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Chemical compound. Chemical names and formulas of substances




Classification of substances All substances can be divided into simple ones consisting of atoms of one element and complex ones - consisting of atoms of different elements. Simple substances are divided into metals and non-metals: Metals - s and d elements. Non-metals - p elements. Compounds are divided into organic and inorganic.

The properties of metals are determined by the ability of atoms to donate their electrons. A characteristic type of chemical bond for metals is the metallic bond. It is characterized by such physical properties: ductility, ductility, thermal conductivity, electrical conductivity. Under room conditions, all metals except mercury are in a solid state.

The properties of non-metals are determined by the ability of atoms to easily accept electrons and poorly give their own. Non-metals have physical properties opposite to metals: their crystals are brittle, there is no "metallic" luster, low values ​​of thermal and electrical conductivity. Some non-metals are gaseous under room conditions.

Classification of organic compounds. According to the structure of the carbon skeleton: Saturated / unsaturated Linear / branched / cyclic According to the presence of functional groups: Alcohols Acids Ethers and esters Carbohydrates Aldehydes and ketones

Oxides are complex substances whose molecules consist of two elements, one of which is oxygen in the -2 oxidation state. Oxides are divided into salt-forming and non-salt-forming (indifferent). Salt-forming oxides are divided into basic, acidic and amphoteric.

Basic oxides are oxides that form salts in reactions with acids or acidic oxides. Basic oxides are formed by metals with a low degree of oxidation (+1, +2) - these are elements of the 1st and 2nd groups of the periodic table. Examples of basic oxides: Na 2 O, Ca. O, Mg. O, Cu. O. Examples of salt formation reactions: Cu. O + 2 HCl Cu. Cl 2 + H 2 O, Mg. O + CO 2 Mg. CO3.

Basic oxides Oxides of alkali and alkaline earth metals react with water to form bases: Na 2 O + H 2 O 2 Na. OHCa. O + H 2 O Ca (OH) 2 Oxides of other metals do not react with water, the corresponding bases are obtained indirectly.

Acid oxides are oxides that form salts in reactions with bases or basic oxides. Acid oxides are formed by elements - non-metals and d - elements in high oxidation states (+5, +6, +7). Examples of acid oxides: N 2 O 5, SO 3, CO 2, Cr. O 3, V 2 O 5. Examples of acid oxide reactions: SO 3 + 2 KOH K 2 SO 4 + H 2 O Ca. O + CO 2 Ca. CO3

Acid oxides Some acid oxides react with water to form the corresponding acids: SO 3 + H 2 O H 2 SO 4 N 2 O 5 + H 2 O 2 HNO 3 Other acid oxides do not react directly with water (Si. O 2, Te. O 3 , Mo. O 3 , WO 3), the corresponding acids are obtained indirectly. One way to obtain acid oxides is to remove water from the corresponding acids. Therefore, acidic oxides are sometimes called "anhydrides".

Amphoteric oxides have the properties of both acidic and basic oxides. With strong acids, such oxides react as basic, and with strong bases as acidic: Sn. O + H 2 SO 4 Sn. SO 4 + H 2 O Sn. O + 2 KOH + H 2 O K 2

Methods for obtaining oxides Oxidation of simple substances: 4 Fe + 3 O 2 2 Fe 2 O 3, S + O 2 SO 2. Combustion of complex substances: CH 4 + 2 O 2 CO 2 + 2 H 2 O, 2 SO 2 + O 2 2 SO 3. Thermal decomposition of salts, bases and acids. Examples respectively: Ca. CO 3 Ca. O + CO 2, Cd (OH) 2 Cd. O + H 2 O, H 2 SO 4 SO 3 + H 2 O.

Nomenclature of oxides The name of the oxide is built according to the formula "oxide + element name in the genitive case". If the element forms several oxides, then after the name in brackets indicate the oxidation state of the element. For example: CO - carbon monoxide (II), CO 2 - carbon monoxide (IV), Na 2 O - sodium oxide. Sometimes, instead of the oxidation state, the name indicates the number of oxygen atoms: monoxide, dioxide, trioxide, etc.

Hydroxides are compounds containing a hydroxo group (-OH) in their composition. Depending on the strength of bonds in the E-O-H series, hydroxides are divided into acids and bases: Acids have the weakest O-H bond, therefore, when they dissociate, E-O- and H + are formed. The bases have the weakest E-O bond, therefore, during dissociation, E + and OH- are formed. In amphoteric hydroxides, either of these two bonds can be broken, depending on the nature of the substance with which the hydroxide is reacting.

Acids The term "acid" in the framework of the theory of electrolytic dissociation has the following definition: Acids are substances that dissociate in solutions with the formation of hydrogen cations and anions of the acid residue. HA H++A Acids are divided into strong and weak (according to their ability to dissociate), one-, two-, and three-basic (according to the number of hydrogen atoms they contain), and oxygen-containing and anoxic acids. For example: H 2 SO 4 - strong, dibasic, oxygen-containing.

Chemical properties of acids 1. Interaction with bases to form salt and water (neutralization reaction): H 2 SO 4 + Cu (OH) 2 Cu. SO 4 + 2 H 2 O. 2. Interaction with basic and amphoteric oxides to form salts and water: 2 HNO 3 + Mg. O Mg (NO 3) 2 + H 2 O, H 2 SO 4 + Zn. O Zn. SO 4 + H 2 O.

Chemical properties of acids 3. Interaction with metals. Metals standing in the “Series of stresses” up to hydrogen displace hydrogen from acid solutions (except for nitric and concentrated sulfuric acids); in this case, a salt is formed: Zn + 2 HCl Zn. Cl 2 + H 2 Metals that are in the “Series of stresses” after hydrogen, hydrogen from acid solutions do not displace Cu + 2 HCl ≠.

Chemical properties of acids 4. Some acids decompose when heated: H 2 Si. O 3 H 2 O + Si. O 2 5. Less volatile acids displace more volatile acids from their salts: H 2 SO 4 conc + Na. Ctv Na. HSO 4 + HCl 6. Stronger acids displace less strong acids from solutions of their salts: 2 HCl + Na 2 CO 3 2 Na. Cl + H 2 O + CO 2

Nomenclature of acids The names of anoxic acids are composed by adding to the root of the Russian name of the acid-forming element (or to the name of a group of atoms, for example, CN - cyan, CNS - rhodan) the suffix "-o-", the ending "hydrogen" and the word "acid". For example: HCl - hydrochloric acid H 2 S - hydrosulfide acid HCN - hydrocyanic acid

Nomenclature of acids The names of oxygen-containing acids are formed according to the formula "element name" + "end" + "acid". The ending varies depending on the degree of oxidation of the acid-forming element. The endings "-ovaya" / "-naya" are used for higher oxidation states. HCl. O 4 - perchloric acid. Then the ending "-ovataya" is used. HCl. O 3 - chloric acid. Then the ending "-ista" is used. HCl. O 2 - chlorous acid. Finally, the last ending is "-woolly" HCl. O is hypochlorous acid.

Nomenclature of acids If an element forms only two oxygen-containing acids (for example, sulfur), then for the highest degree of oxidation, the ending is used “–ovaya” / “-naya”, and for a lower ending “-isto”. Example for sulfur acids: H 2 SO 4 - sulfuric acid H 2 SO 3 - sulfurous acid

Nomenclature of acids If one acid oxide attaches a different number of water molecules in the formation of an acid, then the acid containing more water is indicated by the prefix "ortho-", and the smaller one "meta-". P 2 O 5 + H 2 O 2 HPO 3 - metaphosphoric acid P 2 O 5 + 3 H 2 O 2 H 3 PO 4 - orthophosphoric acid.

Bases The term "base" in the framework of the theory of electrolytic dissociation has the following definition: Bases are substances that dissociate in solutions to form hydroxide ions (OH‾) and metal ions. Bases are classified into weak and strong (according to the ability to dissociate), into one-, two-, three-acid (according to the number of hydroxo groups that can be replaced by an acid residue) into soluble (alkali) and insoluble (according to the ability to dissolve in water). For example, KOH is strong, single acid, soluble.

Chemical properties of bases 1. Interaction with acids: Ca(OH)2 + H 2 SO 4 Ca. SO 4 + H 2 O 2. Interaction with acid oxides: Ca (OH) 2 + CO 2 Ca. CO 3 + H 2 O 3. Interaction with amphoteric oxides: 2 KOH + Sn. O + H 2 O K 2

Chemical properties of bases 4. Interaction with amphoteric bases: 2 Na. OH + Zn(OH)2 Na 2 5. Thermal decomposition of bases with the formation of oxides and water: Ca(OH)2 Ca. O + H 2 O. Alkali metal hydroxides do not decompose when heated. 6. Interaction with amphoteric metals (Zn, Al, Pb, Sn, Be): Zn + 2 Na. OH + 2 H 2 O Na 2 + H 2

Base nomenclature The name of the base is formed by the formula "hydroxide" + "name of the metal in the genitive case". If an element forms several hydroxides, then its oxidation state is indicated in brackets. For example, Cr (OH) 2 is chromium (II) hydroxide, Cr (OH) 3 is chromium (III) hydroxide. Sometimes in the name, the prefix to the word “hydroxide” indicates the number of hydroxo groups - monohydroxide, dihydroxide, trihydroxide, etc.

Salts The term "base" in the framework of the theory of electrolytic dissociation has the following definition: Salts are substances that dissociate in solutions or in melts with the formation of positively charged ions other than hydrogen ions and negatively charged ions other than hydroxide ions. Salts are considered as a product of partial or complete replacement of hydrogen atoms by metal atoms or hydroxo groups by an acid residue. If the substitution occurs completely, then a normal (medium) salt is formed. If the substitution occurs partially, then such salts are called acidic (there are hydrogen atoms), or basic (there are hydroxo groups).

Chemical properties of salts 1. Salts enter into ion exchange reactions if a precipitate is formed, a weak electrolyte or gas is released: salts react with alkalis, the metal cations of which correspond to insoluble bases: Cu. SO 4 + 2 Na. OH Na 2 SO 4 + Cu (OH) 2 ↓ salts interact with acids: a) whose cations form an insoluble salt with the anion of a new acid: Ba. Cl 2 + H 2 SO 4 Ba. SO 4 ↓ + 2 HCl b) whose anions correspond to an unstable carbonic or any volatile acid (in the latter case, the reaction is carried out between a solid salt and a concentrated acid): Na 2 CO 3 + 2 HCl 2 Na. Cl + H 2 O + CO 2, Na. Ctv + H 2 SO 4 conc. Na. HSO 4 + HCl;

Chemical properties of salts c) whose anions correspond to a sparingly soluble acid: Na 2 Si. O 3 + 2 HCl H 2 Si. O 3↓ + 2 Na. Cl d) whose anions correspond to a weak acid: 2 CH 3 COONa + H 2 SO 4 Na 2 SO 4 + 2 CH 3 COOH 2. salts interact with each other if one of the new salts formed is insoluble or decomposes (completely hydrolyzes) with gas evolution or sediment: Ag. NO 3 + Na. ClNa. NO 3+ Ag. Cl↓ 2 Al. Cl 3 + 3 Na 2 CO 3 + 3 H 2 O 2 Al (OH) 3 ↓ + 6 Na. Cl + 3 CO 2

Chemical properties of salts 3. Salts can interact with metals if the metal to which the salt cation corresponds is in the “Row of stresses” to the right of the reacting free metal (the more active metal displaces the less active metal from its salt solution): Zn + Cu. SO 4 Zn. SO 4 + Cu 4. Some salts decompose when heated: Ca. CO 3 Ca. O + CO 2 5. Some salts are able to react with water and form crystalline hydrates: Cu. SO 4 + 5 H 2 O Cu. SO 4 * 5 H 2 O

Chemical properties of salts 6. Salts undergo hydrolysis. This process will be discussed in detail in later lectures. 7. The chemical properties of acidic and basic salts differ from the properties of medium salts in that acidic salts also enter into all reactions characteristic of acids, and basic salts enter into all reactions characteristic of bases. For example: Na. HSO 4 + Na. OH Na 2 SO 4 + H 2 O, Mg. OHCl + HCl Mg. Cl 2 + H 2 O.

Preparation of salts 1. Interaction of basic oxide with acid: Cu. O + H 2 SO 4 Cu. SO 4 + H 2 O 2. The interaction of a metal with a salt of another metal: Mg + Zn. Cl2Mg. Cl 2 + Zn 3. Interaction of metal with acid: Mg + 2 HCl Mg. Cl 2 + H 2 4. Interaction of a base with an acid oxide: Ca (OH) 2 + CO 2 Ca. CO 3 + H 2 O 5. Interaction of a base with an acid: Fe (OH) 3 + 3 HCl Fe. Cl 3 + 3 H 2 O

Preparation of salts 6. Interaction of salt with base: Fe. Cl 2 + 2 KOH Fe (OH) 2 + 2 KCl 7. Interaction of two salts: Ba (NO 3) 2 + K 2 SO 4 Ba. SO 4 + 2 KNO 3 8. Interaction of metal with non-metal: 2 K + S K 2 S 9. Interaction of acid with salt: Ca. CO 3 + 2 HCl Ca. Cl 2 + H 2 O + CO 2 10. Interaction of acidic and basic oxides: Ca. O + CO 2 Ca. CO3

Salt nomenclature The name of the middle salt is formed according to the following rule: “name of the acid residue in the nominative case” + “name of the metal in the genitive case”. If the metal can be part of the salt in several oxidation states, then the oxidation state is indicated in brackets after the name of the salt.

Names of acid residues. For oxygen-free acids, the name of the acid residue consists of the root of the Latin name of the element and the ending "id". For example: Na 2 S - sodium sulfide, Na. Cl is sodium chloride. For oxygen-containing acids, the name of the residue consists of the root of the Latin name and several endings.

Names of acid residues. For an acidic residue with elements in the highest oxidation state, the ending "at" is used. Na 2 SO 4 - sodium sulfate. For an acidic residue with a lower oxidation state (-ic acid), the ending "-it" is used. Na 2 SO 3 - sodium sulfite. For an acidic residue with an even lower oxidation state (-oate acid), the prefix "hippo-" and the ending "-it" are used. Na. Cl. O is sodium hypochlorite.

Names of acid residues. Some acidic residues are called historical names Na. Cl. O 4 - sodium perchlorate. The prefix "hydro" is added to the name of acid salts, and in front of it is another prefix indicating the number of unsubstituted (remaining) hydrogen atoms. For example Na. H 2 PO 4 - sodium dihydroorthophosphate. Similarly, the prefix "hydroxo-" is added to the name of the metal of the basic salts. For example, Cr(OH)2 NO 3 is dihydroxochrome (III) nitrate.

Names and formulas of acids and their residues Acid formula Acid residue Name of acid residue 2 3 4 Nitric HNO 3 ‾ nitrate Nitrogenous HNO 2 ‾ nitrite Hydrobromic HBr Br ‾ bromide Hydroiodic HI I ‾ iodide Silicon H 2 Si. O 32¯ silicate Manganese HMn. O 4¯ permanganate Manganese H 2 Mn. O 42¯ manganate Metaphosphoric HPO 3¯ H 3 As. O 43¯ Acid name 1 Arsenic metaphosphate arsenate

Acid formula Arsenic H 3 As. O 3 Orthophosphoric H 3 PO 4 Acid name Pyrophosphoric H 4 P 2 O 7 Dichromic Rhodohydrogen sulfide Phosphoric Hydrofluoric (hydrofluoric) Hydrochloric (hydrochloric) Chloric Chloric Chloric Chromic Hydrocyanic (hydrocyanic) H 2 Cr 2 O 7 HCNS H 2 SO 4 H 2 SO 3 H 3 PO 3 Acid The name of the acid residue of the As residue. O 33¯ arsenite PO 43¯ orthophosphate (phosphate) pyrophosphate P 2 O 7 4 ¯ (diphosphate) Cr 2 O 72¯ dichromate CNS¯ thiocyanate SO 42¯ sulfate SO 32¯ sulfite PO 33¯ phosphite HF F¯ HCl. O 4 HCl. O 3 HCl. O 2 HCl. O H 2 Cr. O4Cl¯Cl. O4¯Cl. O3¯Cl. O2¯Cl. O¯Cr. O 42¯ HCN CN¯ fluoride chloride perchlorate chlorite hypochlorite chromate cyanide

All substances can be divided into simple (consisting of atoms of one chemical element) and complex (consisting of atoms of different chemical elements). Elementary substances are divided into metals and nonmetals.

Metals have a characteristic “metallic” luster, malleability, malleability, can be rolled into sheets or drawn into wire, have good thermal and electrical conductivity. At room temperature, all metals except mercury are in a solid state.

Non-metals do not have luster, are brittle, and do not conduct heat and electricity well. At room temperature, some non-metals are in a gaseous state.

Compounds are divided into organic and inorganic.

Organic compounds are commonly referred to as carbon compounds. Organic compounds are part of biological tissues and are the basis of life on Earth.

All other connections are called inorganic (rarely mineral). Simple carbon compounds (CO, CO 2 and a number of others) are usually referred to as inorganic compounds, they are usually considered in the course of inorganic chemistry.

Classification of inorganic compounds

Inorganic substances are divided into classes either by composition (binary and multi-element; oxygen-containing, nitrogen-containing, etc.) or by functional features.

Salts, acids, bases, and oxides are among the most important classes of inorganic compounds isolated according to their functional characteristics.

salt are compounds that dissociate in solution into metal cations and acid residues. Examples of salts are, for example, barium sulfate BaSO 4 and zinc chloride ZnCl 2 .

acids- substances that dissociate in solutions with the formation of hydrogen ions. Examples of inorganic acids are hydrochloric (HCl), sulfuric (H 2 SO 4), nitric (HNO 3), phosphoric (H 3 PO 4) acids. The most characteristic chemical property of acids is their ability to react with bases to form salts. According to the degree of dissociation in dilute solutions, acids are divided into strong acids, acids of medium strength and weak acids. According to the redox ability, oxidizing acids (HNO 3) and reducing acids (HI, H 2 S) are distinguished. Acids react with bases, amphoteric oxides and hydroxides to form salts.



Foundations- substances that dissociate in solutions with the formation of only hydroxide anions (OH 1-). Water-soluble bases are called alkalis (KOH, NaOH). A characteristic property of bases is the interaction with acids to form salt and water.

oxides are compounds of two elements, one of which is oxygen. There are basic, acidic and amphoteric oxides. Basic oxides are formed only by metals (CaO, K 2 O), they correspond to bases (Ca (OH) 2, KOH). Acid oxides are formed by non-metals (SO 3, P 2 O 5) and metals that exhibit a high degree of oxidation (Mn 2 O 7), they correspond to acids (H 2 SO 4, H 3 PO 4, HMnO 4). Amphoteric oxides, depending on the conditions, exhibit acidic and basic properties, interact with acids and bases. These include Al 2 O 3 , ZnO, Cr 2 O 3 and a number of others. There are oxides that exhibit neither basic nor acidic properties. Such oxides are called indifferent (N 2 O, CO, etc.)

Classification of organic compounds

Carbon in organic compounds, as a rule, forms stable structures based on carbon-carbon bonds. In its ability to form such structures, carbon is unmatched by other elements. Most organic molecules consist of two parts: a fragment that remains unchanged during the reaction, and a group that undergoes transformations. In this regard, the belonging of organic substances to one or another class and a number of compounds is determined.

An unchanged fragment of a molecule of an organic compound is usually considered as the backbone of the molecule. It may be hydrocarbon or heterocyclic in nature. In this regard, four large series of compounds can be conventionally distinguished: aromatic, heterocyclic, alicyclic and acyclic.

In organic chemistry, additional series are also distinguished: hydrocarbons, nitrogen-containing compounds, oxygen-containing compounds, sulfur-containing compounds, halogen-containing compounds, organometallic compounds, organosilicon compounds.

As a result of the combination of these fundamental series, compound series are formed, for example: "Acyclic hydrocarbons", "Aromatic nitrogen-containing compounds".

The presence of certain functional groups or atoms of elements determines whether the compound belongs to the corresponding class. Among the main classes of organic compounds, alkanes, benzenes, nitro and nitroso compounds, alcohols, phenols, furans, ethers, and a large number of others are distinguished.

Types of chemical bonds

A chemical bond is an interaction that holds two or more atoms, molecules, or any combination of them. By its very nature, a chemical bond is an electrical force of attraction between negatively charged electrons and positively charged atomic nuclei. The magnitude of this attractive force depends mainly on the electronic configuration of the outer shell of atoms.

The ability of an atom to form chemical bonds is characterized by its valency. The electrons involved in the formation of a chemical bond are called valence electrons.

There are several types of chemical bonds: covalent, ionic, hydrogen, metallic.

At education covalent bond there is a partial overlap of electron clouds of interacting atoms, electron pairs are formed. The covalent bond is the stronger, the more the interacting electron clouds overlap.

Distinguish between polar and non-polar covalent bonds.

If a diatomic molecule consists of identical atoms (H 2 , N 2), then the electron cloud is distributed in space symmetrically with respect to both atoms. This covalent bond is called non-polar (homeopolar). If a diatomic molecule consists of different atoms, then the electron cloud is shifted towards the atom with a higher relative electronegativity. This covalent bond is called polar (heteropolar). Examples of compounds with such a bond are HCl, HBr, HJ.

In the examples considered, each of the atoms has one unpaired electron; when two such atoms interact, a common electron pair is created - a covalent bond arises. An unexcited nitrogen atom has three unpaired electrons; due to these electrons, nitrogen can participate in the formation of three covalent bonds (NH 3). A carbon atom can form 4 covalent bonds.

The overlapping of electron clouds is possible only if they have a certain mutual orientation, while the overlapping region is located in a certain direction with respect to the interacting atoms. In other words, a covalent bond is directional.

The energy of covalent bonds is in the range of 150–400 kJ/mol.

The chemical bond between ions, carried out by electrostatic attraction, is called ionic bond . An ionic bond can be viewed as the limit of a polar covalent bond. Unlike a covalent bond, an ionic bond is neither directional nor saturable.

An important type of chemical bonding is the bonding of electrons in a metal. Metals are made up of positive ions, which are held at the nodes of the crystal lattice, and free electrons. When a crystal lattice is formed, the valence orbitals of neighboring atoms overlap and electrons move freely from one orbital to another. These electrons no longer belong to a particular metal atom, they are in giant orbitals that extend throughout the crystal lattice. A chemical bond resulting from the binding of positive ions of the metal lattice by free electrons is called metallic.

There can be weak bonds between molecules (atoms) of substances. One of the most important - hydrogen bond , which may be intermolecular and intramolecular. A hydrogen bond occurs between the hydrogen atom of a molecule (it is partially positively charged) and a strongly electronegative element of the molecule (fluorine, oxygen, etc.).

The hydrogen bond energy is much less than the covalent bond energy and does not exceed 10 kJ/mol. However, this energy is sufficient to create associations of molecules that make it difficult for the molecules to separate from each other. Hydrogen bonds play an important role in biological molecules (proteins and nucleic acids) and largely determine the properties of water.

Van der Waals forces are also considered weak ties. They are due to the fact that any two neutral molecules (atoms) at very close distances are weakly attracted due to the electromagnetic interactions of the electrons and nuclei of one molecule with the electrons and nuclei of the other.

Characteristic features of chemical compounds:

  • 1. The crystal lattice is different from the lattices of the components that form the compound.
  • 2. A simple multiple ratio of components is always preserved in a compound. This makes it possible to express their composition by the simple formula AnBm, where A and B are the corresponding elements; P and t are prime numbers.
  • 3. The properties of the compound differ sharply from the properties of its constituent components.
  • 4. The melting (dissociation) temperature is constant.
  • 5. The formation of a chemical compound is accompanied by a significant thermal effect.

Unlike solid solutions, chemical compounds are usually formed between components that have a large difference in the electronic structure of atoms and crystal lattices.

As an example of typical chemical compounds with normal valency, one can point to magnesium compounds with elements of groups IV-VI of the periodic system: Mg2Sn, Mg2Pb, Mg2P, Mg8Sb, Mg3Bia, MgS, etc.

Compounds of some metals with others - intermetallics (intermetallic compounds).

Compounds of a metal with a non-metal (nitrides, carbides, hydrides, etc.) that may have an Me bond - metal connections.

A large number of chemical compounds formed in metal alloys differ in some features from typical chemical compounds, since they do not obey the laws of valence and do not have a constant composition.

Implementation phases.

Transition metals (Fe, Mn, Cr, Mo, etc.) form compounds with carbon, nitrogen, boron and hydrogen (have a small atomic radius): carbides, nitrides, borides and hydrides. They have a common structure and properties .

Interstitial phases have the formula M4X (Fe4N, Mn4N, etc.), M2X (W2C, Mo2C, Fe2N, etc.), MX (WC, VC, TiC, NbC, TiN, VN, etc.).

The crystal structure of the interstitial phases is determined by the ratio of the atomic radii of the nonmetal (Rx) and metal (Rm). If a Rx/Rm< 59, то атомы металла в этих фазах расположены по типу одной из простых кристаллических решеток: кубической (К8, К12) или гексагональной (Г12), в которую внедряются атомы неметалла, занимая в ней определенные поры.

The intercalation phases are phases of variable composition. Carbides and nitrides related to interstitial phases have high hardness.

The interstitial solid solutions considered above are formed at a much lower concentration of the second component(C, N, I) and have a solvent metal lattice, while the interstitial phases receive a crystal lattice different from that of the metal.

If condition RX/RM< 0,59 не выполняется, как это наблюдается для карбида железа, марганца и хрома, то образуются соединения с более сложными решетками, и такие соединения нельзя считать фазами внедрения. На базе фаз внедрения легко образуются subtraction Solid Solutions, sometimes called solid solutions with a defective lattice. In subtraction solid solutions, some of the lattice sites, which should be occupied by atoms of one of the components, turn out to be free. In excess compared to the stoichiometric ratio MPHt there is another component.

Electronic connections

Univalent Me and NeMe transition groups are connected to simple Me with a valency of 2 to 5 (Cu, Ag, Co, Fe). They have a definitive ratio of the number of valence e to the number of atoms (e concentration): 3/2 (1.5); 21/13 (1.62); 7/4 (1.75).

Unlike chem. connect. With normal valency, they form solid solutions in a wide concentration range.

Laves phases.

These phases have the formula AB2 and are formed between components of type A and B at a ratio of atomic diameters DA/DB= 1.2 (usually 1.1-1.6). Laves phases have a close-packed hexagonal (MgZn2 and MgNi2) or face-centered cubic (MgCu2) crystal lattice. Laves phases include AgBe2, CaAl2, TiBe2, TiCr2, etc. (MgCu2 type) or BaMg2, MoBe2, TiMn2, etc. (MgZn2 type).

The classification of inorganic substances and their nomenclature are based on the simplest and most constant characteristic over time - chemical composition, which shows the atoms of the elements that form a given substance, in their numerical ratio. If a substance is made up of atoms of one chemical element, i.e. is a form of existence of this element in a free form, then it is called a simple substance; if the substance is made up of atoms of two or more elements, then it is called complex substance. All simple substances (except monatomic) and all complex substances are called chemical compounds, since in them the atoms of one or different elements are interconnected by chemical bonds.

The nomenclature of inorganic substances consists of formulas and names. Chemical formula - depiction of the composition of a substance with the help of symbols of chemical elements, numerical indices and some other signs. chemical name - a representation of the composition of a substance using a word or group of words. The construction of chemical formulas and names is determined by the system nomenclature rules.

Symbols and names of chemical elements are given in the Periodic system of elements of D.I. Mendeleev. Elements are conditionally divided into metals and nonmetals . Non-metals include all elements of the VIIIA group (noble gases) and VIIA group (halogens), elements of the VIA group (except polonium), elements nitrogen, phosphorus, arsenic (VA group); carbon, silicon (IVA-group); boron (IIIA-group), as well as hydrogen. The remaining elements are classified as metals.

When compiling the names of substances, Russian names of elements are usually used, for example, dioxygen, xenon difluoride, potassium selenate. By tradition, for some elements, the roots of their Latin names are introduced into derivative terms:

For example: carbonate, manganate, oxide, sulfide, silicate.

Titles simple substances consist of one word - the name of a chemical element with a numerical prefix, for example:

The following numerical prefixes:

An indefinite number is indicated by a numerical prefix n- poly.

For some simple substances also use special names such as O 3 - ozone, P 4 - white phosphorus.

Chemical formulas complex substances are made up of the designation electropositive(conditional and real cations) and electronegative(conditional and real anions) components, for example, CuSO 4 (here Cu 2+ is a real cation, SO 4 2 is a real anion) and PCl 3 (here P + III is a conditional cation, Cl -I is a conditional anion).

Titles complex substances make up the chemical formulas from right to left. They consist of two words - the names of the electronegative components (in the nominative case) and the electropositive components (in the genitive case), for example:

CuSO 4 - copper(II) sulfate
PCl 3 - phosphorus trichloride
LaCl 3 - lanthanum(III) chloride
CO - carbon monoxide

The number of electropositive and electronegative components in the names is indicated by the numerical prefixes given above (universal method), or by the oxidation states (if they can be determined by the formula) using Roman numerals in parentheses (the plus sign is omitted). In some cases, the ion charge is given (for complex cations and anions), using Arabic numerals with the corresponding sign.

The following special names are used for common multielement cations and anions:

H 2 F + - fluoronium

C 2 2 - - acetylenide

H 3 O + - oxonium

CN - - cyanide

H 3 S + - sulfonium

CNO - - fulminate

NH 4 + - ammonium

HF 2 - - hydrodifluoride

N 2 H 5 + - hydrazinium (1+)

HO 2 - - hydroperoxide

N 2 H 6 + - hydrazinium (2+)

HS - - hydrosulfide

NH 3 OH + - hydroxylaminium

N 3 - - azide

NO + - nitrosyl

NCS - - thiocyanate

NO 2 + - nitroyl

O 2 2 - - peroxide

O 2 + - dioxygenyl

O 2 - - superoxide

PH 4 + - phosphonium

O 3 - - ozonide

VO 2 + - vanadyl

OCN - - cyanate

UO 2 + - uranyl

OH - - hydroxide

For a small number of well-known substances also use special titles:

1. Acid and basic hydroxides. salt

Hydroxides - a type of complex substances, which include atoms of a certain element E (except for fluorine and oxygen) and the hydroxo group OH; general formula of hydroxides E (OH) n, where n= 1÷6. Hydroxide form E(OH) n called ortho-form; at n> 2 hydroxide can also be found in meta-form, including, in addition to E atoms and OH groups, oxygen atoms O, for example, E (OH) 3 and EO (OH), E (OH) 4 and E (OH) 6 and EO 2 (OH) 2.

Hydroxides are divided into two chemically opposite groups: acidic and basic hydroxides.

Acid hydroxides contain hydrogen atoms, which can be replaced by metal atoms, subject to the rule of stoichiometric valency. Most acid hydroxides are found in meta-form, and hydrogen atoms in the formulas of acid hydroxides are put in the first place, for example, H 2 SO 4, HNO 3 and H 2 CO 3, and not SO 2 (OH) 2, NO 2 (OH) and CO (OH) 2. The general formula of acid hydroxides is H X EO at, where the electronegative component EO y x - called an acid residue. If not all hydrogen atoms are replaced by a metal, then they remain in the composition of the acid residue.

The names of common acid hydroxides consist of two words: their own name with the ending "aya" and the group word "acid". Here are the formulas and proper names of common acid hydroxides and their acid residues (a dash means that the hydroxide is not known in free form or in an acidic aqueous solution):

acid hydroxide

acid residue

HAsO 2 - metaarsenous

AsO 2 - - metaarsenite

H 3 AsO 3 - orthoarsenic

AsO 3 3 - - orthoarsenite

H 3 AsO 4 - arsenic

AsO 4 3 - - arsenate

B 4 O 7 2 - - tetraborate

ВiО 3 - - bismuthate

HBrO - bromine

BrO - - hypobromite

HBrO 3 - bromine

BrO 3 - - bromate

H 2 CO 3 - coal

CO 3 2 - - carbonate

HClO - hypochlorous

ClO- - hypochlorite

HClO 2 - chloride

ClO 2 - - chlorite

HClO 3 - chlorine

ClO 3 - - chlorate

HClO 4 - chlorine

ClO 4 - - perchlorate

H 2 CrO 4 - chrome

CrO 4 2 - - chromate

НCrO 4 - - hydrochromate

H 2 Cr 2 O 7 - dichromic

Cr 2 O 7 2 - - dichromate

FeO 4 2 - - ferrate

HIO 3 - iodine

IO3- - iodate

HIO 4 - metaiodine

IO 4 - - metaperiodate

H 5 IO 6 - orthoiodic

IO 6 5 - - orthoperiodate

HMnO 4 - manganese

MnO4- - permanganate

MnO 4 2 - - manganate

MoO 4 2 - - molybdate

HNO 2 - nitrogenous

NO 2 - - nitrite

HNO 3 - nitrogen

NO 3 - - nitrate

HPO 3 - metaphosphoric

PO 3 - - metaphosphate

H 3 PO 4 - orthophosphoric

PO 4 3 - - orthophosphate

HPO 4 2 - - hydrogen orthophosphate

H 2 PO 4 - - dihydrootophosphate

H 4 P 2 O 7 - diphosphoric

P 2 O 7 4 - - diphosphate

ReO 4 - - perrhenate

SO 3 2 - - sulfite

HSO 3 - - hydrosulfite

H 2 SO 4 - sulfuric

SO 4 2 - - sulfate

НSO 4 - - hydrosulphate

H 2 S 2 O 7 - dispersed

S 2 O 7 2 - - disulfate

H 2 S 2 O 6 (O 2) - peroxodisulfur

S 2 O 6 (O 2) 2 - - peroxodisulfate

H 2 SO 3 S - thiosulfuric

SO 3 S 2 - - thiosulfate

H 2 SeO 3 - selenium

SeO 3 2 - - selenite

H 2 SeO 4 - selenium

SeO 4 2 - - selenate

H 2 SiO 3 - metasilicon

SiO 3 2 - - metasilicate

H 4 SiO 4 - orthosilicon

SiO 4 4 - - orthosilicate

H 2 TeO 3 - telluric

TeO 3 2 - - tellurite

H 2 TeO 4 - metatellurium

TeO 4 2 - - metatellurate

H 6 TeO 6 - orthotelluric

TeO 6 6 - - orthotellurate

VO3- - metavanadate

VO 4 3 - - orthovanadate

WO 4 3 - - tungstate

Less common acid hydroxides are named according to the nomenclature rules for complex compounds, for example:

The names of acid residues are used in the construction of the names of salts.

Basic hydroxides contain hydroxide ions, which can be replaced by acidic residues, subject to the rule of stoichiometric valency. All basic hydroxides are found in ortho-form; their general formula is M(OH) n, where n= 1.2 (rarely 3.4) and M n+ - metal cation. Examples of formulas and names of basic hydroxides:

The most important chemical property of basic and acid hydroxides is their interaction with each other with the formation of salts ( salt formation reaction), for example:

Ca (OH) 2 + H 2 SO 4 \u003d CaSO 4 + 2H 2 O

Ca (OH) 2 + 2H 2 SO 4 \u003d Ca (HSO 4) 2 + 2H 2 O

2Ca(OH) 2 + H 2 SO 4 = Ca 2 SO 4 (OH) 2 + 2H 2 O

Salts - a type of complex substances, which include cations M n+ and acid residues*.

Salts with the general formula M X(EO at)n called average salts, and salts with unsubstituted hydrogen atoms - sour salts. Sometimes salts also contain hydroxide and/or oxide ions; such salts are called main salts. Here are examples and names of salts:

calcium orthophosphate

Calcium dihydroorthophosphate

Calcium hydrogen phosphate

Copper(II) carbonate

Cu 2 CO 3 (OH) 2

Dicopper dihydroxide carbonate

Lanthanum(III) nitrate

Titanium oxide dinitrate

Acid and basic salts can be converted to medium salts by reaction with the corresponding basic and acidic hydroxide, for example:

Ca (HSO 4) 2 + Ca (OH) \u003d CaSO 4 + 2H 2 O

Ca 2 SO 4 (OH) 2 + H 2 SO 4 \u003d Ca 2 SO 4 + 2H 2 O

There are also salts containing two different cations: they are often called double salts, for example:

2. Acid and basic oxides

Oxides E X O at- products of complete dehydration of hydroxides:

Acid hydroxides (H 2 SO 4, H 2 CO 3) meet acidic oxides(SO 3, CO 2), and basic hydroxides (NaOH, Ca (OH) 2) - mainoxides(Na 2 O, CaO), and the oxidation state of the element E does not change when moving from hydroxide to oxide. An example of formulas and names of oxides:

Acid and basic oxides retain the salt-forming properties of the corresponding hydroxides when interacting with hydroxides of opposite properties or with each other:

N 2 O 5 + 2NaOH \u003d 2NaNO 3 + H 2 O

3CaO + 2H 3 PO 4 = Ca 3 (PO 4) 2 + 3H 2 O

La 2 O 3 + 3SO 3 \u003d La 2 (SO 4) 3

3. Amphoteric oxides and hydroxides

Amphoteric hydroxides and oxides - a chemical property consisting in the formation of two rows of salts by them, for example, for hydroxide and aluminum oxide:

(a) 2Al(OH) 3 + 3SO 3 = Al 2 (SO 4) 3 + 3H 2 O

Al 2 O 3 + 3H 2 SO 4 \u003d Al 2 (SO 4) 3 + 3H 2 O

(b) 2Al(OH) 3 + Na 2 O = 2NaAlO 2 + 3H 2 O

Al 2 O 3 + 2NaOH \u003d 2NaAlO 2 + H 2 O

Thus, hydroxide and aluminum oxide in reactions (a) exhibit the properties major hydroxides and oxides, i.e. react with acid hydroxides and oxide, forming the corresponding salt - aluminum sulfate Al 2 (SO 4) 3, while in reactions (b) they also exhibit properties acidic hydroxides and oxides, i.e. react with basic hydroxide and oxide, forming a salt - sodium dioxoaluminate (III) NaAlO 2 . In the first case, the aluminum element exhibits the property of a metal and is part of the electropositive component (Al 3+), in the second - the property of a non-metal and is part of the electronegative component of the salt formula (AlO 2 -).

If these reactions proceed in an aqueous solution, then the composition of the resulting salts changes, but the presence of aluminum in the cation and anion remains:

2Al(OH) 3 + 3H 2 SO 4 = 2 (SO 4) 3

Al(OH) 3 + NaOH = Na

Here square brackets denote complex ions 3+ - hexaaquaaluminum(III) cation, - - tetrahydroxoaluminate(III)-ion.

Elements that exhibit metallic and non-metallic properties in compounds are called amphoteric, these include elements of the A-groups of the Periodic system - Be, Al, Ga, Ge, Sn, Pb, Sb, Bi, Po, etc., as well as most elements of B- groups - Cr, Mn, Fe, Zn, Cd, Au, etc. Amphoteric oxides are called the same as the main ones, for example:

Amphoteric hydroxides (if the oxidation state of the element exceeds + II) can be in ortho- or (and) meta- form. Here are examples of amphoteric hydroxides:

Amphoteric oxides do not always correspond to amphoteric hydroxides, since when trying to obtain the latter, hydrated oxides are formed, for example:

If several oxidation states correspond to an amphoteric element in compounds, then the amphotericity of the corresponding oxides and hydroxides (and, consequently, the amphotericity of the element itself) will be expressed differently. For low oxidation states, hydroxides and oxides have a predominance of basic properties, and the element itself has metallic properties, so it is almost always a part of cations. For high oxidation states, on the contrary, hydroxides and oxides have a predominance of acidic properties, and the element itself has non-metallic properties, so it is almost always included in the composition of anions. Thus, manganese(II) oxide and hydroxide are dominated by basic properties, and manganese itself is part of the 2+ type cations, while acidic properties are dominant in manganese(VII) oxide and hydroxide, and manganese itself is part of the anion of the MnO 4 - . Amphoteric hydroxides with a large predominance of acidic properties are assigned formulas and names based on the model of acid hydroxides, for example HMn VII O 4 - manganese acid.

Thus, the division of elements into metals and non-metals is conditional; between elements (Na, K, Ca, Ba, etc.) with purely metallic properties and elements (F, O, N, Cl, S, C, etc.) with purely non-metallic properties, there is a large group of elements with amphoteric properties.

4. Binary connections

An extensive type of inorganic complex substances is binary compounds. These include, first of all, all two-element compounds (except basic, acidic and amphoteric oxides), for example H 2 O, KBr, H 2 S, Cs 2 (S 2), N 2 O, NH 3, HN 3, CaC 2 , SiH 4 . The electropositive and electronegative components of the formulas of these compounds include single atoms or bonded groups of atoms of the same element.

Multi-element substances, in the formulas of which one of the components contains atoms of several elements that are not interconnected, as well as single-element or multi-element groups of atoms (except hydroxides and salts), are considered as binary compounds, for example CSO, IO 2 F 3, SBrO 2 F, CrO (O 2) 2 , PSI 3 , (CaTi)O 3 , (FeCu)S 2 , Hg(CN) 2 , (PF 3) 2 O, VCl 2 (NH 2). Thus, CSO can be represented as a CS 2 compound in which one sulfur atom is replaced by an oxygen atom.

The names of binary compounds are built according to the usual nomenclature rules, for example:

OF 2 - oxygen difluoride

K 2 O 2 - potassium peroxide

HgCl 2 - mercury(II) chloride

Na 2 S - sodium sulfide

Hg 2 Cl 2 - dirtuti dichloride

Mg 3 N 2 - magnesium nitride

SBr 2 O - sulfur oxide-dibromide

NH 4 Br - ammonium bromide

N 2 O - dinitrogen oxide

Pb (N 3) 2 - lead (II) azide

NO 2 - nitrogen dioxide

CaC 2 - calcium acetylenide

For some binary compounds, special names are used, the list of which was given earlier.

The chemical properties of binary compounds are quite diverse, so they are often divided into groups according to the name of the anions, i.e. halides, chalcogenides, nitrides, carbides, hydrides, etc. are considered separately. Among binary compounds, there are also those that have some signs of other types of inorganic substances. So, the compounds CO, NO, NO 2, and (Fe II Fe 2 III) O 4, whose names are built using the word oxide, cannot be attributed to the type of oxides (acidic, basic, amphoteric). Carbon monoxide CO, nitrogen monoxide NO and nitrogen dioxide NO 2 do not have the corresponding acidic hydroxides (although these oxides are formed by non-metals C and N), they do not form salts, the anions of which would include atoms C II, N II and N IV. Double oxide (Fe II Fe 2 III) O 4 - oxide of diiron (III) - iron (II), although it contains atoms of the amphoteric element - iron, in the composition of the electropositive component, but in two different degrees of oxidation, as a result of which, when interacting with acid hydroxides, it forms not one, but two different salts.

Binary compounds such as AgF, KBr, Na 2 S, Ba (HS) 2 , NaCN, NH 4 Cl, and Pb (N 3) 2 are built, like salts, from real cations and anions, therefore they are called saline binary compounds (or just salts). They can be considered as products of substitution of hydrogen atoms in the compounds HF, HCl, HBr, H 2 S, HCN, and HN 3 . The latter in an aqueous solution have an acidic function, and therefore their solutions are called acids, for example HF (aqua) - hydrofluoric acid, H 2 S (aqua) - hydrosulfide acid. However, they do not belong to the type of acid hydroxides, and their derivatives do not belong to the salts within the classification of inorganic substances.

All simple substances in inorganic chemistry are divided into two large groups: Metals - Non-metals.

Metal (the name comes from the Latin metallum - mine) - one of the classes of elements that, unlike non-metals (and metalloids), have characteristic metallic properties. Metals are the majority of chemical elements (about 70%). The most common metal in the earth's crust is aluminum.

Characteristic properties of metals: - metallic luster (except for iodine. Despite its metallic luster, crystalline iodine is a non-metal); - good electrical conductivity; - the possibility of easy machining (for example, plasticity); - high density; - high melting point (excluding mercury, etc.); - high thermal conductivity; - in the reactions are reducing agents.

All metals (except mercury) are solid under normal conditions. Melting points range from −39°C (mercury) to 3410°C (tungsten). Depending on their density, metals are divided into light (density 0.53 ÷ 5 g/cm³) and heavy (5 ÷ 22.5 g/cm³).

On the outer electronic layer, most metals have a small number of electrons (1-3), so in most reactions they act as reducing agents (that is, they “give away” their electrons).

All metals react with oxygen except gold and platinum. The reaction with silver occurs at high temperatures, but silver(II) oxide is practically not formed, because it is thermally unstable. Depending on the metal, the output may be oxides, peroxides, superoxides: 2Li + O2 = 2Li2O lithium oxide; 2Na + O2 = Na2O2 sodium peroxide; K + O2 = KO2 potassium superoxide. To obtain oxide from peroxide, the peroxide is reduced with a metal: Na2O2 + 2Na = 2Na2O. With medium and low-active metals, the reaction occurs when heated: 3Fe + 2O2 = Fe3O4; 2Hg + O2 = 2HgO; 2Cu + O2 = 2CuO.

Only the most active metals react with nitrogen, only lithium interacts at room temperature: 6Li + N2 = 2Li3N. When heated: 2AL + N2 = 2AlN; 3Ca + N2 = 2Ca3N2.

All metals react with sulfur except gold and platinum.

Nonmetals. Elements with typically non-metallic properties occupy the upper right corner of the Periodic Table. Their location in the main subgroups of the respective periods is as follows:

2nd period

3rd period

4th period

5th period

6th period

A characteristic feature of non-metals is a larger (compared with metals) number of electrons at the external energy level of their atoms. This determines their greater ability to add additional electrons and exhibit higher oxidative activity than metals.

Nonmetals have high electron affinities, high electronegativity, and high redox potential.

Due to the high ionization energies of nonmetals, their atoms can form covalent chemical bonds with atoms of other nonmetals and amphoteric elements. In contrast to the predominantly ionic nature of the structure of typical metal compounds, simple non-metallic substances, as well as non-metal compounds, have a covalent nature of the structure.

In free form, there can be gaseous non-metallic simple substances - fluorine, chlorine, oxygen, nitrogen, hydrogen, solid - iodine, astatine, sulfur, selenium, tellurium, phosphorus, arsenic, carbon, silicon, boron, at room temperature there is bromine in the liquid state .

All complex substances (that is, consisting of two or more chemical elements) are divided into the following groups:

Oxides - Salts - Bases - Acids

Oxide (oxide, oxide) - a compound of a chemical element with oxygen, in which oxygen itself is associated only with a less electronegative element. Apart from fluorine, oxygen is the most electronegative chemical element, therefore almost all compounds of chemical elements with oxygen belong to oxides. Exceptions include, for example, oxygen difluoride OF2.

Oxides are a very common type of compounds found in the earth's crust and in the universe in general. Examples of such compounds are rust, water, sand, carbon dioxide, a number of dyes. Oxides are a class of minerals that are compounds of a metal with oxygen.

Compounds containing oxygen atoms connected to each other are called peroxides (peroxides) and superoxides. They do not belong to the category of oxides.

Depending on the chemical properties, there are: salt-forming oxides; basic oxides (for example, sodium oxide Na2O, copper(II) oxide CuO); acidic oxides (for example, sulfur(VI) oxide SO3, nitric oxide(IV) NO2); amphoteric oxides (for example, zinc oxide ZnO, aluminum oxide Al2O3); non-salt-forming oxides (for example, carbon monoxide (II) CO, nitric oxide (I) N2O, nitric oxide (II) NO).

salt - a class of chemical compounds, crystalline substances, in appearance similar to ordinary table salt.

Salts have an ionic structure. When dissolved (dissociated) in aqueous solutions, salts give positively charged metal ions and negatively charged ions of acidic residues (sometimes also hydrogen ions or hydroxo groups). Depending on the ratio of the amounts of acid and base, salts of different composition can be formed in neutralization reactions.

Salt types:

Medium (normal) salts - all hydrogen atoms in acid molecules are replaced by metal atoms. Example: Na2CO3, K3PO4;

Acid salts - hydrogen atoms in acid molecules are partially replaced by metal atoms. They are obtained by neutralizing the base with an excess of acid. Example: NaHCO3, K2HPO4;

Basic salts - hydroxo groups of the base (OH-) are partially replaced by acidic residues. Obtained with an excess of base. Example: Mg(OH)Cl;

Double salts - are formed when the hydrogen atoms in the acid are replaced by atoms of two different metals. Example: CaCO3 MgCO3, Na2KPO4;

Mixed salts contain one cation and two anions. Example: Ca(OCl)Cl;

Hydrated salts (crystal hydrates) - they contain molecules of crystallization water. Example: CuSO4 5H2O;

Complex salts are a special class of salts. These are complex substances, in the structure of which a coordination sphere is distinguished, consisting of a complexing agent (central particle) and surrounding ligands. Example: K2, Cl3, (NO3)2;

A special group is made up of salts of organic acids, the properties of which differ significantly from those of mineral salts.

Foundations - (basic hydroxides) - a class of chemical compounds, substances whose molecules consist of metal ions or an ammonium ion and one (or more) hydroxo group (hydroxide) -OH. In an aqueous solution, they dissociate with the formation of cations and anions OH-. The name of the base usually consists of two words: "metal/ammonium hydroxide". Bases that are readily soluble in water are called alkalis.

According to another definition, bases are one of the main classes of chemical compounds, substances whose molecules are proton acceptors. In organic chemistry, by tradition, bases are also called substances capable of producing adducts (“salts”) with strong acids, for example, many alkaloids are described both in the form of “alkaloid-base” and in the form of “salts of alkaloids”.

Base classification: water-soluble bases (alkalis): LiOH, NaOH, KOH, Ca(OH)2; practically water-insoluble hydroxides: Mg(OH)2, Zn(OH)2, Cu(OH)2, Al(OH)3, Fe(OH)3; other bases: NH3 × H2O.

Chemical properties:

1. Action on indicators: litmus - blue, methyl orange - yellow, phenolphthalein - raspberry,

2. Base + acid = Salts + water NaOH + HCl = NaCl + H2O

3. Alkali + acid oxide \u003d salts + water 2NaOH + SiO2 \u003d Na2SiO3 + H2O

4. Alkali + salts = (new) base + (new) salt Ba(OH)2 + Na2SO4 = BaSO4&darr + 2NaOH

acids - one of the main classes of chemical compounds. They got their name from the sour taste of most acids, such as nitric or sulfuric. By definition, an acid is a protolith (a substance involved in reactions involving the transfer of a proton) that donates a proton in reaction with a base, that is, a substance that accepts a proton. In the light of the theory of electrolytic dissociation, an acid is an electrolyte; during electrolytic dissociation, only hydrogen cations are formed from cations.

Acid classification:

By basicity - the number of hydrogen atoms: monobasic (HPO3), dibasic (H2SeO4, Azelaic acid), tribasic (H3PO4);

By strength: strong (dissociate almost completely, dissociation constants greater than 1 10-3 (HNO3)) and weak (dissociation constant less than 1 10-3 (acetic acid Kd = 1.7 10-5));

By stability: stable (H2SO4) and unstable (H2CO3);

By belonging to the classes of chemical compounds: inorganic (HBr), organic (HCOOH);

By volatility: volatile (H2S) and non-volatile;

By solubility: soluble (H2SiO3) and insoluble.