Nitrites of metals to the degree of oxidation +2 form crystal hydrates with one, two or four water molecules. Nitrites form double and triple salts, for example. CSNO 2. AGNO 2 or BA (NO 2) 2. Ni (NO 2) 2. 2KNO 2, as well as complex compounds, for example Na 3.
Crystal structures are known only for several anhydrous nitrites. Anion NO2 has a nonlinear configuration; ONO 115 ° corner, n-o 0.115 nm communication length; Communication type M-NO 2 ion-covalent.
Well soluble in water nitrites K, Na, Ba, bad - nitrite Ag, Hg, Cu. With an increase in temperature, the solubility of nitrite increases. Almost all nitrites are poorly soluble in alcohols, ether and low-polar solvents.
Nitrites are thermally poorly resistant; We melt without decomposition only nitrite of alkali metal, nitrite of the remaining metals decompose at 25-300 ° C. The mechanism decomposition of nitrite is complex and includes a number of parallel-consecutive reactions. The main gaseous decomposition products - NO, NO 2, N 2 and O 2, solid - metal oxide or element metal. The allocation of a large amount of gases determine the explosive decomposition of some nitrite, for example NH 4 NO 2, which decomposes on N 2 and H 2 O.
The characteristic features of nitrites are associated with their thermal insuffosuit and the ability of nitrite-ion to be both an oxidizing agent, and the reducing agent, depending on the environment and nature of the reagents. In the neutral medium, nitrites are usually restored to NO, oxidized to nitrates. Oxygen and CO 2 do not interact with solid nitrites and their aqueous solutions. Nitrites contribute to the decomposition of nitrogen-containing organic substances, in particular amines, amides, etc. with organic halides RXN. React to the formation of both Rono nitrites and RNO 2 nitros compounds.
Industrial production of nitrites is based on the absorption of nitrose gas (mixture NO + NO 2) with solutions of Na 2 CO 3 or NaOH with a sequential crystallization of Nano 2; Nitrites of the remaining metal in industry and laboratories are obtained by an exchange reaction of metals salts with Nano 2 or the restoration of these metals nitrates.
Nitrites are used for the synthesis of azocrase, in the production of caprolactam, as oxidizing agents and reducing agents in the rubber, textile and metalworking industries, like preservatives of food products. Nitrites for example Nano 2 and Kno 2, toxic, cause headache, vomiting, inhibit breathing, etc. With Nano 2 poisoning, methemoglobin is formed in the blood, the erythrocyte membranes are damaged. It is possible to form nitrosamines from Nano 2 and amines directly in the gastrointestinal tract.
6. Sulfates, Salt sulfuric acid. The average sulfates with an anion SO 4 2- acid, or hydrosulfate, with HSO 4 anion, basic, comprising along with an anion SO 4 2- - group, such as Zn 2 (OH) 2 SO 4, are known. There are also double sulfates, including two different cations. These include two large sulfate groups - alum, as well as chenites M 2 E (SO 4) 2. 6H 2 O, where M-monotair cation, e - mg, zn and other two-chain cations. Known triple sulphate K 2 SO 4. MgSO 4. 2Caso 4. 2H 2 O (Polygalitis Mineral), Double Basic Sulfuses, for example Minerals of Alunite Groups and Yarosit M 2 SO 4. Al 2 (SO 4) 3. 4Al (OH 3 and M 2 SO 4. Fe 2 (SO 4) 3. 4Fe (OH) 3, where M is a single-charge cation. Sulfates can be part of mixed salts, for example 2NA 2 SO 4. Na 2 CO 3 ( Mineral Berkeit), MgSO 4. KCL. 3H 2 O (Cainit).
Sulfates - crystalline substances, medium and acidic in large cases are well soluble in water. Calcium, strontium, lead sulfates, strontium, lead and some dr., Practically insoluble Baso 4, Raso 4. The main sulfates are usually small-soluble or practically insoluble, or hydrolyzed with water. From aqueous solutions, sulfates can crystallize as crystallohydrates. Crystal hydrates of some heavy metals are called vitriors; Copper cunery sunso 4. 5H 2 O, FESO 4 Iron Campground. 7N 2 O.
The average alkali metal sulfates are thermally stable, while acidic sulfates are decomposed when heated, turning into pyrosulfates: 2khso 4 \u003d H 2 O + K 2 S 2 O 7. The average sulfates of other metals, as well as basic sulfates, when heated to sufficiently high temperatures, are usually decomposed to form metal oxides and the release of SO 3.
Sulfates are widespread in nature. They are found in the form of minerals, for example, CASO 4 gypsum. H 2 O, Miracycite Na 2 SO 4. 10H 2 O, and also part of sea and river water.
Many sulfates can be obtained by the interaction of H 2 SO 4 with metals, their oxides and hydroxides, as well as the decomposition of volatile salts with sulfuric acid.
Inorganic sulfates are widely used. For example, ammonium sulfate -zotny fertilizer, sodium sulfate is used in glass, paper industry, viscose production, etc. Natural sulfate minerals - the raw materials of the industrial production of compounds of various metals, builds materials, etc.
7.Sulfitis Salt sulfuric acid H 2 SO 3. The average sulfites with an anion SO 3 2- and acidic (hydrosulfite) with HSO 3 anion are distinguished. Medium sulfite - crystalline substances. Ammonium and alkali metal sulfites are well soluble in water; Solubility (g in 100 g): (NH 4) 2 SO 3 40.0 (13 ° C), K 2 SO 3 106.7 (20 ° C). In aqueous solutions, hydrosulfites form. Sulfites of alkaline-land and some other metals are practically not soluble in water; The solubility of MgSO 3 1 g per 100 g (40 ° C). Known crystallohydrates (NH 4) 2 SO 3. H 2 O, Na 2 SO 3. 7H 2 O, to 2 SO 3. 2N 2 O, MgSO 3. 6H 2 O and others.
Anhydrous sulfite, when heated without air access in the sealed vessels, disproportionate on sulphides and sulfates, while heating in the current N 2 lose SO 2, and when heated in air is easily oxidized to sulphates. With SO 2 in an aqueous medium, the average sulfites form hydrosulfites. Sulfites are relatively strong reducing agents, oxidized in chlorine solutions, bromom, H 2 O 2, etc. to sulfates. Decomposed with strong acids (for example, NS1) with the release of SO 2.
Crystal hydrosulfites are known for K, RB, CS, NH 4 +, they are small. The remaining hydrosulfites exist only in aqueous solutions. Density NH 4 HSO 3 2.03 g / cm3; Solubility in water (g 100 g): NH 4 HSO 3 71.8 (0 ° C), KNSO 3 49 (20 ° C).
When the crystalline hydrosulfite Na is heated or or when satuating SO 2 of the kishing pulp M 2 SO 3, pyrosulphites are formed (obsolete -metabisulphites) m 2 S 2 O 5 - salts of an unknown in the free state of pirosnoy acid H 2 S 2 O 5; crystals, small resistant; Density (g / cm3): Na 2 S 2 O 5 1.48, K 2 S 2 O 5 2.34; above ~ 160 ° C are decomposed with the release of SO 2; dissolved in water (with decomposition to HSO 3 -), the solubility (g of 100 g): Na 2 S2O 5 64.4, K 2 S 2 O 5 44.7; Form hydrates Na 2 S 2 O 5. 7H 2 O and ZK 2 S 2 O 5. 2N 2 o; Restorers.
The average alkali metal sulfites is obtained by the interaction of an aqueous solution M 2 CO 3 (or MON) with SO 2, A MSO 3 - transmittance SO 2 through an aqueous suspension MCO 3; Used mainly SO 2 of the exhaust gas of contact sulfuric acid industries. Sulfites are used when bleaching, dyeing and printing fabrics, fibers, leather for canning grain, green feed, forage industrial waste (NaHSO 3,Na 2 S 2 O 5). Caso 3 and Ca (NSO 3) 2 - disinfectants in winemaking and sugar industry. NaNSO 3, MgSO 3, NN 4 NSO 3 - Components of sulfite liquor at cooking cellulose; (NH 4) 2SO 3 - SO 2 absorber; NaHSO 3 is an H 2 S absorber from exhaust gases of production, a reducing agent in the production of sulfur dyes. K 2 S 2 O 5 - Component of acidic fixes in the photo, antioxidant, antiseptic.
Basins may interact:
- with non-metals -
6KOH + 3S → K2SO 3 + 2K 2 S + 3H 2 O;
- with acid oxides -
2NAOH + CO 2 → Na 2 CO 3 + H 2 O;
- with salts (precipitation loss, gas release) -
2KOH + FECL 2 → FE (OH) 2 + 2KCL.
There are also other methods for obtaining:
- the interaction of two salts -
CUCL 2 + Na 2 S → 2NACL + CUS ↓;
- metal and Nemetalov reaction -
- compound of acid and main oxides -
SO 3 + Na 2 O → Na 2 SO 4;
- metal salts interaction -
Fe + Cuso 4 → Feso 4 + Cu.
Chemical properties
The soluble salts are electrolytes and are subject to dissociation reaction. When interacting with water, they disintegrate, i.e. dissociated on positive and negatively charged ions - cations and anions, respectively. Cations are metal ions, anions - acid residues. Examples of ion equations:
- NaCl → Na + + Cl -;
- Al 2 (SO 4) 3 → 2AL 3 + + 3SO 4 2-;
- Caclbr → CA2 + + CL - + BR -.
In addition to cation of metals in salts, ammonium cations (NH4 +) and phosphonia (PH4 +) may be present.
Other reactions are described in the table of chemical properties of salts.
Fig. 3. Selection of precipitate when interacting with the grounds.
Some salts decompose depending on the species when heated on metal oxide and an acidic residue or for simple substances. For example, CACO 3 → CAO + CO 2, 2AGCL → AG + CL 2.
What did we know?
From the lesson of 8 class of chemistry learned about features and types of salts. Complicated inorganic compounds consist of metals and acid residues. May include hydrogen (acidic salts), two metal or two acid residues. These are solid crystalline substances that are formed as a result of acid reactions or alkalis with metals. React with bases, acids, metals, other salts.
1) Metal with non-metallol: 2NA + CL 2 \u003d 2NACL
2) Acid metal: Zn + 2HCl \u003d ZnCl 2 + H 2
3) Metal with solid solid less active metal Fe + Cuso 4 \u003d Feso 4 + Cu
4) main oxide with acid oxide: MGO + CO 2 \u003d Mgco 3
5) Basic acid oxide Cuo + H 2 SO 4 \u003d Cuso 4 + H 2 O
6) base with acid oxide Ba (OH) 2 + CO 2 \u003d Baco 3 + H 2 O
7) Acid base: Ca (OH) 2 + 2HCl \u003d CaCl 2 + 2H 2 O
8) Acid Salts: Mgco 3 + 2HCl \u003d MgCl 2 + H 2 O + CO 2
BACL 2 + H 2 SO 4 \u003d BASO 4 + 2HCL
9) base solution with salt solution: Ba (OH) 2 + Na 2 SO 4 \u003d 2NAOH + BASO 4
10) solutions of two salts of 3caCL 2 + 2NA 3 PO 4 \u003d Ca 3 (PO 4) 2 + 6NACL
2. Obtaining acidic salts:
1. Acid interaction with a lack of foundation. KOH + H 2 SO 4 \u003d KHSO 4 + H 2 O
2. The interaction of the base with excess acid oxide
Ca (OH) 2 + 2CO 2 \u003d Ca (HCO 3) 2
3. The interaction of medium salt with acid Ca 3 (PO 4) 2 + 4H 3 PO 4 \u003d 3CA (H 2 PO 4) 2
3. Getting the main salts:
1. Hydrolysis of salts formed by weak base and severe acid
ZnCl 2 + H 2 O \u003d CL + HCl
2. Adding (dropwise) small amounts of alkalis to solutions of average metal salts AlCl 3 + 2NAOH \u003d Cl + 2NACL
3. The interaction of weak acid salts with medium salts
2MGCl 2 + 2NA 2 CO 3 + H 2 O \u003d 2 CO 3 + CO 2 + 4NACL
4. Preparation of complex salts:
1. Salts reactions with ligands: AGCL + 2NH 3 \u003d CL
FECL 3 + 6KCN] \u003d K 3 + 3KCL
5. Getting double salts:
1. Joint crystallization of two salts:
CR 2 (SO 4) 3 + K 2 SO 4 + 24H 2 O \u003d 2 + NaCl
4. Redox reactions due to the properties of a cation or anion. 2kmno 4 + 16hcl \u003d 2mnCl 2 + 2KCl + 5Cl 2 + 8H 2 O
2. Chemical properties of acidic salts:
Thermal decomposition with the formation of medium salt
Ca (HCO 3) 2 \u003d Caco 3 + CO 2 + H 2 O
Interaction with pitching. Getting an average salt.
BA (HCO 3) 2 + BA (OH) 2 \u003d 2Baco 3 + 2H 2 O
3. Chemical properties of basic salts:
Thermal decomposition. 2 CO 3 \u003d 2CUO + CO 2 + H 2 O
Acid interaction: the formation of medium salt.
Sn (OH) CL + HCl \u003d SNCl 2 + H 2 O Chemical element - A combination of atoms with the same charge of the nucleus and the number of protons coinciding with the sequence (atomic) number in the Mendeleev table. Each chemical element has its own name and symbol that are given in the periodic system of Mendeleev elements.
The form of the existence of chemical elements in free form is simple substances (single element).
At the moment (March 2013), 118 chemical elements are known (they are not all officially recognized).
Chemicals can consist of both one chemical element (simple substance) and from different (complex substance or chemical compound).
Chemical elements form about 500 simple substances. The ability of one element to exist in the form of various simple substances, differing in properties, is called allotropy. In most cases, the names of the simple substances coincide with the name of the corresponding elements (for example, zinc, aluminum, chlorine), however, in the case of the existence of several allotropic modifications, the name of the simple substance and the element may differ, for example oxygen (dicksorod, O 2) and ozone (O 3) ; Diamond, graphite and a number of other alto carbon altopic modifications exist along with amorphous carbon forms.
Confirmed experimentally in 1927. The dual nature of an electron, which has the properties not only particles, but also prompted scientists to create a new theory of the structure of an atom, which takes into account both of these properties. The modern theory of the structure of the atom relies on the quantum mechanics.
The duality of the electron properties is manifested in the fact that it, on the one hand, has the properties of the particle (it has a certain mass of rest), and on the other - its movement reminds the wave and can be described by a certain amplitude, wavelength, frequency of oscillations, etc. Therefore, you can't talk. About any particular trajectory of the electron movement - it is only possible to judge one or another probability of its location at this point of space.
Consequently, an electron orbit should be understood as a certain line of movement of an electron, but some part of the space around the kernel, within which the probability of the electron's stay is the highest. In other words, the electronic orbit does not characterize the sequence of movement of the electron from the point to the point, and is determined by the probability of finding an electron at a certain distance from the kernel.
The presence of the wave properties of the electron was the first to spoke by the French accounting L. de Broglie. De Broglya equation: \u003d H / MV. If the electron has wave properties, the electron beam should experience the effect of diffraction and interference phenomena. The wave nature of the electrons was confirmed when the electron beam diffraction is observed in the structure of the crystal mortgage. Since the electron has the wave properties, its position inside the volume of the atom is not defined. The position of the electron in the atomic volume is described by a probabilistic function if the e¨ is portrayed in a tr¨-dimensional space, then we get the body of rotation (Fig.)
Salts can also be considered as products of complete or partial substitution of hydrogen ions in metal molecules with metal ions (or complex positive ions, for example, an ammonium ion NH) or as a product of complete or partial substitution of hydroxochroups in the main hydroxide molecules with acid residues. With full replacement medium (normal) salts. In case of incomplete replacement of H + ions in acid molecules sour salts, with incomplete substitution of groups, it - in the base molecules - basic salts. Examples of salting formation:
H 3 PO 4 + 3NAOH 
Na 3 PO 4 + 3H 2 O
Na 3 PO 4 ( phosphate sodium) - medium (normal salt);
H 3 PO 4 + NaOH 
NaN 2 PO 4 + H 2 O
NaN 2 PO 4 (Digidrophosphate sodium) - sour salt;
MQ (OH) 2 + HCl 
MQOHCL + H 2 O
MQOHCL ( hydroxychloride Magnesium) - the main salt.
Salts formed by two metals and one acid are called double salts. For example, potassium-aluminum sulfate (alumokalia alum) Kal (SO 4) 2 * 12H 2 O.
Salts formed by one metal and two acids are called mixed salts. For example, CACL calcium hypochloride chloride (CLO) or CaOCl 2 is a calcium salt of hydrochloric HCl and chlorinous HCLO acids.
Double and mixed salts when dissolved in water dissociate on all ions constituting their molecules.
For example, KAL (SO 4) 2 
K + + Al 3+ + 2SO 
;
CACL (CLO) 
CA 2+ + CL - + CLO -.
Complex salts - these are complex substances in which you can allocate central Atom. (complexing agent) and associated molecules and ions - ligands. Central atom and ligands form complex (internal sphere)which, when recording, the complex compound formula is enclosed in square brackets. The number of ligands in the inner sphere is called coordination number. Molecules and ions surrounding complex form forest sphere.
Central Atom Ligand
To 3.
Coordination number
The name of the salts is formed from the name of the anion, followed by the name of the cation.
For salts of oxless acids to the name of Nemmetalla, suffix is \u200b\u200badded - iDfor example, NaCl sodium chloride, FES iron sulphide (II).
With the name of the salts of oxygen-containing acids to the Latin root of the name of the element adds the end -AT.for higher oxidation degrees, -Et.for lower (for some acids, the prefix is \u200b\u200bused hypofor low degrees of nonmetal oxidation; for chlorine and manganese acid salts is used first). For example, CASSO 3 - calcium carbonate, Fe 2 (SO 4) 3 iron sulfate (III), FESO 3 - iron sulfite (II), COSL - Hypochlorite Potassium, KSLO 2 - chlorite potassium, KSLO 3 - Potassium chloro - Perchlorate of potassium, kmno 4 - permanganate potassium, K 2 CR 2 O 7 - Dichromate Potassium.
In the names of complex ions, ligands are first indicated. The name of the complex ion is completed with the title of the metal, indicating the corresponding oxidation degree (Roman numbers in brackets). In the names of complex cations, Russian metals names are used, for example, [ Cu (NH 3) 4] Cl 2 - Copper Tetraammmin (II) chloride. The names of complex anions are used by the Latin Names of Metals with Suffix -At,for example, K is potassium tetrahydroxalulum.
Chemical properties of salts
See the properties of the base.
See the properties of acids.
SiO 2 + Caco 3 
Casio 3 + CO 2 
.
Amphoteric oxides (they are all non-volatile) displace when fusing volatile oxides from their salts
Al 2 O 3 + K 2 CO 3 
2kalo 2 + CO 2.
5. Salt 1 + Salt 2 
salt 3 + salt 4.
The exchange reaction between the salts proceeds in the solution (both salts must be soluble) only if at least one of the products - the precipitate
AQNO 3 + NaCl 
AQCL 
+ Nano 3.
6. Salt less active metal + metal more active 
Metal is less active + salt.
Exceptions - alkaline and alkaline earth metals in the solution primarily interact with water
Fe + Cucl 2 
FECL 2 + CU.
7. Sol 
the products of thermal decomposition.
I) nitric acid salts. Products of thermal decomposition of nitrates depend on the position of metal in a row of metals voltages:
a) if the metal left MQ (excluding Li): MENO 3 
MENO 2 + O 2;
b) if the metal is from MQ to Cu, as well as Li: MENO 3 
MEO + NO 2 + O 2;
c) if the metal is right to CU: MENO 3 
ME + NO 2 + O 2.
Ii) carbonic acid salts. Almost all carbonates decompose to the appropriate metal and CO 2. Alkaline and alkaline earth metal carbonates, except Li, do not decompose when heated. Silver and mercury carbonates decompose to free metal
Meso 3. 
Meo + CO 2;
2AQ 2 CO 3 
4AQ + 2CO 2 + O 2.
All bicarbonates decompose to the appropriate carbonate.
ME (HCO 3) 2 
MECO 3 + CO 2 + H 2 O.
Iii) ammonium salts. Many ammonium salts are decomposable with the release of NH 3 and the corresponding acid or its decomposition products. Some ammonium salts containing oxidizing anions are decomposed with the release of N 2, NO, NO 2
NH 4 Cl. 
NH 3. 
+ HCL 
;
NH 4 NO 2 
N 2 + 2H 2 O;
(NH 4) 2 CR 2 O 7 
N 2 + CR 2 O 7 + 4H 2 O.
In tab. 1 shows the names of acids and their middle salts.
Names of essential acids and their middle salts
|
Name |
||
|
Metaluminous |
Metalüminat. |
|
|
Arsenic | ||
|
Arsenic | ||
|
Metal |
Metabrat |
|
|
Ortobornaya |
Ortoborate |
|
|
Fourbacked |
Tetraborat |
|
|
Bromoomomodnaya | ||
|
Muraury | ||
|
Acetic | ||
|
Cyanogenic (Sinyl Acid) | ||
|
Coal |
Carbonate |
|
Ending table. one
|
Name |
||
|
Savleless | ||
|
Herbonic (hydrochloric acid) | ||
|
Chlornoty |
Hypochlorite |
|
|
Chloride | ||
|
Chlorna | ||
|
Perchlorate |
||
|
Metachromoy |
Metachromit |
|
|
Chrome | ||
|
Two-volume |
Dichromat |
|
|
Iodomodnaya | ||
|
Periodate |
||
|
MARRONTSOVA |
Permanganate |
|
|
Asian hydrogen: nitrogen-breeding) | ||
|
Azorous | ||
|
Metaphosphorus |
Metaphosphate |
|
|
Ortophosphorus |
Orthophosphate |
|
|
Doubleosphorus |
Diffosfat. |
|
|
Fluid hydrogen (floating acid) | ||
|
Hydrogen sulfide | ||
|
Rodanovoyrona | ||
|
SERNY | ||
|
Double |
Dieulfat |
|
|
Peroxoderous |
Peroxodisulfat |
|
|
Silicon | ||
Examples of solving problems
Task 1.Write the formulas of the following compounds: calcium carbonate, calcium carbide, magnesium hydrophosphate, sodium hydrofide, iron (III) nitrate, lithium nitride, copper hydroxycarbonate, ammonium dichromate, barium bromide, hexaciatorrat (II) potassium, sodium tetrahydroxalulum.
Decision.Calcium carbonate - CASSO 3, calcium carbide - CAC 2, magnesium hydrophosphate - MQHPO 4, sodium hydrosulfide - NaHS, iron nitrate (III) - Fe (NO 3) 3, Lithium nitride - Li 3 n, copper hydroxycarbonate (II) - 2 CO 3, ammonium dichromate - (NH 4) 2 Cr 2 O 7, Barium bromide - BABR 2, potassium hexaciatorrat (II) - K 4, Tetrahydroxalumumute sodium - Na.
Task 2.Give examples of salt formation: a) from two simple substances; b) from two complex substances; c) from simple and complex substances.
Decision.
a) Iron when heated with gray forms iron sulphide (II):
Fe + S. 
FES;
b) salts enter each other into metabolic reactions in an aqueous solution, if one of the products falls into a precipitate:
AQNO 3 + NaCl 
AQCL 
+ Nano 3;
c) salts are formed when dissolved metals in acids:
Zn + H 2 SO 4 
ZNSO 4 + H 2.
Task 3.During the decomposition of the magnesium carbonate, carbon oxide (IV) was separated, which was missed through lime water (taken in excess). At the same time, a precipitate for a mass of 2.5g. Calculate the mass of magnesium carbonate taken to the reaction.
Decision.
Compile equations of appropriate reactions:
MQCO 3. 
MQO + CO 2;
CO 2 + CA (OH) 2 
Caco 3 + H 2 O.
2. Calculate the molar masses of calcium carbonate and magnesium carbonate, using a periodic system of chemical elements:
M (sasso 3) \u003d 40 + 12 + 16 * 3 \u003d 100g / mol;
M (MQCO 3) \u003d 24 + 12 + 16 * 3 \u003d 84 g / mol.
3. Calculate the amount of calcium carbonate substance (substance resolved):
N (Caco 3) \u003d 
.
From the reaction equations it follows that
n (MQCO 3) \u003d n (Caco 3) \u003d 0.025 mol.
We calculate the calcium carbonate mass taken for the reaction:
m (MQCO 3) \u003d n (MQCO 3) * M (MQCO 3) \u003d 0.025mol * 84g / mol \u003d 2.1g.
Answer: M (MQCO 3) \u003d 2.1g.
Task 4.Write the reactions equations that allow the following transformations:
MQ. 
MQSO 4. 
MQ (NO 3) 2 
MQO. 
(CH 3 COO) 2 MQ.
Decision.
Magnesium dissolves in diluted sulfuric acid:
MQ + H 2 SO 4 
MQSO 4 + H 2.
Magnesium sulfate enters the exchange reaction in an aqueous solution with barium nitrate:
MQSO 4 + BA (NO 3) 2 
BASO 4 + MQ (NO 3) 2.
With a strong calcination, magnesium nitrate decomposes:
2mq (NO 3) 2 
2MQO + 4NO 2 + O 2.
4. Magnesium oxide - main oxide. It dissolves in acetic acid
MQO + 2SH 3 coxy 
(CH 3 Soo) 2 MQ + H 2 O.
Glinka, N.L. General chemistry. / N.L. Glinka.- M.: Integral press, 2002.
Glinka, N.L. Tasks and exercises for general chemistry. / N.L. Glinka. - M.: Integral press, 2003.
Gabrielyan, O.S. Chemistry. Grade 11: studies. For general education. institutions. / O.S. Gabrielyan, G.G. Lysov. - M.: Drop, 2002.
Akhmetov, N.S. General and inorganic chemistry. / N.S. Akhmetov. - 4th ed. - M.: Higher School, 2002.
Chemistry. Classification, nomenclature and reaction capabilities of inorganic substances: Methodical instructions for practical and independent work for students of all forms of training and all specialties
Chemical equations
Chemical equation - This is an expression of the reaction with the help of chemical formulas. Chemical equations show which substances enter the chemical reaction and which substances are formed as a result of this reaction. The equation is drawn up on the basis of the law of preserving the mass and shows the quantitative relations of the substances involved in the chemical reaction.
As an example, consider the interaction of potassium hydroxide with phosphoric acid:
H 3 PO 4 + 3 KON \u003d K 3 PO 4 + 3N 2 O.
It can be seen from the equation that 1 mole of orthophosphoric acid (98 g) reacts with 3 moles of potassium hydroxide (3 · 56 g). As a result of the reaction, 1 mol of potassium phosphate (212 g) and 3 water praying (3 × 18 g) are formed.
98 + 168 \u003d 266 g; 212 + 54 \u003d 266 g We see that the mass of substances that have entered the reaction is equal to the mass of the reaction products. The chemical reaction equations makes it possible to produce various calculations associated with this reaction.
Painst substances are divided into four classes: oxides, bases, acids and salts.
Oxides. - these are complex substances consisting of two elements, one of which oxygen, i.e. Oxide is a compound of an element with oxygen.
The name of the oxides is formed from the name of the element included in the composition of the oxide. For example, Bao - barium oxide. If the oxide element has a variable valence, then after the name of the element in brackets, its valence of the Roman number is indicated. For example, FEO - iron oxide (I), Fe2O3 - iron oxide (III).
All oxides are divided into salt-forming and non-forming.
Shaft-forming oxides are such oxides, which as a result of chemical reactions form salts. These are oxides of metals and non-metals, which, when interacting with water, form appropriate acids, and when interacting with bases, corresponding acidic and normal salts. For example, copper oxide (CUO) is salt-forming oxide, because, for example, in the interaction of it with hydrochloric acid (HCl), salt is formed:
CUO + 2HCL → CUCL2 + H2O.
As a result of chemical reactions, other salts can be obtained:
Cuo + SO3 → CUSO4.
No oxides are called such oxides that do not form salts. An example is CO, N2O, NO.
Shaft-forming oxides are 3 types: the main (from the word "base"), acid and amphoteric.
The main oxides are metal oxides, which correspond to the hydroxides relating to the base class. The main oxides include, for example, Na2O, K2O, MGO, CaO, etc.
Chemical properties of major oxides
1. Water soluble main oxides react with water, forming bases:
Na2O + H2O → 2NAOH.
2. interact with acid oxides, forming appropriate salts
Na2O + SO3 → Na2SO4.
3. React with acids, forming salt and water:
Cuo + H2SO4 → CUSO4 + H2O.
4. React with amphoteric oxides:
Li2O + Al2O3 → 2lialo2.
5. Main oxides react with acid oxides, forming salts:
Na2O + SO3 \u003d Na2SO4
If the composition of oxides as the second element will be non-metall or metal, manifesting the highest valence (usually exhibit from IV to VII), then such oxides will be acidic. Acid oxides (acid anhydrides) are such oxides, which correspond to hydroxides relating to the class of acids. This is, for example, CO2, SO3, P2O5, N2O3, CL2O5, MN2O7, etc. Acid oxides dissolve in water and alkalis, forming salt and water.
Chemical properties of acid oxides
1. Interact with water, forming an acid:
SO3 + H2O → H2SO4.
But not all acidic oxides are directly reacting with water (SiO2 et al.).
2. React with based oxides with salt formation:
CO2 + CAO → Caco3
3. Interact with alkalis, forming salt and water:
CO2 + BA (OH) 2 → BacO3 + H2O.
The composition of amphoteric oxide includes an element that has amphoteric properties. Under amphoteriness understand the ability of compounds to exercise depending on the conditions of acid and basic properties. For example, Zno zinc oxide can be both base and acid (Zn (OH) 2 and H2ZNO2). Amphoterity is expressed in the fact that, depending on the conditions of amphoteric oxides, are manifested either based on them, or acidic properties, for example - Al2O3, CR2O3, MNO2; Fe2O3 zno. For example, the amphoter character of zinc oxide is manifested when it interacts with hydrochloric acid and sodium hydroxide:
Zno + 2HCl \u003d ZnCl 2 + H 2 O
Zno + 2NaOH \u003d Na 2 ZnO 2 + H 2 O
Since far from all amphoteric oxides of rowing in water, then prove the amphoterity of such oxides is noticeably more difficult. For example, alumina (III) oxide in the fusion reaction with potassium disulphate shows the basic properties and when fusing with hydroxides acidic:
Al2O3 + 3K2S2O7 \u003d 3K2SO4 + A12 (SO4) 3
Al2O3 + 2KOH \u003d 2kalo2 + H2O
In various amphoteric oxides, the duality of properties can be expressed in varying degrees. For example, zinc oxide is equally easily soluble in acids, and alkalis, and iron (III) oxide - FE2O3 - has mainly the main properties.
Chemical properties of amphoteric oxides
1. Interact with acids, forming salt and water:
Zno + 2HCl → ZnCl2 + H2O.
2. react with solid alkalis (when fusing), forming a sodium cinat and water as a result of the reaction.
Zno + 2NAOH → Na2 ZnO2 + H2O.
When the zinc oxide interacts with alkali solution (the same NaOH), another reaction flows:
Zno + 2 NaOH + H2O \u003d\u003e Na2.
The coordination number is a characteristic that determines the number of nearest particles: atoms or yn in a molecule or crystal. For each amphoteric metal, its coordination number is characteristic. For BE and ZN - this is 4; For and Al are 4 or 6; For and CR is 6 or (very rare) 4;
Amphoteric oxides usually do not dissolve in water and do not react with it.
Methods for obtaining oxides from simple substances is either a direct reaction of an oxygen element:
either decomposition of complex substances:
a) oxides
4cr3 \u003d 2Cr2O3 + 3O2-
b) hydroxides
Ca (OH) 2 \u003d Cao + H2O
c) acids
H2CO3 \u003d H2O + CO2-
Caco3 \u003d Cao + CO2
As well as the interaction of acids - oxidizing agents with metals and non-metals:
Cu + 4hnO3 (concluded) \u003d Cu (NO3) 2 + 2NO2 + 2H2O
Oxides can be obtained with the direct interaction of oxygen with another element and indirectly (for example, with decomposition of salts, bases, acids). Under normal conditions, oxides are in a solid, liquid and gaseous state, this type of compounds are very common in nature. Oxides are contained in the earth's crust. Rust, sand, water, carbon dioxide are oxides.
Basis - These are complex substances, in the molecules of which metal atoms are connected to one or more hydroxyl groups.
The bases are electrolytes, which, during dissociation, form only hydroxide ions as anions.
NaOH \u003d Na + + Oh -
Ca (OH) 2 \u003d CaOH + + OH - \u003d Ca 2 + + 2OH -
There are several signs of base classification:
Depending on the solubility in water, the bases are divided into risks and insoluble. Alkali are alkali metal hydroxides (Li, Na, k, Rb, Cs) and alkaline earth metals (CA, SR, BA). All other bases are insoluble.
Depending on the degree of dissociation, the base is divided into strong electrolytes (all rubber) and weak electrolytes (insoluble bases).
Depending on the number of hydroxyl groups in the base molecule, they are divided into one-acid (1 group of it), for example, sodium hydroxide, potassium hydroxide, two-cell (2 groups), for example, calcium hydroxide, copper hydroxide (2), and multi-acid.
Chemical properties.
Ions he - in solution determine the alkaline environment.
Alkali solutions change the color of the indicators:
Phenolphthalein: colorless ® Raspberry,
Lacmus: Violet ® Blue,
Methylorant: orange ® yellow.
Alkali solutions interact with acidic oxides to form salts of those acids that correspond to reacting acidic oxides. Depending on the number of lumps, medium or acidic salts are formed. For example, when calcium hydroxide interacts with carbon oxide (IV), calcium carbonate and water are formed:
Ca (OH) 2 + CO2 \u003d Caco3? + H2O.
And with the interaction of calcium hydroxide with an excess of carbon oxide (IV), calcium bicarbonate is formed:
Ca (OH) 2 + CO2 \u003d CA (HCO3) 2
Ca2 + + 2OH- + CO2 \u003d CA2 + 2HCO32-
All bases interact with acids to form salt and water, for example: in the interaction of sodium hydroxide with hydrochloric acid, sodium chloride and water are formed:
NaOH + HCl \u003d NaCl + H2O
Na + + oh- + h + + cl- \u003d na + + cl- + h2o
The hydroxide of copper (II) is dissolved in hydrochloric acid to form copper (II) chloride and water:
Cu (OH) 2 + 2HCl \u003d CUCL2 + 2H2O
Cu (OH) 2 + 2H + + 2Cl- \u003d Cu2 + 2Cl- + 2H2O
Cu (OH) 2 + 2H + \u003d Cu2 + 2H2o.
The reaction between acid and the base is called neutralization reaction.
Insoluble bases in heating are decomposed on water and corresponding to the base of metal oxide, for example:
Cu (OH) 2 \u003d Cuo + H2 2Fe (OH) 3 \u003d Fe2O3 + 3H2O
The lumps come into interaction with salt solutions if one of the conditions for the reaction of the ion exchange to the end (precipitates falls),
2Naoh + Cuso4 \u003d Cu (OH) 2? + Na2SO4.
2OH- + Cu2 + \u003d Cu (OH) 2
The reaction occurs due to the binding of copper cations with hydroxide ions.
When the barium hydroxide interacts with sodium sulfate solution, the barium sulfate precipitate is formed.
Ba (OH) 2 + Na2SO4 \u003d Baso4? + 2Naoh.
Ba2 + + SO42- \u003d Baso4
The reaction flows due to the binding of barium cations and and sulfate anions.
Acids -these are complex substances, the molecules of which include hydrogen atoms capable of replacing or exchanged on metal atoms and acid residue.
According to the presence or absence of oxygen in the acid molecule are divided into oxygen-containing (H2SO4 sulfuric acid, H2SO3 sulfuric acid, HNO3 nitric acid, H3PO4 phosphoric acid, H2CO3 coal acid, H2SIO3 silicic acid) and oxygen-free (HF fluoride acid, HCl chloride acid (hydrochloric acid) , HBr Bromomrogenic acid, Hi iodomiculture acid, H2S hydrogen sulfide acid).
Depending on the number of hydrogen atoms in an acid acid molecule, one-axis (with 1 H atom), two-axis (with 2 H atoms) and three-axis (with 3 H atoms).
To and with l about t
A part of the acid molecule without hydrogen is called the acid residue.
Acid residues can consist of one atom (-cl, -br, -i) - these are simple acid residues, and can be from a group of atoms (-so3, -po4, -sio3) - these are complex residues.
In aqueous solutions, acid residues are not destroyed in aqueous solutions:
H2SO4 + CUCL2 → CUSO4 + 2 HCl
The word anhydride means anhydrous, that is, acid without water. For example,
H2SO4 - H2O → SO3. Noiseless anhydride acids do not have.
Its name of the acid is obtained from the name of the acid forming an element (acid formator) with adding the expirations of "naya" and less commonly "WAY": H2SO4 - sulfur; H2SO3 - coal; H2SIO3 - Silicon, etc.
The element can form several oxygen acids. In this case, the indicated endings in the names of the acids will be when the element exhibits the highest valence (in the acid molecule, the large content of oxygen atoms). If the element exhibits lower valence, the ending in the acid name will be "based": HNO3 - nitrogen, HNO2 is nitrogenous.
Acids can be obtained by dissolving anhydrides in water. In case anhydrides in water are not soluble, the acid can be obtained by the action of another stronger acid on the salt of the necessary acid. This method is characteristic of both oxygen and oxygenic acids. Oxygenic acids are also obtained by direct synthesis of hydrogen and nonmetal, followed by dissolving the resulting compound in water:
H2 + CL2 → 2 HCl;
The solutions of the obtained gaseous substances HCl and H2S are acids.
Under conventional acid conditions, both in liquid and solid state.
Chemical properties of acids
1. Acid solutions act on indicators. All acids (except silicon) are well soluble in water. Special substances - indicators allow you to determine the presence of an acid.
Indicators are a substance of a complex structure. They change their painting depending on the interaction with different chemicals. In neutral solutions - they have one color, in the solutions of the base - another. When interacting with acid, they change their color: Methyl orange indicator is painted in red, the lactium indicator is also red.
2. Interact with bases with the formation of water and salt, which contains a constant acid residue (neutralization reaction):
H2SO4 + CA (OH) 2 → Caso4 + 2 H2O.
3. Interact with based oxide to the formation of water and salt. Salt contains the acid residue of the acid that was used in the neutralization reaction:
H3PO4 + Fe2O3 → 2 FEPO4 + 3 H2O.
4. Interate with metals.
For the interaction of acids with metals, some conditions must be performed:
1. The metal must be sufficiently active with respect to the acids (in a number of metal activity, it should be placed to hydrogen). The left is the metal in a row of activity, the more intense it interacts with the acids;
K, CA, Na, Mn, Al, Zn, Fa, Ni, Sn, Pie, N2, Cu, Ng, Ag, Au.
But the reaction between the hydrochloric acid solution and copper is impossible, as copper stands in a row of stresses after hydrogen.
2. The acid should be sufficiently strong (that is, capable of giving hydrogen ions H +).
With the flow of chemical reactions with metals with metals, hydrogen is produced and hydrogen is distinguished (except for the interaction of metals with nitric and concentrated sulfuric acids,):
Zn + 2hcl → ZnCl2 + H2;
CU + 4HNO3 → CUNO3 + 2 NO2 + 2 H2O.
However, no matter how different acids are, they all form in the dissociation of hydrogen cations, which cause a number of common properties: sour taste, change in the color of the indicators (Lacmus and methyl orange), interaction with other substances.
Also, the reaction proceeds between metals oxides and most acids
Cuo + H2SO4 \u003d CUSO4 + H2O
We describe the reaction:
2) at a second reaction should be soluble salt. In many cases, the interaction of metal with acid practically does not occur because the resulting non-soluble salt and covers the surface of the metal with a stitched film, for example:
PB + H2SO4 \u003d / PBSO4 + H2
Insoluble lead sulfate (II) stops access to metal, and the reaction stops, hardly time to begin. For this reason, most heavy metals practically does not interact with phosphate, coal and hydrogen sulfide acids.
3) The third reaction is characteristic of acid solutions, therefore non-soluble acids, for example, silicon, do not react with metals. The concentrated solution of sulfuric acid and a solution of nitric acid of any concentration interact with metals is somewhat different, therefore the equations of reactions between metals and these acids are recorded by a girlfriend. Diluted sulfuric acid solution interacts with metals. Standing in a row voltage to hydrogen, forming salt and hydrogen.
4) The fourth reaction is a typical ion exchange reaction pro proceed only if the sediment or gas is formed.
Salt -these are complex substances whose molecules consist of metal atoms and acid residues (sometimes hydrogen can contain). For example, NaCl - sodium chloride, saso4 - calcium sulfate, etc.
Almost all salts are ionic compounds, therefore, acid residual ions and metal ions are connected in the salts:
Na + Cl - sodium chloride
CA2 + SO42 - calcium sulfate, etc.
Salt is a product of partial or complete substitution with metal atoms of hydrogen acid.
From here, the following types of salts are distinguished:
1. Medium salts - all hydrogen atoms in acid substituted with metal: Na2CO3, KNO3, etc.
2. Acid salts - not all hydrogen atoms in acid substituted with metal. Of course, acidic salts can form only two- or multi-axis acids. Simple acid salts can not be given: NaHCO3, NaH2PO4 IT. d.
3. Double salts - hydrogen atoms of two- or polypic acid substituted not with one metal, but two different: nakco3, kal (SO4) 2, etc.
4. Main salts can be considered as incomplete, or partial products, replacement of hydroxyl base groups with acid residues: AL (OH) SO4, Zn (OH) Cl, etc.
In the international nomenclature, the name of the salt of each acid comes from the Latin name of the element. For example, sulfuric acid salts are called sulphates: Case4 - calcium sulfate, MG SO4 - magnesium sulfate, etc.; Salt hydrochloric acids are called chlorides: NaCl - sodium chloride, Znci2 - zinc chloride, etc.
A particle "bi" or "hydro": Mg (HCl3) 2 is a bicarbonate or magnesium bicarbonate is added to the name of dioxide salts.
Provided that only one hydrogen atom is replaced in a three-axis acid, then the "dihydro" prefix is \u200b\u200badded: NaH2PO4 - sodium dihydrophosphate.
Salts are solid substances with the most varying solubility in water.
Chemical properties of salts are determined by the properties of cations and anions, which are included in their composition.
1. Some salts decompose when calcining:
Caco3 \u003d Cao + CO2
2. Interact with acids with the formation of a new salt and a new acid. To carry out this reaction, it is necessary that the acid is stronger than the salt on which the acid affects:
2NACL + H2 SO4 → Na2SO4 + 2HCl.
3. Interact with the grounds, forming a new salt and a new base:
Ba (OH) 2 + Mg SO4 → Baso4 ↓ + Mg (OH) 2.
4. Interact with each other with the formation of new salts:
NaCl + AGNO3 → AGCl + Nano3.
5. Interact with metals that stand in the rudd of activity to a metal, which is part of the salt.
