Are the following statements about carbon correct? Solution of exam options in chemistry

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 electron layers. There are 2 electrons on the first layer, 5 on the second. 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.

In what series of chemical elements do the non-metallic properties of the simple substances corresponding to them weaken?

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.

A 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 decreasing order of valency in hydrogen compounds, the elements are arranged in the following order:

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 order of decreasing valency of hydrogen in their hydrogen compounds:

SiH4 (IV) → PH3 (III) → H2S (II) → HCl (I)

The correct answer is 1.

Task number 5.

Amphoteric oxides include each of two substances:

1. Iron (II) oxide and iron (III) oxide

2. Nitric oxide (IV) and nitric 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 classified as amphoteric. 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: a neutralization reaction takes place between a base and an acid, resulting in a salt and water. This description fits the answer option 3. 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. GD 2. BGE 3. AGE 4. VGE

Explanation: cations - ions of metals, hydrogen or ammonium (and many others). In this case, we will choose: ammonium ion, hydrogen ion and magnesium ion, that is, GFD. The correct answer is 1.

Task number 8.

A precipitate is formed by the interaction:

1. CaCO3 and H2SO4

2. Ca(OH)2 and CO2(g)

3. Na2CO3 and HNO3

4. Ca(OH)2 and CO2(lack)

Explanation:

1. In the first reaction, carbon dioxide and poorly soluble calcium sulfate are formed.

2. Ca(OH)2 + CO2(ex) = CaCO3↓ + H2O

3. Na2CO3 and 2HNO3 = 2NaNO3 + H2O + CO2

4. Ca (OH) 2 and CO2 (lack) \u003d 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 a reaction whose equation 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) +2e → (-2) - oxidizing agent

2. (+4) -2e → (+6) - reducing agent

3. (+6) → (+6) - no change in oxidation state

4. (0) -4e → (+4) - reducing agent

The correct answer is 1.

Task number 10.

Among the substances, the formulas of which are C, FeO, NaOH - in the reaction with carbon monoxide (II) enters (-yut):

1. Only NaOH

2. Only FeO

3. C and FeO

4. NaOH and FeO

Explanation: carbon does not react with carbon monoxide, nor does sodium hydroxide. And iron oxide (II) 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: hydrosulfide acid, potassium hydroxide, zinc - a substance interacts, the formula of which is:

1. Pb(NO3)2

2. Na2SO3

3.KBr

4. MgCl2

Explanation: among these 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 statements 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 judgments are correct

4. Both judgments are wrong

Explanation: CO2 is not poisonous, unlike carbon monoxide - carbon monoxide. The correct answer is 2.

Task number 14.

In the redox reaction equation

NO2 + Mg → MgO + N2

the coefficient in front of the oxidizing agent formula is

1. 4

2. 3

3. 2

4. 1

Explanation: write down the balance.

2N(+4) +8e → N2(0) | 1 - oxidizer

Mg(0) -2e → Mg(+2) | 4 - reducing agent

We set the coefficients.

2NO2 + 4Mg → 4MgO + N2

The oxidizing agent is preceded by a factor of 2.

The correct answer is 3.

Task number 15.

What distribution of 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: find the mass fractions of nitrogen, hydrogen, sulfur and oxygen in ammonium sulfate.

M ((NH4) 2SO4) \u003d 18 x 2 + 32 + 64 \u003d 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.

What phosphorus and sulfur have in common is

1. The presence of the same number of electrons on the outer electron layer of their atoms

2. Existence of simple substances corresponding to them in the form of diatomic molecules

3. The formation of acid oxides in the highest degree of oxidation

4. The fact that in reactions they exhibit properties of both an oxidizing agent and a reducing agent

5. That their electronegativity value is less than that of silicon

Explanation: phosphorus and sulfur are non-metals, both are in the third period and have three electron layers. But phosphorus has 5 electrons on the outer electron layer, and sulfur has 6. They form acidic oxides, while they are in the highest oxidation state - P2O5 and SO3. And 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 bonded 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 a liquid substance at room temperature

Explanation: the formula of acetylene is H-C≡C-H, that is, carbon atoms are connected 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 addition reactions of water, hydrogen, halogens, and hydrogen halides. The correct answer is 13.

Task number 18.

Match the two substances with a reagent that can be used to distinguish between these substances.

Substances

A) HCl(sol.) and Ba(OH)2(sol.)

B) K2SO4 (solution) and KBr

C) Al(OH)3 and NH3(sol.)

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 environment (phenolphthalein is colorless), and barium hydroxide is alkaline (phenolphthalein orange). Potassium sulfate and bromine are distinguishable with a solution of barium nitrate, since in the reaction between barium sulfate and barium nitrate, insoluble barium sulfate is formed. Aluminum hydroxide and ammonia solution are distinguishable using 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 the substance and the reagents with which this substance can interact.

Substance name

A) iron

B) Iron oxide (III)

C) Iron sulfate (II)

Reagents

1. BaCl2(sol.), NaOH(sol.)

2. HCl(sol.), O2

3. Al, H2SO4(razb)

4. H2SO4(conc), O2

Explanation: iron reacts with hydrochloric acid and 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 agent and reducing agent.

Explanation: in this redox reaction, zinc and sulfur change the oxidation state. Let's write the balance.

Zn(0) -2e → Zn(+2) | 4 - reducing agent

S(+6) +8e→ Zn(-2) | 1 - oxidizer

We set 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% solution of nitric acid. What is the mass of salt formed?

Explanation: write the reaction equation.

HNO3 + NaOH → NaNO3 + H2O

Find the mass of nitric acid.

m(HNO3) = 63 x 0.2 = 12.6 g

Find the amount of nitric acid.

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 salt formed 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 us write down the abbreviated ionic equation.

Pb² + + 2OH‾ → Pb(OH)2↓

A1. The isotopes are
1) S 2- and S 6+
2) white phosphorus and red phosphorus
3) 1H and 3H
4) 40 K and 40 Ar

Decision. Isotopes are atoms of the same element with different masses. The mass number of an isotope is placed at the top left of the element symbol. The first answer shows different degrees of oxidation of sulfur, the second - allotropic modifications of phosphorus, the third - hydrogen atoms with different masses. These are isotopes. The fourth option is atoms of different elements with the same mass. Such atoms are called isobars.

Correct answer: 3

A2. Among the elements of the fourth period, the maximum atomic radius has
1) copper
2) potassium
3) nickel
4) krypton

Decision. In a period, the radius of an atom decreases from left to right, i.e. from the beginning of the period to its end. Potassium is in the fourth period at the very beginning, therefore, it is its atom that has the maximum radius.

Correct answer: 2

A3. Longest bond length in a molecule
1) HF
2) HCl
3) H 2 O
4) H 2 S

Decision. Of the atoms that make up the listed compounds with hydrogen, the sulfur atom has the largest radius (sulfur in the Periodic system of the listed elements is lower and to the right of the rest), given that the radius of the hydrogen atom is the same in all these compounds, we find that the maximum bond length in the molecule hydrogen sulfide.

Correct answer: 4

A4. The oxidation state +3 has a chlorine atom in the compound
1) ClO 3
2) Cl 2 O 6
3) Ba(ClO 2) 2
4) KClO 3

Decision. We calculate the oxidation states of chlorine in the listed compounds from the condition of electroneutrality (the algebraic sum of the oxidation states of elements in an electrically neutral molecule is zero) and taking into account that the oxidation state of oxygen is -2, potassium +1, barium +2 and assuming that the oxidation state of chlorine is x. We get for ClO 3: x + 3 (-2) \u003d 0, x \u003d +6. Not suitable. For Cl 2 O 6: 2x + 6(-2) = 0, x = +6. And this one doesn't fit. For Ba (ClO 2) 2: 2 + 2x + 4 (-2) \u003d 0, x \u003d +3. In this compound, the oxidation state of chlorine is +3. In KClO 3: 1 + x + 3(-2) = 0, x = +5.

Correct answer: 3

A5. The non-molecular structure is
1) iron
2) hydrogen
3) oxygen
4) carbon monoxide

Decision. Of these substances, only iron does not have a molecular structure.

Correct answer: 1

A6. In the list of substances
1) CO 2 2) Fe 2 O 3 3) Fe 3 O 4 4) CaO 5) Cl 2 O 7 6) CrO 3
acid oxides include substances whose formulas are indicated by numbers
1) 2,3,6
2) 1,5,6
3) 1,4,5
4) 2,3,5

Decision. Acid oxides form non-metals and transition metals in higher oxidation states. Hence, acidic oxides include CO 2, Cl 2 O 7 - carbon and chlorine - non-metals, and CrO 3 - chromium in this oxide has a maximum oxidation state of +6. In the list, these substances are numbered 1.5 and 6.

Correct answer: 2

A7. In order of increasing metallic properties, the elements are arranged in the following order:
1) calcium, zinc, strontium
2) strontium, cadmium, barium
3) cadmium, barium, mercury
4) cadmium, barium, radium

Decision. The metallic properties are enhanced in the main subgroups from top to bottom; in the elements of the secondary subgroups, the metallic properties are less pronounced than in the elements of the main ones. Option 1: calcium, zinc, strontium - zinc is an element of a side subgroup, its metallic properties are less pronounced than that of calcium. Drops out. Option 2: strontium, cadmium, barium - also disappears, cadmium is an element of a side subgroup. Option 3: cadmium, barium, mercury - no, barium is in the middle of the list. Option 4: cadmium, barium, radium - here the metallic properties increase from cadmium to barium (cadmium is a secondary subgroup, barium is the main one) and to radium (it is also the main subgroup and is located below barium). This is the correct option.

Correct answer: 4

A8. Formula of higher tellurium oxide
1) Te2O
2) TeO 2
3) TeO 3
4) Te2O7

Decision. The oxidation state of an element in the higher oxide corresponds to the number of the group in which the element is located. Let us calculate the oxidation states of tellurium in the listed oxides using the electroneutrality condition (see A4). Te 2 O tellurium oxidation state +1, TeO 2: +4, TeO 3: +6 and Te 2 O 7: +7. It is noticeable that in the third oxide the nomen of the group coincides with the oxidation state of tellurium, and this is the answer.

Correct answer: 3

A9. Are the following statements about zinc correct?
A. Zinc(II) hydroxide is an amphoteric hydroxide.
B. Zinc dissolves in dilute nitric acid.
1) only A is true
2) only B is true
3) both judgments are true
4) both judgments are wrong

Decision. Zinc hydroxide (II) is an amphoteric hydroxide (you need to know this, if you didn’t know, then you already knew). Zinc is not passivated by nitric acid at any concentration and is soluble in dilute nitric acid. Both judgments are correct.

Correct answer: 3

A10. Phosphorus(V) oxide does not interact with:
1) water
2) sodium chloride
3) potassium hydroxide
4) calcium oxide

Decision. Phosphorus (V) oxide is an acidic oxide that interacts with water, forming phosphoric acids, with alkalis (KOH) and basic oxides (CaO), forming salts. The only substance listed that phosphorus (V) oxide will not interact with is sodium chloride.

Correct answer: 2

A11. Are the following statements about sulfuric acid correct?
A. Concentrated sulfuric acid is a dewatering agent.
B. Dilute sulfuric acid dissolves copper but does not dissolve silver.
1) only A is true
2) only B is true
3) both judgments are true
4) both judgments are wrong

Decision. Concentrated sulfuric acid is a dehydrating agent, so A is correct. Dilute sulfuric acid is not an oxidizing acid and does not interact with metals to the right of hydrogen in the voltage series. Copper and zinc are to the right of hydrogen in a series of voltages, therefore B is incorrect.

Correct answer: 1

A12. Bicarbonates in solution turn into carbonates when exposed to
1) any salt
2) any acid
3) any oxide
4) any alkali

Decision. Acid salts - in this case, bicarbonates - turn into medium (carbonates) under the action of alkali or some basic oxides, therefore the only answer is: under the action of any alkali.

Correct answer: 4

A13. To carry out transformations in accordance with the scheme:
Al amalgam Al(OH) 3 Al(NO 3) 3 must be used consistently.
1) water n nitrogen
2) potassium hydroxide and nitric acid
3) water and nitric acid
4) potassium hydroxide and potassium nitrate

Decision. Amalgamated aluminum dissolves in water with the formation of hydroxide (the aluminum oxide film is destroyed):
2Al amalgam + 6H 2 O \u003d 2Al (OH) 3 + 3H 2

Nitrate can be obtained from aluminum hydroxide by the action of nitric acid:

2Al(OH) 3 + 3НNO 3 = Al(NO 3) 3 + 3Н 2 O

Correct answer: 3

A14. The isomer of cyclohexane is
1) 3-methylhexane
2) cyclopentane
3) benzene
4) hexene-2

Decision. Cyclohexane has the gross formula C 6 H 12 . Formula 3-methylhexane C 7 H 16, cyclopentane C 5 H 10, benzene - C 6 H 6, hexene-2 ​​- C 6 H 12. Comparing the gross formulas, one can see that the formula of the fourth substance coincides with the original formula, therefore this is the cyclohexane isomer.

Correct answer: 4

A15. A single -electron system is formed in a molecule
1) cyclobutane
2) butene-1
3) methylcyclohexane
4) benzene

Decision. A single -electronic system among the listed substances - only in the benzene molecule.

Correct answer: 4

A16. Phenol forms a white precipitate when reacted with
1) bromine water
2) nitric acid
3) potassium hydroxide
4) ammonia

Decision. The only poorly soluble product of the reaction of phenol with the listed reagents is 2,4,6-tribromophenol, which is formed by the interaction of phenol with bromine water:

Correct answer: 1

A17. Are the following statements about fats correct?
A. All fats are solid under normal conditions.
B. From a chemical point of view, fats are esters.
1) only A is true
2) only B is true
3) both judgments are true
4) both judgments are wrong

Decision. Among fats there are liquids, for example, some vegetable fats (vegetable oil). Therefore statement A is false. Fats are esters, so B is right.

Correct answer: 2

A18. In the transformation scheme:
C 2 H 6 X C 2 H 5 OH substance X is
1) etin
2) ethanediol
3) ethene
4) dibromoethane

Decision. These transformations can be carried out as follows: first, dehydrogenate ethane by heating in the presence of a catalyst

C 2 H 6 \u003d C 2 H 4 + H 2

and then adding water to the resulting ethylene when heated in the presence of sulfuric acid:

C 2 H 4 + H 2 O \u003d C 2 H 5 OH

The intermediate substance X is ethylene (according to IUPAC - ethene).

Correct answer: 3

A19. Exothermic reactions include the interaction
1) nitrogen with oxygen
2) carbon with carbon dioxide
3) water with carbon
4) propene with bromine

Decision. The first three reactions are endothermic (see textbook). The only exothermic reaction is the interaction of propene with bromine.

Correct answer: 4

A20. Reaction rate of zinc with sulfuric acid solution does not depend from
1) the number of zinc granules taken
2) the degree of grinding of zinc
3) concentration of sulfuric acid
4) temperature

Decision. The rate of dissolution of zinc in sulfuric acid depends on the size of the metal surface (i.e., on the degree of grinding), on the acid concentration and temperature. The speed does not depend on the number of zinc granules taken.

Correct answer: 1

A21. To shift the equilibrium towards the initial substances in the system
N 2(g) + 3H 2(g) 2NH 3(g) + Q necessary
1) increase the temperature
2) increase pressure
3) increase the concentration of nitrogen
4) reduce the temperature

Decision. The forward reaction is exothermic, therefore the reverse (towards the original) substances is endothermic. The equilibrium can be shifted towards an endothermic reaction in accordance with the Le Chatelier principle by increasing the temperature (answer 1). The remaining options for influencing the system will lead to a shift of equilibrium to the right - towards ammonia.

Correct answer: 1

A22. Both are electrolytes:
1) acetic acid and ethyl acetate
2) hydrogen bromide and ethanol
3) propanol and acetone
4) propionic acid and sodium acetate

Decision. Of these substances, electrolytes include salts and organic acids. At the same time, both classes are present only in the 4th answer.

Correct answer: 4

A23. Gas is released during the interaction of aqueous solutions
1) CaCl 2 and Ba (NO 3) 2
2) Ba (NO 3) 2 and Al 2 (SO 4) 3
3) NaHCO 3 and HI
4) AlCl 3 and Ba(NO 3) 2

Decision. The only gas option in this task is CO 2 . It can be formed by the decomposition of carbonic acid, which, in turn, is formed by displacing it from the salt with a stronger acid. Suitable option 3:

NaHCO 3 + HI \u003d NaI + CO 2 + H 2 O

Correct answer: 3

A24. Shows the strongest restorative properties
1) iodine
2) hydrogen
3) copper
4) nitric oxide (II)

Decision. The most powerful reducing agent of the listed substances is hydrogen (recall the properties of substances).

Correct answer: 2

A25. The aqueous solution has an acidic reaction
1) KHCO3
2) K2SO3
3) CuSO4
4) Na 2 SO 4

Decision. All of the listed substances are salts, acidic environment

Correct answer:

A26. Are the following statements about alkynes correct?
A. All alkyne molecules contain two -bonds.
B. Acetylene decolorizes an aqueous solution of potassium permanganate.
1) only A is true
2) only B is true
3) both judgments are true
4) both judgments are wrong

Decision. In alkyne molecules, there is one triple bond, which, in turn, consists of one or two -bonds. So A is correct. Acetylene decolorizes an aqueous solution of potassium permanganate, this is a qualitative reaction for a multiple bond. And B is correct.

Correct answer: 3

A27. Ethanol forms an ester when reacted with
1) methanol
2) glycine
3) propyne
4) sodium

Decision. Esters are formed by the interaction of alcohols with acids (esterification reaction). The carboxyl group (a functional group of carboxylic acids) contains the amino acid glycine.

Correct answer: 2

A28. Are the following judgments about the rules of work in the laboratory correct?
A. In the laboratory, you can not get acquainted with the smell of substances.
B. All sodium and potassium salts, even in moderate doses, are poisonous to humans.
1) only A is true
2) only B is true
3) both judgments are true
4) both judgments are wrong

Decision. It is possible to get acquainted with the smell of substances in the laboratory (only carefully), therefore A is true. Sodium and potassium salts in moderate doses are not only harmless, but even useful, for example, table salt - sodium chloride (salt the soup) or potassium bromide - a sedative. So B is wrong.

Correct answer: 4

A29. The industrial production of ammonia is based on the reaction, the scheme of which is:
1) Ca (OH) 2 + NH 4 Cl
2) Mg 3 N 2 + H 2 O
3) H 2 + N 2
4) NH4Cl

Decision. In industry, ammonia is synthesized from simple substances - nitrogen and hydrogen at 400-450 ° C, a pressure of 200-1000 atm in the presence of a catalyst - activated sponge iron.

Correct answer: 3

A30. When interacting 40 liters of oxygen and 40 liters of hydrogen will remain in excess
1) 20 liters of hydrogen
2) 10 liters of oxygen
3) 10 liters of hydrogen
4) 20 liters of oxygen

Decision. Write a reaction:
2H 2 + O 2 \u003d 2H 2 O According to the law of multiple ratios, the volumes of the reacting gases (if they are measured under the same conditions) are related as coefficients in the reaction equation. If hydrogen is 40 l, then oxygen will be required 2 times less (in the equation, the coefficient for hydrogen is 2, for oxygen 1), i.e. 20 l. Of the 40 liters of initial oxygen, 40 liters - 20 liters \u003d 20 liters will remain.

For answers to tasks 20-22, use a separate sheet. First write down the task number (20, 21, 22), and then a detailed answer to it. Write your answers clearly and legibly.

Using the electron balance method, write the equation for the reaction

Na 2 SO 3 + KMnO 4 + KOH → Na 2 SO 4 + K 2 MnO 4 + H 2 0.

Determine the oxidizing agent 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)

Mn +7 (KMn +7 O 4 due to Mn +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 volume of a 60% nitric acid solution with a density of 1.305 g/ml can be obtained using a nitrogen-containing catalytic oxidation product of 896 liters (N.S.) of ammonia?

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Reaction equations:

4NH 3 + 5O 2 \u003d 4NO + 6H 2 O 2NO + O 2 \u003d 2NO 2

4NO 2 + O 2 + 2H 2 O = 4HNO 3

NH3 ... → HNO3

2) Calculate the amount of ammonia substance: n \u003d V r / V m, n (NH 3) \u003d 896 / 22.4 \u003d 40 mol

3) Calculate the volume of HNO 3 solution:

a) according to the scheme for calculating n (HNO 3) \u003d n (NH 3) \u003d 40 mol

n = m in-va / M in-va,

M(HNO 3) = 63 g/mol; m (HNO 3) \u003d 40 63 \u003d 2520 g

b) ω \u003d m in-va / m p-pa, m p-pa \u003d m in-va / ω

m solution (HNO 3) \u003d 2520 / 0.6 \u003d 4200 g

V p-pa (HNO 3) \u003d 4200 / 1.305 \u003d 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 ongoing reactions. For an ion exchange reaction, write an abbreviated ionic equation.

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Experiment scheme

СuО → Cu(NO 3) 2 → Сu(OH) 2

1) CuO + 2HNO 3 \u003d Cu (NO 3) 2 + H 2 O

СuО + 2Н + = Сu 2+ + Н 2 O

Ion exchange reaction. Copper(II) oxide is a black substance that dissolves in nitric acid to form a blue solution.

2) Cu(NO 3) 2 + 2NaOH = Cu(OH) 2 ↓ + 2NaNO 3

Cu 2+ + 2OH - \u003d Cu (OH) 2

Ion exchange reaction. When a solution of copper(II) nitrate is added to a solution of sodium hydroxide, a blue precipitate is formed.

13.1. Carbon

A1. The history of a person's acquaintance with this element goes far into the depths of 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 the plant and animal world. It occurs in nature both in free form and in compounds. Its atoms can combine in a variety of ways with each other and with atoms of other elements. This element:

1) C; 2) Si; 3) Ge; 4) sn.

A2. Carbon monoxide(IV) interacts with a pair of substances:

1) hydrogen chloride and potassium hydroxide;

2) calcium hydroxide and sodium oxide;

3) sodium hydroxide and sulfuric 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 statements about the chemical properties of carbon correct?

a) carbon in reactions can exhibit both the properties of an oxidizing agent and a reducing agent;

b) does carbon exhibit non-metallic properties more clearly than beryllium?

1) Only a is true;

2) only b is true;

3) both judgments are true;

4) both judgments are wrong.

A5. The methane molecule is tetrahedral because:

1) the carbon atom is in sp 3 - hybridization;

2) this geometric shape corresponds to the energy minimum;

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 end 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 is obtained in the laboratory 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 series:

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 upon calcination in a muffle furnace (1000 °C):

1) sodium carbonate;

2) calcium carbonate;

3) sodium bicarbonate;

4) calcium bicarbonate.

A12. During the electrolysis of an aqueous solution of sodium acetate, the following 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 easily hydrolyzed by water. Electrolysis of which of the following carbides produces methane?

1) CaC 2; 2) Mg 2 C 3; 3) Al 4 C 3; 4) Na 2 C.

A14. As a result of calcination of aluminum oxide with coke, aluminum carbide and carbon monoxide are formed. The coefficient in front of the reducing agent formula in the equation for this reaction is:

1) 2; 2) 5; 3) 7; 4) 9.

A15. 20 ml of carbon monoxide(II) are exploded with 20 ml of oxygen. After the explosion and bringing the gases to the initial conditions (25 ° C, 1 atm), the volume of gases turned out to be equal to:

1) 30 ml CO 2 and 5 ml O 2;

2) 20 ml of CO 2 and 10 ml of O 2;

3) 20 ml CO 2 and 15 ml O 2;

4) 15 ml of CO 2 and 20 ml of O 2.

13.2. Silicon

A16. An 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 statements about the chemical properties of elements correct?

a) silicon exhibits greater electronegativity than carbon;

b) silicon exhibits non-metallic properties more brightly than sulfur?

1) Only a is true;

2) only b is true;

3) both judgments are true;

4) both judgments are wrong.

A18. Each of two substances has an atomic crystal lattice:

1) silicon(IV) oxide and carbon monoxide(IV);

2) diamond and silicon;

3) chlorine and iodine;

4) potassium chloride and iron(III) fluoride.

A19. silicon oxide not is included in:

1) silica; 2) river sand;

3) granite; 4) dolomite.

A20. In the series S ->P ->Si ->Al:

1) the number of electron 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 atoms increase.

A21. The statement that the structural particle of a given substance is an atom is true only for:

1) carbon dioxide; 2) table salt;

3) silicon oxide; 4) nitrogen.

A22. Reduced 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 nature of oxides from basic to acidic changes in the series:

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. Completely decomposed by water:

1) CCl 4 ; 2) CS 2 ; 3) SiCl 4 ; 4) PbCl2.

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. Reacts with alkalis when heated:

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 access to air. Mandatory component of this mixture:

1) SiO2; 2) Na 2 SiO 3; 3) SiC; 4) Si.

A30. When carbon dioxide is passed through a solution of sodium silicate, its turbidity is observed. The formula for the resulting precipitate:

1) SiO2; 2) H 2 SiO 3; 3) SiCO3; 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.

IN 3. Establish a correspondence between the redox reaction scheme and the substance that is the reducing agent in it.

AT 4. Establish a correspondence between the starting materials and the sum of the coefficients in the short ionic equation.

S e c o n t i o n s	Sum m a c o f e f i t i e n t s in brief e r e
a) Pb (OH) 2 + HNO 3 (razb.) -> ; b) HCl + Sn(OH) 2 ->; c) SiO 2 + NaOH ->; d) Pb + AgNO 3 ->.	1) 4;

AT 5. Match the picture 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) widely used in the manufacture of car batteries;

4) its oxide is the main component of river sand;

5) when exposed to its vapors or dust, stannosis can develop - damage to the lungs;

6) absorbs x-rays well.

AT 9. As a result of the fusion of silicon oxide with an excess of sodium hydroxide, 9 g of water was formed. What mass (in g) of silicon oxide reacted? Give your answer to the nearest integer.

AT 10 O'CLOCK. An excess of hydrochloric acid solution was added to 20.8 g of a mixture of calcium and aluminum carbides. 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.

Chapter 13 Test Answers

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	IN 3	AT 4	AT 5	AT 6	AT 7	AT 8	AT 9	AT 10 O'CLOCK
1323	1352	1356	3323	2135	134	356	124	30	30,8

To be continued