Are the following judgments about carbon adsorption correct? Solution of exam options in chemistry
File name "Are the judgments of CARBON AND SILICON"
Carbon and its compounds
1). Are the following judgments about the properties of carbon and its compounds correct?
A). When interacting with active metals, carbon and silicon exhibit oxidizing properties
B). Sodium carbonate solution interacts with all substances of the series:
A). CH 3 COOH, CuSO 4, CO 2
2). Are the following judgments about the properties of carbon and its compounds correct?
A). Diamond has an atomic structure, while graphite has a molecular structure.
B). Unlike diamond, graphite conducts electricity
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
3). Are the following judgments about the properties of carbon and its compounds correct?
A). In the laboratory, carbon dioxide is mainly produced by the interaction of marble (chalk) with a strong acid
B). "Dry ice" is solid carbon monoxide (IV)
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
4). Are the following judgments about the properties of carbon and its compounds correct?
A). With an increase in the nuclear charge for group IVA elements, the binding energy in hydrogen compounds composition EN 4
B). Lime water is a reagent for carbon dioxide.
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
5). Are the following judgments about the properties of carbon and its compounds correct?
A). A mixture of carbon monoxide and hydrogen is used industrially to produce methanol.
B). In industry, carbon dioxide is obtained by calcining limestone.
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
6). Are the following judgments about the properties of carbon and its compounds correct?
A). It is possible to increase the yield of carbon monoxide in the reaction C (tv) + CO 2 (gas) ↔ 2СО (gas) - 119.8 kJ by increasing the pressure
B). The main component of chalk, marble, limestone is soda ash.
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
7). Are the following judgments about the properties of carbon and its compounds correct?
A). The most pronounced acidic properties of higher oxides formed by elements of group IV of the main subgroup are possessed by lead (IV) oxide
B). Potassium and sodium carbonates do not decompose when heated
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
Silicon and its compounds.
1). Are the following judgments about the properties of silicon and its compounds true?
A). Silicon oxide reacts under certain conditions with hydrofluoric acid, but does not react with nitric acid;
B). The SiC compound is called corundum.
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
2). Are the following judgments about the properties of silicon and its compounds true?
A). Silicon (IV) oxide is part of glass.
B). Silicic acid cannot be obtained by direct interaction of silicon (IV) oxide and water.
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
3). Are the following judgments about the properties of silicon and its compounds true?
A). In the laboratory, silicon is obtained by calcining silicon dioxide with coal;
B). Silicon does not react with alkalis.
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
4). Are the following judgments about the properties of silicon and its compounds true?
A). Silicic acid stains litmus red;
B). When heated, silicon reacts with active metals.
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
5). Are the following judgments about the properties of silicon and its compounds true?
A). At room temperature, silicon reacts with all halogens.
B). Silane ignites spontaneously in air.
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
6). Are the following judgments about the properties of silicon and its compounds true?
A). Silicon forms two oxides: SiO and SiO 2. Both oxides are acidic.
B). Crystalline silica has an atomic lattice.
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
7). Are the following judgments about the properties of silicon and its compounds true?
A). When heated, silicon oxide (IV) displaces more volatile acidic oxides from salts.
B). Liquid glass is Na 2 O ∙ CaO ∙ 6SiO 2.
1) only A is true 2) only B is true 3) both statements are true 4) both statements are false
Carbon, answers: 1-3; 2-2; 3-3; 4-2; 5-3; 6-4; 7-2.
Silicon, answers: 1-1; 2 3; 3-4; 4-2; 5-2; 6-2; 7-1.
13.1. Carbon
A1. The history of a person's acquaintance with this element goes back centuries, the name of the one who discovered it is unknown. It is not known which of its allotropic modifications was discovered earlier. This element is the main component of flora and fauna. It is found in nature both in free form and in compounds. Its atoms can combine in a variety of ways with each other and with the atoms of other elements. This item:
1) C; 2) Si; 3) Ge; 4) Sn.
A2. Carbon monoxide (IV) interacts with a couple of substances:
1) hydrogen chloride and potassium hydroxide;
2) calcium hydroxide and sodium oxide;
3) sodium hydroxide and sulphuric acid;
4) nitric acid and barium hydroxide.
A3. Carbon exhibits the properties of a reducing agent in the reaction:
1) Mg + CO 2 ->;
2) FeO + CO ->;
3) MgO + CO 2 ->;
4) C + H 2 ->.
A4. Are the following judgments about the chemical properties of carbon true:
a) carbon in reactions can exhibit both the properties of an oxidizing agent and a reducing agent;
b) carbon exhibits brighter non-metallic properties than beryllium?
1) Only a is true;
2) only b is true;
3) both judgments are correct;
4) both judgments are wrong.
A5. The methane molecule is tetrahedral because:
1) the carbon atom is in sp 3-hybridization;
2) given geometric shape corresponds to a minimum of energy;
3) carbon is an element of the second period;
4) carbon is in an excited electronic state.
A6. Gas, not capable of burning in an oxygen atmosphere is:
1) carbon monoxide (IV); 2) carbon monoxide (II);
3) methane; 4) acetylene.
A7. The final product (X 1) in the chain of transformations
is an:
1) carbon monoxide; 2) carbon dioxide;
3) iron carbide; 4) iron carbonate.
A8. Carbon monoxide in the laboratory is obtained by decomposition (in the presence of sulfuric acid when heated):
1) acetic acid; 2) formic acid;
3) carbonic acid; 4) formaldehyde.
A9. The oxidation state of carbon increases in the following order:
1) C 2 H 2, CO, C 6 H 6;
2) CH 3 OH, H 2 C 2 O 4, CO 2;
3) CaC 2, CaCO 3, KHCO 3;
4) CO, H 2 C 2 O 4, CH 4.
A10. Potassium carbonate in solution not interacts with:
1) nitric acid; 2) carbon dioxide;
3) sodium sulfate; 4) copper (II) chloride.
A11. Not decomposes when calcined in a muffle furnace (1000 ° C):
1) sodium carbonate;
2) calcium carbonate;
3) sodium bicarbonate;
4) calcium bicarbonate.
A12. During electrolysis aqueous solution sodium acetate are formed:
1) HCOONa + CO 2;
2) CH 3 CHO + NaOH;
3) CH 4 + CO 2 + NaHCO 3;
4) CH 3 CH 3 + 2CO 2 + H 2 + 2NaOH.
A13. Many metal carbides are readily hydrolyzed with water. Which of the following carbides electrolysis produces methane?
1) CaC 2; 2) Mg 2 C 3; 3) Al 4 C 3; 4) Na 2 C.
A14. As a result of calcining aluminum oxide with coke, aluminum carbide and carbon monoxide are formed. The coefficient in front of the reducing agent formula in the equation of this reaction is:
1) 2; 2) 5; 3) 7; 4) 9.
A15. 20 ml of carbon monoxide (II) exploded with 20 ml of oxygen. After the explosion and bringing the gases to the initial conditions (25 ° C, 1 atm), the volume of the gases turned out to be:
1) 30 ml of CO 2 and 5 ml of O 2;
2) 20 ml of CO 2 and 10 ml of O 2;
3) 20 ml of CO 2 and 15 ml of O 2;
4) 15 ml of CO 2 and 20 ml of O 2.
13.2. Silicon
A16. The element of the 3rd period, the highest oxidation state of which is +4, is:
1) phosphorus; 2) aluminum;
3) sulfur; 4) silicon.
A17. Are the following judgments about chemical properties elements:
a) silicon exhibits greater electronegativity than carbon;
b) does silicon show non-metallic properties brighter than sulfur?
1) Only a is true;
2) only b is true;
3) both judgments are correct;
4) both judgments are wrong.
A18. Each of two substances has an atomic crystal lattice:
1) silicon oxide (IV) and carbon monoxide (IV);
2) diamond and silicon;
3) chlorine and iodine;
4) potassium chloride and iron (III) fluoride.
A19. Silicon oxide not is a part of:
1) silica; 2) river sand;
3) granite; 4) dolomite.
A20. In the series S -> P -> Si -> Al:
1) the number of electronic layers in atoms decreases;
2) non-metallic properties are enhanced;
3) the number of protons in the nuclei of atoms increases;
4) the radii of the atoms increase.
A21. The statement that the structural particle of a given substance is an atom is valid only for:
1) carbon dioxide; 2) table salt;
3) silicon oxide; 4) nitrogen.
A22. Abbreviated ionic equation
2HR + = H 2 SiO 3 + 2R -
corresponds to the reaction between:
1) quartz sand and hydrochloric acid;
2) sodium silicate and calcium nitrate;
3) sodium silicate and formic acid;
4) river sand and potassium hydroxide.
A23. The character of oxides from basic to acidic varies in the following order:
1) Na 2 O -> MgO -> Al 2 O 3 -> SiO 2;
2) Cl 2 O 7 -> SO 2 -> P 2 O 5 -> NO 2;
3) BeO -> B 2 O 3 -> Al 2 O 3 -> MgO;
4) CO 2 -> B 2 O 3 -> A1 2 O 3 -> Li 2 O.
A24. Not interact with each other at room temperature:
1) CaO and H 2 O; 2) SiO 2 and H 2 O;
3) Na and H 2 O; 4) Ca and H 2 O.
A25. Fully biodegradable:
1) CCl 4; 2) CS 2; 3) SiCl 4; 4) PbCl 2.
A26. Silicon forms a binary compound that is part of artificial abrasive materials. This connection is:
1) silicon carbide; 2) silicon oxide;
3) silicon nitride; 4) silicon fluoride.
A27. When heated, reacts with alkalis:
1) Si; 2) C; 3) Mg; 4) Fe.
A28. Reacts with silicon oxide:
1) hydrofluoric acid;
2) hydrochloric acid;
3) hydrobromic acid;
4) hydroiodic acid.
A29. To obtain phosphorus, calcium phosphate with coal is calcined without air access. An obligatory component of this mixture:
1) SiO 2; 2) Na 2 SiO 3; 3) SiC; 4) Si.
A30. When carbon dioxide is passed through a sodium silicate solution, its turbidity is observed. Formula of the precipitate formed:
1) SiO 2; 2) H 2 SiO 3; 3) SiCO 3; 4) NaHSiO 3.
IN 2. Establish a correspondence between the symbol of a chemical element and the formulas of its hydrogen compound and higher hydroxide.
AT 3. Establish a correspondence between the scheme of a redox reaction and a substance that is a reducing agent in it.
AT 4. Establish a correspondence between the starting materials and the sum of the coefficients in the short ionic equation.
| And s h o d n e s | S u m m a k o e f f and c i n t about v in k r and t to about m and about n about m u r a n e |
| a) Pb (OH) 2 + HNO 3 (dil.) ->; b) HCl + Sn (OH) 2 ->; c) SiO 2 + NaOH ->; d) Pb + AgNO 3 ->. |
1) 4; |
AT 5. Match the figure to the name of the allotropic modification of carbon.
AT 6. Carbon dioxide reacts with:
1) calcium hydroxide;
2) calcium carbonate without water;
3) calcium carbonate in the presence of water;
4) magnesium;
5) hydrogen;
6) oxygen.
AT 7. Carbon monoxide reacts with:
1) water; 2) aluminum;
3) iron (III) oxide; 4) sodium;
5) iron; 6) sodium peroxide.
AT 8. The correct characteristic of silicon is as follows:
1) has an atomic crystal lattice;
2) used in the manufacture of microelectronics;
3) It is widely used in the manufacture of batteries for cars;
4) its oxide is the main component of river sand;
5) when exposed to its vapors or dust, stanosis can develop - damage to the lungs;
6) absorbs X-rays well.
AT 9. As a result of fusion of silicon oxide with an excess of sodium hydroxide, 9 g of water was formed. What mass (in g) of silicon oxide has reacted? Give your answer to the nearest whole.
AT 10. An excess of solution was added to 20.8 g of a mixture of calcium and aluminum carbides of hydrochloric acid... In this case, 8.96 liters of a mixture of gases were released. Determine the mass fraction (in%) of calcium carbide in the mixture. Give your answer to the nearest tenth.
Answers to test tasks Chapter 13
| A1 | A2 | A3 | A4 | A5 | A6 | A7 | A8 | A9 | A10 |
| 1 | 2 | 2 | 3 | 2 | 1 | 1 | 2 | 2 | 3 |
| A11 | A12 | A13 | A14 | A15 | A16 | A17 | A18 | A19 | A20 |
| 1 | 4 | 3 | 4 | 2 | 4 | 4 | 2 | 4 | 4 |
| A21 | A22 | A23 | A24 | A25 | A26 | A27 | A28 | A29 | A30 |
| 3 | 3 | 1 | 2 | 3 | 1 | 1 | 1 | 1 | 2 |
| IN 1 | IN 2 | AT 3 | AT 4 | AT 5 | AT 6 | AT 7 | AT 8 | AT 9 | AT 10 |
| 1323 | 1352 | 1356 | 3323 | 2135 | 134 | 356 | 124 | 30 | 30,8 |
To be continued
Use a separate sheet for answers to tasks 20-22. First write down the task number (20, 21, 22), and then the detailed answer to it. Write down your answers clearly and legibly.
Using the method electronic balance, write the reaction equation
Na 2 SO 3 + KMnO 4 + KOH → Na 2 SO 4 + K 2 MnO 4 + H 2 0.
Determine the oxidizing and reducing agent.
Show Answer
Na_2S ^ (+ 4) O_3 + KMn ^ (+ 7) O_4 + KOH \ rightarrow Na_2S ^ (+ 6) O_4 + H_2O
Mn ^ (+ 7) + \ overline e = Mn ^ (+ 6) \; \; \; \ vert \; \; \ cdot \; 2 \; - recovery process
S ^ (+ 4) -2 \ overline e = S ^ (+ 6) \; \; \; \ vert \; \; \ cdot \; 1 \; - oxidation process
2Mn ^ (+ 7) \; + \; S ^ (+ 4) \; = \; 2Mn ^ (+ 6) \; + \; S ^ (+ 6)
Мn +7 (КМn +7 O 4 due to Мn +7) - oxidizing agent S +4 (Na 2 S +4 O 3 due to S +4) - reducing agent Molecular equation
Na 2 SO 3 + 2KMnO 4 + 2KOH = Na 2 SO 4 + 2K 2 MnO 4 + H 2 O.
What is the volume of a 60% solution nitric acid with a density of 1.305 g / ml can be obtained using the nitrogen-containing product of catalytic oxidation 896 L (n.u.) of ammonia?
Show Answer
Reaction equations:
4NH 3 + 5O 2 = 4NO + 6H 2 O 2NO + O 2 = 2NO 2
4NO 2 + O 2 + 2H 2 O = 4HNO 3 Since all nitrogen atoms included in NH 3 pass into HNO 3 (no nitrogen-containing by-products are formed in the process), you can draw up a scheme for calculating:
NH 3 ... → HNO 3
2) We calculate the amount of ammonia substance: n = V r / V m, n (NH 3) = 896 / 22.4 = 40 mol
3) Calculate the volume of the HNO 3 solution:
a) according to the scheme for calculating n (HNO 3) = n (NH 3) = 40 mol
n = m in-va / M in-va,
M (HNO 3) = 63 g / mol; m (HNO 3) = 40 63 = 2520 g
b) ω = m in-va / m p-pa, m p-pa = m in-va / ω
m solution (HNO 3) = 2520 / 0.6 = 4200 g
V p-pa (HNO 3) = 4200 / 1.305 = 3218.4 ml ≈ 3.22 l.
Substances are given: CaCO 3, CuO, solutions of HNO 3, K 2 SO 4 NaOH, H 2 O 2. Using water and the necessary substances only from this list, get copper (II) hydroxide in two stages. Describe the signs of the reactions being carried out. For the ion exchange reaction, write the abbreviated ionic equation.
Show Answer
Experiment scheme
CuO → Cu (NO 3) 2 → Cu (OH) 2
1) СuО + 2HNO 3 = Cu (NO 3) 2 + Н 2 O
CuO + 2H + = Cu 2+ + H 2 O
Ion exchange reaction. Copper (II) oxide is a black substance that dissolves in nitric acid and a blue solution is formed.
2) Cu (NO 3) 2 + 2NaOH = Cu (OH) 2 ↓ + 2NaNO 3
Cu 2+ + 2OH - = Cu (OH) 2
Ion exchange reaction. When sodium hydroxide solution is added to the copper (II) nitrate solution, a blue precipitate is formed.
Task number 1.
This figure shows a model of an atom
1. Fluorine
2. Nitrogen
3. Bora
4. Carbon
Explanation: the atom of the element shown in the picture has two electronic layers. On the first layer there are 2 electrons, on the second - 5. This means that this element is in the second period in the fifth group. This is nitrogen. The correct answer is 2.
Task number 2.
Which row chemical elements the non-metallic properties of the corresponding simple substances?
1. Oxygen → sulfur → selenium
2. Aluminum → phosphorus → chlorine
3. Carbon → nitrogen → oxygen
4. Silicon → phosphorus → sulfur
Explanation: non-metallic properties weaken in the period from right to left and in the group from top to bottom. We find such a dependence - this is a series from oxygen to selenium. The correct answer is 1.
Task number 3.
The covalent polar bond is formed by:
1. Calcium sulfide
2. Potassium oxide
3. Hydrogen sulfide
4. Hydrogen
Explanation: a covalent polar bond is formed between two non-metals, as in hydrogen sulfide. The correct answer is 3.
Task number 4.
In order of decreasing valence in hydrogen compounds, the elements are arranged in a row:
1.Si → P → S → Cl
2.F → N → C → O
3. Cl → S → P → Si
4.O → S → Se → Te
Explanation: in the first answer, the elements are arranged in the order of decreasing valence of hydrogen in their hydrogen compounds:
SiH4 (IV) → PH3 (III) → H2S (II) → HCl (I)
The correct answer is 1.
Task number 5.
Amphoteric oxides each includes two substances:
1. Iron (II) oxide and iron (III) oxide
2. Nitric oxide (IV) and nitrogen oxide (II)
3. Zinc oxide and chromium (III) oxide
4. Phosphorus (V) oxide and boron (III) oxide
Explanation: amphoteric oxides - oxides of transition metals. You can view the properties of amphoteric oxides. Of the listed oxides, zinc oxide and chromium (III) oxide are referred to as amphoteric oxides. The correct answer is 3.
Task number 6.
Neutralization reaction equation:
1.CaO + 2HCl = CaCl2 + H2O
2. Ba (NO3) 2 + K2SO4 = BaSO3 + 2KNO3
3. HNO3 + KOH = KNO3 + H2O
4.ZnSO4 + 2NaOH = Zn (OH) 2 + Na2SO4
Explanation: the neutralization reaction takes place between a base and an acid, resulting in salt and water. Answer 3 fits this description. The correct answer is 3.
Task number 7.
In the list of ions
A. Nitrate ion
B. Ammonium ion
B. Hydroxide ion
D. Hydrogen ion
D. Phosphate ion
E. Magnesium ion
cations are:
1. BGD 2. BGE 3. AGE 4. HE
Explanation: cations - ions of metals, hydrogen or ammonium (and many others). V this case choose: ammonium ion, hydrogen ion and magnesium ion, that is, BGD. The correct answer is 1.
Task number 8.
The precipitate is formed by interaction:
1. CaCO3 and H2SO4
2.Ca (OH) 2 and CO2 (g)
3. Na2CO3 and HNO3
4. Ca (OH) 2 and CO2 (insufficient)
Explanation:
1. In the first reaction, carbon dioxide and poorly soluble calcium sulfate are formed.
2.Ca (OH) 2 + CO2 (g) = CaCO3 ↓ + H2O
3. Na2CO3 and 2HNO3 = 2NaNO3 + H2O + CO2
4. Ca (OH) 2 and CO2 (short) = Ca (HCO3) 2
A precipitate is formed in the second reaction. The correct answer is 2.
Task number 9.
Sulfur is an oxidizing agent in the reaction, the equation of which is:
1. Zn + S = ZnS
2.2SO2 + O2 = 2SO3
3. H2O + SO3 = H2SO4
4.S + O2 = SO2
Explanation: determine the changes in the oxidation states of sulfur in each reaction.
1. (0) + 2е → (-2) - oxidizing agent
2. (+4) -2e → (+6) - reducing agent
3. (+6) → (+6) - no change in the oxidation state
4. (0) -4е → (+4) - reducing agent
The correct answer is 1.
Task number 10.
Among the substances, the formulas of which are C, FeO, NaOH - react with carbon monoxide (II):
1. Only NaOH
2. Only FeO
3.C and FeO
4. NaOH and FeO
Explanation: carbon does not react with carbon monoxide, as does sodium hydroxide. And iron (II) oxide reacts:
FeO + CO = Fe + CO2
The correct answer is 2.
Task number 11.
A substance will interact with iron (III) hydroxide, the formula of which is:
1. CuSO4
2. BaCl2
3. CaO
4. HNO3
Explanation: Iron hydroxide is an amphoteric hydroxide and of the substances presented, only nitric acid reacts with it, a neutralization reaction occurs, during which iron (III) nitrate and water are formed. The correct answer is 4.
Task number 12.
With each of the substances: hydrogen sulfide acid, potassium hydroxide, zinc - a substance interacts, the formula of which is:
1. Pb (NO3) 2
2. Na2SO3
3. KBr
4. MgCl2
Explanation: among the listed substances, zinc can only react with lead nitrate, since zinc, as a metal, is stronger than lead. Let's write down all the reactions.
H2S + Pb (NO3) 2 = PbS ↓ + 2HNO3
2KOH + Pb (NO3) 2 = 2KNO3 + Pb (OH) 2 ↓
Zn + Pb (NO3) 2 = Zn (NO3) 2 + Pb
The correct answer is 1.
Task number 13.
Are the following judgments about carbon oxides correct?
A. Carbon monoxide (IV) is poisonous.
B. Carbon monoxide (II) causes poisoning of the body.
1. Only A is true
2. Only B is true
3. Both statements are correct
4. Both judgments are wrong
Explanation: CO2 is not toxic, unlike carbon monoxide - carbon monoxide. The correct answer is 2.
Task number 14.
In the equation of the redox reaction
NO2 + Mg → MgO + N2
the coefficient in front of the oxidizer formula is
1. 4
2. 3
3. 2
4. 1
Explanation: let's write down the balance.
2N (+4) + 8e → N2 (0) | 1 - oxidizing agent
Mg (0) -2e → Mg (+2) | 4 - reducing agent
We place the coefficients.
2NO2 + 4Mg → 4MgO + N2
The oxidizer is preceded by a factor of 2.
The correct answer is 3.
Task number 15.
What is the distribution of the mass fractions of elements corresponds to the quantitative composition of ammonium sulfate:
1. 49, 21, 6, 24%
2. 41, 24, 7, 28%
3. 49, 14, 4, 33%
4. 56, 12, 4, 28%
Explanation: we find the mass fractions of nitrogen, hydrogen, sulfur and oxygen in ammonium sulfate.
M ((NH4) 2SO4) = 18 x 2 + 32 + 64 = 132 g / mol
Ar (N) = 14 g / mol
Ar (H) = 1 g / mol
Ar (S) = 32 g / mol
Ar (O) = 16 g / mol
ω (N) = (14x2) / 132 x 100% = 21%
ω (H) = 8/132 x 100% = 6%
ω (S) = 32/132 x 100% = 24%
ω (O) = (16x4) / 132 x 100% = 49%
The correct answer is 1.
Task number 16.
Common to phosphorus and sulfur is
1. The presence of the same number of electrons on the outer electron layer of their atoms
2. The existence of the corresponding simple substances in the form of diatomic molecules
3. Their education in the highest degree acid oxide oxidation
4. The fact that in reactions they exhibit the properties of both an oxidizing agent and a reducing agent
5. That the value of their electronegativity is less than that of silicon
Explanation: phosphorus and sulfur are non-metals, both are in the third period and have three electronic layers. But phosphorus has 5 electrons on the outer electron layer, and sulfur has 6. They form acidic oxides, while being in the highest oxidation state - P2O5 and SO3. They also exhibit the properties of both a reducing agent and an oxidizing agent, that is, they both give and receive electrons. Their electronegativity is higher than that of silicon. The correct answer is 34.
Task number 17.
Acetylene is characterized by the following statements
1. Has carbon atoms linked by three pairs of electrons
2. Does not discolor bromine water
3. Easily enters into addition reactions
4. Does not react with complex substances
5. Is liquid at room temperature substance
Explanation: the acetylene formula is H-C≡C-H, that is, the carbon atoms are linked by three bonds (three pairs of electrons). Among these bonds, 2π-bonds and one - σ, π-bonds are less strong and are easily broken in the reactions of addition of water, hydrogen, halogens, and hydrogen halides. The correct answer is 13.
Task number 18.
Establish a correspondence between two substances and a reagent with which you can distinguish between these substances.
Substances
A) HCl (solution) and Ba (OH) 2 (solution)
B) K2SO4 (solution) and KBr
B) Al (OH) 3 and NH3 (solution)
Reagent
1. Ba (NO3) 2 (solution)
2.H2SiO3
3. NaOH (solution)
4. Phenolphthalein
Explanation: hydrochloric acid and barium hydroxide are distinguishable by phenolphthalein, since the acid has an acidic medium (phenolphthalein is colorless), and barium hydroxide is alkaline (phenolphthalein orange). Potassium sulfate and bromine are distinguishable with barium nitrate solution, since insoluble barium sulfate is formed in the reaction between barium sulfate and barium nitrate. Aluminum hydroxide and ammonia solution are distinguishable using a sodium hydroxide solution, in the reaction between aluminum and sodium hydroxides, a complex salt is obtained - sodium tetrahydroxoaluminate, and the reaction does not proceed with ammonia. The correct answer is 413.
Task number 19.
Establish a correspondence between the name of a substance and the reagents with which this substance can interact.
Substance name
A) Iron
B) Iron (III) oxide
C) Iron (II) sulfate
Reagents
1.BaCl2 (solution), NaOH (solution)
2.HCl (solution), O2
3. Al, H2SO4 (diluted)
4.H2SO4 (conc), O2
Explanation: iron reacts with hydrochloric acid solution and with oxygen.
Fe + 2HCl = FeCl2 + H2
3Fe + 2O2 = Fe3O4
Iron (III) oxide reacts with aluminum and dilute sulfuric acid.
Fe2O3 + 2Al = Al2O3 + 2Fe
Fe2O3 + 3H2SO4 = Fe2 (SO4) 3 + 3H2O
Iron (II) sulfate reacts with barium chloride and sodium hydroxide.
FeSO4 + BaCl2 = BaSO4 ↓ + FeCl2
FeSO4 + 2NaOH = Fe (OH) 2 ↓ + Na2SO4
The correct answer is 231.
Task number 20.
Using the electronic balance method, arrange the coefficients in the reaction equation, the scheme of which
Zn + H2SO4 (conc) → ZnSO4 + H2S + H2O
Determine the oxidizing and reducing agent.
Explanation: in this redox reaction change the oxidation state of zinc and sulfur. Let's write down the balance.
Zn (0) -2e → Zn (+2) | 4 - reducing agent
S (+6) + 8e → Zn (-2) | 1 - oxidizing agent
We place the coefficients.
4Zn + 5H2SO4 (conc) → 4ZnSO4 + H2S + 4H2O
Task number 21.
An excess of sodium hydroxide solution was added to 63 g of a 20% nitric acid solution. What is the mass of the salt formed?
Explanation: we write down the reaction equation.
HNO3 + NaOH → NaNO3 + H2O
Let's find the mass of the nitric acid substance.
m (HNO3) = 63 x 0.2 = 12.6 g
Find the amount of nitric acid substance.
n (HNO3) = 12.6 / 63 = 0.2 mol
The amount of nitric acid substance is equal to the amount of sodium nitrate substance.
n (NaNO3) = n (HNO3) = 0.2 mol
m (NaNO3) = 0.2 x (23 + 14 + 48) = 17 g
Answer: the mass of the formed salt is 17 g.
Task number 22.
Substances are given: PbO, O2, Fe, HNO3 (), KOH, SO3. Using water and the necessary substances only from this list, get lead (II) hydroxide in two stages. Describe the signs of reactions. For an ion exchange reaction, write the abbreviated ionic reaction equation.
Explanation: first we get lead sulfate.
PbO + SO3 → PbSO4
Now we get lead (II) hydroxide.
PbSO4 + 2KOH → Pb (OH) 2 ↓ + K2SO4
Let's write down the reduced ionic equation.
Pb² + + 2OH‾ → Pb (OH) 2 ↓
