Chemical properties of acidic oxides. Chemical properties of water

Today we begin our acquaintance with the most important classes inorganic compounds... Inorganic substances are divided according to their composition, as you already know, into simple and complex ones.

OXIDE

ACID

BASE

SALT

E x O y

NnA

A - acid residue

Me (OH)b

OH - hydroxyl group

Me n A b

Complex inorganic substances are divided into four classes: oxides, acids, bases, salts. We start with the oxide class.

OXIDES

Oxides - These are complex substances, consisting of two chemical elements, one of which is oxygen, with a valency equal to 2. Only one chemical element - fluorine, combining with oxygen, forms not an oxide, but oxygen fluoride OF 2.
They are called simply - "oxide + element name" (see table). If the valence chemical element variable, then it is indicated by a Roman numeral, enclosed in parentheses, after the name of the chemical element.

Formula	Name	Formula	Name
	carbon monoxide (II)	Fe 2 O 3	iron (III) oxide
	nitric oxide (II)	CrO 3	chromium (VI) oxide
Al 2 O 3	aluminium oxide		zinc oxide
N 2 O 5	nitric oxide (V)	Mn 2 O 7	manganese (VII) oxide

Classification of oxides

All oxides can be divided into two groups: salt-forming (basic, acidic, amphoteric) and non-salt-forming or indifferent.

Metal oxides Me x O y

Nonmetal oxides notMe x O y

The main

Acidic

Amphoteric

Acidic

Indifferent

I, II

V-VII

ZnO, BeO, Al 2 O 3,

Fe 2 O 3, Cr 2 O 3

> II

not me

I, II

not me

CO, NO, N 2 O

1). Basic oxides Are the oxides to which the bases correspond. Basic oxides include oxides metals 1 and 2 groups, as well metals side subgroups with valence I and II (except for ZnO - zinc oxide and BeO - beryllium oxide):

2). Acidic oxides Are oxides to which acids correspond. Acid oxides include nonmetal oxides (except for non-salt-forming - indifferent), as well as metal oxides side subgroups with a valency of V before Vii (For example, CrO 3 is chromium (VI) oxide, Mn 2 O 7 is manganese (VII) oxide):

3). Amphoteric oxides- these are oxides, which correspond to bases and acids. These include metal oxides major and minor subgroups with valence III , sometimes IV as well as zinc and beryllium (For example, BeO, ZnO, Al 2 O 3, Cr 2 O 3).

4). Non-salt-forming oxides- these are oxides indifferent to acids and bases. These include nonmetal oxides with valence I and II (For example, N 2 O, NO, CO).

Conclusion: the nature of the properties of oxides primarily depends on the valence of the element.

For example, chromium oxides:

CrO (II- main);

Cr 2 O 3 (III- amphoteric);

CrO 3 (Vii- acidic).

Classification of oxides

(by solubility in water)

Acidic oxides

Basic oxides

Amphoteric oxides

Soluble in water.

Exception - SiO 2

(insoluble in water)

Only oxides of alkali and alkaline earth metals dissolve in water

(these are metals

I "A" and II "A" groups,

excluding Be, Mg)

They do not interact with water.

Insoluble in water

Complete tasks:

1. Write down separately the chemical formulas of salt-forming acid and basic oxides.

NaOH, AlCl 3, K 2 O, H 2 SO 4, SO 3, P 2 O 5, HNO 3, CaO, CO.

2. Given substances : CaO, NaOH, CO 2, H 2 SO 3, CaCl 2, FeCl 3, Zn (OH) 2, N 2 O 5, Al 2 O 3, Ca (OH) 2, CO 2, N 2 O, FeO, SO 3, Na 2 SO 4, ZnO, CaCO 3, Mn 2 O 7, CuO, KOH, CO, Fe (OH) 3

Write down oxides and classify them.

Obtaining oxides

Simulator "Interaction of oxygen with simple substances"

1. Combustion of substances (Oxidation with oxygen)	a) simple substances Training apparatus	2Mg + O 2 = 2MgO
1. Combustion of substances (Oxidation with oxygen)	b) complex substances	2H 2 S + 3O 2 = 2H 2 O + 2SO 2
2.Decomposition of complex substances (use acid table, see appendices)	a) salts SALTt= BASIC OXIDE + ACID OXIDE	СaCO 3 = CaO + CO 2
	b) Insoluble bases Me (OH)bt= Me x O y+ H 2 O	Cu (OH) 2 t = CuO + H 2 O
	c) oxygenated acids NnA =ACID OXIDE + H 2 O	H 2 SO 3 = H 2 O + SO 2

Physical properties of oxides

At room temperature most oxides are solids (CaO, Fe 2 O 3, etc.), some are liquids (H 2 O, Cl 2 O 7, etc.) and gases (NO, SO 2, etc.).

Chemical properties of oxides

CHEMICAL PROPERTIES OF BASIC OXIDES

1. Basic oxide + Acidic oxide = Salt (p. Compound)

CaO + SO 2 = CaSO 3

2. Basic oxide + Acid = Salt + H 2 O (p. Exchange)

3 K 2 O + 2 H 3 PO 4 = 2 K 3 PO 4 + 3 H 2 O

3. Basic oxide + Water = Alkali (p. Compound)

Na 2 O + H 2 O = 2 NaOH

CHEMICAL PROPERTIES OF ACID OXIDES

1. Acid oxide + Water = Acid (p. Compound)

C O 2 + H 2 O = H 2 CO 3, SiO 2 - does not react

2. Acid oxide + Base = Salt + H 2 O (p. Exchange)

P 2 O 5 + 6 KOH = 2 K 3 PO 4 + 3 H 2 O

3. Basic oxide + Acidic oxide = Salt (p. Compound)

CaO + SO 2 = CaSO 3

4. The less volatile displace the more volatile ones from their salts

CaCO 3 + SiO 2 = CaSiO 3 + CO 2

CHEMICAL PROPERTIES OF AMPHOTHERIC OXIDES

They interact with both acids and alkalis.

ZnO + 2 HCl = ZnCl 2 + H 2 O

ZnO + 2 NaOH + H 2 O = Na 2 [Zn (OH) 4] (in solution)

ZnO + 2 NaOH = Na 2 ZnO 2 + H 2 O (when fusion)

Application of oxides

Some oxides do not dissolve in water, but many enter into a compound reaction with water:

SO 3 + H 2 O = H 2 SO 4

CaO + H 2 O = Ca( OH) 2

The result is often highly desirable and useful compounds. For example, H 2 SO 4 is sulfuric acid, Ca (OH) 2 is slaked lime, etc.

If oxides are insoluble in water, then people skillfully use this property as well. For example, zinc oxide ZnO is a substance white, therefore it is used to prepare white oil paint(zinc white). Since ZnO is practically insoluble in water, zinc white can be used to paint any surfaces, including those that are exposed to atmospheric precipitation. Insolubility and non-toxicity make it possible to use this oxide in the manufacture of cosmetic creams and powders. Pharmacists make it an astringent and drying powder for external use.

Titanium (IV) oxide - TiO 2 possesses the same valuable properties. It also has a beautiful white color and is used to make titanium white. TiO 2 does not dissolve not only in water, but also in acids; therefore, coatings made of this oxide are especially resistant. This oxide is added to the plastic to give it a white color. It is part of enamels for metal and ceramic dishes.

Chromium (III) oxide - Cr 2 O 3 - very strong crystals of dark green color, insoluble in water. Cr 2 O 3 is used as a pigment (paint) in the manufacture of decorative green glass and ceramics. The GOI paste known to many (abbreviated from the name "State Optical Institute") is used for grinding and polishing optics, metal products, in jewelry.

Due to the insolubility and strength of chromium (III) oxide, it is also used in printing inks (for example, for coloring banknotes). In general, oxides of many metals are used as pigments for a wide variety of paints, although this is far from their only application.

Tasks for consolidation

1. Write down separately the chemical formulas of salt-forming acid and basic oxides.

NaOH, AlCl 3, K 2 O, H 2 SO 4, SO 3, P 2 O 5, HNO 3, CaO, CO.

2. Given substances : CaO, NaOH, CO 2, H 2 SO 3, CaCl 2, FeCl 3, Zn (OH) 2, N 2 O 5, Al 2 O 3, Ca (OH) 2, CO 2, N 2 O, FeO, SO 3, Na 2 SO 4, ZnO, CaCO 3, Mn 2 O 7, CuO, KOH, CO, Fe (OH) 3

Choose from the list: basic oxides, acidic oxides, indifferent oxides, amphoteric oxides and give them names.

3. Finish CCM, indicate the type of reaction, name the reaction products

Na 2 O + H 2 O =

N 2 O 5 + H 2 O =

CaO + HNO 3 =

NaOH + P 2 O 5 =

K 2 O + CO 2 =

Cu (OH) 2 =? +?

4. Carry out the transformations according to the scheme:

1) K → K 2 O → KOH → K 2 SO 4

2) S → SO 2 → H 2 SO 3 → Na 2 SO 3

3) P → P 2 O 5 → H 3 PO 4 → K 3 PO 4

Modern chemical science represents many different branches, and each of them, in addition to the theoretical basis, has great applied value, practical. Whatever you touch, everything around is chemical products. The main sections are inorganic and organic chemistry... Let us consider which main classes of substances are classified as inorganic and what properties they possess.

Main categories of inorganic compounds

These include the following:

Oxides.
Salt.
Foundations.
Acids.

Each of the classes is represented by a wide variety of compounds of inorganic nature and is important in almost any structure of human economic and industrial activity. All the main properties characteristic of these compounds, being in nature and receiving, are studied in the school chemistry course without fail, in grades 8-11.

There is a general table of oxides, salts, bases, acids, which presents examples of each of the substances and their state of aggregation, being in nature. Interactions describing chemical properties are also shown. However, we will look at each of the classes separately and in more detail.

Group of compounds - oxides

4. Reactions as a result of which the elements change CO

Me + n O + C = Me 0 + CO

1. Reagent water: acid formation (SiO 2 exclusion)

KO + water = acid

2. Reactions with bases:

CO 2 + 2CsOH = Cs 2 CO 3 + H 2 O

3. Reactions with basic oxides: salt formation

P 2 O 5 + 3MnO = Mn 3 (PO 3) 2

4. OVR reactions:

CO 2 + 2Ca = C + 2CaO,

They exhibit dual properties, interact according to the principle of the acid-base method (with acids, alkalis, basic oxides, acid oxides). They do not interact with water.

1.With acids: formation of salts and water

AO + acid = salt + H 2 O

2.With bases (alkalis): formation of hydroxo complexes

Al 2 O 3 + LiOH + water = Li

3. Reactions with acidic oxides: obtaining salts

FeO + SO 2 = FeSO 3

4. Reactions with RO: salt formation, fusion

MnO + Rb 2 O = double salt Rb 2 MnO 2

5. Fusion reactions with alkalis and alkali metal carbonates: salt formation

Al 2 O 3 + 2LiOH = 2LiAlO 2 + H 2 O

They form neither acids nor alkalis. Show narrowly specific properties.

Each higher oxide, formed by both metal and non-metal, dissolves in water, gives a strong acid or alkali.

Organic and inorganic acids

In the classical sound (based on the positions of ED - electrolytic dissociation - acids are compounds, in aquatic environment dissociating into H + cations and anions of acid residues An -. However, acids have been thoroughly studied in anhydrous conditions today, so there are many different theories for hydroxides.

Empirical formulas of oxides, bases, acids, salts are composed only of symbols, elements and indices indicating their amount in a substance. For example, inorganic acids are expressed by the formula H + acidic residue n-. Organic matter have a different theoretical mapping. In addition to the empirical one, for them you can write the full and abbreviated structural formula, which will reflect not only the composition and number of the molecule, but also the order of arrangement of atoms, their bond with each other and the main functional group for carboxylic acids -COOH.

In an inorganic, all acids are divided into two groups:

oxygen-free - HBr, HCN, HCL and others;
oxygen-containing (oxo acids) - HClO 3 and everything where there is oxygen.

Also, inorganic acids are classified by stability (stable or stable - everything except carbonic and sulphurous, unstable or unstable - carbonic and sulphurous). In terms of strength, acids can be strong: sulfuric, hydrochloric, nitric, chloric and others, as well as weak: hydrogen sulfide, hypochlorous and others.

Organic chemistry offers far less variety. Acids that are organic in nature are carboxylic acids. Their common feature- the presence of a functional group -COOH. For example, HCOOH (formic), CH 3 COOH (acetic), C 17 H 35 COOH (stearic) and others.

There are a number of acids that are especially emphasized when considering this topic in a school chemistry course.

Salt.
Nitrogen.
Orthophosphoric.
Hydrobromic.
Coal.
Hydrogen iodide.
Sulfuric.
Acetic, or ethane.
Butane, or oil.
Benzoin.

These 10 acids in chemistry are the fundamental substances of the corresponding class both in the school course and in industry and synthesis in general.

Properties of inorganic acids

The main physical properties include, first of all, a different state of aggregation. After all, there are a number of acids in the form of crystals or powders (boric, orthophosphoric) at normal conditions... The overwhelming majority of the well-known inorganic acids are different liquids. Boiling and melting points also vary.

Acids can cause severe burns, as they have a force that destroys organic tissue and skin. Indicators are used to detect acids:

methyl orange (in a normal environment - orange, in acids - red),
litmus (in neutral - violet, in acids - red) or some others.

The most important chemical properties include the ability to interact with both simple and complex substances.

Chemical properties inorganic acids

What they interact with	Example reaction
1. With simple substances, metals. A prerequisite: the metal must stand in the EHRNM before hydrogen, since the metals that are after hydrogen are not able to displace it from the composition of acids. The reaction always produces hydrogen gas and salt.
2. With bases. The result of the reaction is salt and water. Such reactions of strong acids with alkalis are called neutralization reactions.	Any acid (strong) + soluble base = salt and water
3. With amphoteric hydroxides. Bottom line: salt and water.	2HNO 2 + beryllium hydroxide = Be (NO 2) 2 (average salt) + 2H 2 O
4. With basic oxides. Bottom line: water, salt.	2HCL + FeO = iron (II) chloride + H 2 O
5. With amphoteric oxides. The net effect is salt and water.	2HI + ZnO = ZnI 2 + H 2 O
6. With salts formed by weaker acids. The net effect is salt and weak acid.	2HBr + MgCO 3 = magnesium bromide + H 2 O + CO 2

When interacting with metals, not all acids react in the same way. Chemistry (grade 9) at school involves a very shallow study of such reactions, however, even at this level, the specific properties of concentrated nitric and sulfuric acid are considered when interacting with metals.

Hydroxides: alkalis, amphoteric and insoluble bases

Oxides, salts, bases, acids - all these classes of substances have a common chemical nature due to the structure crystal lattice, as well as the mutual influence of atoms in the composition of molecules. However, while it was possible to give a very specific definition for oxides, it is more difficult to do it for acids and bases.

Just like acids, according to the theory of ED, bases are called substances capable of aqueous solution decompose into metal cations Ме n + and anions of hydroxo groups ОН -.

Soluble or alkalis (strong bases that change. Formed by metals of groups I, II. Example: KOH, NaOH, LiOH (that is, only elements of the main subgroups are taken into account);
Slightly soluble or insoluble (medium strength, do not change the color of indicators). Example: hydroxide of magnesium, iron (II), (III) and others.
Molecular (weak bases, in an aqueous medium reversibly dissociate into ions-molecules). Example: N 2 H 4, amines, ammonia.
Amphoteric hydroxides (show dual basic acid properties). Example: beryllium, zinc, and so on.

Each group represented is studied in the school chemistry course in the "Foundations" section. Grade 8-9 chemistry involves a detailed study of alkalis and poorly soluble compounds.

The main characteristic properties of the bases

All alkalis and poorly soluble compounds are in nature in a solid crystalline state. At the same time, their melting points, as a rule, are low, and poorly soluble hydroxides decompose when heated. The color of the bases is different. If the alkali is white, then the crystals of poorly soluble and molecular bases can be of very different colors. The solubility of most compounds of this class can be seen in the table, which presents the formulas of oxides, bases, acids, salts, shows their solubility.

Alkalis can change the color of indicators as follows: phenolphthalein - raspberry, methyl orange - yellow. This is ensured by the free presence of hydroxyl groups in the solution. That is why poorly soluble bases do not give such a reaction.

The chemical properties of each group of bases are different.

Chemical properties

Alkalis

Slightly soluble bases

Amphoteric hydroxides

I. Interact with KO (total - salt and water):

2LiOH + SO 3 = Li 2 SO 4 + water

II. Interact with acids (salt and water):

normal neutralization reactions (see acids)

III. Interact with AO to form a hydroxo complex of salt and water:

2NaOH + Me + n O = Na 2 Me + n O 2 + H 2 O, or Na 2

IV. Interact with amphoteric hydroxides to form hydroxocomplex salts:

The same as with AO, only without water

V. Interact with soluble salts to form insoluble hydroxides and salts:

3CsOH + iron (III) chloride = Fe (OH) 3 + 3CsCl

Vi. React with zinc and aluminum in aqueous solution to form salts and hydrogen:

2RbOH + 2Al + water = complex with hydroxide ion 2Rb + 3H 2

I. When heated, they can decompose:

insoluble hydroxide = oxide + water

II. Reactions with acids (total: salt and water):

Fe (OH) 2 + 2HBr = FeBr 2 + water

III. Interact with KO:

Me + n (OH) n + KO = salt + H 2 O

I. React with acids to form salt and water:

(II) + 2HBr = CuBr 2 + water

II. Reacts with alkalis: total salt and water (condition: fusion)

Zn (OH) 2 + 2CsOH = salt + 2H 2 O

III. They react with strong hydroxides: the result is salts, if the reaction proceeds in an aqueous solution:

Cr (OH) 3 + 3RbOH = Rb 3

These are most of the chemical properties that bases exhibit. The chemistry of bases is simple enough and obeys general patterns all inorganic compounds.

Class of inorganic salts. Classification, physical properties

Based on the position of ED, salts can be called inorganic compounds, in an aqueous solution dissociating into metal cations Ме + n and anions of acid residues An n-. This is how salts can be imagined. The definition of chemistry gives more than one, but it is the most accurate.

Moreover, by their chemical nature, all salts are subdivided into:

Acidic (containing a hydrogen cation). Example: NaHSO 4.
Basic (containing a hydroxyl group). Example: MgOHNO 3, FeOHCL 2.
Medium (consist only of a metal cation and an acid residue). Example: NaCL, CaSO 4.
Double (includes two different metal cations). Example: NaAl (SO 4) 3.
Complex (hydroxocomplexes, aquacomplexes and others). Example: K 2.

Salt formulas reflect their chemical nature, and also speak about the qualitative and quantitative composition of the molecule.

Oxides, salts, bases, acids have different solubility properties, which can be found in the corresponding table.

If we talk about the state of aggregation of salts, then one should notice their uniformity. They only exist in a solid, crystalline or powdery state. The range of colors is quite varied. Solutions of complex salts, as a rule, have bright, saturated colors.

Chemical interactions for the class of medium salts

They have similar chemical properties of base, acid, salt. Oxides, as we have already considered, differ somewhat from them in this factor.

In total, 4 main types of interactions can be distinguished for medium salts.

I. Interaction with acids (only strong in terms of ED) with the formation of another salt and a weak acid:

KCNS + HCL = KCL + HCNS

II. Reactions with soluble hydroxides with the appearance of salts and insoluble bases:

CuSO 4 + 2LiOH = 2LiSO 4 soluble salt + Cu (OH) 2 insoluble base

III. Interaction with other soluble salt to form insoluble salt and soluble:

PbCL 2 + Na 2 S = PbS + 2NaCL

IV. Reactions with metals standing in the EHRNM to the left of the one that forms the salt. In this case, the metal that reacts should not interact with water under normal conditions:

Mg + 2AgCL = MgCL 2 + 2Ag

These are the main types of interactions that occur with medium salts. The formulas of complex, basic, double and acidic salts speak for themselves about the specificity of the displayed chemical properties.

Formulas of oxides, bases, acids, salts reflect the chemical essence of all representatives of these classes of inorganic compounds, and in addition, give an idea of the name of the substance and its physical properties... Therefore, their writing should be addressed Special attention... A huge variety of compounds offers us in general amazing science- chemistry. Oxides, bases, acids, salts are just a part of the immense variety.

Na 2 O + H 2 O = 2NaOH;

CaO + H 2 O = Ca (OH) 2;

with acidic compounds (acidic oxides, acids) with the formation of salts and water:

CaO + CO 2 = CaCO 3;

CaO + 2HCl = CaCl 2 + H 2 O;

3) with compounds of an amphoteric nature:

Li 2 O + Al 2 O 3 = 2Li AlO 2;

3NaOH + Al (OH) 3 = Na 3 AlO 3 + 3H 2 O;

Acidic oxides react:

1) with water with the formation of acids:

SO 3 + H 2 O = H 2 SO 4;

2) with compounds of a basic nature (basic oxides and bases) with the formation of salts and water:

SO 2 + Na 2 O = Na 2 SO 3;

CO 2 + 2NaOH = Na 2 CO 3 + H 2 O;

with amphoteric compounds

CO 2 + ZnO = ZnCO 3;

CO 2 + Zn (OH) 2 = ZnCO 3 + H 2 O;

Amphoteric oxides exhibit the properties of both basic and acidic oxides. They are answered by amphoteric hydroxides:

acidic medium alkaline medium Be (OH) 2 BeO H 2 BeO 2

Zn (OH) 2 ZnO Н 2 ZnО 2

Al (OH) 3 Al 2 O 3 H 3 AlO 3, HAlO 2

Cr (OH) 3 Cr 2 O 3 HCrO 2

Pb (OH) 2 PbO Н 2 PbО 2

Sn (OH) 2 SnO Н 2 SnО 2

Amphoteric oxides interact with acidic and basic compounds:

ZnO + SiO 2 = ZnSiO 3;

ZnO + H 2 SiO 3 = ZnSiO 3 + H 2 O;

Al 2 O 3 + 3Na 2 O = 2Na 3 AlO 3;

Al 2 O 3 + 2NaOH = 2NaAlO 2 + H 2 O.

Variable valence metals can form all three types of oxides. For example:

CrO basic Cr (OH) 2;

Cr 2 O 3 amphoteric Cr (OH) 3;

Cr 2 O 7 acidic H 2 Cr 2 O 7;

MnO, Mn 2 O 3 basic;

MnO 2 amphoteric;

Mn 2 O 7 acidic HMnO 4.

Foundations

Bases are complex substances, which include metal atoms and one or more hydroxide groups (OH ‾). The general formula of the bases is Me (OH) y, where y is the number of hydroxide groups equal to the valence of the metal.

Nomenclature

The name of the base is made up of the word "hydroxide" + the name of the metal.

If the metal has a variable valence, then it is indicated at the end in parentheses. For example: CuOH - copper (I) hydroxide, Cu (OH) 2 - copper (II) hydroxide, NaOH - sodium hydroxide.

Bases (hydroxides) are electrolytes. Electrolytes are substances that decompose into ions in melts or solutions of polar liquids: positively charged cations and negatively charged anions. The breakdown of a substance into ions is called electrolytic dissociation.

All electrolytes can be divided into two groups: strong and weak. Strong electrolytes in aqueous solutions are almost completely dissociated. Weak electrolytes dissociate only partially and in solutions a dynamic equilibrium is established between undissociated molecules and ions: NH 4 OH NH 4 + + OH -.

2.2. Classification

a) by the number of hydroxide groups in the molecule. The number of hydroxide groups in the base molecule depends on the valence of the metal and determines the acidity of the base.

The grounds are divided into:

Monoacid, the molecules of which contain one hydroxide group: NaOH, KOH, LiOH, etc.;

Two-acid, the molecules of which contain two hydroxide groups: Ca (OH) 2, Fe (OH) 2, etc.;

Three-acid, the molecules of which contain three hydroxide groups: Ni (OH) 3, Bi (OH) 3, etc.

Two- and three-acid bases are called polyacid.

b) by strength, the grounds are divided into:

Strong (alkalis): LiOH, NaOH, KOH, RbOH, CsOH, Ca (OH) 2, Sr (OH) 2, Ba (OH) 2;

Weak: Cu (OH) 2, Fe (OH) 2, Fe (OH) 3, etc.

Strong bases are soluble in water, while weak bases are insoluble.

Dissociation of bases

Strong bases dissociate almost completely:

Ca (OH) 2 = Ca 2+ + 2OH -.

Weak bases dissociate in steps. With the sequential cleavage of the hydroxide ion from multi-acid bases, basic hydroxocation residues are formed, for example:

Fe (OH) 3 OH - + Fe (OH) 2 + iron dihydroxocations;

Fe (OH) 2 + OH - + FeOH 2+ iron hydroxocations;

Fe (OH) 2+ OH - + Fe 3+ iron cations.

The number of basic residues is equal to the acidity of the base.

Oxides.

These are complex substances consisting of TWO elements, one of which is oxygen. For example:

CuO - copper (II) oxide

AI 2 O 3 - aluminum oxide

SO 3 - sulfur oxide (VI)

Oxides are divided (classified) into 4 groups:

Na 2 O - Sodium oxide

CaO - Calcium oxide

Fe 2 O 3 - iron (III) oxide

2). Acidic- These are oxides non-metals... And sometimes metals if the oxidation state of the metal is> 4. For example:

CO 2 - Carbon monoxide (IV)

Р 2 О 5 - Phosphorus (V) oxide

SO 3 - Sulfur oxide (VI)

3). Amphoteric- These are oxides that have the properties of both basic and acidic oxides. You need to know the five most common amphoteric oxides:

BeO – beryllium oxide

ZnO - Zinc oxide

AI 2 O 3 - Aluminum oxide

Cr 2 O 3 - Chromium (III) oxide

Fe 2 O 3 - Iron (III) oxide

4). Non-salt-forming (indifferent)- These are oxides that do not exhibit the properties of either basic or acidic oxides. There are three oxides to remember:

CO - carbon monoxide (II) carbon monoxide

NO - nitric oxide (II)

N 2 O - nitric oxide (I) laughing gas, nitrous oxide

Methods for producing oxides.

1). Combustion, i.e. interaction with oxygen of a simple substance:

4Na + O 2 = 2Na 2 O

4P + 5O 2 = 2P 2 O 5

2). Combustion, i.e. interaction with oxygen of a complex substance (consisting of two elements) in this case, two oxides.

2ZnS + 3O 2 = 2ZnO + 2SO 2

4FeS 2 + 11O 2 = 2Fe 2 O 3 + 8SO 2

3). Decomposition three weak acids. Others do not decompose. In this case, acidic oxide and water are formed.

H 2 CO 3 = H 2 O + CO 2

H 2 SO 3 = H 2 O + SO 2

H 2 SiO 3 = H 2 O + SiO 2

4). Decomposition insoluble grounds. Basic oxide and water are formed.

Mg (OH) 2 = MgO + H 2 O

2Al (OH) 3 = Al 2 O 3 + 3H 2 O

5). Decomposition insoluble salts. A basic oxide and an acidic oxide are formed.

CaCO 3 = CaO + CO 2

MgSO 3 = MgO + SO 2

Chemical properties.

I... Basic oxides.

alkali.

Na 2 O + H 2 O = 2NaOH

CaO + H 2 O = Ca (OH) 2

СuO + H 2 O = the reaction does not proceed, because possible base containing copper - insoluble

2). Reacts with acids to form salt and water. (Basic oxide and acids react ALWAYS)

K 2 O + 2HCI = 2KCl + H 2 O

CaO + 2HNO 3 = Ca (NO 3) 2 + H 2 O

3). Interaction with acidic oxides to form salt.

Li 2 O + CO 2 = Li 2 CO 3

3MgO + P 2 O 5 = Mg 3 (PO 4) 2

4). Interaction with hydrogen, thus forming metal and water.

CuO + H 2 = Cu + H 2 O

Fe 2 O 3 + 3H 2 = 2Fe + 3H 2 O

II.Acidic oxides.

1). Interaction with water, while acid.(OnlySiO 2 does not interact with water)

CO 2 + H 2 O = H 2 CO 3

P 2 O 5 + 3H 2 O = 2H 3 PO 4

2). Interaction with soluble bases (alkalis). This produces salt and water.

SO 3 + 2KOH = K 2 SO 4 + H 2 O

N 2 O 5 + 2KOH = 2KNO 3 + H 2 O

3). Interaction with basic oxides. In this case, only salt is formed.

N 2 O 5 + K 2 O = 2KNO 3

Al 2 O 3 + 3SO 3 = Al 2 (SO 4) 3

Basic exercises.

1). Complete the reaction equation. Determine its type.

K 2 O + P 2 O 5 =

Solution.

To write down what is formed as a result, it is necessary to determine what substances entered into the reaction - here it is potassium oxide (basic) and phosphorus oxide (acidic) according to the properties - the result should be SALT (see property No. 3) and the salt consists of atoms metals (in our case, potassium) and an acid residue, which contains phosphorus (i.e., PO 4 -3 - phosphate) Therefore

3K 2 O + R 2 O 5 = 2K 3 PO 4

type of reaction - compound (since two substances react, and one is formed)

2). Carry out transformations (chain).

Ca → CaO → Ca (OH) 2 → CaCO 3 → CaO

Solution

To complete this exercise, you must remember that each arrow is one equation (one chemical reaction). Let's number each arrow. Therefore, it is necessary to write 4 equations. The substance written to the left of the arrow (starting substance) reacts, and the substance written to the right is formed as a result of the reaction (reaction product). Let's decipher the first part of the entry:

Ca +… .. → CaO We draw your attention to the fact that a simple substance enters into a reaction, and an oxide is formed. Knowing the methods of obtaining oxides (No. 1), we come to the conclusion that in this reaction it is necessary to add –oxygen (О 2)

2Са + О 2 → 2СаО

Go to transformation # 2

CaO → Ca (OH) 2

CaO + …… → Ca (OH) 2

We come to the conclusion that here it is necessary to apply the property of basic oxides - interaction with water, since only in this case a base is formed from the oxide.

CaO + H 2 O → Ca (OH) 2

Moving on to transformation # 3

Ca (OH) 2 → CaCO 3

Ca (OH) 2 +… .. = CaCO 3 + …….

We come to the conclusion that here it comes about carbon dioxide CO 2 because only it, when interacting with alkalis, forms a salt (see property No. 2 of acidic oxides)

Ca (OH) 2 + CO 2 = CaCO 3 + H 2 O

Moving on to transformation # 4

CaCO 3 → CaO

CaCO 3 =… .. CaO + ……

We come to the conclusion that CO 2 is also formed here, since CaCO 3 is an insoluble salt and it is during the decomposition of such substances that oxides are formed.

CaCO 3 = CaO + CO 2

3). Which of the listed substances does CO 2 interact with? Write down the reaction equations.

A). Hydrochloric acid B). Sodium hydroxide B). Potassium oxide d). Water

D). Hydrogen E). Sulfur oxide (IV).

We determine that CO 2 is an acidic oxide. And acid oxides react with water, alkalis and basic oxides ... Therefore, from the given list we choose answers B, C, D And it is with them that we write down the reaction equations:

1). CO 2 + 2NaOH = Na 2 CO 3 + H 2 O

2). CO 2 + K 2 O = K 2 CO 3

Oxides complex substances are called, the molecules of which include oxygen atoms in the oxidation state - 2 and some other element.

can be obtained by direct interaction of oxygen with another element, and indirectly (for example, by decomposition of salts, bases, acids). Under normal conditions, oxides are in a solid, liquid and gaseous state, this type of compound is very common in nature. Oxides are found in the Earth's crust. Rust, sand, water, carbon dioxide Are oxides.

They are salt-forming and non-salt-forming.

Salt-forming oxides- these are oxides that, as a result chemical reactions form salts. These are oxides of metals and non-metals, which, when interacting with water, form the corresponding acids, and when interacting with bases, they form the corresponding acidic and normal salts. For example, copper oxide (CuO) is a salt-forming oxide, because, for example, when it interacts with hydrochloric acid (HCl), a salt is formed:

CuO + 2HCl → CuCl 2 + H 2 O.

Other salts can be obtained as a result of chemical reactions:

CuO + SO 3 → CuSO 4.

Non-salt-forming oxides such oxides are called which do not form salts. An example is CO, N 2 O, NO.

Salt-forming oxides, in turn, are of 3 types: basic (from the word « base » ), acidic and amphoteric.

Basic oxides such metal oxides are called, which correspond to hydroxides belonging to the class of bases. Basic oxides include, for example, Na 2 O, K 2 O, MgO, CaO, etc.

Chemical properties of basic oxides

1. Water-soluble basic oxides react with water to form bases:

Na 2 O + H 2 O → 2NaOH.

2. React with acidic oxides to form the corresponding salts

Na 2 O + SO 3 → Na 2 SO 4.

3. React with acids to form salt and water:

CuO + H 2 SO 4 → CuSO 4 + H 2 O.

4. React with amphoteric oxides:

Li 2 O + Al 2 O 3 → 2LiAlO 2.

If in the composition of the oxides as the second element there is a non-metal or a metal exhibiting the highest valence (usually from IV to VII), then such oxides will be acidic. Acidic oxides (acid anhydrides) are those oxides that correspond to hydroxides belonging to the class of acids. These are, for example, CO 2, SO 3, P 2 O 5, N 2 O 3, Cl 2 O 5, Mn 2 O 7, etc. Acidic oxides dissolve in water and alkalis to form salt and water.

Chemical properties of acidic oxides

1. Interact with water, forming acid:

SO 3 + H 2 O → H 2 SO 4.

But not all acidic oxides react directly with water (SiO 2, etc.).

2. React with base oxides to form salt:

CO 2 + CaO → CaCO 3

3. Interact with alkalis, forming salt and water:

CO 2 + Ba (OH) 2 → BaCO 3 + H 2 O.

Part amphoteric oxide includes an element that has amphoteric properties. Amphotericity is understood as the ability of compounds to exhibit acidic and basic properties, depending on the conditions. For example, zinc oxide ZnO can be both a base and an acid (Zn (OH) 2 and H 2 ZnO 2). Amphotericity is expressed in the fact that, depending on the conditions, amphoteric oxides exhibit either basic or acidic properties.

Chemical properties of amphoteric oxides

1. Interact with acids, forming salt and water:

ZnO + 2HCl → ZnCl 2 + H 2 O.

2. React with solid alkalis (when fusion), forming as a result of the reaction salt - sodium zincate and water:

ZnO + 2NaOH → Na 2 ZnO 2 + H 2 O.

When zinc oxide interacts with an alkali solution (the same NaOH), another reaction occurs:

ZnO + 2 NaOH + H 2 O => Na 2.

The coordination number is a characteristic that determines the number of the nearest particles: atoms or inov in a molecule or crystal. Each amphoteric metal has its own coordination number. For Be and Zn it is 4; For and, Al is 4 or 6; For and, Cr is 6 or (very rarely) 4;

Amphoteric oxides usually do not dissolve or react with water.

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