Aluminum powder was added to the sodium hydroxide solution. Chemistry tasks to prepare for the exam
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TASKS FOR PREPARING FOR USE Prepared by: Sviridova N.A.
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A simple substance obtained by heating calcium phosphate with coke and silicon oxide was fused with metallic calcium. The reaction product was treated with water, and the evolved gas was collected and passed through a hydrochloric acid solution. Write down the equations for the reactions described. Ca3 (PO4) 2 + 5C + 3SiO2 → 3CaSiO3 + 2P + 5CO 2P + 3Ca → Ca3P2 Ca3P2 + 6H2O → 3Ca (OH) 2 + 2PH3 PH3 + HCl → PH4Cl
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The solution of ferric chloride was treated with sodium hydroxide solution, the precipitate that formed was separated and heated. The solid reaction product was mixed with soda ash and calcined. Sodium nitrate and sodium hydroxide were added to the remaining substance and heated for a long time at a high temperature. Write down the equations for the reactions described. FeCl3 + 3NaOH → Fe (OH) 3 + 3NaCl 2Fe (OH) 3 → Fe2O3 + 3H2O Fe2O3 + Na2CO3 → 2NaFeO2 + CO2 2NaFeO2 + 3NaNO3 + 2NaOH → 2Na2FeO4 + 3NaNO2 + H2O
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Concentrated hydrochloric acid was added to lead (IV) oxide with heating. The evolved gas was passed through a heated potassium hydroxide solution. The salt of the oxygen-containing acid, which precipitated out on cooling the solution, was filtered off and dried. When the resulting salt is heated with hydrochloric acid, a poisonous gas is released, and when it is heated in the presence of manganese dioxide, a gas that is part of the atmosphere is released. Write down the equations for the reactions described. PbO2 + 4HCl → Cl2 + PbCl2 + 2H2O 3Cl2 + 6KOH → 5KCl + KClO3 + 3H2O KClO3 + 6HCl → 3Cl2 + KCl + 3H2O 2KClO3 → 2KCl + 3O2
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An excess of sodium hydroxide solution was added to the aluminum sulfate solution. Hydrochloric acid was added to the resulting solution in small portions, while the formation of a bulk white precipitate was observed, which dissolved upon further addition of acid. Sodium carbonate solution was poured into the resulting solution. Write down the equations for the reactions described. Al2 (SO4) 3 + 8NaOH → 2Na + 3Na2SO4 2Na + 3HCl → Al (OH) 3 + 3NaCl + 3H2O Al (OH) 3 + 3HCl → AlCl3 + 3H2O 2 AlCl3 + 3H2O + 3Na2CO3 → 2 Al (OH) 3 + 6NaCl + 3CO2
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After a short heating of an unknown powdery orange substance, a spontaneous reaction begins, which is accompanied by a color change to green, the release of gas and sparks. The solid residue was mixed with caustic potassium and heated, the resulting substance was introduced into a dilute solution of hydrochloric acid, while a green precipitate was formed, which was dissolved in an excess of acid. Write down the equations for the reactions described. (NH4) 2Cr2O7 → N2 + Cr2O3 + 4H2O Cr2O3 + 2KOH → 2KCrO2 + H2O KCrO2 + H2O + HCl → KCl + Cr (OH) 3 Cr (OH) 3 + 3HCl → CrCl3 + 4H2O
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The nitric acid was neutralized with baking soda, the neutral solution was carefully evaporated and the residue was calcined. The resulting substance was introduced into a solution of potassium permanganate acidified with sulfuric acid, and the solution became discolored. The nitrogen-containing reaction product was placed in a sodium hydroxide solution and zinc dust was added, while a gas with a pungent characteristic odor was released. Write down the equations for the reactions described. HNO3 + NaHCO3 → NaNO3 + H2O + CO2 2NaNO3 → 2NaNO2 + O2 5NaNO2 + 2KMnO4 + 3H2SO4 → 5NaNO3 + K2SO4 + 2MnSO4 + 3H2O NaNO3 + 4Zn + 7NaOH + 4H2O2 + NH3
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The substance obtained at the cathode during the electrolysis of sodium chloride melt was burned in oxygen. The resulting product was sequentially treated with sulfur dioxide and barium hydroxide solution. Write down the equations for the reactions described. 2NaCl (melt) → 2Na + Cl2 (electrolysis) 2Na + O2 → Na2O2 Na2O2 + SO2 → Na2SO4 Na2SO4 + Ba (OH) 2 → BaSO4 + 2NaOH
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Copper wire was introduced into the heated concentrated sulfuric acid, the released gas was passed through an excess of sodium hydroxide solution. The solution was carefully evaporated, the solid residue was dissolved in water and heated with powdered sulfur. Unreacted sulfur was separated by filtration and sulfuric acid was added to the solution, while the formation of a precipitate and the evolution of gas with a pungent odor were observed. Write down the equations for the reactions described. 2H2SO4 (conc) + Cu → CuSO4 + SO2 + 2H2O 2NaOH + SO2 → Na2SO3 + H2O Na2SO3 + S → Na2S2O3 Na2S2O3 + H2SO4 → Na2SO4 + SO2 + S + H2O
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The substance formed during the fusion of magnesium with silicon was treated with water, as a result of which a precipitate formed and a colorless gas evolved. The precipitate was dissolved in hydrochloric acid, and the gas was passed through a solution of potassium permanganate, with the formation of two water-insoluble binary substances. Write down the equations for the reactions described. 2Mg + Si → Mg2Si Mg2Si + 4H2O → 2Mg (OH) 2 + SiH4 Mg (OH) 2 + 2HCl → MgCl2 + 2H2O 3SiH4 + 8KMnO4 → 8MnO2 + 3SiO2 + 8KOH + 2H2O
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The salt obtained by the interaction of zinc oxide with sulfuric acid was calcined at 800 ° C. The solid reaction product was treated with a concentrated alkali solution and carbon dioxide was passed through the resulting solution. Write down the equations for the reactions described. ZnO + H2SO4 → ZnSO4 + H2O 2ZnSO4 → 2ZnO + 2SO2 + O2 ZnO + 2NaOH + H2O → Na2 Na2 + CO2 → Na2CO3 + Zn (OH) 2 + H2O
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Phosphine was passed through a hot solution of concentrated nitric acid. The reaction products were neutralized with quicklime, the precipitate formed was separated, mixed with coke and silica, and calcined. The reaction product, which glows in air, was heated in a sodium hydroxide solution. Write down the equations for the reactions described. PH3 + 8HNO3 (conc) → H3PO4 + 8NO2 + 4H2O H3PO4 + 3CaO → Ca3 (PO4) 2 + 3H2O Ca3 (PO4) 2 + 3SiO2 + 5C → 3CaSiO3 + 5CO + 2P P4 + 3NaOH + 3H2O → 3NaH2P
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The substance obtained at the anode during the electrolysis of a sodium iodide solution on inert electrodes was reacted with potassium. The reaction product was heated with concentrated sulfuric acid, the evolved gas was passed through a hot potassium chromate solution. Write down the equations for the reactions described. 2NaI + 2H2O → 2NaOH + H2 + I2 (electrolysis) I2 + 2K → 2KI 8KI + 5H2SO4 (conc) → 4I2 + H2S + 4K2SO4 + 4H2O 3H2S + 2K2Cr2O4 + 2H2O → 2Cr (OH) 3 + 3S + 4KOH
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The two salts turn the flame purple. One of them is colorless, and when it is slightly heated with concentrated sulfuric acid, the liquid is distilled off, in which copper dissolves; the last transformation is accompanied by the evolution of brown gas. When the second salt of the sulfuric acid solution is added to the solution, the yellow color of the solution changes to orange, and when the resulting solution is neutralized with alkali, the original color is restored. Write down the equations for the reactions described. KNO3 (solid) + H2SO4 (conc) → KHSO4 + HNO3 Cu + 4HNO3 (conc) → Cu (NO3) 2 + 2NO2 + 2H2O 2K2CrO4 + H2SO4 → K2Cr2O7 + K2SO4 + H2O K2Cr2O7 + 2KOH → H2K2CrO4 +
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The substance obtained at the cathode during the electrolysis of sodium chloride with inert electrodes reacts with iodine when heated. The reaction product interacts with concentrated sulfuric acid with the evolution of gas, which was passed through a potassium hydroxide solution. Write down the equations for the reactions described. 2NaCl + 2H2O → 2NaOH + H2 + Cl2 (electrolysis) H2 + I2 → 2HI 2HI + H2SO4 (conc) → I2 + SO2 + 2H2O or 8HI + H2SO4 (conc) → 4I2 + H2S + 4H2O SO2 + 2KOH → K2SO3 + H2O or H2S + 2KOH → K2S + 2H2O
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The salt obtained by dissolving iron in hot concentrated sulfuric acid was treated with an excess of sodium hydroxide solution. The resulting brown precipitate was filtered off and calcined. The resulting substance was fused with iron. Write down the equations for the reactions described. 2Fe + 6H2SO4 (conc) → Fe2 (SO4) 3 + 3SO2 + 6H2O Fe2 (SO4) 3 + NaOH → 2Fe (OH) 3 + 3Na2SO4 2Fe (OH) 3 → Fe2O3 + 3H2O Fe2O3 + Fe → 2FeO
Task 32 on the Unified State Exam in Chemistry (the former task C2 of the "new type") contains a description of an experiment consisting of sequentially conducted chemical reactions and laboratory methods for separating reaction products ( thought experiment).
According to my observations, this task is difficult for many students. This is largely due to the increasingly academic nature of teaching chemistry in schools and courses, when not enough attention is paid to the study of the features of work in the laboratory and the actual conduct of laboratory experiments.
Therefore, I decided to systematize and summarize the material on the so-called. "Laboratory" chemistry. This article examines examples of assignment 32 in the exam in chemistry-2018 (the former assignment C2), with a detailed analysis and analysis of the solution.
This assignment requires a good understanding of some topics of general chemistry and element chemistry, namely: the main , chemical properties and production, acids, and salts, and the relationship between different classes of inorganic substances; properties of simple substances - metals and non-metals; ; ; , , halogens.
- The solution obtained by reacting copper with concentrated nitric acid was evaporated and the precipitate was calcined. The gaseous products of the decomposition reaction are completely absorbed in water, and hydrogen was passed over the solid residue. Write down the equations for the reactions described.
Analysis and solution.
"Keywords" - concentrated nitric acid and copper.
Copper is an inactive metal, exhibiting the properties of a reducing agent.
Keywords: " … The resulting product was sequentially treated with sulfur dioxide and barium hydroxide solution". Sodium sulfate obtained in the previous step enters into an ion exchange reaction with barium hydroxide to precipitate barium sulfate (equation 4).
1) 2NaCl = 2Na + Cl 2
2) 2Na + O 2 = Na 2 O 2
3) Na 2 O 2 + SO 2 = Na 2 SO 4
4) Na 2 SO 4 + Ba (OH) 2 = NaOH + BaSO 4
5.The decomposition products of ammonium chloride were sequentially passed through a heated tube containing copper (II) oxide and then through a bottle with phosphorus (V) oxide. Write down the equations for the reactions described.
Analysis and solution.
Keywords: " Decomposition products of ammonium chloride... ". Ammonium chloride is a salt that decomposes when solid salt is heated into gaseous ammonia and hydrogen chloride gas (equation 1)
Further, the products of reactions 2 and 3 are passed through a container with phosphorus (V) oxide. We analyze the possibility of a chemical reaction between substances. The simple substance copper is chemically inactive and does not react with phosphorus. The simple substance nitrogen is also chemically inactive; it does not react with phosphorus (V) oxide. But with acidic oxide of phosphorus (V), water vapor reacts perfectly with the formation of orthophosphoric acid (equation 4).
1) NH 4 Cl = NH 3 + HCl
2) CuO + 2HCl = CuCl 2 + H2O
3) 3CuO + 2NH 3 = 3Cu + N 2 + 3H2O
4) 3H 2 O + P 2 O 5 = 2H 3 PO 4
6. A solution of hydrochloric acid was poured into the water-insoluble white salt, which occurs in nature in the form of a mineral widely used in construction and architecture, as a result, the salt dissolved and gas was released, when passed through lime water, a white precipitate formed; the precipitate dissolved upon further gas passage. When the resulting solution is boiled, a precipitate forms. Write down the equations for the reactions described.
Analysis and solution.
It is well known from the school chemistry course that the water-insoluble white salt, which occurs in nature in the form of a mineral widely used in construction and architecture, is calcium carbonate CaCO 3. Insoluble salts dissolve under the action of stronger acids, in this case, hydrochloric acid (equation 1).
Generated gas passed through lime water Ca (OH) 2. Carbon dioxide is a typical acidic oxide that, when reacted with alkali, forms a salt called calcium carbonate (equation 2). Further the precipitate dissolved upon further gas passage. A very important property is discussed here: medium salts of polybasic acids under the action of an excess of acid form more acidic salts ... Calcium carbonate in excess of carbon dioxide forms a more acidic salt - calcium bicarbonate Ca (HCO 3) 2, which is highly soluble in water (equation 3).
The properties of acidic salts are largely composed of the properties of the compounds that form acidic salts.. The properties of calcium bicarbonate are determined by the properties of the compounds forming it - carbonic acid H 2 CO 3 and calcium carbonate. It is easy to deduce that when boiled, bicarbonate will decompose into calcium carbonate (it is distributed at higher temperatures, about 1200 degrees Celsius), carbon dioxide and water (equation 4).
1) CaCO 3 + 2HCl = CaCl 2 + CO 2 + H 2 O
2) CO 2 + Ca (OH) 2 = CaCO 3 + H 2 O
3) CaCO 3 + H 2 O + CO 2 = Ca (HCO 3) 2
4) Ca (HCO 3) 2 = CaCO 3 + H 2 O + CO 2
7. Substance obtained at anode during the electrolysis of sodium iodide solution with inert electrodes, reacted with hydrogen sulfide. The resulting solid was fused with aluminum and the product was dissolved in water. Write down the equations for the reactions described.
Analysis and solution.
The electrolysis of a sodium iodide solution with inert electrodes is described by the equation:
1.2NaI + 2H 2 O = 2NaOH + H 2 + I 2
2.I 2 0 + H 2 S -2 = 2HI - + S 0
This resulted in the formation of solid sulfur. Sulfur reacts with aluminum when alloyed to form aluminum sulfide. Most non-metals react with metals to form binary compounds:
3.3S 0 + 2Al 0 = Al 2 +3 S 3 -2
The product of the reaction of aluminum with sulfur - aluminum sulfide - when dissolved in water, irreversibly decomposes into aluminum hydroxide and hydrogen sulfide:
4.Al 2 S 3 + 12H 2 O = 2Al (OH) 3 + 3H 2 S
Such reactions are also referred to as reactions. Cases of irreversible hydrolysis are discussed in detail in.
8 ... The gas released during the interaction of hydrogen chloride with potassium permanganate reacts with iron. The reaction product was dissolved in water, and sodium sulfide was added thereto. The lighter of the formed insoluble substances was separated and reacted with hot concentrated nitric acid. Write down the equations for the reactions described.
9. Chromium (III) sulfide was treated with water, while gas evolved and an insoluble substance remained. A sodium hydroxide solution was added to this substance and chlorine gas was passed through, while the solution acquired a yellow color. The solution was acidified with sulfuric acid; as a result, the color changed to orange; gas evolved during the treatment of sulfide with water was passed through the resulting solution, and the color of the solution changed to green. Write down the equations for the reactions described.
Analysis and solution.
Keywords: " Chromium (III) sulfide was treated with water, while gas evolved and an insoluble substance remained«. Chromium (III) sulfide decomposes under the action of water into hydroxide and hydrogen sulfide ... The hydrolysis reactions of such compounds are discussed in detail in. (reaction 1)
1) Cr 2 S 3 + 6H 2 O = 2Cr (OH) 3 + 3H 2 S
Key words: "... added a solution of caustic soda and let in gaseous chlorine, while the solution acquired a yellow color." Under the influence of chlorine in an alkaline environment, chromium +3 is oxidized to chromium +6 ... Chromium +6 forms acid oxide and hydroxide, in a solution of sodium hydroxide forms a stable yellow salt - sodium chromate (reaction 2).
2) 2Cr +3 (OH) 3 + 3Cl 0 2 + 10NaOH = 2Na 2 Cr +6 O 4 + 6NaCl - + 8H 2 O
Further, the keywords: “ The solution was acidified with sulfuric acid, as a result, the color changed to orange«. Salt-chromates in an acidic medium pass into dichromates. Yellow sodium chromate in an acidic medium turns into orange sodium dichromate (reaction 3). This is not an OVR!
3) 2Na 2 CrO 4 + H 2 SO 4 = Na 2 Cr 2 O 7 + Na 2 SO 4 + H 2 O.
Further: "... through the resulting solution passed the gas released during the treatment of sulfide with water, and the color of the solution changed to green". Sodium dichromate is a strong oxidizing agent; when interacting with hydrogen sulfide, it is reduced to a trivalent chromium salt. Chromium (III) compounds are amphoteric and form salts in an acidic medium. Chromium (III) salts color the solution green (reaction 4).
4) Na 2 Cr +6 2 O 7 + 3H 2 S -2 + 4H 2 SO 4 = 3S 0 + Cr +3 2 (SO 4) 3 + Na 2 SO 4 + 7H 2 O
10. Obtaining a black-and-white image when photographing is based on the decomposition of a salt of an unknown metal under the action of light. When this metal is dissolved in dilute nitric acid, a colorless gas is released, which in air quickly changes its color to brown, and a salt is formed that interacts with sodium bromide to form a yellowish curdled precipitate. The anion in the salt used in photography is the anion of an acid that forms simultaneously with sulfuric acid, when bromine water and sulfur dioxide react. Write down the equations for the reactions described.
11. Sodium hydroxide solution was added dropwise to the solution obtained by the interaction of aluminum with dilute sulfuric acid until a precipitate was formed. The formed white precipitate was filtered off and calcined. The resulting material was fused with sodium carbonate. Write down the equations for the reactions described.
Analysis and solution.
Diluted sulfuric acid, when interacting with metals, behaves like ordinary mineral acid. Metals located in the series of electrochemical activity to the left of hydrogen, when interacting with mineral acids, displace hydrogen:
1.2Al 0 + 3H + 2 SO 4 = Al +3 2 (SO 4) 3 + 3H 0 2
Further, aluminum sulfate reacts with sodium hydroxide. The condition states that sodium hydroxide was added dropwise. This means that sodium hydroxide was in short supply, and aluminum sulfate was in significant excess. Under these conditions, a precipitate of aluminum hydroxide is formed:
2. Al 2 (SO 4) 3 + 6NaOH = 2Al (OH) 3 + 3Na 2 SO 4
The white precipitate is aluminum hydroxide, insoluble in water. NS When ignited, insoluble hydroxides decompose into water and the corresponding oxide :
3. 2Al (OH) 3 = Al 2 O 3 + 3H 2 O
The resulting substance - aluminum oxide - was fused with sodium carbonate. In the melt, less volatile oxides displace more volatile ones from salts. Carbonate is a salt that corresponds to a volatile oxide, carbon dioxide. Accordingly, when alkali metal carbonates are fused with solid oxides (acidic and amphoteric), a salt corresponding to this oxide and carbon dioxide are formed:
4. Al 2 O 3 + Na 2 CO 3 = 2NaAlO 2 + CO 2
12. A constant electric current was passed through a solution of copper (II) chloride using graphite electrodes. The electrolysis product released at the cathode was dissolved in concentrated nitric acid. The resulting gas was collected and passed through a sodium hydroxide solution. The gaseous electrolysis product released at the anode was passed through a hot sodium hydroxide solution. Write down the equations for the reactions described.
13. A simple substance obtained by heating a mixture of calcium phosphate with coke and silicon oxide dissolves in a solution of caustic potassium. The evolved gaseous substance was burned, the combustion products were collected and cooled, and silver nitrate was added to the resulting solution. Write down the equations for the reactions described.
14. The offensive liquid formed by the interaction of hydrogen bromide with potassium permanganate was separated and heated with iron shavings. The reaction product was dissolved in water, and a cesium hydroxide solution was added thereto. The formed precipitate was filtered off and calcined. Write down the equations for the reactions described.
15. Electric discharges were passed over the surface of the caustic soda solution, while the air turned brown, and the color disappeared after a while. The resulting solution was carefully evaporated and the solid residue was found to be a mixture of two salts. Keeping a mixture of salts in air leads to the formation of one substance. Write down the equations for the reactions described.
16. Calcium was dissolved in water. When passing through the resulting solution of sulfur dioxide, a white precipitate is formed, which dissolves when passing an excess of gas. Adding alkali to the resulting solution leads to the formation of a white precipitate. Write down the equations for the reactions described.
17. When a simple yellow substance is burned in air, a gas with a pungent odor is formed. This gas is also released when some iron-containing mineral is burned in air. When diluted sulfuric acid acts on a substance consisting of the same elements as the mineral, but in a different ratio, a gas is released with a characteristic smell of rotten eggs. When the released gases interact with each other, an initial simple substance is formed. Write down the equations for the reactions described.
18. The gaseous product of the interaction of dry sodium chloride with concentrated sulfuric acid was reacted with a solution of potassium permanganate. The evolved gas was passed through a sodium sulfide solution. The precipitated yellow precipitate is dissolved in a concentrated solution of sodium hydroxide. Write down the equations for the reactions described.
19. The gas formed by passing hydrogen chloride through a hot potassium chromate solution interacts with iron. The reaction product was dissolved in water, and sodium sulfide was added thereto. The lighter of the formed insoluble substances was separated and reacted with concentrated sulfuric acid while heating. Write down the equations for the reactions described.
20. The two salts contain the same cation. The thermal decay of the first of them resembles a volcanic eruption, with the release of an inactive colorless gas that is part of the atmosphere. When the second salt interacts with a solution of silver nitrate, a white cheesy precipitate is formed, and when it is heated with an alkali solution, a colorless poisonous gas with a pungent odor is released; this gas can also be obtained by the interaction of magnesium nitride with water. Write down the equations for the reactions described.
21. An excess of sodium hydroxide solution was added to the aluminum sulfate solution. Hydrochloric acid was added to the resulting solution in small portions, while the formation of a bulk white precipitate was observed, which dissolved upon further addition of acid. Sodium carbonate solution was poured into the resulting solution. Write down the equations for the reactions described.
22. Electric discharges were passed over the surface of the caustic soda solution poured into the flask, while the air in the flask turned brown, which disappeared after some time. The resulting solution was carefully evaporated and the solid residue was found to be a mixture of two salts. When this mixture is heated, gas is released and only one substance remains. Write down the equations for the reactions described.
23. Zinc oxide was dissolved in a solution of hydrochloric acid and the solution was neutralized by adding sodium hydroxide. The separated white gelatinous substance was separated and treated with an excess of alkali solution, while the precipitate was completely dissolved. Neutralization of the resulting solution with an acid, for example, nitric acid, leads to the re-formation of a gelatinous precipitate. Write down the equations for the reactions described.
24. The substance obtained at the cathode during the electrolysis of molten copper (II) chloride reacts with sulfur. The resulting product was treated with concentrated nitric acid and the evolved gas was passed through a barium hydroxide solution. Write down the equations for the reactions described.
25. A mixture of calcium orthophosphate, coke and sand was heated in an electric furnace. One of the products of this reaction can spontaneously ignite in air. The solid combustion product of this substance was dissolved in water when heated, and gaseous ammonia was passed through the resulting solution. Write down the equations for the reactions described.
26. The substance obtained at the cathode during the electrolysis of a solution of iron (II) chloride was fused with sulfur and the product of this reaction was fired. The resulting gas was passed through a barium hydroxide solution. Write down the equations for the reactions described.
27. Copper wire was introduced into the heated concentrated sulfuric acid and the evolved gas was passed through an excess of sodium hydroxide solution. The solution was carefully evaporated, the solid residue was dissolved in water and heated with powdered sulfur. Unreacted sulfur was separated by filtration and sulfuric acid was added to the solution, while the formation of a precipitate and the evolution of gas with a pungent odor were observed. Write down the equations for the reactions described.
28. After a short heating of an unknown powdery orange substance, a spontaneous reaction begins, which is accompanied by a change in color to green, the release of gas and sparks. The solid residue was mixed with caustic potassium and heated, the resulting substance was introduced into a dilute solution of hydrochloric acid, and a green precipitate was formed, which dissolves in an excess of acid. Write down the equations for the reactions described.
29. The two salts turn the flame purple. One of them is colorless, and when it is slightly heated with concentrated sulfuric acid, the liquid is distilled off, in which copper dissolves; the last transformation is accompanied by the evolution of brown gas. When the second salt of the sulfuric acid solution is added to the solution, the yellow color of the solution changes to orange, and when the resulting solution is neutralized with alkali, the original color is restored. Write down the equations for the reactions described.
30. The iron (III) chloride solution was electrolyzed with graphite electrodes. The brown precipitate formed as a by-product of electrolysis was filtered off and calcined. The substance formed at the cathode was dissolved in concentrated nitric acid with heating. The product released at the anode was passed through a cold potassium hydroxide solution. Write down the equations for the reactions described.
31. The gas released during the interaction of hydrogen chloride with berthollet's salt was reacted with aluminum. The reaction product was dissolved in water and sodium hydroxide was added until the precipitation ceased, which was separated and calcined. Write down the equations for the reactions described.
32. The unknown salt is colorless and turns the flame yellow. When this salt is slightly heated with concentrated sulfuric acid, the liquid is distilled off, in which copper dissolves; the last transformation is accompanied by the evolution of brown gas and the formation of a copper salt. During the thermal decomposition of both salts, oxygen is one of the decomposition products. Write down the equations for the reactions described.
33. The substance obtained at the anode during the electrolysis of sodium iodide melt with inert electrodes was isolated and introduced into interaction with hydrogen sulfide. The gaseous product of the last reaction was dissolved in water and ferric chloride was added to the resulting solution. The formed precipitate was filtered off and treated with hot sodium hydroxide solution. Write down the equations for the reactions described.
34. The gases that are released when coal is heated in concentrated nitric and sulfuric acids are mixed with each other. The reaction products were passed through milk of lime. Write down the equations for the reactions described.
35. A mixture of iron powder and a solid product obtained by the interaction of sulfur dioxide and hydrogen sulfide was heated without access to air. The resulting product was calcined in air. The resulting solid reacts with aluminum to generate a large amount of heat. Write down the equations for the reactions described.
36. A black substance was obtained by calcining the precipitate that forms during the interaction of solutions of sodium hydroxide and copper (II) sulfate. When this substance is heated with coal, a red metal is obtained, which dissolves in concentrated sulfuric acid. Write down the equations for the reactions described.
37. A simple substance, a mixture of which with berthollet's salt is used in matches and ignites upon friction, was burned in excess of oxygen. The white solid from the combustion was dissolved in an excess of sodium hydroxide solution. The resulting salt with a solution of silver nitrate forms a bright yellow precipitate. Write down the equations for the reactions described.
38. The zinc was dissolved in very dilute nitric acid and an excess of alkali was added to the resulting solution to give a clear solution. Write down the equations for the reactions described.
39. The solution obtained by passing sulfur dioxide through bromine water was neutralized with barium hydroxide. The formed precipitate was separated, mixed with coke and calcined. When processing the calcined product with hydrochloric acid, a gas with the smell of rotten eggs is released. Write down the equations for the reactions described.
40. The substance formed by adding zinc powder to the ferric chloride solution was separated by filtration and dissolved in hot dilute nitric acid. The solution was evaporated, the solid residue was calcined, and the evolved gases were passed through a sodium hydroxide solution. Write down the equations for the reactions described.
41. The gas evolved upon heating a solution of hydrogen chloride with manganese (IV) oxide was introduced into interaction with aluminum. The reaction product was dissolved in water and first an excess of sodium hydroxide solution was added, and then hydrochloric acid (excess). Write down the equations for the reactions described.
42. A mixture of two colorless, colorless and odorless gases A and B was passed while heating over a catalyst containing iron, and the resulting gas B neutralized the solution of hydrobromic acid. The solution was evaporated and the residue was heated with caustic potash, resulting in the evolution of colorless gas B with a pungent odor. When gas B is burned in air, water and gas A are formed. Write the equations for the described reactions.
43. Sulfur dioxide was passed through a hydrogen peroxide solution. Water was evaporated from the resulting solution and magnesium turnings were added to the residue. The evolved gas was passed through a solution of copper sulfate. The precipitated black precipitate was separated and fired. Write down the equations for the reactions described.
44. A solution of hydrochloric acid was added to the water-insoluble white salt, which occurs in nature in the form of a mineral widely used in construction and architecture, as a result, the salt dissolved and gas was released, when passed through lime water, a white precipitate was formed, which dissolved later passing gas. When an excess of lime water is added to the resulting solution, a precipitate forms. Write down the equations for the reactions described.
45. When some mineral A, consisting of two elements, is fired, a gas is formed that has a characteristic pungent odor and decolorizes bromine water with the formation of two strong acids in solution. When substance B, consisting of the same elements as mineral A, but in a different ratio, interacts with concentrated hydrochloric acid, a poisonous gas with the smell of rotten eggs is released. When the released gases interact with each other, a simple yellow substance and water are formed. Write down the equations for the reactions described.
46. The substance released at the cathode during the electrolysis of the sodium chloride melt was burned in oxygen. The resulting product was placed in a gas meter filled with carbon dioxide. The resulting substance was added to the ammonium chloride solution and the solution was heated. Write down the equations for the reactions described.
47. The nitric acid was neutralized with baking soda, the neutral solution was carefully evaporated and the residue was calcined. The resulting substance was introduced into a solution of potassium permanganate acidified with sulfuric acid, and the solution became discolored. The nitrogen-containing reaction product was placed in a sodium hydroxide solution and zinc dust was added, while a gas with a pungent characteristic odor was released. Write down the equations for the reactions described.
48. When a solution of salt A interacted with alkali, a gelatinous water-insoluble blue substance was obtained, which was dissolved in colorless liquid B to form a blue solution. The solid product remaining after careful evaporation of the solution was calcined; At the same time, two gases were released, one of which is brown, and the second is part of the atmospheric air, and a black solid remains, which dissolves in liquid B with the formation of substance A. Write the equations for the described reactions.
49. White phosphorus dissolves in a solution of caustic potash, producing a garlic-smelling gas that ignites spontaneously in air. The solid product of the combustion reaction reacted with sodium hydroxide in such a ratio that the resulting white substance contains one hydrogen atom; when the latter is ignited, sodium pyrophosphate is formed. Write down the equations for the reactions described.
50. The solution of ferric chloride was treated with sodium hydroxide solution, the precipitate that formed was separated and heated. The solid reaction product was mixed with soda ash and calcined. Both sodium nitrate and sodium hydroxide were added to the remaining substance and heated for a long time at a high temperature. Write down the equations for the reactions described.
The gas released during the interaction of hydrogen chloride with potassium permanganate was passed through a solution of sodium tetrahydroxoaluminate. The formed precipitate was filtered off, calcined, and the solid residue was treated with hydrochloric acid. Write down the equations for the reactions described.
The nitrogen-hydrogen mixture was heated to a temperature of 500 ° C and passed under high pressure over an iron catalyst. The reaction products were passed through a nitric acid solution until it was neutralized. The resulting solution was carefully evaporated, the solid residue was calcined and the gas evolved during this process was passed over copper while heating, as a result a black solid was formed. Write down the equations for the reactions described.
Trivalent chromium hydroxide was treated with hydrochloric acid. Potash was added to the resulting solution, the separated precipitate was separated and introduced into a concentrated solution of potassium hydroxide, as a result the precipitate was dissolved. After adding an excess of hydrochloric acid, a green solution was obtained. Write down the equations for the reactions described.
The substance obtained at the anode during the electrolysis of a sodium iodide solution with inert electrodes was reacted with potassium. The reaction product was heated with concentrated sulfuric acid and the evolved gas was passed through a hot potassium chromate solution. Write down the equations for the reactions described.
Ferrous oxide was heated with dilute nitric acid. The solution was carefully evaporated, the solid residue was dissolved in water, iron powder was added to the resulting solution, and after a while it was filtered. A solution of potassium hydroxide was added to the filtrate, the precipitate that formed was separated and left in air, while the color of the substance changed. Write down the equations for the reactions described.
One of the substances formed by the fusion of silicon oxide with magnesium dissolves in alkali. The evolved gas was reacted with sulfur, and the product of their interaction was treated with chlorine. Write down the equations for the reactions described.
The solid substance formed by the interaction of sulfur dioxide and hydrogen sulfide, when heated, interacts with aluminum. The reaction product was dissolved in dilute sulfuric acid, and potash was added to the resulting solution. Write down the equations for the reactions described.
An unknown metal was burned in oxygen. The reaction product, interacting with carbon dioxide, forms two substances: a solid, which interacts with a hydrochloric acid solution with the release of carbon dioxide, and a gaseous simple substance that supports combustion. Write down the equations for the reactions described.
The product of the interaction of nitrogen and lithium was treated with water. The gas evolved as a result of the reaction was mixed with an excess of oxygen and, when heated, passed over a platinum catalyst; the resulting gas mixture had a brown color. Write down the equations for the reactions described.
The copper shavings were dissolved in dilute nitric acid and the solution was neutralized with caustic potassium. The liberated blue substance was separated, calcined (the color of the substance changed to black), mixed with coke and re-calcined. Write down the equations for the reactions described.
The phosphorus was burned in excess of chlorine, the resulting solid was mixed with phosphorus and heated. The reaction product was treated with water, while a colorless gas with a pungent odor evolved. The solution was added to a solution of potassium permanganate acidified with sulfuric acid, which became colorless as a result of the reaction. Write down the equations for the reactions described.
The ferric chloride was treated with concentrated nitric acid while heating and the solution was carefully evaporated. The solid product was dissolved in water, potash was added to the resulting solution, and the precipitate formed was separated and calcined. Hydrogen gas was passed over the obtained substance while heating. Write down the equations for the reactions described.
An unknown salt, when interacting with a silver nitrate solution, forms a white precipitate and colors the burner flame yellow. When concentrated sulfuric acid interacts with this salt, a poisonous gas is formed, which is highly soluble in water. Iron dissolves in the resulting solution, and a very light colorless gas is released, which is used to obtain metals, such as copper, from their oxides. Write down the equations for the reactions described.
The magnesium silicide was treated with a solution of hydrochloric acid and the evolved gas was burned. The solid reaction product was mixed with soda ash, the mixture was heated to melting and held for some time. After cooling, the reaction product (commonly known as “liquid glass”) was dissolved in water and treated with a sulfuric acid solution. Write down the equations for the reactions described.
A gas mixture of ammonia and a large excess of air was passed while heating over platinum, and after a while the reaction products were absorbed in a sodium hydroxide solution. After evaporation of the solution, a single product was obtained. Write down the equations for the reactions described.
Soda ash was added to the ferric chloride solution, and the precipitate formed was separated and calcined. Carbon monoxide was passed over the resulting substance while heating and the solid product of the last reaction was introduced into interaction with bromine. Write down the equations for the reactions described.
The product of the interaction of sulfur with aluminum (the reaction proceeds when heated) was dissolved in cold dilute sulfuric acid and potassium carbonate was added to the solution. The formed precipitate was separated, mixed with sodium hydroxide and heated. Write down the equations for the reactions described.
Silicon (IV) chloride was heated in a mixture with hydrogen. The reaction product was mixed with magnesium powder, heated and treated with water; one of the resulting substances ignites spontaneously in air. Write down the equations for the reactions described.
Brown gas was passed through the excess potassium hydroxide solution in the presence of a large excess of air. Magnesium shavings were added to the resulting solution and heated; the released gas neutralized nitric acid. The resulting solution was carefully evaporated, and the solid reaction product was calcined. Write down the equations for the reactions described.
Iron oxide was dissolved in concentrated nitric acid with heating. The solution was carefully evaporated and the reaction product was dissolved in water. Iron powder was added to the resulting solution, after a while the solution was filtered and the filtrate was treated with a potassium hydroxide solution; as a result, a light green precipitate was formed, which quickly darkened in air. Write down the equations for the reactions described.
To a solution of soda ash was added a solution of aluminum chloride, the separated substance was separated and introduced into the sodium hydroxide solution. A solution of hydrochloric acid was added dropwise to the resulting solution until the formation of a precipitate ceased, which was separated and calcined. Write down the equations for the reactions described.
Copper shavings were added to the mercury (II) nitrate solution. After the end of the reaction, the solution was filtered and the filtrate was added dropwise to a solution containing sodium hydroxide and ammonium hydroxide. In this case, a short-term formation of a precipitate was observed, which dissolved with the formation of a bright blue solution. When an excess of sulfuric acid solution was added to the resulting solution, a color change occurred. Write down the equations for the reactions described.
The reaction product of magnesium phosphide with water was burned and the reaction products were absorbed in water. The resulting substance is used in industry to obtain double superphosphate from phosphorite. Write down the equations for the reactions described.
The salt obtained by reacting zinc oxide with sulfuric acid was calcined at 800 ° C. The solid reaction product was treated with a concentrated alkali solution and carbon dioxide was passed through the resulting solution. Write the reaction equations for the described transformations.
Iron powder was added to the ferric chloride solution and after a while the solution was filtered. Sodium hydroxide was added to the filtrate, the separated precipitate was separated and treated with hydrogen peroxide. An excess of potassium hydroxide and bromine solution was added to the resulting substance; as a result of the reaction, the color of bromine disappeared. Write down the equations for the reactions described.
Copper (I) oxide was treated with concentrated nitric acid, the solution was carefully evaporated, and the solid residue was calcined. The gaseous reaction products were passed through a large amount of water and magnesium chips were added to the resulting solution, resulting in the release of a gas used in medicine. Write down the equations for the reactions described.
Sulfur dioxide was passed through a hydrogen peroxide solution. The solution was evaporated and copper shavings were added to the remaining liquid. The evolved gas was mixed with the gas that forms when iron (II) sulfide interacts with a solution of hydrobromic acid. Write down the equations for the reactions described.
When a yellow salt, which turns the flame purple, and dilute hydrochloric acid, was added to the solution, the color changed to orange-red. After neutralizing the solution with concentrated alkali, the color of the solution returned to its original color. When barium chloride is added to the resulting solution, a yellow precipitate forms. The precipitate was filtered off and silver nitrate solution was added to the filtrate. Write down the equations for the reactions described.
Magnesium silicide was treated with a solution of hydrochloric acid, the reaction product was burned, the resulting solid was mixed with soda ash and heated to melting. After cooling the melt, it was treated with water and nitric acid was added to the resulting solution. Write down the equations for the reactions described.
The insoluble substance formed by adding sodium hydroxide to the ferric chloride solution was separated and dissolved in dilute sulfuric acid. Zinc dust was added to the resulting solution, the separated precipitate was filtered off and dissolved in concentrated hydrochloric acid. Write down the equations for the reactions described.
Aluminum nitrate was calcined, the reaction product was mixed with soda ash and heated to melting. The resulting substance was dissolved in nitric acid and the resulting solution was neutralized with an ammonia solution, while the formation of a bulky gelatinous precipitate was observed. Write down the equations for the reactions described.
Magnesium nitride was treated with excess water. When the evolved gas is passed both through bromine water or through a neutral solution of potassium permanganate, and when it is burned, the same gaseous product is formed. Write down the equations for the reactions described.
Chlorine water smells like chlorine. When alkalinized, the smell disappears, and when hydrochloric acid is added, it becomes stronger than it was before. Write down the equations for the reactions described.
The solid substance formed by heating malachite was heated in a hydrogen atmosphere. The reaction product was treated with concentrated sulfuric acid and, after separation from sulfuric acid, was introduced into a sodium chloride solution containing copper filings, and as a result a precipitate formed. Write down the equations for the reactions described.
Phosphine was passed through a hot solution of concentrated nitric acid. The solution was neutralized with quicklime, the precipitate formed was separated, mixed with coke and silica and calcined. The reaction product, which glows in air, was heated in a sodium hydroxide solution. Write down the equations for the reactions described.
The iron powder was dissolved in a large amount of dilute sulfuric acid, and air was passed through the resulting solution, and then a gas with the smell of rotten eggs was passed. The formed insoluble salt was separated and dissolved in a hot solution of concentrated nitric acid. Write down the equations for the reactions described.
Colorless gases are released when concentrated sulfuric acid is kept with both sodium chloride and sodium iodide. When these gases are passed through an aqueous ammonia solution, salts are formed. Write down the equations for the reactions described.
The magnesium powder was mixed with silicon and heated. The reaction product was treated with cold water and the evolved gas was passed through hot water. The formed precipitate was separated, mixed with sodium hydroxide and heated to melting. Write down the equations for the reactions described.
One of the products of the interaction of ammonia with bromine - a gas that is part of the atmosphere, was mixed with hydrogen and heated in the presence of platinum. The resulting gas mixture was passed through a hydrochloric acid solution and potassium nitrite was added to the resulting solution with slight heating. Write down the equations for the reactions described.
The salt obtained by dissolving copper in dilute nitric acid was electrolyzed using graphite electrodes. The substance released at the anode was brought into interaction with sodium, and the resulting reaction product was placed in a vessel with carbon dioxide. Write down the equations for the reactions described.
Unknown substance A dissolves in concentrated hydrochloric acid, the dissolution process is accompanied by the release of gas with the smell of rotten eggs; after neutralization of the solution with alkali, a voluminous white (light green) precipitate is formed. When substance A is fired, two oxides are formed. One of them is a gas that has a characteristic pungent odor and decolorizes bromine water with the formation of two strong acids in solution. Write down the equations for the reactions described.
Magnesium was heated in a vessel filled with gaseous ammonia. The resulting substance was dissolved in a concentrated solution of hydrobromic acid, the solution was evaporated and the residue was heated until an odor appeared, after which an alkali solution was added. Write down the equations for the reactions described.
Soda ash was added to the trivalent chromium sulfate solution. The separated precipitate was separated, transferred to a sodium hydroxide solution, bromine was added and heated. After neutralization of the reaction products with sulfuric acid, the solution acquires an orange color, which disappears after passing sulfur dioxide through the solution. Write down the equations for the reactions described.
Quicklime was calcined with an excess of coke. The reaction product after treatment with water is used to absorb sulfur dioxide and carbon dioxide. Write down the equations for the reactions described.
The sulfide of ferrous iron was treated with a solution of hydrochloric acid, the released gas was collected and burned in the air. The reaction products were passed through an excess of potassium hydroxide solution, after which a solution of potassium permanganate was added to the resulting solution. Write down the equations for the reactions described.
The solid product of the thermal decomposition of malachite was dissolved by heating in concentrated nitric acid. The solution was carefully evaporated and the solid residue was calcined to give a black substance, which was heated in excess of ammonia (gas). Write down the equations for the reactions described.
Red phosphorus was burned in a chlorine atmosphere. The reaction product was treated with excess water and powdered zinc was added to the solution. The evolved gas was passed over heated ferrous oxide. Write the reaction equations for the described transformations.
A silvery-gray metal, which is attracted by a magnet, was added to hot concentrated sulfuric acid and heated. The solution was cooled and sodium hydroxide was added until the formation of an amorphous brown precipitate ceased. The precipitate was separated, calcined, and dissolved in concentrated hydrochloric acid while heating. Write down the equations for the reactions described.
Magnesium shavings were heated in a nitrogen atmosphere, and the reaction product was sequentially treated with boiling water, solutions of sulfuric acid and barium nitrate. Write down the equations for the reactions described.
The thermal decomposition of salt A in the presence of manganese dioxide resulted in the formation of binary salt B and a gas that supports combustion and is part of the air; when this salt is heated without a catalyst, salt B and a salt of a higher oxygen-containing acid are formed. When salt A interacts with hydrochloric acid, a yellow-green poisonous gas (a simple substance) is released and salt B is formed. Salt B colors the flame purple; when it interacts with a solution of silver nitrate, a white precipitate forms. Write down the equations for the reactions described.
The precipitate obtained by adding caustic soda to the aluminum sulfate solution was separated, calcined, mixed with soda ash and heated to melting. After treating the residue with sulfuric acid, the starting aluminum salt was obtained. Write down the equations for the reactions described.
The substance formed during the fusion of magnesium with silicon was treated with water, as a result of which a precipitate formed and a colorless gas evolved. The precipitate was dissolved in hydrochloric acid, and the gas was passed through a solution of potassium permanganate, with the formation of two water-insoluble binary substances. Write down the equations for the reactions described.
The substance obtained by heating iron scale in a hydrogen atmosphere was introduced into hot concentrated sulfuric acid and heated. The resulting solution was evaporated, the residue was dissolved in water and treated with a solution of barium chloride. The solution was filtered and a copper plate was introduced into the filtrate, which after a while dissolved. Write down the equations for the reactions described.
Quicklime was "quenched" with water. A gas was passed into the resulting solution, which is released during the calcination of sodium bicarbonate, while the formation and subsequent dissolution of the precipitate was observed. Write down the equations for the reactions described.
A mixture of nitrogen and hydrogen was sequentially passed over heated platinum and through a sulfuric acid solution. Barium chloride was added to the solution and, after separating the precipitated sediment, milk of lime was added and heated. Write down the equations for the reactions described.
Give examples of interaction:
two acids
two reasons
two acidic salts
two acidic oxides
Write down the equations for the reactions described.
A solution of a medium salt formed by passing a sulfur dioxide gas through an alkali solution was left in air for a long time. The solid formed after the solution was evaporated was mixed with coke and heated to a high temperature. When hydrochloric acid is added to the solid product of the reaction, a gas with the smell of rotten eggs is released. Write down the equations for the reactions described.
A solution of dilute sulfuric acid was added to the black powdery substance and heated. A solution of sodium hydroxide was poured into the resulting blue solution until the precipitation ceased. The precipitate was filtered off and heated. The reaction product was heated under a hydrogen atmosphere to give a red solid. Write down the equations for the reactions described.
Red phosphorus was burned in a chlorine atmosphere and a small amount (a few drops) of water was added to the reaction product. The liberated substance was dissolved in an excess of water, iron powder was added to the resulting solution, and the gaseous reaction product was passed over a heated copper plate oxidized to bivalent copper oxide. Write the reaction equations for the described transformations.
The iron (III) chloride solution was electrolyzed with graphite electrodes. The brown precipitate formed during electrolysis was filtered off and dissolved in a sodium hydroxide solution, after which an amount of sulfuric acid was added, which was necessary to form a clear solution. The product released at the anode was passed through a hot potassium hydroxide solution. Write down the equations for the reactions described.
Aluminum chloride was added to the crystalline soda solution, the separated precipitate was separated and treated with sodium hydroxide solution. The resulting solution was neutralized with nitric acid, the separated precipitate was separated and calcined. Write down the equations for the reactions described.
Ammonia was mixed with a large excess of air, heated in the presence of platinum, and after a while absorbed in water. Copper shavings added to the resulting solution dissolve with the release of brown gas. Write down the equations for the reactions described.
When a solution of acid A is added to manganese dioxide, a poisonous gas of yellow-green color is released. Having passed the released gas through a hot solution of caustic potassium, a substance is obtained that is used in the manufacture of matches and some other incendiary compositions. During the thermal decomposition of the latter in the presence of manganese dioxide, a salt is formed, from which, when interacting with concentrated sulfuric acid, it is possible to obtain the original acid A, and a colorless gas included in the composition of atmospheric air. Write down the equations for the reactions described.
The product of the interaction of silicon with chlorine is easily hydrolyzed. When a solid hydrolysis product fusion with both caustic and soda ash, water glass is formed. Write down the equations for the reactions described.
To the solution obtained by dissolving iron in hot concentrated hydrochloric acid, sodium hydroxide was added. The separated precipitate was separated, left in air for a long time, and then dissolved in dilute hydrochloric acid. Write down the equations for the reactions described.
When heated, the orange-colored substance decomposes; Decomposition products include a colorless gas and a green solid. The released gas reacts with lithium even when heated slightly. The product of the last reaction interacts with water, while a gas with a pungent odor is released, which can reduce metals, such as copper, from their oxides. Write down the equations for the reactions described.
A rotten egg smell gas was passed through concentrated sulfuric acid at room temperature. The formed precipitate was separated and treated with hot concentrated nitric acid; the evolved gas was dissolved in a large amount of water and a piece of copper was added to the resulting solution. Write the reaction equations for the described transformations.
The salt obtained by dissolving iron in hot concentrated sulfuric acid was treated with an excess of sodium hydroxide solution. The resulting brown precipitate was filtered off and calcined. The resulting substance was fused with iron. Write down the equations for the reactions described.
Metallic zinc was added to concentrated sulfuric acid. The resulting salt was isolated, dissolved in water, and barium nitrate was added to the solution. After separating the precipitate, magnesium chips were introduced into the solution, the solution was filtered, the filtrate was evaporated and calcined. Write down the equations for the reactions described.
The unknown red substance was heated in chlorine and the reaction product was dissolved in water. An alkali was added to the resulting solution, the precipitated blue precipitate was filtered off and calcined. On heating the black calcined product, a red starting material was obtained with coke. Write down the equations for the reactions described.
Iodine was heated with excess phosphorus and the reaction product was treated with a small amount of water. The gaseous reaction product was completely neutralized with sodium hydroxide solution and silver nitrate was added to the resulting solution. Write down the equations for the reactions described.
The iron was burned in chlorine. The reaction product was dissolved in water and iron filings were added to the solution. After a while, the solution was filtered and sodium sulfide was added to the filtrate. The separated precipitate was separated and treated with 20% sulfuric acid, obtaining an almost colorless solution. Write down the equations for the reactions described.
The gas evolved when heating solid sodium chloride with concentrated sulfuric acid was passed through a solution of potassium permanganate. The gaseous reaction product was taken up in a cold sodium hydroxide solution. After adding hydroiodic acid to the resulting solution, a pungent odor appears and the solution becomes dark in color. Write down the equations for the reactions described.
Through the solution obtained by slaking lime, gas was passed, which is formed when obtaining quicklime from limestone; the result is a white precipitate. When acetic acid acts on the resulting precipitate, the same gas is released, which is formed when calcining calcium carbonate. Write down the equations for the reactions described.
The red substance, which is used in the manufacture of matches, was burned in excess air and the reaction product was dissolved in a large amount of water when heated. After neutralizing the resulting solution with baking soda, silver nitrate was added to it. Write down the equations for the reactions described.
Through the sodium bromide solution, the gas evolved from the interaction of hydrochloric acid with potassium permanganate was passed. After the end of the reaction, the solution was evaporated, the residue was dissolved in water and subjected to electrolysis with graphite electrodes. The gaseous reaction products were mixed with each other and illuminated, and the result was an explosion. Write down the equations for the reactions described.
The gas formed during the combustion of coke was in contact with hot coal for a long time. The reaction product was subsequently passed through a layer of heated iron ore and quicklime. Write down the equations for the reactions described.
Copper shavings were added to heated concentrated sulfuric acid, and the released gas was passed through a sodium hydroxide solution (excess). The reaction product was isolated, dissolved in water and heated with sulfur, which was dissolved as a result of the reaction. Dilute sulfuric acid was added to the resulting solution. Write down the equations for the reactions described.
Hydrochloric acid was added to solutions of substances L and B, which color the flame yellow: When a solution of substance A interacts with hydrochloric acid, a colorless gas with an unpleasant odor is released, which forms a black precipitate when lead (II) nitrate is passed through the solution. When a solution of substance B with hydrochloric acid is heated, the color of the solution changes from yellow to green, and a poisonous gas of yellow-green color with a characteristic pungent odor is released. When barium nitrate is added to the solution of substance B, a yellow precipitate forms. Write down the equations for the reactions described.
A solution of hydrochloric acid was carefully added to the pyrolusite, and the evolved gas was passed into a beaker half filled with a cold solution of potassium hydroxide. After the end of the reaction, the glass was covered with a cardboard and left, while the glass was illuminated by the sun's rays; after a while, a smoldering splinter was brought into the glass, which flashed brightly. Write down the equations for the reactions described.
The precipitate obtained by the interaction of a solution of an aluminum salt and an alkali was calcined. The reaction product was dissolved in a concentrated hot alkali solution. Carbon dioxide was passed through the resulting solution, resulting in the formation of a precipitate. Write the equations for the described transformations.
The black powder, which was formed upon prolonged heating of the red metal in excess air, was dissolved in 10% sulfuric acid and a blue solution was obtained. Alkali was added to the solution, and the precipitate formed was separated and dissolved in an excess of ammonia solution. Write down the equations for the reactions described.
Phosphorus was added to the solid matter that forms when phosphorus is burned in excess of chlorine and the mixture was heated. The reaction product was treated with a small amount of hot water and a solution of potassium permanganate acidified with sulfuric acid was added to the resulting solution. Write down the equations for the reactions described.
Carbon dioxide was passed through barite water. Barium hydroxide was added to the resulting solution, the reaction product was separated and dissolved in phosphoric acid. Write down the equations for the reactions described.
Zinc nitrate was calcined, and the reaction product was treated with sodium hydroxide solution while heating. Carbon dioxide was passed through the resulting solution until the precipitation ceased, after which it was treated with an excess of concentrated ammonia, and the precipitate dissolved. Write down the equations for the reactions described.
Two vessels contain solutions of unknown substances. When barium chloride is added to the solution of the first substance, a white precipitate is formed, insoluble in water and acids. A white precipitate also falls out when the silver nitrate solution is added to the sample taken from the second vessel. When the sample of the first solution with sodium hydroxide is heated, a pungent odor is emitted into the gas. When the second solution interacts with sodium chromate, a yellow precipitate forms. Write down the equations for the reactions described.
Sulfur dioxide was dissolved in water and the solution was neutralized by adding sodium hydroxide. Hydrogen peroxide was added to the resulting solution, and after the end of the reaction, sulfuric acid was added. Write down the equations for the reactions described.
The zinc was dissolved in very dilute nitric acid, the resulting solution was carefully evaporated and the residue was calcined. The reaction products were mixed with coke and heated. Make up the reaction equations for the described transformations.
Substances released at the cathode and anode during the electrolysis of sodium iodide solution with graphite electrodes react with each other. The reaction product interacts with concentrated sulfuric acid with the evolution of gas, which was passed through a potassium hydroxide solution. Write down the equations for the reactions described.
The substance, which is formed during the electrolysis of bauxite melt in cryolite, dissolves both in a hydrochloric acid solution and in an alkali solution with the release of the same gas. When the resulting solutions are mixed, a white bulk precipitate is formed. Write down the equations for the reactions described.
Concentrated hydrochloric acid was added to lead (IV) oxide with heating. The evolved gas was passed through a heated potassium hydroxide solution. The solution was cooled, the oxygenate acid salt was filtered off and dried. When the resulting salt is heated with hydrochloric acid, a poisonous gas is released, and when heated in the presence of manganese dioxide, the gas is included and the composition of the atmosphere. Write down the equations for the reactions described.
The brown precipitate obtained by the interaction of sodium sulfite with an aqueous solution of potassium permanganate was filtered off and treated with concentrated sulfuric acid. The evolved gas when heated reacts with aluminum, and the resulting substance - with a solution of hydrochloric acid. Write the reaction equations for the described transformations.
Calcium was heated in a hydrogen atmosphere. The reaction product was treated with water, the evolved gas was passed over heated zinc oxide, and soda ash was added to the solution. Write down the equations for the reactions described.
Silver nitrate was calcined and the solid reaction product was heated in oxygen. The resulting substance is dissolved in an excess of concentrated ammonia. When passing through the resulting solution of hydrogen sulfide, a black precipitate is formed. Write down the equations for the reactions described.
The solid substance, which is formed by heating phosphorus and phosphorus pentachloride, was dissolved in a large amount of water. Part of the resulting solution was added to a solution of potassium permanganate acidified with sulfuric acid, the latter discolored. Write down the equations for the reactions described.
Several zinc granules were introduced into a vessel with concentrated sulfuric acid. The evolved gas was passed through a solution of lead (II) acetate, the precipitate was separated, subjected to roasting, and the resulting gas was brought into interaction with an aqueous solution of potassium permanganate. Write down the equations for the reactions described.
Several zinc granules were dissolved by heating in a sodium hydroxide solution. Nitric acid was added to the resulting solution in small portions until a precipitate was formed. The precipitate was separated, dissolved in dilute nitric acid, the solution was carefully evaporated, and the residue was calcined. Write down the equations for the reactions described.
The gas released during the dissolution of copper in hot concentrated nitric acid can interact with both the gas released during the treatment of copper with hot concentrated sulfuric acid and with copper. Write down the equations for the reactions described.
The iron (III) chloride solution was electrolyzed with graphite electrodes. The separated brown precipitate (a by-product of electrolysis) was filtered off, calcined, and fused with the substance formed at the cathode. Another substance, also released at the cathode, was introduced into a reaction with the product released during electrolysis at the anode; the reaction proceeds under illumination and with an explosion. Write down the equations for the reactions described.
Water-insoluble white salt that meets It occurs in nature in the form of a mineral widely used in construction and architecture, calcined at 1000 ° C. After cooling, water was added to the solid residue, and the gaseous product of the decomposition reaction was passed through the resulting solution; as a result, a white precipitate was formed, which dissolved upon further passing the gas. Write down the equations for the reactions described.
1) Copper nitrate was calcined, the resulting solid precipitate was dissolved in sulfuric acid. Hydrogen sulfide was passed through the solution, the resulting black precipitate was calcined, and the solid residue was dissolved by heating in concentrated nitric acid.
2) Calcium phosphate was fused with coal and sand, then the resulting simple substance was burned in an excess of oxygen, the combustion product was dissolved in an excess of sodium hydroxide. A solution of barium chloride was added to the resulting solution. The resulting precipitate was treated with an excess of phosphoric acid.
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Ca 3 (PO 4) 2 → P → P 2 O 5 → Na 3 PO 4 → Ba 3 (PO 4) 2 → BaHPO 4 or Ba (H 2 PO 4) 2 Ca 3 (PO 4) 2 + 5C + 3SiO 2 → 3CaSiO 3 + 2P + 5CO |
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3) Copper was dissolved in concentrated nitric acid, the resulting gas was mixed with oxygen and dissolved in water. Zinc oxide was dissolved in the resulting solution, then a large excess of sodium hydroxide solution was added to the solution.
4) Dry sodium chloride was acted upon with concentrated sulfuric acid under low heating, the resulting gas was passed into a solution of barium hydroxide. Potassium sulfate solution was added to the resulting solution. The resulting precipitate was fused with coal. The resulting material was treated with hydrochloric acid.
5) A sample of aluminum sulfide was treated with hydrochloric acid. In this case, gas was evolved and a colorless solution was formed. An ammonia solution was added to the resulting solution, and the gas was passed through a lead nitrate solution. The resulting precipitate was treated with a hydrogen peroxide solution.
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Al (OH) 3 ← AlCl 3 ← Al 2 S 3 → H 2 S → PbS → PbSO 4 Al 2 S 3 + 6HCl → 3H 2 S + 2AlCl 3 |
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6) Aluminum powder was mixed with sulfur powder, the mixture was heated, the resulting substance was treated with water, while gas was released and a precipitate was formed, to which an excess of potassium hydroxide solution was added until complete dissolution. This solution was evaporated and calcined. An excess of hydrochloric acid solution was added to the resulting solid.
7) A solution of potassium iodide was treated with a solution of chlorine. The resulting precipitate was treated with sodium sulfite solution. To the resulting solution, a solution of barium chloride was added first, and after separation of the precipitate, a solution of silver nitrate was added.
8) A gray-green powder of chromium (III) oxide was fused with an excess of alkali, the resulting substance was dissolved in water, and a dark green solution was obtained. Hydrogen peroxide was added to the resulting alkaline solution. The result is a yellow solution, which becomes orange when added with sulfuric acid. When hydrogen sulfide is passed through the resulting acidified orange solution, it becomes cloudy and turns green again.
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Cr 2 O 3 → KCrO 2 → K → K 2 CrO 4 → K 2 Cr 2 O 7 → Cr 2 (SO 4) 3 Cr 2 O 3 + 2KOH → 2KCrO 2 + H 2 O |
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9) Aluminum was dissolved in a concentrated solution of potassium hydroxide. Carbon dioxide was passed through the resulting solution until precipitation ceased. The precipitate was filtered off and calcined. The resulting solid residue was fused with sodium carbonate.
10) Silicon was dissolved in a concentrated solution of potassium hydroxide. An excess of hydrochloric acid was added to the resulting solution. The cloudy solution was heated. The separated precipitate was filtered off and calcined with calcium carbonate. Write down the equations for the reactions described.
11) Copper (II) oxide was heated in a stream of carbon monoxide. The resulting substance was burned in a chlorine atmosphere. The reaction product was dissolved in water. The resulting solution was divided into two parts. Potassium iodide solution was added to one part, and silver nitrate solution to the second. In both cases, the formation of a precipitate was observed. Write the equations for the four reactions described.
12) Copper nitrate was calcined, the resulting solid was dissolved in dilute sulfuric acid. The resulting salt solution was subjected to electrolysis. The substance released at the cathode was dissolved in concentrated nitric acid. Dissolution proceeded with the evolution of brown gas. Write the equations for the four reactions described.
13) Iron was burned in a chlorine atmosphere. The resulting material was treated with an excess of sodium hydroxide solution. A brown precipitate formed, which was filtered off and calcined. The residue after calcination was dissolved in hydroiodic acid. Write the equations for the four reactions described.
14) Powder of metallic aluminum was mixed with solid iodine and a few drops of water were added. Sodium hydroxide solution was added to the resulting salt until a precipitate formed. The resulting precipitate was dissolved in hydrochloric acid. Upon subsequent addition of the sodium carbonate solution, precipitation was again observed. Write the equations for the four reactions described.
15) As a result of incomplete combustion of coal, a gas was obtained, in a stream of which iron (III) oxide was heated. The resulting material was dissolved in hot concentrated sulfuric acid. The resulting salt solution was subjected to electrolysis. Write the equations for the four reactions described.
16) Some zinc sulfide was divided into two parts. One of them was treated with nitric acid, and the other was fired in air. A simple substance was formed during the interaction of the evolved gases. This substance was heated with concentrated nitric acid, and a brown gas was evolved. Write the equations for the four reactions described.
17) Potassium chlorate was heated in the presence of a catalyst, while a colorless gas was evolved. By burning iron in an atmosphere of this gas, iron scale was obtained. It was dissolved in an excess of hydrochloric acid. To the resulting solution was added a solution containing sodium dichromate and hydrochloric acid.
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1) 2КClО 3 → 2КСl + 3О 2 2) ЗFe + 2O 2 → Fe 3 O 4 3) Fe 3 O 4 + 8HCI → FeCl 2 + 2FeCl 3 + 4H 2 O 4) 6 FeCl 2 + Na 2 Cr 2 O 7 + 14 НСІ → 6 FeCl 3 + 2 CrCl 3 + 2NaCl + 7Н 2 О 18) Iron was burned in chlorine. The resulting salt was added to the sodium carbonate solution, and a brown precipitate formed. This precipitate was filtered off and calcined. The resulting substance was dissolved in hydroiodic acid. Write the equations for the four reactions described. 1) 2Fe + 3Cl 2 → 2FeCl 3 2) 2FeCl 3 + 3Na 2 CO 3 → 2Fe (OH) 3 + 6NaCl + 3CO 2 3) 2Fe (OH) 3 Fe 2 O 3 + 3H 2 O 4) Fe 2 O 3 + 6HI → 2FeI 2 + I 2 + 3H 2 O |
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19) A solution of potassium iodide was treated with an excess of chlorine water, while the formation of a precipitate was observed first, and then its complete dissolution. The resulting iodine-containing acid was isolated from the solution, dried and heated carefully. The resulting oxide reacted with carbon monoxide. Write down the equations of the described reactions.
20) Powder of chromium (III) sulfide was dissolved in sulfuric acid. In this case, gas was released and a colored solution was formed. An excess of ammonia solution was added to the resulting solution, and the gas was passed through lead nitrate. The resulting black precipitate turned white after treatment with hydrogen peroxide. Write down the equations of the described reactions.
21) Aluminum powder was heated with sulfur powder, the resulting substance was treated with water. The precipitate that formed was treated with an excess of concentrated potassium hydroxide solution until it was completely dissolved. To the resulting solution was added a solution of aluminum chloride and again observed the formation of a white precipitate. Write down the equations of the described reactions.
22) Potassium nitrate was heated with powdered lead until the reaction was terminated. The product mixture was treated with water, and then the resulting solution was filtered. The filtrate was acidified with sulfuric acid and treated with potassium iodide. The separated simple substance was heated with concentrated nitric acid. In the atmosphere of the resulting brown gas, red phosphorus was burned. Write down the equations of the described reactions.
23) Copper was dissolved in dilute nitric acid. An excess of ammonia solution was added to the resulting solution, observing first the formation of a precipitate, and then its complete dissolution with the formation of a dark blue solution. The resulting solution was treated with sulfuric acid until the characteristic blue color of copper salts appeared. Write down the equations of the described reactions.
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1) 3Cu + 8HNO 3 → 3Cu (NO 3) 2 + 2NO + 4H 2 O 2) Cu (NO 3) 2 + 2NH 3 H 2 O → Cu (OH) 2 + 2NH 4 NO 3 3) Cu (OH) 2 + 4NH 3 H 2 O → (OH) 2 + 4H 2 O 4) (OH) 2 + 3H 2 SO 4 → CuSO 4 +2 (NH 4) 2 SO 4 + 2H 2 O |
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24) Magnesium was dissolved in dilute nitric acid, and no gas evolution was observed. The resulting solution was treated with an excess of potassium hydroxide solution with heating. The gas released during this process was burned in oxygen. Write down the equations of the described reactions.
25) A mixture of potassium nitrite and ammonium chloride powders was dissolved in water and the solution was heated carefully. The released gas reacted with magnesium. The reaction product was added to an excess of hydrochloric acid solution, and no gas evolution was observed. The obtained magnesium salt in solution was treated with sodium carbonate. Write down the equations of the described reactions.
26) Aluminum oxide was fused with sodium hydroxide. The reaction product was introduced into the ammonium chloride solution. The released gas with a pungent odor is absorbed by the sulfuric acid. The resulting middle salt was calcined. Write down the equations of the described reactions.
27) Chlorine has reacted with hot potassium hydroxide solution. When the solution was cooled, crystals of Berthollet's salt precipitated. The crystals obtained were introduced into a hydrochloric acid solution. The resulting simple substance reacted with metallic iron. The reaction product was heated with a new weight of iron. Write down the equations of the described reactions.
28) Copper was dissolved in concentrated nitric acid. An excess of ammonia solution was added to the resulting solution, observing first the formation of a precipitate and then its complete dissolution. The resulting solution was treated with an excess of hydrochloric acid. Write down the equations of the described reactions.
29) Iron was dissolved in hot concentrated sulfuric acid. The resulting salt was treated with an excess of sodium hydroxide solution. The resulting brown precipitate was filtered off and calcined. The resulting substance was fused with iron. Write the equations for the four reactions described.
30) As a result of incomplete combustion of coal, a gas was obtained, in the current of which iron oxide (III) was heated. The resulting material was dissolved in hot concentrated sulfuric acid. The resulting salt solution was treated with an excess of potassium sulfide solution.
31) Some zinc sulfide was split in two. One of them was treated with hydrochloric acid, and the other was fired in air. A simple substance was formed during the interaction of the evolved gases. This substance was heated with concentrated nitric acid, and a brown gas was released.
32) Sulfur was fused with iron. The reaction product was treated with hydrochloric acid. The gas released during this was burned in an excess of oxygen. The combustion products were absorbed in an aqueous solution of iron sulfate (III).
Test, you need to pass in an hour!
1) what volume of hydrogen will be released during the interaction of 2.3 g of sodium with ethyl alcohol, if the H2 yield is 80%
2) Perform reactions
C2H5OH-C2H4 - [- CH2-CH2-]
/ \
СО2 С2H4Br
Thank you in advance!
for
the experiment proposed the following reagents: copper, hydrochloric acid and
copper sulfate solutions (II ),
ammonium chloride, sodium hydroxide and hydrogen peroxide. We need to get copper chloride 2
An excess of silver nitrate solution was added to 134 g of a solution with a mass fraction of copper (II) chloride of 2%. Determine the mass of precipitated sediment.
To 106 g of a solution with a mass fraction of potassium phosphate 4% was added an excess of copper chloride (II) solution. Determine the mass of precipitated sediment.
An excess of aluminum nitrate solution was added to 56 g of a solution with a mass fraction of potassium hydroxide of 6%. Determine the mass of precipitated sediment.
An excess of sodium sulfide solution was added to 132.4 g of a solution with a mass fraction of lead nitrate of 5%. Determine the mass of the dropped out residue.
An excess of potassium sulfide solution was added to 63.5 g of a solution with a mass fraction of iron (II) chloride of 6%. Determine the mass of precipitated sediment.
When an excess of aluminum sulfate solution was added to the solution of barium chloride with a mass fraction of 4%, a precipitate weighing 4.66 g was formed. Determine the mass of the initial barium chloride solution.
When copper (ll) with a mass fraction of 4% of an excess of potassium hydroxide solution was added to the sodium solution, a precipitate weighing 4.9 g was formed. Determine the mass of the original salt solution.
An excess of sodium hydroxide solution was added to 240 g of a solution with a mass fraction of iron (ll) nitrate of 2%. Determine the mass of precipitated sediment.
After passing through the potassium hydroxide solution 1.12 liters of carbon dioxide (n.u.), 138 g of a potassium carbonate solution were obtained. Calculate the mass fraction of salt in the resulting solution.
In chemistry, I don’t fury (
# 1) What is a pure substance as opposed to a mixture? 1) air 2) stainless steel 3) "aqua regia" 4) sucrose No. 2 Whatrefers to homogeneous mixtures?
2) alcohol solution
No. 3 A solid mixture is a mixture in which:
1) gaseous particles are distributed in the liquid
2) gaseous particles are distributed in the gas
3) one liquid is crushed into another liquid that does not dissolve it
4) solid particles are distributed in a solid
# 4 What is a heterogeneous mixture?
1) iodine solution in alcohol
2) copper (II) sulfate solution
3) alkali solution
No. 5 What is the name of the method for cleaning a homogeneous mixture?
1) filtering
2) cooling
3) evaporation
4) upholding
# 6 What happens to gases during dissolution when the temperature rises?
1) their solubility decreases
2) their solubility does not change
3) their solubility increases
4) their solubility first decreases and then increases
# 7 What gas dissolves only when air is passed through water?
1) oxygen only
2) only nitrogen
3) oxygen and nitrogen
4) carbon dioxide
# 8 What is a gaseous mixture?
2) a carbonated drink
3) a mixture of hydrogen and oxygen
HELP PLEASE !!! BIG THANKS IN ADVANCE !!!
2Al + 3Cl 2at the cathode at the anode
4Al (NO 3) 3 2Al 2 O 3 + 12NO 2 + 3O 2
2Al 2 (SO 4) 3 2Al 2 O 3 + 6SO 2 + 3O 2
2 (AlCl 3 ∙ 6H 2 O) Al 2 O 3 + 6HCl + 9H 2 O
Al 2 (SO 4) 3 + 6NaHSO 3 = 2Al (OH) 3 + 6SO 2 + 3Na 2 SO 4
Al (NO 3) 3 + 4KOH (excess) = K + 3KNO 3
AlCl 3 + 3 (NH 3 ∙ H 2 O) = Al (OH) 3 + 3NH 4 Cl
Al 2 (SO 4) 3 + 6 (NH 3 ∙ H 2 O) = 2Al (OH) 3 ↓ + 3 (NH 4) 2 SO 4
Al 2 (SO 4) 3 + 8NaOH (excess) = 2Na + 3Na 2 SO 4
AlCl 3 + 3NaOH (deficiency) = Al (OH) 3 ↓ + 3NaCl
Al (NO 3) 3 + 4KOH KAlO 2 + 3KNO 3 + 2H 2 O
KAlO 2 + 4HCl = KCl + AlCl 3 + 2H 2 O
NaAlO 2 + 4HCl = AlCl 3 + NaCl + 2H 2 O
KAlO 2 + H 2 O = K
NaAlO 2 + 2H 2 O = Na
When the solutions are mixed, hydrolysis occurs both by the cation of the weak base and by the anion of the weak acid:
2AlBr 3 + 3Na 2 CO 3 + 3H 2 O = 2Al (OH) 3 ↓ + CO 2 + 6NaBr
2Al (NO 3) 3 + 3Na 2 CO 3 + 3H 2 O = 2Al (OH) 3 ↓ + 6NaNO 3 + 3CO 2
2AlCl 3 + 3Na 2 S + 6H 2 O = 2Al (OH) 3 + 3H 2 S + 6NaCl
Binaryconnections.
Al 2 S 3 + 8HNO 3 = Al 2 (SO 4) 3 + 8NO 2 + 4H 2 O
Al 2 S 3 + 30HNO 3 (conc. Hot.) = 2Al (NO 3) 3 + 24NO 2 + 3H 2 SO 4 + 12H 2 O
Al 2 S 3 + 6H 2 O = 2Al (OH) 3 ↓ + 3H 2 S
Al 4 C 3 + 12H 2 O = 4Al (OH) 3 + 3CH 4
AlN + 3HCl = AlCl 3 + NH 3
AlN + 3H 2 O = Al (OH) 3 ↓ + NH 3
Aluminum. Aluminum compounds
1. Sodium hydroxide solution was added dropwise to the solution obtained by the interaction of aluminum with dilute sulfuric acid until a precipitate was formed. The formed white precipitate was filtered off and calcined. The resulting material was fused with sodium carbonate. Write down the equations for the reactions described.
2. An excess of sodium hydroxide was added to the aluminum sulfate solution. Hydrochloric acid was added to the resulting solution in small portions, while the formation of a bulk white precipitate was observed, which dissolved upon further addition of acid. Sodium carbonate solution was poured into the resulting solution. Write down the equations for the reactions described.
3. The gas released during the interaction of hydrogen chloride with potassium permanganate was passed through a solution of sodium tetrahydroxoaluminate. The formed precipitate was filtered off, calcined, and the solid residue was treated with hydrochloric acid. Write down the equations for the reactions described.
4. The solid substance formed by the interaction of sulfur dioxide and hydrogen sulfide, when heated, interacts with aluminum. The reaction product was dissolved in dilute sulfuric acid, and potash was added to the resulting solution. Write down the equations for the reactions described.
5. The product of the interaction of sulfur with aluminum (the reaction proceeds with heating) was dissolved in cold dilute sulfuric acid and potassium carbonate was added to the solution. The formed precipitate was separated, mixed with sodium hydroxide and heated. Write down the equations for the reactions described.
6. To the solution of soda ash was added a solution of aluminum chloride, the separated substance was separated and introduced into the sodium hydroxide solution. A solution of hydrochloric acid was added dropwise to the resulting solution until the formation of a precipitate ceased, which was separated and calcined. Write down the equations for the reactions described.
7. Aluminum nitrate was calcined, the reaction product was mixed with soda ash and heated to melt. The resulting substance was dissolved in nitric acid and the resulting solution was neutralized with an ammonia solution, while the formation of a bulky gelatinous precipitate was observed. Write down the equations for the reactions described.
8. The precipitate obtained by adding caustic soda to the aluminum sulfate solution was separated, calcined, mixed with soda ash and heated to melting. After treating the residue with sulfuric acid, the starting aluminum salt was obtained. Write down the equations for the reactions described.
9. Aluminum chloride was added to the crystalline soda solution, the separated precipitate was separated and treated with sodium hydroxide solution. The resulting solution was neutralized with nitric acid, the separated precipitate was separated and calcined. Write down the equations for the reactions described.
10. The precipitate obtained by the interaction of a solution of an aluminum salt and an alkali was calcined. The reaction product was dissolved in a concentrated hot alkali solution. Carbon dioxide was passed through the resulting solution, resulting in the formation of a precipitate. Write down the equations for the reactions described.
11. The substance, which is formed during the electrolysis of bauxite melt in cryolite, dissolves both in a hydrochloric acid solution and in an alkali solution with the release of the same gas. When the resulting solutions are mixed, a white bulk precipitate is formed. Write down the equations for the reactions described.
12. A weighed portion of aluminum was dissolved in dilute nitric acid, and a gaseous simple substance was evolved. Sodium carbonate was added to the resulting solution until gas evolution completely ceased. The formed precipitate was filtered off and calcined. The filtrate was evaporated, the resulting solid residue was fused with ammonium chloride. The evolved gas was mixed with ammonia and the resulting mixture was heated. Write the equations of the described reactions
13. Alumina was fused with sodium carbonate and the resulting solid was dissolved in water. Sulfur dioxide was passed through the resulting solution until the interaction was completely terminated. The precipitate that formed was filtered off, and bromine water was added to the filtered solution. The resulting solution was neutralized with sodium hydroxide. Write down the equations for the reactions described.
14. A weighed portion of aluminum sulfide was treated with hydrochloric acid. In this case, gas was evolved and a colorless solution was formed. An ammonia solution was added to the resulting solution, and the gas was passed through a lead nitrate solution. The resulting precipitate was treated with a hydrogen peroxide solution. Write down the equations for the reactions described.
15. Aluminum powder was mixed with sulfur powder, the mixture was heated, the resulting substance was treated with water, gas evolved and a precipitate formed, to which an excess of potassium hydroxide solution was added until complete dissolution. This solution was evaporated and calcined. An excess of hydrochloric acid solution was added to the resulting solid. Write down the equations for the reactions described.
16. The gas released during the interaction of hydrogen chloride with berthollet's moth was introduced into the reaction with aluminum. The reaction product was dissolved in water and sodium hydroxide was added until the precipitation ceased, which was separated and calcined. Write down the equations for the reactions described.
17. The gas evolved by heating a solution of hydrogen chloride with manganese (IV) oxide was brought into interaction with aluminum. The reaction product was dissolved in water and first an excess of sodium hydroxide solution was added, and then hydrochloric acid. Write down the equations for the reactions described.
18. Metallic aluminum was dissolved in sodium hydroxide solution. An excess of carbon dioxide was passed through the resulting solution. The precipitate that formed was calcined, and the resulting product was fused with sodium carbonate. Write down the equations for the reactions described.
19) Aluminum oxide was fused with soda. The resulting product was dissolved in hydrochloric acid and treated with excess ammonia water. The precipitate that formed was dissolved in an excess of potassium hydroxide solution. Write down the equations for the reactions described.
20) Aluminum oxide was fused with sodium hydroxide. The reaction product was introduced into the ammonium chloride solution. The released gas with a pungent odor is absorbed by the sulfuric acid. The resulting middle salt was calcined. Write down the equations for the reactions described.
21) Aluminum powder was heated with sulfur powder, the resulting substance was treated with water. the precipitate that formed was treated with an excess of potassium hydroxide solution until it was completely dissolved. To the resulting solution was added a solution of aluminum chloride and again observed the formation of a white precipitate. Write down the equations for the reactions described.
22) The precipitate obtained by the interaction of solutions of aluminum sulfate and barium nitrate was filtered off. The filtrate was treated with sodium hydroxide in a molar ratio of 1: 3. The precipitate that formed was separated and calcined. The resulting material was treated with an excess of hydrochloric acid solution. Write down the equations for the reactions described.
23) When the aluminum sulfate solution interacts with the potassium sulfide solution, a gas was released, which was passed through the potassium hexahydroxoaluminate solution. The formed precipitate was filtered off, washed, dried and heated. The solid residue was fused with sodium hydroxide. Write down the equations for the reactions described.
24) Aluminum powder was mixed with sulfur and heated. The resulting substance was placed in water. The resulting precipitate was divided into two parts. Hydrochloric acid was added to one part, and sodium hydroxide solution to the other. Write down the equations for the reactions described.
25) Metallic aluminum was dissolved in sodium hydroxide solution. An excess of carbon dioxide was passed through the resulting solution. The precipitate that formed was calcined and the resulting product was dissolved in dilute sulfuric acid. Write down the equations for the reactions described.
26) The interaction of aluminum oxide and nitric acid formed a salt. The salt was dried and calcined. The residue formed during calcination was subjected to electrolysis in molten cryolite. The resulting metal was heated with concentrated potassium hydroxide and potassium nitrate. At the same time, a gas with a pungent odor was released. Write down the equations for the reactions described.
27) Aluminum powder was added to the sodium hydroxide solution. An excess of carbon dioxide was passed through the solution of the resulting substance. The formed precipitate was separated and calcined. The resulting product was fused with sodium carbonate. Write down the equations for the reactions described.
28) Powder of metallic aluminum was mixed with solid iodine, and a few drops of water were added. Sodium hydroxide solution was added to the resulting salt until a precipitate formed. The resulting precipitate was dissolved in hydrochloric acid. With the subsequent addition of the sodium carbonate solution, precipitation is again observed. Write down the equations for the reactions described.
29) Aluminum was dissolved in hydrochloric acid. An excess of potassium carbonate solution was added to the resulting solution. The precipitate that formed was dissolved in an excess of potassium hydroxide solution, and the released gas was passed over a hot coal. Write down the equations for the reactions described.
30) Aluminum was dissolved in an aqueous solution of hot sodium hydroxide. to the resulting solution was added dropwise dilute hydrochloric acid until the precipitation stopped. The gas evolved during the reaction period was passed over the red-hot copper (II) oxide. The resulting simple substance was dissolved in dilute nitric acid. Write down the equations for the reactions described.
31) Aluminum has reacted with. The resulting mixture of substances was dissolved in a concentrated solution of sodium hydroxide and filtered. The solid was burned under chlorine and the filtrate was treated with concentrated aluminum chloride solution. Write down the equations for the reactions described.
Aluminum. Aluminum compounds
1) 2Al + 3H 2 SO 4 = Al 2 (SO 4) 3 + 3H 2
Al 2 (SO 4) 3 + 6NaOH (deficiency) = 2Al (OH) 3 ↓ + 3Na 2 SO 4
2Al (OH) 3 Al 2 O 3 + 3H 2 O
2) Al 2 (SO 4) 3 + 8NaOH (excess) = 2Na + 3Na 2 SO 4
Na + НCl (deficiency) = Al (OH) 3 ↓ + NaCl + H 2 O
Al (OH) 3 + 3НCl = AlCl 3 + 3H 2 O
2AlCl 3 + 3Na 2 CO 3 + 3H 2 O = 2Al (OH) 3 ↓ + 6NaCl + 3CO 2
3) 2KMnO 4 + 16HCl = 2MnCl 2 + 5Cl 2 + 2KCl + 8H 2 O
2Na + Cl 2 = 2Al (OH) 3 ↓ + NaCl + NaClO + H 2 O
2Al (OH) 3 Al 2 O 3 + 3H 2 O
Al 2 O 3 + 6HCl = 2AlCl 3 + 3H 2 O
4) SO 2 + 2H 2 S = 3S ↓ + 2H 2 O
2Al + 3S = Al 2 S 3
Al 2 S 3 + H 2 SO 4 = Al 2 (SO 4) 3 + H 2 S
Al 2 (SO 4) 3 + 3K 2 CO 3 + 3H 2 O = 2Al (OH) 3 ↓ + 3CO 2 + 3K 2 SO 4
5) 2Al + 3S Al 2 S 3
Al 2 S 3 + 3H 2 SO 4 = Al 2 (SO 4) 3 + 3H 2 S
Al 2 (SO 4) 3 + 3K 2 CO 3 + 3H 2 O = 2Al (OH) 3 ↓ + 3CO 2 + 3K 2 SO 4
Al (OH) 3 + NaOH NaAlO 2 + 2H 2 O
6) 2AlCl 3 + 3Na 2 CO 3 + 3H 2 O = 2Al (OH) 3 ↓ + 6NaCl + 3CO 2
Na + HCl (deficiency) = Al (OH) 3 ↓ + NaCl + H 2 O
2Al (OH) 3 Al 2 O 3 + 3H 2 O
7) 4Al (NO 3) 3 2Al 2 O 3 + 12NO 2 + 3O 2
Al 2 O 3 + Na 2 CO 3 2NaAlO 2 + CO 2
NaAlO 2 + 4HNO 3 = Al (NO 3) 3 + NaNO 3 + 2H 2 O
Al (NO 3) 3 + 3 (NH 3 ∙ H 2 O) = Al (OH) 3 ↓ + 3NH 4 Cl
8) Al 2 (SO 4) 3 + 6NaOH = 2Al (OH) 3 ↓ + 3Na 2 SO 4
2Al (OH) 3 Al 2 O 3 + 3H 2 O
Al 2 O 3 + Na 2 CO 3 2NaAlO 2 + CO 2
2NaAlO 2 + 4H 2 SO 4 = Al 2 (SO 4) 3 + Na 2 SO 4 + 4H 2 O
9) 2AlCl 3 + 3Na 2 CO 3 + 3H 2 O = 2Al (OH) 3 ↓ + 6NaCl + 3CO 2
Al (OH) 3 + NaOH = Na
Na + HNO 3 (deficiency) = Al (OH) 3 ↓ + NaNO 3 + H 2 O
2Al (OH) 3 Al 2 O 3 + 3H 2 O
10) AlCl 3 + 3NaOH = Al (OH) 3 ↓ + 3NaCl
2Al (OH) 3 Al 2 O 3 + 3H 2 O
Al 2 O 3 + 2NaOH + 3H 2 O = 2Na
