Inorganic chemistry what the table reacts with. Types of chemical reactions
Classification inorganic substances based on chemical composition- the simplest and most constant characteristic in time. Chemical composition substance shows which elements are present in it and in what numerical ratio for their atoms.
Elements conventionally divided into elements with metallic and non-metallic properties. The first of these is always included in cations multielement substances (metal properties), the second - in the composition anions (non-metallic properties). In accordance with Periodic Law in periods and groups between these elements are amphoteric elements that simultaneously exhibit metallic and non-metallic to one degree or another (amphoteric, dual) properties. Elements of the VIIIA-group continue to be considered separately (noble gases), although for Kr, Xe and Rn clearly non-metallic properties were found (the elements He, Ne, Ar are chemically inert).
The classification of simple and complex inorganic substances is given in Table. 6.
Below are the definitions (definitions) of classes of inorganic substances, their most important Chemical properties and methods of obtaining.
inorganic substances- compounds formed by all chemical elements (except most organic compounds carbon). They are divided according to their chemical composition:
Simple substances made up of atoms of the same element. They are divided according to their chemical properties:
Metals- simple substances of elements with metallic properties (low electronegativity). Typical metals:
Metals have a high reduction ability compared to typical non-metals. In the electrochemical series of voltages, they are much to the left of hydrogen, they displace hydrogen from water (magnesium - during boiling):
The simple substances of the elements Cu, Ag and Ni are also referred to as metals, since their oxides CuO, Ag 2 O, NiO and hydroxides Cu(OH) 2, Ni(OH) 2 are dominated by basic properties.
non-metals- simple substances of elements with non-metallic properties (high electronegativity). Typical non-metals: F 2, Cl 2, Br 2, I 2, O 2, S, N 2, P, C, Si.
Nonmetals have a high oxidizing power compared to typical metals.
Amphigenes- amphoteric simple substances formed by elements with amphoteric (dual) properties (electronegativity is intermediate between metals and non-metals). Typical amphigenes: Be, Cr, Zn, Al, Sn, Pb.
Amphigenes have a lower reducing power compared to typical metals. In the electrochemical series of voltages, they adjoin hydrogen on the left or stand behind it on the right.
Aerogens- noble gases, monatomic simple substances of elements of group VIIIA: He, Ne, Ar, Kr, Xe, Rn. Of these, He, Ne, and Ar are chemically passive (compounds with other elements have not been obtained), while Kr, Xe, and Rn exhibit some of the properties of non-metals with high electronegativity.
Complex Substances made up of atoms of different elements. Divided by composition and chemical properties:
oxides- compounds of elements with oxygen, the oxidation state of oxygen in oxides is always equal to (-II). Divided by composition and chemical properties:
The elements He, Ne and Ar do not form compounds with oxygen. Compounds of elements with oxygen in other oxidation states are not oxides, but binary compounds, for example O + II F 2 -I and H 2 + I O 2 -I. Do not apply to oxides and mixed binary compounds, for example S + IV Cl 2 -I O -II.
Basic oxides- products of complete dehydration (real or conditional) of basic hydroxides retain the chemical properties of the latter.
Of the typical metals, only Li, Mg, Ca, and Sr form the oxides Li 2 O, MgO, CaO, and SrO when burned in air; oxides of Na 2 O, K 2 O, Rb 2 O, Cs 2 O and BaO are obtained by other methods.
Oxides CuO, Ag 2 O and NiO are also classified as basic.
Acid oxides- products of complete dehydration (real or conditional) of acid hydroxides, retain the chemical properties of the latter.
Of the typical non-metals, only S, Se, P, As, C and Si form oxides SO 2, SeO 2, P 2 O 5, As 2 O 3, CO 2 and SiO 2 when burned in air; oxides Cl 2 O, Cl 2 O 7 , I 2 O 5 , SO 3 , SeO 3 , N 2 O 3 , N 2 O 5 and As 2 O 5 are obtained by other methods.
Exception: NO 2 and ClO 2 oxides do not have corresponding acidic hydroxides, but they are considered acidic, since NO 2 and ClO 2 react with alkalis, forming salts of two acids, and ClO 2 with water, forming two acids:
a) 2NO 2 + 2NaOH \u003d NaNO 2 + NaNO 3 + H 2 O
b) 2ClO 2 + H 2 O (cold) = HClO 2 + HClO 3
2ClO 2 + 2NaOH (cold) = NaClO 2 + NaClO 3 + H 2 O
Oxides CrO 3 and Mn 2 O 7 (chromium and manganese in the highest degree oxidation) are also acidic.
Amphoteric oxides- products of complete dehydration (real or conditional) of amphoteric hydroxides retain the chemical properties of amphoteric hydroxides.
Typical amphigenes (except Ga) when burned in air form the oxides BeO, Cr 2 O 3 , ZnO, Al 2 O 3 , GeO 2 , SnO 2 and PbO; amphoteric oxides Ga 2 O 3 , SnO and PbO 2 are obtained by other methods.
double oxides are formed either by atoms of one amphoteric element in different oxidation states, or by atoms of two different (metallic, amphoteric) elements, which determines their chemical properties. Examples:
(Fe II Fe 2 III) O 4 , (Рb 2 II Pb IV) O 4 , (MgAl 2) O 4 , (CaTi) O 3 .
Iron oxide is formed by the combustion of iron in air, lead oxide - by weak heating of lead in oxygen; oxides of two different metals are obtained by other methods.
Non-salt-forming oxides- oxides of non-metals that do not have acidic hydroxides and do not enter into salt formation reactions (difference from basic, acidic and amphoteric oxides), for example: CO, NO, N 2 O, SiO, S 2 O.
Hydroxides- compounds of elements (except fluorine and oxygen) with hydroxo groups O -II H, may also contain oxygen O -II. In hydroxides, the oxidation state of an element is always positive (from +I to +VIII). The number of hydroxo groups is from 1 to 6. They are divided by chemical properties:
Basic hydroxides (bases) formed by elements with metallic properties.
Obtained by the reactions of the corresponding basic oxides with water:
M 2 O + H 2 O \u003d 2MON (M \u003d Li, Na, K, Rb, Cs)
MO + H 2 O \u003d M (OH) 2 (M \u003d Ca, Sr, Ba)
Exception: Mg(OH) 2, Cu(OH) 2 and Ni(OH) 2 hydroxides are obtained by other methods.
When heated, real dehydration (loss of water) occurs for the following hydroxides:
2LiOH \u003d Li 2 O + H 2 O
M (OH) 2 \u003d MO + H 2 O (M \u003d Mg, Ca, Sr, Ba, Cu, Ni)
Basic hydroxides replace their hydroxo groups with acidic residues to form salts; metallic elements retain their oxidation state in salt cations.
Basic hydroxides that are readily soluble in water (NaOH, KOH, Ca (OH) 2, Ba (OH) 2, etc.) are called alkalis, since it is with their help that an alkaline environment is created in the solution.
Acid hydroxides (acids) formed by elements with non-metallic properties. Examples:
Upon dissociation in dilute aqueous solution cations H + are formed (more precisely, H 3 O +) and the following anions, or acid residues:
Acids can be obtained by reactions of the corresponding acid oxides with water (the following are the actual reactions taking place):
Cl 2 O + H 2 O \u003d 2HClO
E 2 O 3 + H 2 O \u003d 2NEO 2 (E \u003d N, As)
As 2 O 3 + 3H 2 O \u003d 2H 3 AsO 3
EO 2 + H 2 O \u003d H 2 EO 3 (E \u003d C, Se)
E 2 O 5 + H 2 O \u003d 2HEO 3 (E \u003d N, P, I)
E 2 O 5 + 3H 2 O \u003d 2H 3 EO 4 (E \u003d P, As)
EO 3 + H 2 O = H 2 EO 4 (E = S, Se, Cr)
E 2 O 7 + H 2 O \u003d 2HEO 4 (E \u003d Cl, Mn)
An exception: SO 2 oxide as acidic hydroxide corresponds to SO 2 polyhydrate n H 2 O (“sulphurous acid H 2 SO 3” does not exist, but acid residues HSO 3 - and SO 3 2- are present in salts).
When some acids are heated, real dehydration occurs and the corresponding acid oxides are formed:
2HAsO 2 \u003d As 2 O 3 + H 2 O
H 2 EO 3 \u003d EO 2 + H 2 O (E \u003d C, Si, Ge, Se)
2HIO 3 \u003d I 2 O 5 + H 2 O
2H 3 AsO 4 \u003d As 2 O 5 + H 2 O
H 2 SeO 4 \u003d SeO 3 + H 2 O
When the (real and formal) hydrogen of acids is replaced by metals and amphigenes, salts are formed, acid residues retain their composition and charge in salts. The acids H 2 SO 4 and H 3 RO 4 in a dilute aqueous solution react with metals and amphigens that are in the series of voltages to the left of hydrogen, while the corresponding salts are formed and hydrogen is released (HNO 3 acid does not enter into such reactions; below are typical metals, except Mg are not listed as they react with water under similar conditions):
M + H 2 SO 4 (pasb.) \u003d MSO 4 + H 2 ^ (M \u003d Be, Mg, Cr, Mn, Zn, Fe, Ni)
2M + 3H 2 SO 4 (razb.) \u003d M 2 (SO 4) 3 + 3H 2 ^ (M \u003d Al, Ga)
3M + 2H 3 PO 4 (diff.) \u003d M 3 (PO 4) 2 v + 3H 2 ^ (M \u003d Mg, Fe, Zn)
Unlike anoxic acids, acidic hydroxides are called oxygenated acids or oxoacids.
Amphoteric hydroxides formed by elements with amphoteric properties. Typical amphoteric hydroxides:
Be(OH) 2 Sn(OH) 2 Al(OH) 3 AlO(OH)
Zn(OH) 2 Pb(OH) 2 Cr(OH) 3 CrO(OH)
He are formed from amphoteric oxides and water, but undergo real dehydration and form amphoteric oxides:
Exception: for iron(III) only metahydroxide FeO(OH) is known, "iron(III) hydroxide Fe(OH) 3" does not exist (not obtained).
Amphoteric hydroxides exhibit the properties of basic and acidic hydroxides; form two types of salts, in which the amphoteric element is part of either salt cations or their anions.
For elements with several oxidation states, the rule applies: the higher the oxidation state, the more pronounced the acidic properties of hydroxides (and/or the corresponding oxides).
salt- connections made up of cations basic or amphoteric (in the role of basic) hydroxides and anions(residues) of acid or amphoteric (in the role of acid) hydroxides. In contrast to the anoxic salts, the salts considered here are called oxygenated salts or oxosalts. They are divided according to the composition of cations and anions:
Medium salts contain medium acid residues CO 3 2- , NO 3 - , PO 4 3- , SO 4 2- and others; for example: K 2 CO 3, Mg (NO 3) 2, Cr 2 (SO 4) 3, Zn 3 (PO 4) 2.
If medium salts are obtained by reactions involving hydroxides, then the reagents are taken in equivalent quantities. For example, salt K 2 CO 3 can be obtained by taking the reagents in the ratios:
2KOH and 1H 2 CO 3, 1K 2 O and 1H 2 CO 3, 2KOH and 1CO 2.
Reactions for the formation of medium salts:
Base + Acid > Salt + Water
1a) basic hydroxide + acid hydroxide >…
2NaOH + H 2 SO 4 \u003d Na 2 SO 4 + 2H 2 O
Cu(OH) 2 + 2HNO 3 = Cu(NO 3) 2 + 2H 2 O
1b) amphoteric hydroxide + acidic hydroxide >…
2Al (OH) 3 + 3H 2 SO 4 \u003d Al 2 (SO 4) 3 + 6H 2 O
Zn (OH) 2 + 2HNO 3 \u003d Zn (NO 3) 2 + 2H 2 O
1c) basic hydroxide + amphoteric hydroxide >…
NaOH + Al (OH) 3 \u003d NaAlO 2 + 2H 2 O (in melt)
2NaOH + Zn(OH) 2 = Na 2 ZnO 2 + 2H 2 O (in melt)
Basic Oxide + Acid = Salt + Water
2a) basic oxide + acidic hydroxide >…
Na 2 O + H 2 SO 4 \u003d Na 2 SO 4 + H 2 O
CuO + 2HNO 3 \u003d Cu (NO 3) 2 + H 2 O
2b) amphoteric oxide + acidic hydroxide >…
Al 2 O 3 + 3H 2 SO 4 \u003d Al 2 (SO 4) 3 + 3H 2 O
ZnO + 2HNO 3 \u003d Zn (NO 3) 2 + H 2 O
2c) basic oxide + amphoteric hydroxide >…
Na 2 O + 2Al (OH) 3 \u003d 2NaAlO 2 + ZN 2 O (in melt)
Na 2 O + Zn(OH) 2 = Na 2 ZnO 2 + H 2 O (in melt)
Base + Acid oxide > Salt + Water
For) basic hydroxide + acid oxide > ...
2NaOH + SO 3 \u003d Na 2 SO 4 + H 2 O
Ba (OH) 2 + CO 2 \u003d BaCO 3 + H 2 O
3b) amphoteric hydroxide + acid oxide >…
2Al (OH) 3 + 3SO 3 \u003d Al 2 (SO 4) 3 + 3H 2 O
Zn (OH) 2 + N 2 O 5 \u003d Zn (NO 3) 2 + H 2 O
Sv) basic hydroxide + amphoteric oxide >…
2NaOH + Al 2 O 3 \u003d 2NaAlO 2 + H 2 O (in melt)
2NaOH + ZnO = Na 2 ZnO 2 + H 2 O (in melt)
Basic oxide + Acid oxide > Salt
4a) basic oxide + acid oxide >…
Na 2 O + SO 3 \u003d Na 2 SO 4, BaO + CO 2 \u003d BaCO 3
4b) amphoteric oxide + acidic oxide >…
Al 2 O 3 + 3SO 3 \u003d Al 2 (SO 4) 3, ZnO + N 2 O 5 \u003d Zn (NO 3) 2
4c) basic oxide + amphoteric oxide >…
Na 2 O + Al 2 O 3 \u003d 2NaAlO 2, Na 2 O + ZnO \u003d Na 2 ZnO 2
Reactions 1c, if they proceed in solution, accompanied by the formation of other products - complex salts:
NaOH (conc.) + Al(OH) 3 = Na
KOH (conc.) + Cr (OH) 3 \u003d K 3
2NaOH (conc.) + M (OH) 2 \u003d Na 2 (M \u003d Be, Zn)
KOH (conc.) + M (OH) 2 \u003d K (M \u003d Sn, Pb)
All medium salts in solution are strong electrolytes (dissociate completely).
Acid salts contain acidic acid residues (with hydrogen) HCO 3 -, H 2 PO 4 2-, HPO 4 2-, etc., are formed by the action of basic and amphoteric hydroxides or medium salts of an excess of acid hydroxides containing at least two hydrogen atoms in the molecule ; the corresponding acid oxides act similarly:
NaOH + H 2 SO 4 (conc.) = NaHSO 4 + H 2 O
Ba (OH) 2 + 2H 3 RO 4 (conc.) \u003d Ba (H 2 RO 4) 2 + 2H 2 O
Zn (OH) 2 + H 3 PO 4 (conc.) \u003d ZnHPO 4 v + 2H 2 O
PbSO 4 + H 2 SO 4 (conc.) = Pb (HSO 4) 2
K 2 HPO 4 + H 3 PO 4 (conc.) \u003d 2KN 2 PO 4
Ca (OH) 2 + 2EO 2 \u003d Ca (HEO 3) 2 (E \u003d C, S)
Na 2 EO 3 + EO 2 + H 2 O \u003d 2NaHEO 3 (E \u003d C, S)
When the hydroxide of the corresponding metal or amphigen is added, the acid salts are converted into medium ones:
NaHSO 4 + NaOH \u003d Na 2 SO 4 + H 2 O
Pb (HSO 4) 2 + Pb (OH) 2 \u003d 2PbSO 4 v + 2H 2 O
Almost all acid salts are highly soluble in water, completely dissociate (KHCO 3 = K + + HCO 3 -).
Basic salts contain OH hydroxo groups, considered as separate anions, for example FeNO 3 (OH), Ca 2 SO 4 (OH) 2, Cu 2 CO 3 (OH) 2, are formed by the action of acid hydroxides excess basic hydroxide containing at least two hydroxo groups in a formula unit:
Co (OH) 2 + HNO 3 \u003d CoNO 3 (OH) v + H 2 O
2Ni(OH) 2 + H 2 SO 4 = Ni 2 SO 4 (OH) 2 v + 2H 2 O
2Cu(OH) 2 + H 2 CO 3 = Cu 2 CO 3 (OH) 2 v + 2H 2 O
Basic salts formed by strong acids, when the corresponding acid hydroxide is added, turn into medium ones:
CoNO 3 (OH) + HNO 3 \u003d Co (NO 3) 2 + H 2 O
Ni 2 SO 4 (OH) 2 + H 2 SO 4 \u003d 2NiSO 4 + 2H 2 O
Most basic salts are sparingly soluble in water; they are precipitated by co-hydrolysis if formed by weak acids:
2MgCl 2 + H 2 O + 2Na 2 CO 3 \u003d Mg 2 CO 3 (OH) 2 v + CO 2 ^ + 4NaCl
double salts contain two chemically different cations; for example: CaMg (CO 3) 2, KAl (SO 4) 2, Fe (NH 4) 2 (SO 4) 2, LiAl (SiO 3) 2. Many double salts are formed (in the form of crystalline hydrates) during the co-crystallization of the corresponding medium salts from a saturated solution:
K 2 SO 4 + MgSO 4 + 6H 2 O \u003d K 2 Mg (SO 4) 2 6H 2 Ov
Often double salts are less soluble in water compared to individual medium salts.
Binary connections- these are complex substances that do not belong to the classes of oxides, hydroxides and salts and consist of cations and oxygen-free anions (real or conditional).
Their chemical properties are varied and are considered in inorganic chemistry separately for non-metals of different groups of the Periodic system; in this case, the classification is carried out according to the type of anion.
Examples:
a) halides: OF 2, HF, KBr, PbI 2, NH 4 Cl, BrF 3, IF 7
b) chalcogenides: H 2 S, Na 2 S, ZnS, As 2 S 3, NH 4 HS, K 2 Se, NiSe
v) nitrides: NH 3, NH 3 H 2 O, Li 3 N, Mg 3 N 2, AlN, Si 3 N 4
G) carbides: CH 4 , Be 2 C, Al 4 C 3 , Na 2 C 2 , CaC 2 , Fe 3 C, SiC
e) silicides: Li 4 Si, Mg 2 Si, ThSi 2
e) hydrides: LiH, CaH 2 , AlH 3 , SiH 4
g) peroxide H 2 O 2, Na 2 O 2, CaO 2
h) superoxides: HO 2, KO 2, Ba (O 2) 2
Type chemical bond among these binary compounds are distinguished:
covalent: OF 2, IF 7, H 2 S, P 2 S 5, NH 3, H 2 O 2
ionic: Nal, K 2 Se, Mg 3 N 2, CaC 2, Na 2 O 2, KO 2
Meet double(with two different cations) and mixed(with two different anions) binary compounds, for example: KMgCl 3 , (FeCu)S 2 and Pb(Cl)F, Bi(Cl)O, SCl 2 O 2 , As(O)F 3 .
All ionic complex salts (except hydroxo complex salts) also belong to this class. complex substances(although usually considered separately), for example:
SO 4 K 4 Na 3
Cl K 3 K 2
Binary compounds include covalent complex compounds without an outer sphere, for example, and [Na(CO) 4].
By analogy with the relationship of hydroxides and salts, oxygen-free acids and salts are isolated from all binary compounds (other compounds are classified as others).
Anoxic acids contain (like oxo acids) mobile hydrogen H + and therefore exhibit some chemical properties of acid hydroxides (dissociation in water, participation in salt formation reactions as an acid). Common anoxic acids are HF, HCl, HBr, HI, HCN and H 2 S, of which HF, HCN and H 2 S are weak acids, and the rest are strong.
Examples salt formation reactions:
2HBr + ZnO = ZnBr 2 + H 2 O
2H 2 S + Ba (OH) 2 \u003d Ba (HS) 2 + 2H 2 O
2HI + Pb (OH) 2 \u003d Pbl 2 v + 2H 2 O
Metals and amphigenes, standing in the series of voltages to the left of hydrogen and not reacting with water, interact with strong acids HCl, HBr and HI (in general view NG) in a dilute solution and displace hydrogen from them (actual reactions are given):
M + 2NG = MG 2 + H 2 ^ (M = Be, Mg, Zn, Cr, Mn, Fe, Co, Ni)
2M + 6NG = 2MG 3 + H 2 ^ (M = Al, Ga)
Anoxic salts formed by cations of metals and amphigens (as well as ammonium cation NH 4 +) and anions (residues) of oxygen-free acids; examples: AgF, NaCl, KBr, PbI 2 , Na 2 S, Ba(HS) 2 , NaCN, NH 4 Cl. They show some chemical properties of oxosalts.
The general method for obtaining oxygen-free salts with single-element anions is the interaction of metals and amphigens with non-metals F 2, Cl 2, Br 2 and I 2 (in the general form G 2) and sulfur S (actual reactions are given):
2M + G 2 = 2MG (M = Li, Na, K, Rb, Cs, Ag)
M + G 2 \u003d MG 2 (M \u003d Be, Mg, Ca, Sr, Ba, Zn, Mn, Co)
2M + ZG 2 = 2MG 3 (M = Al, Ga, Cr)
2M + S \u003d M 2 S (M \u003d Li, Na, K, Rb, Cs, Ag)
M + S = MS (M = Be, Mg, Ca, Sr, Ba, Zn, Mn, Fe, Co, Ni)
2M + 3S = M 2 S 3 (M = Al, Ga, Cr)
Exceptions:
a) Cu and Ni react only with halogens Cl 2 and Br 2 (products MCl 2, MBr 2)
b) Cr and Mn react with Cl 2, Br 2 and I 2 (products CrCl 3, CrBr 3, CrI 3 and MnCl 2, MnBr 2, MnI 2)
c) Fe reacts with F 2 and Cl 2 (products FeF 3, FeCl 3), with Br 2 (mixture of FeBr 3 and FeBr 2), with I 2 (product FeI 2)
d) Cu reacts with S to form a mixture of products Cu 2 S and CuS
Other binary compounds- all substances of this class, except for oxygen-free acids and salts allocated to separate subclasses.
The methods for obtaining binary compounds of this subclass are diverse, the simplest is the interaction of simple substances (actual reactions are given):
a) halides:
S + 3F 2 \u003d SF 6, N 2 + 3F 2 \u003d 2NF 3
2P + 5G 2 = 2RG 5 (G = F, CI, Br)
C + 2F 2 = CF 4
Si + 2Г 2 = Sir 4 (Г = F, CI, Br, I)
b) chalcogenides:
2As + 3S = As2S3
2E + 5S = E 2 S 5 (E = P, As)
E + 2S = ES 2 (E = C, Si)
c) nitrides:
3H 2 + N 2 2NH 3
6M + N 2 \u003d 2M 3 N (M \u003d Li, Na, K)
3M + N 2 \u003d M 3 N 2 (M \u003d Be, Mg, Ca)
2Al + N 2 = 2AlN
3Si + 2N 2 \u003d Si 3 N 4
d) carbides:
2M + 2C \u003d M 2 C 2 (M \u003d Li, Na)
2Be + C \u003d Be 2 C
M + 2C = MC 2 (M = Ca, Sr, Ba)
4Al + 3C \u003d Al 4 C 3
e) silicides:
4Li + Si = Li 4 Si
2M + Si = M 2 Si (M = Mg, Ca)
f) hydrides:
2M + H 2 \u003d 2MH (M \u003d Li, Na, K)
M + H 2 \u003d MH 2 (M \u003d Mg, Ca)
g) peroxides, superoxides:
2Na + O 2 \u003d Na 2 O 2 (combustion in air)
M + O 2 \u003d MO 2 (M \u003d K, Rb, Cs; combustion in air)
Many of these substances completely react with water (more often they are hydrolyzed without changing the oxidation states of the elements, but hydrides act as reducing agents, and superoxides enter into dismutation reactions):
PCl 5 + 4H 2 O \u003d H 3 PO 4 + 5HCl
SiBr 4 + 2H 2 O \u003d SiO 2 v + 4HBr
P 2 S 5 + 8H 2 O \u003d 2H 3 PO 4 + 5H 2 S ^
SiS 2 + 2H 2 O \u003d SiO 2 v + 2H 2 S
Mg 3 N 2 + 8H 2 O \u003d 3Mg (OH) 2 v + 2 (NH 3 H 2 O)
Na 3 N + 4H 2 O \u003d 3NaOH + NH 3 H 2 O
Be 2 C + 4H 2 O \u003d 2Be (OH) 2 v + CH 4 ^
MC 2 + 2H 2 O \u003d M (OH) 2 + C 2 H 2 ^ (M \u003d Ca, Sr, Ba)
Al 4 C 3 + 12H 2 O \u003d 4Al (OH) 3 v + 3CH 4 ^
MH + H 2 O \u003d MOH + H 2 ^ (M \u003d Li, Na, K)
MgH 2 + 2H 2 O \u003d Mg (OH) 2 v + H 2 ^
CaH 2 + 2H 2 O \u003d Ca (OH) 2 + H 2 ^
Na 2 O 2 + 2H 2 O \u003d 2NaOH + H 2 O 2
2MO 2 + 2H 2 O = 2MOH + H 2 O 2 + O 2 ^ (M = K, Rb, Cs)
Other substances, on the contrary, are resistant to water, among them SF 6, NF 3, CF 4, CS 2, AlN, Si 3 N 4, SiC, Li 4 Si, Mg 2 Si and Ca 2 Si.
Examples of tasks for parts A, B, C1. Simple substances are
1) fullerene
2. In formula units of reaction products
Si + CF1 2 >…, Si + O 2 >…, Si + Mg >…
3. In metal-containing reaction products
Na + H 2 O >…, Ca + H 2 O >…, Al + HCl (solution) >…
the total sum of the number of atoms of all elements is
4. Calcium oxide can react (individually) with all substances of the set
1) CO 2, NaOH, NO
2) HBr, SO 3, NH 4 Cl
3) BaO, SO 3 , KMgCl 3
4) O 2, Al 2 O 3, NH 3
5. There will be a reaction between sulfur oxide (IV) and
6. Salt МAlO 2 is formed during fusion
2) Al 2 O 3 and KOH
3) Al and Ca (OH) 2
4) Al 2 O 3 and Fe 2 O 3
7. In the molecular reaction equation
ZnO + HNO 3 > Zn(NO 3) 2 +…
the sum of the coefficients is
8. The products of the reaction N 2 O 5 + NaOH > ... are
1) Na 2 O, HNO 3
3) NaNO 3 , H 2 O
4) NaNO 2, N 2, H 2 O
9. A set of bases is
1) NaOH, LiOH, ClOH
2) NaOH, Ba (OH) 2, Cu (OH) 2
3) Ca (OH) 2, KOH, BrOH
4) Mg (OH) 2, Be (OH) 2, NO (OH)
10. Potassium hydroxide reacts in solution (separately) with the substances of the set
4) SO 3, FeCl 3
11–12. The residue corresponding to the acid named
11. sulfuric
12. Nitrogen
has the formula
13. From hydrochloric and dilute sulfuric acids does not highlight gas only metal
14. amphoteric hydroxide- it
15-16. According to the given formulas of hydroxides
15. H 3 PO 4 , Pb(OH) 2
16. Cr(OH) 3 , HNO 3
the formula for average salt is derived
1) Pb 3 (PO 4) 2
17. After passing excess H 2 S through a solution of barium hydroxide, the final solution will contain salt
18. Possible reactions:
1) CaSO 3 + H 2 SO 4 >…
2) Ca(NO 3) 2 + HNO 3 >…
3) NaHCOg + K 2 SO 4 >…
4) Al(HSO 4) 3 + NaOH >…
19. In the reaction equation (CaOH) 2 CO 3 (t) + H 3 PO 4 > CaHPO 4 v + ...
the sum of the coefficients is
20. Establish a correspondence between the formula of the substance and the group to which it belongs.
21. Establish a correspondence between the starting materials and reaction products.
22. In the scheme of transformations
substances A and B are indicated in the set
1) NaNO 3, H 2 O
4) HNO 3, H 2 O
23. Make equations of possible reactions according to the scheme
FeS > H 2 S + PbS > PbSO 4 > Pb(HSO 4) 2
24. Make equations for four possible reactions between substances:
1) Nitric acid(conc.)
2) carbon (graphite or coke)
3) calcium oxide
During chemical reactions from some substances others are obtained (not to be confused with nuclear reactions, in which one chemical element is converted into another).
Any chemical reaction is described by a chemical equation:
Reagents → Reaction products
The arrow indicates the direction of the reaction.
For instance:
In this reaction, methane (CH 4) reacts with oxygen (O 2), resulting in the formation of carbon dioxide (CO 2) and water (H 2 O), or rather, water vapor. This is exactly the reaction that happens in your kitchen when you light a gas burner. The equation should be read like this: one molecule of methane gas reacts with two molecules of oxygen gas, resulting in one molecule of carbon dioxide and two molecules of water (steam).
The numbers in front of the components of a chemical reaction are called reaction coefficients.
Chemical reactions are endothermic(with energy absorption) and exothermic(with energy release). The combustion of methane is a typical example of an exothermic reaction.
There are several types of chemical reactions. The most common:
- compound reactions;
- decomposition reactions;
- single substitution reactions;
- double substitution reactions;
- oxidation reactions;
- redox reactions.
Connection reactions
In a compound reaction, at least two elements form one product:
2Na (t) + Cl 2 (g) → 2NaCl (t)- the formation of salt.
Attention should be paid to an essential nuance of compound reactions: depending on the conditions of the reaction or the proportions of the reactants that enter into the reaction, different products can be its result. For example, under normal conditions of combustion of coal, carbon dioxide is obtained:
C (t) + O 2 (g) → CO 2 (g)
If there is not enough oxygen, then deadly carbon monoxide is formed:
2C (t) + O 2 (g) → 2CO (g)
Decomposition reactions
These reactions are, as it were, opposite in essence to the reactions of the compound. As a result of the decomposition reaction, the substance decomposes into two (3, 4...) simpler elements (compounds):
- 2H 2 O (g) → 2H 2 (g) + O 2 (g)- water decomposition
- 2H 2 O 2 (g) → 2H 2 (g) O + O 2 (g)- decomposition of hydrogen peroxide
Single substitution reactions
As a result of single substitution reactions, the more active element replaces the less active element in the compound:
Zn (t) + CuSO 4 (solution) → ZnSO 4 (solution) + Cu (t)
The zinc in the copper sulfate solution displaces the less active copper, resulting in a zinc sulfate solution.
The degree of activity of metals in ascending order of activity:
- The most active are alkali and alkaline earth metals.
The ionic equation for the above reaction will be:
Zn (t) + Cu 2+ + SO 4 2- → Zn 2+ + SO 4 2- + Cu (t)
The ionic bond CuSO 4, when dissolved in water, decomposes into a copper cation (charge 2+) and an anion sulfate (charge 2-). As a result of the substitution reaction, a zinc cation is formed (which has the same charge as the copper cation: 2-). Note that the sulfate anion is present on both sides of the equation, i.e., by all the rules of mathematics, it can be reduced. The result is an ion-molecular equation:
Zn (t) + Cu 2+ → Zn 2+ + Cu (t)
Double substitution reactions
In double substitution reactions, two electrons are already replaced. Such reactions are also called exchange reactions. These reactions take place in solution to form:
- insoluble solid (precipitation reaction);
- water (neutralization reactions).
Precipitation reactions
When mixing a solution of silver nitrate (salt) with a solution of sodium chloride, silver chloride is formed:
Molecular equation: KCl (solution) + AgNO 3 (p-p) → AgCl (t) + KNO 3 (p-p)
Ionic equation: K + + Cl - + Ag + + NO 3 - → AgCl (t) + K + + NO 3 -
Molecular-ionic equation: Cl - + Ag + → AgCl (t)
If the compound is soluble, it will be in solution in ionic form. If the compound is insoluble, it will precipitate, forming a solid.
Neutralization reactions
These are reactions between acids and bases, as a result of which water molecules are formed.
For example, the reaction of mixing a solution of sulfuric acid and a solution of sodium hydroxide (lye):
Molecular equation: H 2 SO 4 (p-p) + 2NaOH (p-p) → Na 2 SO 4 (p-p) + 2H 2 O (l)
Ionic equation: 2H + + SO 4 2- + 2Na + + 2OH - → 2Na + + SO 4 2- + 2H 2 O (l)
Molecular-ionic equation: 2H + + 2OH - → 2H 2 O (g) or H + + OH - → H 2 O (g)
Oxidation reactions
These are reactions of interaction of substances with gaseous oxygen in the air, in which, as a rule, a large amount of energy is released in the form of heat and light. A typical oxidation reaction is combustion. At the very beginning of this page, the reaction of the interaction of methane with oxygen is given:
CH 4 (g) + 2O 2 (g) → CO 2 (g) + 2H 2 O (g)
Methane refers to hydrocarbons (compounds of carbon and hydrogen). When a hydrocarbon reacts with oxygen, a lot of heat energy is released.
Redox reactions
These are reactions in which electrons are exchanged between the atoms of the reactants. The reactions discussed above are also redox reactions:
- 2Na + Cl 2 → 2NaCl - compound reaction
- CH 4 + 2O 2 → CO 2 + 2H 2 O - oxidation reaction
- Zn + CuSO 4 → ZnSO 4 + Cu - single substitution reaction
The most detailed redox reactions with a large number of examples of solving equations by the method electronic balance and the half-reaction method are described in the section
The material world in which we live and of which we are a tiny part is one and at the same time infinitely diverse. The unity and diversity of the chemical substances of this world is most clearly manifested in the genetic connection of substances, which is reflected in the so-called genetic series. Let us highlight the most characteristic features of such series.
1. All substances of this series must be formed by one chemical element. For example, a series written using the following formulas:
2. Substances formed by the same element must belong to different classes, i.e., reflect different forms his existence.
3. Substances that form the genetic series of one element must be connected by mutual transformations. On this basis, one can distinguish between complete and incomplete genetic series.
For example, the above genetic series of bromine will be incomplete, incomplete. And here is the next row:
can already be regarded as complete: it began a simple substance bromine and they also ended.
Summarizing the above, we can give the following definition of the genetic series.
genetic series- this is a number of substances - representatives of different classes, which are compounds of the same chemical element, connected by mutual transformations and reflecting the common origin of these substances or their genesis.
genetic connection- the concept is more general than the genetic series, which is, albeit a vivid, but particular manifestation of this connection, which is realized in any mutual transformations of substances. Then, obviously, the first given series of substances also fits this definition.
There are three types of genetic series:
The richest series of metals, which exhibit different degrees of oxidation. As an example, consider the genetic series of iron with oxidation states +2 and +3:
Recall that for the oxidation of iron to iron (II) chloride, you need to take a weaker oxidizing agent than to obtain iron (III) chloride:
Similarly to the metal series, the non-metal series with different oxidation states is richer in bonds, for example, the genetic series of sulfur with oxidation states +4 and +6:
Difficulty can cause only the last transition. Follow the rule: in order to obtain a simple substance from an oxidized compound of an element, you need to take its most reduced compound for this purpose, for example, a volatile one. hydrogen bond non-metal. In our case:
By this reaction, sulfur is formed from volcanic gases in nature.
Similarly for chlorine:
3. The genetic series of the metal, which corresponds to the amphoteric oxide and hydroxide,it is very rich in bonds, because, depending on the conditions, they exhibit either acidic or basic properties.
For example, consider the genetic series of zinc:
Genetic relationship between classes of inorganic substances
Reactions between representatives of different genetic series are characteristic. Substances from the same genetic series, as a rule, do not interact.
For instance:
1. metal + non-metal = salt
Hg + S = HgS
2Al + 3I 2 = 2AlI 3
2. basic oxide + acid oxide = salt
Li 2 O + CO 2 \u003d Li 2 CO 3
CaO + SiO 2 \u003d CaSiO 3
3. base + acid = salt
Cu(OH) 2 + 2HCl \u003d CuCl 2 + 2H 2 O
FeCl 3 + 3HNO 3 \u003d Fe (NO 3) 3 + 3HCl
salt acid salt acid
4. metal - basic oxide
2Ca + O 2 \u003d 2CaO
4Li + O 2 \u003d 2Li 2 O
5. non-metal - acid oxide
S + O 2 \u003d SO 2
4As + 5O 2 \u003d 2As 2 O 5
6. basic oxide - base
BaO + H 2 O \u003d Ba (OH) 2
Li 2 O + H 2 O \u003d 2LiOH
7. acid oxide - acid
P 2 O 5 + 3H 2 O \u003d 2H 3 PO 4
SO 3 + H 2 O \u003d H 2 SO 4
