Reactions of oxides with metals. Chemical properties of acid oxides

1. Metal + Non-metal. Inert gases do not enter into this interaction. The higher the electronegativity of a non-metal, the more metals it will react with. For example, fluorine reacts with all metals, and hydrogen only with active ones. The further to the left a metal is in the activity series of metals, the more non-metals it can react with. For example, gold reacts only with fluorine, lithium with all non-metals.

2. Non-metal + non-metal. In this case, a more electronegative non-metal acts as an oxidizing agent, less EO - as a reducing agent. Non-metals with close electronegativity interact poorly with each other, for example, the interaction of phosphorus with hydrogen and silicon with hydrogen is practically impossible, since the equilibrium of these reactions is shifted towards the formation of simple substances. Helium, neon and argon do not react with non-metals, other inert gases under harsh conditions can react with fluorine.
Oxygen does not interact with chlorine, bromine and iodine. Oxygen can react with fluorine at low temperatures.

3. Metal + acid oxide. Metal restores non-metal from oxide. The excess metal can then react with the resulting non-metal. For example:

2 Mg + SiO 2 \u003d 2 MgO + Si (for lack of magnesium)

2 Mg + SiO 2 \u003d 2 MgO + Mg 2 Si (with excess magnesium)

4. Metal + acid. Metals to the left of hydrogen in the voltage series react with acids to release hydrogen.

The exception is acids - oxidizing agents (concentrated sulfuric and any nitric acid), which can react with metals that are in the series of voltages to the right of hydrogen, hydrogen is not released in the reactions, but water and the acid reduction product are obtained.

It is necessary to pay attention to the fact that when a metal interacts with an excess of a polybasic acid, an acid salt can be obtained: Mg +2 H 3 PO 4 \u003d Mg (H 2 PO 4) 2 + H 2.

If the product of the interaction of an acid and a metal is an insoluble salt, then the metal is passivated, since the surface of the metal is protected by the insoluble salt from the action of the acid. For example, the action of dilute sulfuric acid on lead, barium or calcium.

5. Metal + salt. in solution this reaction involves a metal to the right of magnesium in the voltage series, including magnesium itself, but to the left of the salt metal. If the metal is more active than magnesium, then it does not react with salt, but with water to form alkali, which then reacts with salt. In this case, the initial salt and the resulting salt must be soluble. The insoluble product passivates the metal.

However, there are exceptions to this rule:

2FeCl 3 + Cu \u003d CuCl 2 + 2FeCl 2;

2FeCl 3 + Fe = 3FeCl 2 . Since iron has an intermediate oxidation state, its salt in the highest oxidation state is easily reduced to a salt in an intermediate oxidation state, oxidizing even less active metals.

in meltsa number of metal stresses do not work. It is possible to determine whether a reaction between a salt and a metal is possible only with the help of thermodynamic calculations. For example, sodium can displace potassium from a potassium chloride melt, since potassium is more volatile: Na + KCl = NaCl + K (this reaction is determined by the entropy factor). On the other hand, aluminum was obtained by displacement from sodium chloride: 3 Na + AlCl 3 \u003d 3 NaCl + Al . This process is exothermic and is determined by the enthalpy factor.

It is possible that the salt decomposes when heated, and the products of its decomposition can react with the metal, such as aluminum nitrate and iron. Aluminum nitrate decomposes when heated to alumina, nitric oxide ( IV ) and oxygen, oxygen and nitric oxide will oxidize iron:

10Fe + 2Al(NO 3) 3 = 5Fe 2 O 3 + Al 2 O 3 + 3N 2

6. Metal + basic oxide. Also, as in molten salts, the possibility of these reactions is determined thermodynamically. Aluminum, magnesium and sodium are often used as reducing agents. For example: 8 Al + 3 Fe 3 O 4 \u003d 4 Al 2 O 3 + 9 Fe exothermic reaction, enthalpy factor);2 Al + 3 Rb 2 O = 6 Rb + Al 2 O 3 (volatile rubidium, enthalpy factor).

8. Non-metal + base. As a rule, the reaction takes place between a non-metal and an alkali. Not all non-metals can react with alkalis: it must be remembered that halogens enter into this interaction (differently depending on temperature), sulfur (when heated), silicon, phosphorus.

KOH + Cl 2 \u003d KClO + KCl + H 2 O (in the cold)

6 KOH + 3 Cl 2 = KClO 3 + 5 KCl + 3 H 2 O (in hot solution)

6KOH + 3S = K 2 SO 3 + 2K 2 S + 3H 2 O

2KOH + Si + H 2 O \u003d K 2 SiO 3 + 2H 2

3KOH + 4P + 3H 2 O = PH 3 + 3KPH 2 O 2

1) non-metal - reducing agent (hydrogen, carbon):

CO 2 + C \u003d 2CO;

2NO 2 + 4H 2 \u003d 4H 2 O + N 2;

SiO 2 + C \u003d CO 2 + Si. If the resulting non-metal can react with the metal used as a reducing agent, then the reaction will go further (with an excess of carbon) SiO 2 + 2 C \u003d CO 2 + Si C

2) non-metal - oxidizing agent (oxygen, ozone, halogens):

2C O + O 2 \u003d 2CO 2.

WITH O + Cl 2 \u003d CO Cl 2.

2 NO + O 2 \u003d 2 N O 2.

10. Acid oxide + basic oxide . The reaction proceeds if the resulting salt exists in principle. For example, alumina can react with sulfuric anhydride to form aluminum sulfate, but cannot react with carbon dioxide, since the corresponding salt does not exist.

11. Water + basic oxide . The reaction is possible if an alkali is formed, that is, a soluble base (or slightly soluble, in the case of calcium). If the base is insoluble or slightly soluble, then there is a reverse reaction of decomposition of the base into oxide and water.

12. Basic oxide + acid . The reaction is possible if the resulting salt exists. If the resulting salt is insoluble, then the reaction may be passivated by blocking the access of the acid to the surface of the oxide. In the case of an excess of a polybasic acid, the formation of an acid salt is possible.

13. acid oxide + base. As a rule, the reaction goes between alkali and acid oxide. If the acid oxide corresponds to a polybasic acid, an acid salt can be obtained: CO 2 + KOH = KHCO 3 .

Acid oxides corresponding to strong acids can also react with insoluble bases.

Sometimes oxides corresponding to weak acids react with insoluble bases, and an average or basic salt can be obtained (as a rule, a less soluble substance is obtained): 2 Mg (OH) 2 + CO 2 \u003d (MgOH) 2 CO 3 + H 2 O.

14. acid oxide + salt. The reaction can take place in the melt and in solution. In the melt, the less volatile oxide displaces the more volatile oxide from the salt. In solution, the oxide corresponding to the stronger acid displaces the oxide corresponding to the weaker acid. For example, Na 2 CO 3 + SiO 2 \u003d Na 2 SiO 3 + CO 2 , in the forward direction, this reaction proceeds in the melt, carbon dioxide is more volatile than silicon oxide; in the opposite direction, the reaction proceeds in solution, carbonic acid is stronger than silicic acid, and silicon oxide precipitates.

It is possible to combine an acid oxide with its own salt, for example, dichromate can be obtained from chromate, and disulfate can be obtained from sulfate, and disulfite can be obtained from sulfite:

Na 2 SO 3 + SO 2 \u003d Na 2 S 2 O 5

To do this, you need to take a crystalline salt and pure oxide, or a saturated salt solution and an excess of acidic oxide.

In solution, salts can react with their own acid oxides to form acid salts: Na 2 SO 3 + H 2 O + SO 2 \u003d 2 NaHSO 3

15. Water + acid oxide . The reaction is possible if a soluble or slightly soluble acid is formed. If the acid is insoluble or slightly soluble, then there is a reverse reaction of the decomposition of the acid into oxide and water. For example, sulfuric acid is characterized by the reaction of obtaining from oxide and water, the decomposition reaction practically does not occur, silicic acid cannot be obtained from water and oxide, but it easily decomposes into these components, but carbonic and sulfurous acids can participate in both direct and back reactions.

16. Base + acid. The reaction proceeds if at least one of the reactants is soluble. Depending on the ratio of reagents, medium, acidic and basic salts can be obtained.

17. Base + salt. The reaction proceeds if both starting materials are soluble, and at least one non-electrolyte or weak electrolyte (precipitate, gas, water) is obtained as a product.

18. Salt + acid. As a rule, the reaction proceeds if both starting materials are soluble, and at least one non-electrolyte or a weak electrolyte (precipitate, gas, water) is obtained as a product.

A strong acid can react with insoluble salts of weak acids (carbonates, sulfides, sulfites, nitrites), and a gaseous product is released.

Reactions between concentrated acids and crystalline salts are possible if a more volatile acid is obtained: for example, hydrogen chloride can be obtained by the action of concentrated sulfuric acid on crystalline sodium chloride, hydrogen bromide and hydrogen iodine by the action of orthophosphoric acid on the corresponding salts. It is possible to act with an acid on its own salt to obtain an acid salt, for example: BaSO 4 + H 2 SO 4 \u003d Ba (HSO 4) 2.

19. Salt + salt.As a rule, the reaction proceeds if both starting materials are soluble, and at least one non-electrolyte or a weak electrolyte is obtained as a product.

1) salt does not exist because irreversibly hydrolyzed . These are the majority of carbonates, sulfites, sulfides, silicates of trivalent metals, as well as some salts of divalent metals and ammonium. Trivalent metal salts are hydrolyzed to the corresponding base and acid, and divalent metal salts to less soluble basic salts.

Consider examples:

2 FeCl 3 + 3 Na 2 CO 3 = Fe 2 ( CO 3 ) 3 + 6 NaCl (1)

Fe 2 (CO 3) 3+ 6H 2 O \u003d 2Fe (OH) 3 + 3 H2CO3

H 2 CO 3 decomposes into water and carbon dioxide, the water in the left and right parts is reduced and it turns out: Fe 2 ( CO 3 ) 3 + 3 H 2 O \u003d 2 Fe (OH) 3 + 3 CO 2 (2)

If we now combine (1) and (2) equations and reduce iron carbonate, we get the total equation reflecting the interaction of ferric chloride ( III ) and sodium carbonate: 2 FeCl 3 + 3 Na 2 CO 3 + 3 H 2 O \u003d 2 Fe (OH) 3 + 3 CO 2 + 6 NaCl

CuSO 4 + Na 2 CO 3 \u003d CuCO 3 + Na 2 SO 4 (1)

The underlined salt does not exist due to irreversible hydrolysis:

2CuCO3+ H 2 O \u003d (CuOH) 2 CO 3 + CO 2 (2)

If we now combine (1) and (2) equations and reduce the copper carbonate, we get the total equation reflecting the interaction of sulfate ( II ) and sodium carbonate:

2CuSO 4 + 2Na 2 CO 3 + H 2 O \u003d (CuOH) 2 CO 3 + CO 2 + 2Na 2 SO 4

oxides- these are complex inorganic compounds consisting of two elements, one of which is oxygen (in the oxidation state -2).

For example, Na 2 O, B 2 O 3, Cl 2 O 7 are oxides. All of these substances contain oxygen and one more element. Substances Na 2 O 2 , H 2 SO 4 , HCl do not belong to oxides: in the first, the oxidation state of oxygen is -1, in the second there are not two, but three elements, and the third does not contain oxygen at all.

If you do not understand the meaning of the term "oxidation state", it's okay. First, you can refer to the relevant article on this site. Secondly, even without understanding this term, you can continue reading. You can temporarily forget about the mention of the degree of oxidation.

Oxides of almost all currently known elements have been obtained, except for some noble gases and "exotic" transuranium elements. Moreover, many elements form several oxides (for nitrogen, for example, six are known).

Nomenclature of oxides

We must learn to name oxides. It's very simple.

Example 1. Name the following compounds: Li 2 O, Al 2 O 3, N 2 O 5, N 2 O 3.

Li 2 O - lithium oxide,
Al 2 O 3 - aluminum oxide,
N 2 O 5 - nitric oxide (V),
N 2 O 3 - nitric oxide (III).

Pay attention to an important point: if the valence of an element is constant, we DO NOT mention it in the name of the oxide. If the valency changes, be sure to indicate it in brackets! Lithium and aluminum have a constant valence, while nitrogen has a variable valence; it is for this reason that the names of nitrogen oxides are supplemented with Roman numerals, symbolizing valence.

Exercise 1. Name the oxides: Na 2 O, P 2 O 3, BaO, V 2 O 5, Fe 2 O 3, GeO 2, Rb 2 O. Do not forget that there are elements with both constant and variable valence.

Another important point: it is more correct to call the substance F 2 O not "fluorine oxide", but "oxygen fluoride"!

Physical properties of oxides

The physical properties are very diverse. This is due, in particular, to the fact that different types of chemical bonds can appear in oxides. Melting and boiling points vary widely. Under normal conditions, oxides can be in the solid state (CaO, Fe 2 O 3, SiO 2, B 2 O 3), liquid state (N 2 O 3, H 2 O), in the form of gases (N 2 O, SO 2, NO, CO).

The color is varied: MgO and Na 2 O are white, CuO is black, N 2 O 3 is blue, CrO 3 is red, etc.

Oxide melts with an ionic type of bond conduct electricity well, covalent oxides, as a rule, have low electrical conductivity.

Classification of oxides

All naturally occurring oxides can be divided into 4 classes: basic, acidic, amphoteric, and non-salt-forming. Sometimes the first three classes are combined into a group of salt-forming oxides, but for us this is not essential now. The chemical properties of oxides from different classes differ very much, so the issue of classification is very important for further study of this topic!

Let's start with non-salt-forming oxides. They need to be remembered: NO, SiO, CO, N 2 O. Just learn these four formulas!

For further advancement, we must remember that in nature there are two types of simple substances - metals and non-metals (sometimes a group of semi-metals or metalloids is also distinguished). If you clearly understand which elements are metals, continue reading this article. If there is the slightest doubt, refer to the material "Metals and non-metals" on that website.

So, I inform you that all amphoteric oxides are metal oxides, but not all metal oxides are amphoteric. I will list the most important of them: BeO, ZnO, Al 2 O 3 , Cr 2 O 3 , SnO. The list is not complete, but the listed formulas should be remembered! In most amphoteric oxides, the metal exhibits an oxidation state of +2 or +3 (but there are exceptions).

In the next part of the article, we will continue to talk about classification; Let's discuss acidic and basic oxides.

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

can be obtained by direct interaction of oxygen with another element, or indirectly (for example, by the decomposition of salts, bases, acids). Under normal conditions, oxides are in a solid, liquid and gaseous state, this type of compounds 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 form salts as a result of chemical reactions. These are oxides of metals and non-metals, which, when interacting with water, form the corresponding acids, and when interacting with bases, the corresponding acidic and normal salts. For example, copper oxide (CuO) is a salt-forming oxide, because, for example, when it reacts with hydrochloric acid (HCl), a salt is formed:

CuO + 2HCl → CuCl 2 + H 2 O.

As a result of chemical reactions, other salts can be obtained:

CuO + SO 3 → CuSO 4.

Non-salt-forming oxides called oxides that 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. Interact with acid oxides, forming 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 the second element in the composition of the oxides is a non-metal or a metal exhibiting a higher valency (usually exhibits from IV to VII), then such oxides will be acidic. Acid oxides (acid anhydrides) are oxides that correspond to hydroxides belonging to the class of acids. This is, for example, CO 2, SO 3, P 2 O 5, N 2 O 3, Cl 2 O 5, Mn 2 O 7, etc. Acid oxides dissolve in water and alkalis, forming salt and water.

Chemical properties of acid oxides

1. Interact with water, forming acid:

SO 3 + H 2 O → H 2 SO 4.

But not all acidic oxides directly react with water (SiO 2 and others).

2. React with based oxides to form a 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 to form salt and water:

ZnO + 2HCl → ZnCl 2 + H 2 O.

2. React with solid alkalis (during 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.

Coordination number - a characteristic that determines the number of nearest particles: atoms or ions 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 it is 6 or (very rarely) 4;

Amphoteric oxides usually do not dissolve in water and do not react with it.

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Chemical properties of water

Interaction of water with metals.

If calcium chips are lowered into a cylinder with water, then gas bubbles will begin to break off from the surface of calcium, as from the surface of zinc placed in a solution of sulfuric acid. When bringing a lighted splinter to the hole of the cylinder, we will observe flashes. It's burning hydrogen. The water in the cylinder becomes cloudy. The white suspended particles that appeared in the cylinder are calcium hydroxide Ca (OH) 2. The ongoing reaction is expressed by the equation:

Ca + 2H 2 0 \u003d 2Ca (OH) 2 + H 2

In this reaction, from a water molecule H 2 O, which can be represented as H-OH (group - OH - hydroxo group), -OH passes into the composition of calcium hydroxide. Since the calcium atom is bivalent, it displaces two hydrogen atoms from two water molecules, and the remaining two -OH groups are connected to the calcium atom.

The reaction of sodium with water proceeds even more vigorously. Drop a piece of sodium into a glass of water. Sodium floats to its surface, melts, turning into a shiny drop. It quickly moves along the surface of the water, emitting a hiss and decreasing in size. Evaporating the solution, we find a white solid - sodium hydroxide NaOH

2Na + 2HOH \u003d 2NaOH + H 2

Sodium and calcium are among the most reactive.

Interaction of water with non-metal oxides .

Let's burn red phosphorus in a jar on a spoon. Pour a little water and wait until the resulting phosphorus oxide (V) P 2 0 5 dissolves. Add a few drops of purple litmus to the solution. The litmus will turn red. This means that the solution contains an acid. Phosphorus (V) oxide is combined with water, and phosphoric acid H 3 P0 4 is obtained:

P 2 0 5 + ZN 2 0 \u003d 2N 3 P0 4

Let's burn sulfur in a jar, into which some water is poured, and examine the resulting solution with a litmus solution. It also turns red. Sulfur oxide (IV) S0 2, formed during the combustion of sulfur, combined with water, and sulfurous acid was obtained:

S0 2 + H 2 0 = H 2 S0 2

Sulfur oxide (VI), interacting with water, forms sulfuric acid H 2 S0 4:

SO2+ H 2 O \u003d H 2 S0 4

Nitrogen can form oxide N205, which reacts with water to form nitric acid:

N 2 0 5 + H 2 0 = 2HN0 3

Compounds of non-metal oxides with water are classified as acids.

Interaction of water with metal oxides.

Consider now the relation to water of metal oxides. We will pour copper oxide CuO, iron oxide Fe 2 0 3, zinc oxide ZnO and calcium oxide CaO into cups and pour a little water into each. Oxides of copper, iron and zinc do not dissolve in water and do not combine with it. Calcium oxide, or quicklime, behaves differently.

When pouring pieces of quicklime with water, such a strong heating is observed that part of the water turns into steam, and pieces of quicklime, crumbling, turn into dry loose powder - slaked lime, or calcium hydroxide Ca (OH) 2:

CaO + H 2 0 \u003d Ca (OH) 2

Like calcium oxide, sodium and potassium oxides combine with water:

Na 2 0 + H 2 0 \u003d 2NaOH

K 2 0 + H 2 0 \u003d 2KOH

These reactions produce sodium hydroxide NaOH and potassium hydroxide KOH.

Thus, some metal oxides do not react with water (most of them), while others (potassium oxide, sodium oxide, calcium oxide, barium oxide, etc.) combine with it, forming hydroxides, which are related to bases.

(Inorganic chemistry grade 7-8 author Yu. V. Khodakov and others)

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

OXIDE

ACID

BASE

SALT

E x O y

HnA

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 valence 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 valency of a chemical element is 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)	Fe2O3	iron(III) oxide
	nitric oxide (II)	CrO3	chromium(VI) oxide
Al2O3	aluminium oxide		zinc oxide
N 2 O 5	nitric oxide (V)	Mn2O7	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

Non-metal oxides neMe x O y

Main

Acidic

Amphoteric

Acidic

Indifferent

I, II

V-VII

ZnO, BeO, Al 2 O 3,

Fe 2 O 3 , Cr 2 O 3

> II

neMe

I, II

neMe

CO, NO, N 2 O

1). Basic oxides are oxides that correspond to bases. The main oxides are oxides metals 1 and 2 groups, as well as metals side subgroups with valence I and II (except ZnO - zinc oxide and BeO – beryllium oxide):

2). Acid oxides are oxides to which acids correspond. Acid oxides are non-metal oxides (except for non-salt-forming - indifferent), as well as metal oxides side subgroups with valence from V before VII (For example, CrO 3 is chromium (VI) oxide, Mn 2 O 7 is manganese (VII) oxide):

3). Amphoteric oxides are oxides, which correspond to bases and acids. These include metal oxides main and secondary 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 are oxides that are indifferent to acids and bases. These include non-metal 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 valency of the element.

For example, chromium oxides:

CrO(II- main);

Cr 2 O 3 (III- amphoteric);

CrO 3 (VII- acid).

Classification of oxides

(by solubility in water)

Acid oxides

Basic oxides

Amphoteric oxides

Soluble in water.

Exception - SiO 2

(not soluble in water)

Only oxides of alkali and alkaline earth metals dissolve in water.

(these are metals

I "A" and II "A" groups,

exception Be , Mg )

They do not interact with water.

Insoluble in water

Complete the tasks:

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

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

2. Substances are given : 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 the oxides and classify them.

Obtaining oxides

Simulator "Interaction of oxygen with simple substances"

1. Combustion of substances (Oxidation by oxygen)	a) simple substances Training apparatus	2Mg + O 2 \u003d 2MgO
1. Combustion of substances (Oxidation by oxygen)	b) complex substances	2H 2 S + 3O 2 \u003d 2H 2 O + 2SO 2
2. Decomposition of complex substances (use table of acids, see appendices)	a) salt SALTt= BASIC OXIDE + ACID OXIDE	CaCO 3 \u003d CaO + CO 2
	b) Insoluble bases Me(OH)bt= Me x O y+ H 2 O	Cu (OH) 2 t \u003d CuO + H 2 O
	c) oxygen-containing acids HnA=ACID OXIDE + H 2 O	H 2 SO 3 \u003d 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 + Acid oxide \u003d Salt (r. compounds)

CaO + SO 2 \u003d CaSO 3

2. Basic oxide + Acid \u003d Salt + H 2 O (r. exchange)

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

3. Basic oxide + Water \u003d Alkali (r. compounds)

Na 2 O + H 2 O \u003d 2 NaOH

CHEMICAL PROPERTIES OF ACID OXIDES

1. Acid oxide + Water \u003d Acid (p. Compounds)

With O 2 + H 2 O \u003d H 2 CO 3, SiO 2 - does not react

2. Acid oxide + Base \u003d Salt + H 2 O (r. exchange)

P 2 O 5 + 6 KOH \u003d 2 K 3 PO 4 + 3 H 2 O

3. Basic oxide + Acid oxide \u003d Salt (p. Compound)

CaO + SO 2 \u003d CaSO 3

4. Less volatiles displace more volatiles from their salts

CaCO 3 + SiO 2 \u003d CaSiO 3 + CO 2

CHEMICAL PROPERTIES OF AMPHOTERIC OXIDES

They interact with both acids and alkalis.

ZnO + 2 HCl = ZnCl 2 + H 2 O

ZnO + 2 NaOH + H 2 O \u003d Na 2 [Zn (OH) 4] (in solution)

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

Application of oxides

Some oxides do not dissolve in water, but many react with water to combine:

SO 3 + H 2 O \u003d H 2 SO 4

CaO + H 2 O = Ca( Oh) 2

The result is often very 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 white substance, therefore it is used to prepare white oil paint (zinc white). Since ZnO is practically insoluble in water, any surface can be painted with zinc white, 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 oxide (IV) - TiO 2 has the same valuable properties. It also has a beautiful white color and is used to make titanium white. TiO 2 is insoluble not only in water, but also in acids; therefore, coatings made of this oxide are particularly stable. This oxide is added to plastic to give it a white color. It is part of the enamels for metal and ceramic utensils.

Chromium oxide (III) - 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 well-known GOI paste (short for 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 by no means their only application.

Tasks for fixing

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

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

Select from the list: basic oxides, acidic oxides, indifferent oxides, amphoteric oxides and name them.

3. Finish UCR, 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 \u003d

K 2 O + CO 2 \u003d

Cu (OH) 2 \u003d? +?

4. Carry out the transformations according to the scheme: