and a mineral fertilizer plant;
"Nizhnekamskneftekhim" (Nizhnekamsk, Tatarstan) - petrochemical company;
Eurochem (Moscow) - fertilizers, feed phosphates, mineral raw materials and industrial products;
Uralkali (Berezniki, Perm region) is the world leader in potassium production.,
"Akron" (Veliky Novgorod) - mineral fertilizers.

Chemicals in food

In chemical products, some chemical additives are unintentional. These are residual effects after fertilizing fields where vegetables or fruits were grown, residues of drugs used to treat animals, substances released from plastic packaging materials.

Intentional chemicals in foods include non-natural preservatives to preserve food for longer.

Safety precautions when working with chemicals

Hazardous chemicals include those that, upon direct contact, harm human health and cause occupational injuries and illnesses. The latter can manifest themselves both immediately after exposure and later, affecting the life expectancy of a person and his children.

When working with poisonous gases, poisonous, toxic, radioactive, flammable substances, or in conditions of increased dust levels, management is obliged to provide conditions to minimize harmful effects. Employees of such enterprises have benefits in terms of working hours, an increase in vacation and salary, and retire earlier. In addition, they are required to regularly undergo specialized medical examinations, and strictly observe caution and safety rules directly at the workplace.

Industrial accidents involving the release of hazardous chemicals

Accidents at chemical plants usually involve spills or releases of hazardous chemicals. This leads to death or chemical contamination of people, food, food raw materials and feed, farm animals and plants, or pollution of the natural environment.

Types of accidents involving the release of chemically hazardous substances:

accidents with the release (threat of release) of chemically hazardous substances (CHS) during their production, processing or storage (disposal);
transport accidents involving the release (threat of release) of hazardous chemicals;
formation and distribution of chemical agents in the process of chemical reactions;
accidents with chemical munitions.

The main indicator of the degree of danger of chemically hazardous objects is the size of the population living in the zone of possible chemical contamination in the event of an accident. Such accidents can occur directly at factories for the processing or production of chemical chemicals, at oil refineries, during their transportation, in warehouses storing chemical chemicals.

Modern chemical enterprises are constantly introducing new production technologies aimed at minimizing the possibility of accidents involving the release of hazardous chemicals.

Chemicals, by definition, pose some degree of danger if used incorrectly and without proper precautions. To know exactly what you can expect from a particular substance, there are classifications of chemicals according to the degree of danger.

According to the established requirements of GOST 12.1.007-76 chemicals are divided into four classes on the level of toxicity and their effects on living organisms, in particular on humans and animals. The hazard class depends on factors such as MPC, KVIO, average lethal dose when applied to the skin or ingested. Another document regulating the level of danger of chemicals is SanPiN 2.1.4. 1074-01.

Classification of chemically hazardous substances

1st hazard class

1st class of danger. These are extremely dangerous substances, the maximum permissible concentration of which is less than 0.1. The inhaled dose to cause death is less than 15 mg/kg of any substance in this toxicity class. Only 100 milligrams or less of such a substance per kilogram is enough to cause death if it comes into contact with the skin. The above doses during the experiments led to the death of more than half of the experimental animals. In the tables they are designated as LD 50 (oral) and LD 50 (dermal).

The next, most important, indicator of the toxicity and danger of a substance is its MPC, or maximum permissible concentration. The maximum permissible concentration for extremely dangerous substances in the atmosphere is about 0.1 milligrams per cubic meter. The coefficient of possibility of inhalation poisoning is more than 300, the zone of acute action is 6.0, the zone of chronic action is 10, the zone of biological action is more than 1000.

Extremely dangerous substances include nicotine, potassium cyanide, and others. Exceeding the above indicators leads to irreversible damage to the ecological system and the death of living organisms.

2nd hazard class

These are highly dangerous substances, LD 50 (oral) of such substances is 15–150 mg/kg, depending on the nature of the substance, and LD 50 (dermal) is 100–500 mg/kg. These substances pose a great danger to humans and animals due to their destructive effects.

They also pose a great danger for, since the maximum permissible concentration of such substances is up to 1.0 milligrams, KVIO - from 30 to 300, ADL - 6.18, ZHD - 5-10, ZBD - 100-100.

Highly hazardous substances include arsenic, chloroform, lead, lithium, and so on. Often these substances are used as poisons or tranquilizers. Most of them are in very limited access.

3rd hazard class

Moderately hazardous substances. The lethal dose of such substances when in contact with the skin is 501-2500 mg/kg, and when ingesting the stomach - 151-5000 mg/kg. The maximum permissible concentration in the atmosphere is up to 10 mg/m3, the coefficient of occurrence of inhalation poisoning at a temperature of 20 degrees Celsius is from 3 to 30. This indicator was established during experiments on laboratory mice.

The zone of acute action is 18–54, the zone of chronic action is 5–2.5, the zone of biological action is from 10 to 100.

The list of moderately hazardous substances includes gasoline, aluminum acid, compounds of aluminum, manganese, and so on. Despite the relatively low rates, such substances should be treated with caution. These substances are actively used not only in production, but also in everyday life, and that is why you need to pay special attention to them.

4th hazard class

Low hazardous substances. These chemicals pose the least threat due to their low hazard and toxicity levels. LD 50 (oral) of such substances is more than 5000 mg/kg, skin - more than 2500 mg/kg, MPC - more than 10, KVIO - less than 0.3, zone of acute action - more than 54, zone of chronic action - less than 2.5, and biological action zone – less than 10.

Everyone knows these substances, since they represent, for the most part, one of the components of our life. The list of low-hazard substances includes the popular fuel kerosene, ammonia, which can be found in almost any first aid kit, aluminum, iron compounds and ethanol. Very often these substances are used to conduct experiments in chemistry lessons.

List of harmful substances according to the nature of their effects on the body

Chemical substances and elements can differ not only in toxicity, but also in the nature of their effect on the body. And in order to have a complete understanding of any substance or compound, you need to take into account the data of both classifications, depending on the class, Each of the substances is assigned its own color, according to the table.

It will be useful for you to know how it is carried out in accordance with SanPiN 2.1.7.2790-10.

In what cases are increasing surcharges applied, read the new standards for fuel consumption.

Read the link for the sequence of entering objects into the “State Register of Waste Disposal Facilities”.

So, exposure to chemicals can be of the following nature:

Nature of irritant action. In case of contact with skin, some redness may occur. Such substances include phosphorus, chlorine, fluorine, hydrogen oxides, etc.
The nature of the cauterizing action. If it comes into contact with the skin or inside the body, burns of varying severity may occur. These are substances such as hydrochloric acid and ammonia.
Asphyxiants. High levels of such substances in the air can lead to asphyxia and subsequently death. Phosgene and chloropicrin have this effect.
Toxic chemicals. These are substances that can adversely affect the human body and cause varying degrees of poisoning. Arsenic hydrogen, hydrogen sulfide, ethylene oxide, hydrocyanic acid - these are the substances that pose a toxic hazard to living organisms.
Narcotic substances. Such substances are addictive; when they enter the body, they destroy it. It is either very difficult or impossible to give up an acquired habit. Such substances are called drugs and should be avoided by the average person. Such substances can only be beneficial in medicine, but even there there are a number of requirements and restrictions. Narcotic substances include nicotine, methyl chloride, methyl bromide, formaldehyde and so on.

Abbreviations:

T kip. - boiling temperature,

T pl. - melting temperature.

Adipic acid (CH 2) 4 (COOH) 2- colorless crystals, soluble in water. T. pl. 153 °C. Forms salts - adipates. Used to remove scale.

Nitric acid HNO 3- a colorless liquid with a pungent odor, unlimitedly soluble in water. T. kip. 82.6 °C. Strong acid, causes deep burns and must be handled with care. Forms salts - nitrates.

Potassium alum KAl(SO 4) 2 .12H 2 O- double salt, colorless crystalline substance, highly soluble in water. T pl. 92°C.

Amyl acetate CH 3 SOOS 5 H 11 (amyl ester of acetic acid)- a colorless liquid with a fruity odor, an organic solvent and fragrance.

Amino acids- organic substances whose molecules contain carboxyl groups COOH and amino groups NH 2. They are part of proteins.

Ammonia NH- a colorless gas with a pungent odor, highly soluble in water, forms ammonia hydrate NH 3 .H 2 O.

Ammonium nitrate, cm. . Aniline (aminobenzene, phenylamine) C 6 H 5 NH 2- a viscous, colorless liquid that darkens in light and air. Insoluble in water, soluble in ethyl alcohol and diethyl ether. T kip. 184 °C. Poisonous.

Arachidonic acid C 19 H 31 COOH- an unsaturated carboxylic acid with four double bonds in the molecule, colorless liquid. T kip. 160-165 °C. Included in vegetable fats.

Ascorbic acid (vitamin C), an organic substance of complex structure - colorless crystals, sensitive to heat. Participates in the redox processes of a living organism.

Squirrels- biopolymers consisting of amino acid residues. They play a vital role in life processes.

Petrol— a mixture of light hydrocarbons; obtained during oil refining. T kip. from 30 to 200 °C. Fuel and organic solvent.

Benzoic acid C 6 H 5 COOH- a colorless crystalline substance, poorly soluble in water. Above 100 °C it decomposes.

Benzene C 6 H 6- aromatic hydrocarbon. T kip. 80 °C. Flammable, poisonous.

Betaine (trimethylglycine) (CH 3) 3 N + CH 2 COO- an organic substance, highly soluble in water, found in plants (for example, beets).

Boric acid B(OH) 3- a colorless crystalline substance, slightly soluble in water, a weak acid.

Sodium bromate NaBrO 3- colorless crystals, soluble in water. Melts at 384 °C with decomposition. In an acidic environment it is a strong oxidizing agent.

Wax- a fat-like amorphous substance of plant origin, a mixture of esters of fatty acids. Melts in the range of 40-90 °C.

Galactose C 6 H 12 O 6 .H 2 O- carbohydrate, monosaccharide, colorless crystalline substance, soluble in water.

Sodium hypochlorite (trihydrate) NaClO .3H 2 O- a greenish-yellow crystalline substance, highly soluble in water. T. pl. 26 °C, above 40 °C decomposes, explodes in the presence of organic substances. Bleach.

Glycerol CH(OH)(CH 2 OH) 2- a colorless viscous liquid, unlimitedly soluble in water and absorbing moisture from the air, trihydric alcohol. It is part of fats in the form of lipids - triglycerides (esters of glycerol with organic acids).

Glucose (grape sugar) C 6 H 12 O 6- carbohydrate, monosaccharide, colorless crystalline substance, highly soluble in water. T pl. 146 °C. Contained in the juice of all plants and in the blood of humans and animals.

Calcium gluconate Ca[CH 2 OH (CHOH) 4 COO] 2.H 2 O (monohydrate)- white crystalline powder, slightly soluble in cold water, practically insoluble in ethyl alcohol.

Gluconic (sugar) acid CH 2 (OH)(CHOH) 4 COOH- a colorless crystalline substance, soluble in water, obtained from the oxidation of glucose. Forms salts - gluconates.

Double superphosphate (calcium dihydrogen orthophosphate monohydrate) Ca(H 2 PO 4) 2 .H 2 O- white powder, soluble in water.

Dibutyl phthalate C 6 H 4 (SOOC 4 H 9) 2 (butyl ester of phthalic acid)- colorless liquid with a fruity odor, slightly soluble in water. Organic solvent and repellent.

Ammonium dihydrogen orthophosphate NH 4 H 2 PO 4- a colorless crystalline substance, soluble in water. Fertilizer (diammo-phos).

Dimetzphthalate C 6 H 4 (COOCH 3) 2 (phthalic acid methyl ester)- colorless volatile liquid. Organic solvent and repellent.

Ferrous sulfate (ferrous sulfate heptahydrate) F e S O 4 .7H 2 O- greenish crystals, soluble in water. In air it gradually oxidizes.

Iron minium— iron(III) oxide Fe 2 O 3 with impurities. Mineral paint of red-brown color.

Yellow blood salt (potassium hexacyanoferrate (II) trihydrate) K 4 [Fe (CN) 6].3H 2 O- light yellow crystals, soluble in water. In the 18th century It was obtained from slaughterhouse waste, hence the name.

Fatty acid- carboxylic acids containing 13 or more carbon atoms.

Soda Ash, cm. .

Camphor C 10 H 16 O- colorless crystals with a characteristic odor. T pl. 179 °C, easily sublimes when heated. Dissolves in organic solvents, slightly soluble in water.

Rosin- a glassy substance of yellow color. T pl. 100-140 °C, consists of resin acids - organic substances of cyclic structure. Soluble in organic solvents and acetic acid, insoluble in water.

Ammonium carbonate (NH 4) 2 CO 3- a colorless crystalline substance, highly soluble in water, decomposes when heated.

Kerosene- a mixture of hydrocarbons obtained during oil refining. T kip. 150-300 °C. Fuel and organic solvent.

Red blood salt K 3 [Fe (CN) 6 ] (potassium hexacyanoferrate (III))- red crystals, soluble in water. In the 18th century was obtained from slaughterhouse waste, hence the name.

Starch [C 6 H 10 O 5 ] n- white amorphous powder, polysaccharide. With prolonged contact with water, it swells, turns into a paste, and when heated, forms dextrin. Contained in potatoes, flour, cereals.

Litmus- natural organic substance, acid-base indicator (blue in alkaline, red in acidic environment).

Butyric acid C 3 H 7 COOH- colorless liquid with an unpleasant odor. T kip. 163 °C.

Mercaptans (thioalcohols)- organic compounds containing the SH group, for example, methyl mercaptan CH 3 SH. They have a disgusting smell.

Iron metahydroxide FeO(OH)- brownish-brown powder, insoluble in water, the basis of rust.

Sodium metasilicate (nonahydrate) Na 2 SiO 3 .9H 2 O- a colorless substance, highly soluble in water. T pl. 47 °C, above 100 °C loses water. Aqueous solutions (silicate glue, soluble glass) have a highly alkaline reaction due to hydrolysis.

Carbon monoxide (carbon monoxide) CO- a colorless and odorless gas, a strong poison. Formed during incomplete combustion of organic substances.

Formic acid HCOOH- a colorless liquid with a pungent odor, infinitely soluble in water, one of the strongest organic acids. T kip. 100.7 °C. Contained in insect secretions, nettles, and pine needles. Forms salts - formates.

Naphthalene C 10 H 8- a colorless crystalline substance with a pungent characteristic odor, insoluble in water. Sublimes at 50 °C. Poisonous.

Ammonia- 5-10% aqueous ammonia solution.

Unsaturated (unsaturated) fatty acids- fatty acids whose molecules contain one or more double bonds.

Polysaccharides- carbohydrates of complex structure (starch, cellulose, etc.).

Propane C 3 H 8- colorless flammable gas, hydrocarbon.

Propionic acid C 2 H 5 COOH- colorless liquid, soluble in water. T kip. 141 °C. Weak acid, forms salts - propionates.

Simple superphosphate- a mixture of water-soluble calcium dihydrogen orthophosphate Ca(H 2 PO 4) 2.H 2 O and insoluble calcium sulfate CaSO 4.

Resorcinol C 6 H 4 (OH) 2- colorless crystals with a characteristic odor, soluble in water and ethyl alcohol. T pl. 109 - 110 °C

Salicylic acid HOC 6 H 4 COOH- a colorless crystalline substance, slightly soluble in cold water, highly soluble in ethyl alcohol. T pl. 160 °C.

Sucrose C 12 H 22 O 11- a colorless crystalline substance, highly soluble in water. T pl. 185 °C.

Lead lead Pb 3 O 4- a finely crystalline substance of red color, insoluble in water. Strong oxidizing agent. Pigment. Poisonous.

Sulfur S 8- a yellow crystalline substance, insoluble in water. T pl. 119.3 °C.

Sulfuric acid H 2 SO 4- a colorless, odorless, oily liquid, infinitely soluble in water (with strong heating). T kip. 338 °C. A strong acid, a caustic substance, forms salts - sulfates and hydrosulfates.

Sulfur color- finely ground sulfur powder.

Hydrogen sulfide H 2 S- a colorless gas with the smell of rotten eggs, soluble in water, formed during the decomposition of proteins. Strong reducing agent. Poisonous.

Silica gel (silicon dioxide polyhydrate) n SiO2 m H2O- colorless granules, insoluble in water. Good adsorbent (absorber) of moisture.

Carbon tetrachloride (carbon tetrachloride) CCl 4- colorless liquid, insoluble in water. T kip. 77 °C. Solvent. Poisonous.

Tetraethyl lead Pb(C 2 H 5) 4- colorless flammable liquid. Additive to automobile fuel (in amounts up to 0.08%). Poisonous.

Sodium tripolyphosphate Na 3 P 3 O 9- a colorless solid, unlimitedly soluble in water; aqueous solutions have an alkaline environment due to hydrolysis.

Hydrocarbons- organic compounds of the composition C x H y (for example, propane C 3 H 8, benzene C 6 H 6).

Carbonic acid H 2 CO 3- a weak acid, exists only in aqueous solution, forms salts - carbonates and bicarbonates.

Acetic acid CH 3 COOH- colorless liquid. Crystallizes at 17°C. Unlimitedly soluble in water and ethyl alcohol. “Glacial” acetic acid contains 99.8% CH 3 COOH.

Acetaldehyde, cm. .

Fructose (fruit sugar) C 6 H 12 O 6 .H 2 O- monosaccharide, colorless crystalline substance, soluble in water. T pl. about 100 °C. One and a half times sweeter than sucrose, found in fruits, flower nectar, and honey.

Hydrogen fluoride HF- a colorless gas with a suffocating odor, highly soluble in water with the formation of hydrofluoric acid.

Citrates- salts of citric acid.

Oxalic acid (dihydrate) H 2 C 2 O 4 .2H 2 O- a colorless crystalline substance, soluble in water. Sublimes at 125 °C. Contained in sorrel, spinach, sorrel in the form of potassium salt.

Ethyl acetate (ethyl acetate) CH 3 COOC 2 H 5- a colorless liquid with a fruity odor, slightly soluble in water. T kip. 77 °C.

Ethylene glycol C 2 H 4 (OH) 2 - colorless viscous liquid, unlimitedly soluble in water. T pl. 12.3 °C, boiling point 197.8 °C. Poisonous.

Ethyl alcohol (ethanol, wine alcohol) C 2 H 5 OH- colorless liquid, unlimitedly soluble in water. T kip. 78°C. Used as a solvent and preservative. In large doses it is a strong poison.

Ethers— organic substances, including fragments of alcohols or alcohols and acids, connected through an oxygen atom.

Malic (hydroxysuccinic) acid CH(OH)CH2 (COOH)2- a colorless crystalline substance, soluble in water. T pl. 100 °C.

Succinic acid (CH 2) 2 (COOH) 2- a colorless crystalline substance, soluble in water. T pl. 183 °C. Forms salts - succinates.

The world around us is material. There are two types of matter: substance and field. The object of chemistry is a substance (including the influence of various fields on the substance - sound, magnetic, electromagnetic, etc.)

Matter is everything that has rest mass (i.e. is characterized by the presence of mass when it is not moving). So, although the rest mass of one electron (the mass of a non-moving electron) is very small - about 10 -27 g, but even one electron is matter.

Substance exists in three states of aggregation - gaseous, liquid and solid. There is another state of matter - plasma (for example, there is plasma in thunderstorms and ball lightning), but in school courses the chemistry of plasma is almost not considered.

Substances can be pure, very pure (needed, for example, to create fiber optics), they can contain noticeable amounts of impurities, or they can be mixtures.

All substances are made up of tiny particles called atoms. Substances consisting of atoms of the same type(from atoms of one element), called simple(for example, charcoal, oxygen, nitrogen, silver, etc.). Substances that contain atoms of different elements interconnected are called complex.

If a substance (for example, air) contains two or more simple substances, and their atoms are not connected to each other, then it is not called a complex substance, but a mixture of simple substances. The number of simple substances is relatively small (about five hundred), but the number of complex substances is enormous. To date, tens of millions of different complex substances are known.

Chemical transformations

Substances are able to interact with each other, and new substances arise. Such transformations are called chemical. For example, a simple substance, coal, interacts (chemists say it reacts) with another simple substance, oxygen, resulting in the formation of a complex substance, carbon dioxide, in which the carbon and oxygen atoms are interconnected. Such transformations of one substance into another are called chemical. Chemical transformations are chemical reactions. So, when sugar is heated in air, a complex sweet substance - sucrose (which sugar is made of) - turns into a simple substance - coal and a complex substance - water.

Chemistry studies the transformation of one substance into another. The task of chemistry is to find out with which substances a particular substance can interact (react) under given conditions and what is formed. In addition, it is important to find out under what conditions a particular transformation can occur and the desired substance can be obtained.

Physical properties of substances

Each substance is characterized by a set of physical and chemical properties. Physical properties are properties that can be characterized using physical instruments. For example, using a thermometer you can determine the melting and boiling points of water. Physical methods can be used to characterize the ability of a substance to conduct electric current, determine the density of the substance, its hardness, etc. During physical processes, substances remain unchanged in composition.

The physical properties of substances are divided into countable (those that can be characterized using certain physical instruments by number, for example, by indicating density, melting and boiling points, solubility in water, etc.) and innumerable (those that cannot be characterized by number or is very difficult - such as color, smell, taste, etc.).

Chemical properties of substances

The chemical properties of a substance are a set of information about what other substances and under what conditions a given substance enters into chemical interactions. The most important task of chemistry is to identify the chemical properties of substances.

Chemical transformations involve the smallest particles of substances - atoms. During chemical transformations, other substances are formed from some substances, and the original substances disappear, and new substances (reaction products) are formed in their place. A atoms at everyone chemical transformations are preserved. Their rearrangement occurs; during chemical transformations, old bonds between atoms are destroyed and new bonds arise.

Chemical element

The number of different substances is huge (and each of them has its own set of physical and chemical properties). There are relatively few atoms in the material world around us that differ from each other in their most important characteristics - about a hundred. Each type of atom has its own chemical element. A chemical element is a collection of atoms with the same or similar characteristics. About 90 different chemical elements are found in nature. To date, physicists have learned to create new types of atoms that are not found on Earth. Such atoms (and, accordingly, such chemical elements) are called artificial (in English - man-made elements). More than two dozen artificially obtained elements have been synthesized to date.

Each element has a Latin name and a one- or two-letter symbol. In Russian-language chemical literature there are no clear rules for pronunciation of symbols of chemical elements. Some pronounce it like this: they call the element in Russian (symbols of sodium, magnesium, etc.), others - in Latin letters (symbols of carbon, phosphorus, sulfur), others - what the name of the element sounds like in Latin (iron, silver, gold, mercury ). We usually pronounce the symbol of the element hydrogen H the way this letter is pronounced in French.

A comparison of the most important characteristics of chemical elements and simple substances is given in the table below. One element may correspond to several simple substances (the phenomenon of allotropy: carbon, oxygen, etc.), or perhaps just one (argon and other inert gases).

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 aggregation 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.

Editor's Choice

Dobrenkov Kravchenko methods of sociological research pdf

M.: 2004. - 768 p. The textbook discusses the methodology, methods and techniques of sociological research. Particular attention is paid...

Test in adaptation of Leontiev's short story

The original question that led to the creation of resilience theory was “what psychological factors contribute to successful coping...

Rudolf Steiner: biography and his books

The nineteenth and twentieth centuries were significant in the history of mankind. In just a hundred years, man has made significant progress in his...

Methodology for multifactorial personality research R

R. Cattell's multifactorial personality technique is currently most often used in personality research and has received...

Psychedelic Medications and Spiritual Practice Post-Ego Selection Methods

Psychedelic substances have been used by most peoples of the world for thousands of years. World experience in healing and spiritual growth with the help of...