Part A. Test tasks with choosing one correct answer and matching
1. The following is not a mixture of substances:
2. A series of formulas in which all substances are acids: 
3. Sulfur manifests greatest degree oxidation in a compound whose formula is:
4. General formula salts is depicted by the following notation: 
5. Number of oxide formulas in next list: NaOH, K2O, MgCl2, SO2, BaSO4, OF2, Ca(OH)2, H2O – equal to: 
6. Mass fraction nitrogen in nitric acid HNO3 is equal to:
7. 30 g of salt was dissolved in 20 g of water. The mass fraction of salt in the resulting solution is equal to:
8. Formula of chromium (III) sulfate:
9. An acid in which the charge of the ion acid residue equals 2-, has the formula:
10. A water-insoluble base is a substance with the formula:
11. Match:
Compound formula: 1. H2SO3 2. SO3 3. BaCl2 4. Ca(OH)2 5. ZnO 6. Al(OH)3
Class of compounds: A. Oxides B. Bases C. Acids D. Salts
12. Match:
Compound formula: 1. KOH 2. Al2(SO4)3 3. H2SO4 4. Cu(OH)2 5. Al(NO3)3 6. H3PO4 7. K2O 8. CuOH
Name of the substance: A. Potassium oxide B. Phosphoric acid C. Copper (II) hydroxide D. Aluminum nitrate
Part B. Free-response questions
13. For a hydroxide (acid or base), write the formula of its corresponding oxide:
A. H2SO4 B. KOH C. Cu(OH)2 
14. Make up chemical formulas connections:
A. Silver (I) oxide B. Zinc hydroxide C. Sulfuric acid D. Aluminum chloride
15. Calculate the volume of methane gas CH4 obtained from 500 liters of natural gas, if it is known that the volume fraction of methane in natural gas is 95%. 
Control test on the topic “Combination of chemical elements”, grade 8. Option 2
Part A.
1. (3 points). Pure substance, in contrast to a mixture, is:A. Sea water.B. Milk.IN. Air.G. Oxygen.
2 (3 points). A series of formulas in which everything is— society - foundations:
A. WITHu(HE) 2 , CuCI 2 , NaOH.B. Ca(OH) 2 , Mg(OH) 2 , MgOHCl.
IN . KOH, Ba(OH) 2, WITHu(HE) 2 . G. NSl, NaOH,NaCl.
3 (3 points). Carbon exhibits the least— oxidation stump in combination with the formula:
A . CH 4 . B. N 2 CO 3 . IN . CO 2 . G. CO.
4 (3 points). The general formula of the oxide is depicted by the following notation:
A. M(OH) x . IN. M x (KO) at
B. E X ABOUT U . G. N X CO.
M - metal, E - element, KO - acid residue.
5 (3 points). Number of salt formulas in the following list:H 2 CO 3 , Fe( OH) 3 , KNO 3 , NaOH, Ba( OH) 2 , CaO, SO 2 , CaCABOUT 3 - equals:
A.1 B.2 C.3 D.4
6 (3 points). Mass fraction of aluminum in aluminum oxide Al 2 Oz is equal to:
A. 52.94%. B. 0.36% C. 26.47% D. 73.00%
7 (3 points). 20 g of NaCl were dissolved in 180 g of water. The mass fraction of sodium chloride in the resulting solution is equal to:
A. 11%. B. 15%. IN. 20%. G. 10%
8 (3 points). Copper chloride formula (II):
A . CuClB . Si 2 SO 4 IN . CuCl 2 . G. CuSO 4 .
9 (3 points). The formula of an acid in which the charge of the acid residue ion is 3 -:
A . NSl. B. N 3 RO 4 . IN. N 2 SO 4 . G. HNO 3 .
10 (3 points). A water-insoluble base is a substance with the formula:
A . NaOH.B . KOH.IN . Fe(OH) 3 . G. Ba( OH) 2 .
11 (6 points) Match.
Compound formula:
1. K 2 O. 2. CaSO 4 . 3. N 2 SO 4. 4. KOH 5. SO 2 6. HNO 3
Connection class:
A. Oxides. B. Reasons. B. Acids. G. Soli.
12.(4 points)Relate.
Compound formula: 1.MnC.L. 2 2. Fe( OH) 2 3. Fe(OH) 3 4. H 2 SO 4 5. MgCl 2 6.MgO 7. MnOName of substance: A. Magnesium oxide. B. Sulfuric acid C. iron hydroxide (3) G. magnesium chloride
Part B Free-response questions
13. (6 points) For a hydroxide (acid or base), write the formula of its corresponding oxide: A.H 2 SiO 3 B.Ca( OH) 2 IN.Fe( OH) 3
14. (4 points)
Make up the chemical formulas of the compounds: A. aluminum oxide (3) B. sodium nitrate C. potassium sulfate D. zinc hydroxide (2)
15. (6 points) Calculate the volume of nitrogen obtained from 200 liters of air if the volume fraction of nitrogen in the air is 78%.
Control test on the topic " Combination of chemical elements",8th grade. Option 1
Part A. Test tasks with the choice of one correct answer and for correlation
1 (3 points). A mixture of substances, unlike individual substance, is:A. Tap water.B . Carbon dioxide.IN. Oxygen.G. Copper
2 (3 points). A series of formulas in which all substances are oxides:A. ZnO, ZnCl 2 , H 2 O. B. CaO, NaOH, N.H. 3 IN. SO 3 , MgO, CuO. G. KOH, K 2 O, MgO.
3 (3 points). Nitrogen exhibits the highest degree of oxidation when combined with the formula:A. N.H. 3 . B. NO 2 . IN. N 2 O 5 . G. NO.
4 (3 points). The general formula of the base is— in conventional notation:
A. M( OH) x . B. E X ABOUT at . IN . E X N at . G. N X KO M - metal, E - element, KO - acid residue.
5
(3 points). Number of acid formulas in the following list: H 2
CO 3
,Fe(OH) 2
, NaOH, H 2
SiO 3
, Ba(OH) 2
,
Cu(OH) 2
, CaO, SO 2
- equals:A.
1
. B.
2
. IN.
3.
G.
4.
6 (3 points). Mass fraction of sulfur in sulfuric acid H 2 SO 4 is equal to:A . 2,04%. B. 65,31%. IN. 52,34%. G . 32,65% .
7
(3 points). 20 g of salt were dissolved in 80 g of water. The mass fraction of salt in the resulting solution is equal to:
A
. 20% .
B.
25% .
IN.
40% .
G.
30% .
8 (3 points). Ferrous sulfate formula (II): A. FeS. B . FeSO 3 . IN . Fe 2 (SO 4 ) 3 . G. FeSO 4
9
(3 points). The formula of an acid in which the charge of the acid residue ion is 2 -:
A.
NSl.
B.
H 2
SO 4
.
IN
.
H 3
P.O. 4
. G.
HNO 3
.
10 (3 points). An alkali is a substance with— muloy:
A. Al(OH)z.B . Fe(OH) 2 , . IN . KOH. G. Cu(OH) 2 .
11 (3 points). Relate.
Formulaconnections:
1. Na 2 ABOUT. 2 .MgSABOUT 4 . 3 .NaOH.4 .HCl.5. CO 2 . 6 . N 3 RO 4 .
Connection class: A. Oxides.B. Grounds.IN. Acids.G. Salt.
12 (3 points). Relate.
Compound formula:
1
. HNO 3
. 2.
Al 2
O 3
.
3.
Ca(OH) 2
. 4.
CaSO 4
.
5.
CaO.
6.
H 3
P.O. 4
.
7.
Al(OH)z.8.
TO 2
SO 4
.
Substance name:
A. Calcium oxide.B. Nitric acid.IN. Aluminum hydroxide.G. Potassium sulfate.
Part B . Free-response questions
13 (6 points). For hydroxides (acids or bases), write the formulas of their corresponding oxides:A. H 2 CO 3 . B. Mg(OH) 2 . IN. Al(OH) 3 .
14 (4 points). Make up the chemical formulas of the compounds:A. Potassium oxide.B . Hydrochloric acid.IN. Calcium phosphate.G. Barium hydroxide.
15 (6 points). Calculate the volume of oxygen obtained from 200 liters of air if it is known that the volume fraction of oxygen in the air is 21%.
Test answer key.
Option 1 | |||||||||||||
question | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | |
answer | G | IN | G | B | B | A | G | IN | B | IN | A-1.5 B-4 C-3.6 D-2 | A-6 B-4 C-3 D-5 |
|
Part A | Option 2 |
||||||||||||
question | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | |
answer | A | IN | IN | A | B | G | A | G | B | IN | A-1.5 B-3 C-4.6 D-2 | A-5 B-1 C-7 D-8 |
|
52-49 points score “5”
48-38 points score “4”
37-28 points score “3”
27- 12 points score “2”
Today we are starting to get acquainted with the most important classes inorganic compounds. Inorganic substances are divided according to their composition, as you already know, into simple and complex.
|
OXIDE |
ACID |
BASE |
SALT |
|
E x O y |
NnA A – acidic 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
- This complex substances, consisting of two chemical elements, one of which is oxygen, with a valence of 2. Only one chemical element - fluorine, when combined with oxygen, forms not an oxide, but oxygen fluoride OF 2.
They are simply called “oxide + name of the element” (see table). If valence chemical element variable, then indicated by a Roman numeral enclosed in parentheses after the name of the chemical element.
|
Formula |
Name |
Formula |
Name |
|
carbon(II) monoxide |
Fe2O3 |
iron(III) oxide |
|
|
nitric oxide (II) |
CrO3 |
chromium(VI) oxide |
|
|
Al2O3 |
aluminium oxide |
zinc oxide |
|
|
N2O5 |
nitric oxide (V) |
Mn2O7 |
manganese(VII) oxide |
Oxides classification
All oxides can be divided into two groups: salt-forming (basic, acidic, amphoteric) and non-salt-forming or indifferent.
|
Metal oxides Fur x O y |
Non-metal oxides neMe x O y |
|||
|
Basic |
Acidic |
Amphoteric |
Acidic |
Indifferent |
|
I, II Meh |
V-VII Me |
ZnO,BeO,Al 2 O 3, Fe 2 O 3 , Cr 2 O 3 |
> II neMe |
I, II neMe CO, NO, N2O |
1). Basic oxides are oxides that correspond to bases. The main oxides include 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). Acidic oxides- These are oxides, which correspond to acids. Acid oxides include non-metal oxides (except for non-salt-forming ones - indifferent), as well as metal oxides side subgroups with valency from V before VII (For example, CrO 3 - chromium (VI) oxide, Mn 2 O 7 - manganese (VII) oxide):
3). Amphoteric oxides- These 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– these are oxides 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 valence of the element.
For example, chromium oxides:
CrO(II- main);
Cr 2 O 3 (III- amphoteric);
CrO3(VII- acidic).
Oxides classification
(by solubility in water)
|
Acidic 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 out 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. Given substances : CaO, NaOH, CO 2, H 2 SO 3, CaCl 2, FeCl 3, Zn(OH) 2, N 2 O 5, Al 2 O 3, Ca(OH) 2, CO 2, N 2 O, FeO,
SO 3, Na 2 SO 4, ZnO, CaCO 3, Mn 2 O 7, CuO, KOH, CO, Fe(OH) 3
Obtaining oxides
Simulator "Interaction of oxygen with simple substances"
|
1. Combustion of substances (Oxidation with oxygen) |
a) simple substances Training apparatus |
2Mg +O 2 =2MgO |
|
b) complex substances |
2H 2 S+3O 2 =2H 2 O+2SO 2 |
|
|
2. Decomposition of complex substances (use table of acids, see appendices) |
a) salts SALTt= BASIC OXIDE+ACID OXIDE |
СaCO 3 =CaO+CO 2 |
|
b) Insoluble bases Me(OH)bt= Me x O y+ H 2 O |
Cu(OH)2t=CuO+H2O |
|
|
c) oxygen-containing acids NnA=ACID OXIDE + H 2 O |
H 2 SO 3 =H 2 O+SO 2 |
Physical properties of oxides
At room temperature most oxides are solids (CaO, Fe 2 O 3, etc.), some are liquids (H 2 O, Cl 2 O 7, etc.) and gases (NO, SO 2, etc.).
Chemical properties of oxides
|
CHEMICAL PROPERTIES OF BASIC OXIDES 1. Basic oxide + Acid oxide = Salt (r. compounds) CaO + SO 2 = CaSO 3 2. Basic oxide + Acid = Salt + H 2 O (exchange solution) 3 K 2 O + 2 H 3 PO 4 = 2 K 3 PO 4 + 3 H 2 O 3. Basic oxide + Water = Alkali (compound) Na 2 O + H 2 O = 2 NaOH |
|
CHEMICAL PROPERTIES OF ACID OXIDES 1. Acid oxide + Water = Acid (r. compounds) C O 2 + H 2 O = H 2 CO 3, SiO 2 – does not react 2. Acid oxide + Base = Salt + H 2 O (exchange exchange rate) P 2 O 5 + 6 KOH = 2 K 3 PO 4 + 3 H 2 O 3. Basic oxide + Acidic oxide = Salt (r. compounds) CaO + SO 2 = CaSO 3 4. Less volatile ones displace more volatile ones from their salts CaCO 3 + SiO 2 = 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 = Na 2 [Zn (OH) 4] (in solution) ZnO + 2 NaOH = Na 2 ZnO 2 + H 2 O (when fused) |
Application of oxides
Some oxides are insoluble in water, but many react with water to form compounds:
SO 3 + H 2 O = H 2 SO 4
CaO + H 2 O = Ca( OH) 2
The result is often very necessary and useful compounds. For example, H 2 SO 4 – sulfuric acid, Ca(OH) 2 – slaked lime, etc.
If oxides are insoluble in water, then people skillfully use this property. For example, oxide zinc ZnO– 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 precipitation. Insolubility and non-toxicity allow this oxide to be used in the manufacture of cosmetic creams and powders. Pharmacists make it into an astringent and drying powder for external use.
Same valuable properties possesses titanium oxide (IV) – TiO 2. He also has a handsome White color and is used for the production of titanium white. TiO 2 is insoluble not only in water, but also in acids, so coatings made from this oxide are especially stable. This oxide is added to plastic to give it a white color. It is part of enamels for metal and ceramic dishes.
Chromium (III) oxide - Cr 2 O 3 - very strong dark green crystals, 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 far from their only application.
Tasks for consolidation
1. Write out 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. Given substances : CaO, NaOH, CO 2, H 2 SO 3, CaCl 2, FeCl 3, Zn(OH) 2, N 2 O 5, Al 2 O 3, Ca(OH) 2, CO 2, N 2 O, FeO, SO 3, Na 2 SO 4, ZnO, CaCO 3, Mn 2 O 7, CuO, KOH, CO, Fe(OH) 3
Select from the list: basic oxides, acid oxides, indifferent oxides, amphoteric oxides and give them names.
3. Complete the CSR, indicate the type of reaction, name the reaction products
Na 2 O + H 2 O =
N 2 O 5 + H 2 O =
CaO + HNO3 =
NaOH + P2O5 =
K 2 O + CO 2 =
Cu(OH) 2 = ? + ?
4. Carry out transformations according to the scheme:
1) K → K 2 O → KOH → K 2 SO 4
2) S→SO 2 →H 2 SO 3 →Na 2 SO 3
3) P→P 2 O 5 →H 3 PO 4 →K 3 PO 4