Write the equations of reactions according to fire schemes 1) Calcium phosphate + bary chloride \u003d barium phosphate + calcium chloride 2) sodium carbonate + potassium nitrate \u003d carbonate

calcium + sodium nitrate 3) sulfuric acid + magnesium hydroxide \u003d magnesium sulfate + vatody 4) lithium oxide + hydrochloric acid \u003d lithium chloride + water 5) sulfur oxide (V1) + sodium hydroxide \u003d sodium sulfate + water 6) aluminum + bomber hydrochloric acid \u003d Aluminum bromide + hydrogen 7) Lead nitrate (11) + sodium sulphide \u003d lead sulfide (11) + silica acid 8) potassium silicate + phosphoric acid \u003d potassium phosphate + silica acid 9) zinc-iodine acid hydroxide \u003d zinc iodide + water 10) Nitrogen oxide (V) + sodium hydroxide \u003d netrat potassium + water 11) barium nitrate + sulfuric acid \u003d barium sulfate + nitric acid 12) carbon oxide (1V) -Hidroxide calcium \u003d calcium carbonate + water 13) sulfur oxide (1V) + oxide Potassium \u003d Potassium sulfate 14) magnesium oxide + phosphorus oxide (V) \u003d magnesium phosphate 15) nitric acid + chromium nitrate (111) \u003d chromium nitrate (111) + water 16) hydrogen sulfide acid + low silver sulfide + nitric acid 17) Iron oxide (111) + hydrogen \u003d iron + water 18) copper nitrate (11) + aluminum \u003d copper + aluminum nitrate 19) aluminum hydroxide \u003d aluminum oxide + water

a) sodium sodium hydroxide - sodium sulphide --- sodium chloride --- sodium sulfate b) magnesium --- magnesium sulfate --- magnesium hydroxide --- magnesium oxide - magnesium chloride

c) lead - lead oxide (II) - lead nitrate (II) - lead hydroxide (II) - lead oxide (II) Sulfate lead (II) d) sulfur --- hydrogen sulfide --- potassium sulfite Potassium chloride - potassium chloride - hydrochloride acid D) calcium - calcium hydroxide --- calcium carbonate - calcium nitrate - nitric acid E) aluminum - aluminum sulfate --- aluminum hydroxide --- aluminum oxide-- Aluminum nitrate) sulfur - sulfur oxide (IV) - Surface acid --- sodium sulfite - sulfuric acid h) oxygen - aluminum oxide - aluminum sulfate - aluminum hydroxide - sodium metalulum K) aluminum - chloride Aluminum - Nitrate aluminum - aluminum hydroxide - aluminum sulfate L) Copper - copper chloride (II) - copper - copper oxide (II) - copper (II) nitrate) iron - iron chloride (II) - Iron hydroxide (II) - iron sulfate (II) - iron H) Iron - iron chloride (III) - iron nitrate (III) - iron sulfate (III) - iron

1. The sodium carbonate aqueous solution reacts

1) potassium sulfate 3) copper sulphide (II)
2) Carbon Oxide (IV) 4) Silician Acid

2. With a solution of chloride barium reacts
1) calcium hydroxide 3) sodium sulfate
2) Hydroxide of copper (II) 4) hydrogen

3. With calcium nitrate solution reacts
1) sodium carbonate 3) silicon
2) zinc 4) bromomic acid

4. When interacting 1 mol and 2 mole KOH formed
1) medium salt 3) acid salt
2) basic salt 4) substances do not react

5. As a result of the reaction of sodium silicate with hydrochloric acid formed
1) Sodium Salicide 3) Silician Acid
2) silicon 4) silicon oxide

1. Salt and pocket form in the interaction of solutions
1)

2. With a solution of nitrate barium reacts
1) sodium chloride 3) potassium carbonate
2) Copper 4) calcium carbonate

3. With a solution of nitrate barium reacts
1) sodium sulfate 3) iron
2) chloride words 4) copper

4. With zinc sulfate solution reacts
1) Magnesium 3) sulfur
2) silicon oxide 4) aluminum hydroxide

5. Chemical reaction (in solution) is possible between

6) Between what substances is the chemical reaction?
1) calcium carbonate and sodium nitrate
2) Magnesium silicate and potassium phosphate
3) Iron sulfate (II) and lead sulfide
4) barium chloride and zinc sulfate

1. 2H 2SO 4 (conc.) + Cu \u003d Cuso 4 + SO 2 + 2H 2O

media sulfate

H 2SO 4 (RSC) + Zn \u003d ZNSO 4 + H 2
zinc sulfate
2. FEO + H 2 \u003d Fe + H 2O
Cuso 4 + Fe \u003d Cu ↓ + Feso 4

3. Sotatim nitric acid salts:
nitric acid formula HNO3 Acid residue NO3- - nitrate
Formulas for salts:
Na + NO3- Solubility Table Determine the charges of ions. Since Sodium ion and nitrate ion have charges "+" and "-", respectively, the indices in this formula are unnecessary. It will turn out this formula:
NA + NO3- - Sodium Nitrate
CA2 + NO3- - on the solubility table Determine the charges of ions. According to the rule of the Cross, we put the indices, but since Nitrate-ion is a complex ion with a charge "-", then it is necessary to take it in brackets:
CA2 + (NO3) -2 - calcium nitrate
Al3 + NO3- - on the solubility table Determine the charges of ions. According to the rule of the Cross, we put the indices, but since Nitrate-ion is a complex ion with a charge "-", then it is necessary to take it in brackets:
Al3 + (NO3) -3 - aluminum nitrate
further metals
zinc chloride ZnCl2.
aluminum nitrate Al (NO3) 3

Copper (CU) refers to the D-elements and is located in the IB group of the Periodic Table of D.I. Iveleeva. The electronic configuration of the copper atom is basically written by 1S 2 2 2 2P 6 3P 6 3P 6 3P 6 34 4S 1, instead of the intended formula 1S 2 2S 2 2p 6 3S 2 3P 6 3D 9 4S 2. In other words, in the case of a copper atom, there is a so-called "deposit of an electron" with a 4S-suite on a 3D-sublevel. For copper, except for zero, the degrees of oxidation are possible +1 and +2. The degree of oxidation is +1 prone to disproportionation and is stable only in insoluble compounds of the Cui, CUCl, Cu 2 O, etc., as well as in complex compounds, for example, CL and OH. Copper compounds in the degree of oxidation +1 do not have a specific color. Thus, the copper oxide (I), depending on the size of the crystals, may be dark red (large crystals) and yellow (small crystals), CUCL and CUI - White, and Cu 2 S - black and blue. More chemically stable is the degree of copper oxidation, equal to +2. Salts containing copper in a given oxidation, have a blue and blue-green color.

Copper is a very soft, damp and plastic metal with high electric and thermal conductivity. Coloring metal copper red-pink. Copper is located in a row of metals to the right of hydrogen, i.e. refers to low-active metals.

with oxygen

Under normal conditions, copper with oxygen does not interact. To leak the reaction between them, heating is required. Depending on the excess or lack of oxygen and the temperature conditions, the oxide of copper (II) and copper oxide (I) may form:

with gray

The sulfur reaction with copper, depending on the conditions of the conduct, can lead to the formation of both copper (I) sulfide and copper sulfide (II). When the mixture of powdered Cu and S is heated to a temperature of 300-400 o C, the sulphide of copper (I) is formed:

With a lack of sulfur and carrying out the reaction at a temperature of more than 400 o C, sulphide copper (II) is formed. However, a simpler method for producing copper (II) sulfide from simple substances is the interaction of copper with gray, dissolved in the servo carbon:

This reaction proceeds at room temperature.

with halogen

With fluorine, chlorine and bromine, copper reacts, forming halides with the general formula Cuhal 2, where HAL - F, CL or Br:

CU + BR 2 \u003d CUBR 2

In the case of iodine - the weakest oxidizing agent among halogen - the copper (I) iodide is formed:

With hydrogen, nitrogen, carbon and silicon, copper does not interact.

with non-acid acids

The non-acid acids are almost all acids, in addition to concentrated sulfuric acid and nitric acid of any concentration. Since the acid-non-acidic acids are able to oxidize only metals in a row of activity to hydrogen; This means that copper with such acids does not react.

with oxidizing acids

- concentrated sulfuric acid

With concentrated sulfuric acid, copper reacts both when heated and at room temperature. When heated, the reaction proceeds in accordance with the equation:

Since copper is not a strong reducing agent, sulfur is restored in this reaction only to the degree of oxidation +4 (in SO 2).

- with dilute nitric acid

Copper reaction with dilute HNO 3 leads to the formation of copper (II) nitrate and nitrogen monoxide:

3CU + 8HNO 3 (RSC) \u003d 3CU (NO 3) 2 + 2NO + 4H 2 O

- with concentrated nitric acid

Concentrated HNO 3 easily reacts with copper under normal conditions. The difference between the reaction of copper with a concentrated nitric acid from reacting with dilute nitric acid is a nitrogen recovery product. In the case of concentrated HNO 3, nitrogen is reduced to a lesser extent: instead of nitrogen oxide (II), nitrogen oxide (IV) is formed, which is associated with greater competition between nitric acid molecules in concentrated acid for reducing electrons (CU):

Cu + 4hno 3 \u003d Cu (NO 3) 2 + 2NO 2 + 2H 2 O

with non-metal oxides

Copper reacts with some non-metal oxides. For example, with such oxides, as NO 2, NO, N 2 O, copper is oxidized to copper oxide (II), and nitrogen is reduced to the degree of oxidation 0, i.e. A simple substance N 2 is formed:

In the case of sulfur dioxide, instead of a simple substance (sulfur), copper sulphide (I) is formed. This is due to the fact that copper with sulfur, unlike nitrogen, reacts:

with metals oxides

When sintering metal copper with copper oxide (II) at a temperature of 1000-2000 oxide, copper (I) can be obtained:

Also, metal copper can restore when calcining iron (III) oxide to iron (II) oxide:

with salts of metals

Copper displaces less active metals (rightly in a row of activity) from solutions of their salts:

Cu + 2AGNO 3 \u003d Cu (NO 3) 2 + 2AG ↓

An interesting reaction also takes place in which the copper dissolves into the salts of a more active metal - iron to the degree of oxidation +3. However, there are no contradictions, because Copper does not displaces iron from its salt, but only restores it with the degree of oxidation +3 to the degree of oxidation +2:

Fe 2 (SO 4) 3 + Cu \u003d Cuso 4 + 2feso 4

CU + 2FECL 3 \u003d CUCL 2 + 2FECL 2

The latter reaction is used in the production of microcircuits at the stage of etching copper boards.

Corrosion of media

Copper over time exposed to corrosion when contact with moisture, carbon dioxide and air oxygen:

2CU + H 2 O + CO 2 + O 2 \u003d (CuoN) 2 \u200b\u200bCO 3

As a result of the flow of this reaction, the copper products are coated with a loose blue-green mold of copper hydroxocarbonate (II).

Chemical properties zinc

Zinc Zn is located in the IIB period of the IV period. Electronic configuration of valence orbitals of the atoms of the chemical element in the main state of 3D 10 4S 2. For zinc, only one single oxidation degree is possible, equal to +2. ZnO zinc oxide and zinc hydroxide Zn (OH) 2 have pronounced amphoteric properties.

Zinc when storing on the air fades, covering the thin layer of ZnO oxide. Especially easily oxidation occurs at high humidity and in the presence of carbon dioxide due to the reaction flow:

2ZN + H 2 O + O 2 + CO 2 → Zn 2 (OH) 2 CO 3

Zinc pairs burns in air, and the thin zinc strip after incandescent in the burner flame burns in it with a greenish flame:

When heated, the metallic zinc also interacts with halogens, gray, phosphorus:

With hydrogen, nitrogen, carbon, silicon and boron, zinc does not directly react.

Zinc reacts with non-oxidant acids with hydrogen release:

Zn + H 2 SO 4 (20%) → ZNSO 4 + H 2

Zn + 2hcl → ZnCl 2 + H 2

Technical zinc is particularly soluble in acids, since it contains impurities of other less active metals, in particular, cadmium and copper. High-grade zinc for certain reasons is resistant to the effects of acids. In order to accelerate the reaction, the zinc sample is highly purity result in contact with copper or add a slight copper salt into a solution.

At a temperature of 800-900 o C (red casing), the metallic zinc, being in the molten state, interacts with a superheated water vapor, highlighting hydrogen from it:

Zn + H 2 O \u003d Zno + H 2

Zinc also reacts with oxidizing acids: sulfur concentrated and nitric.

Zinc as an active metal can form with concentrated sulfuric acid sulfur gas, elementary sulfur and even hydrogen sulfide.

Zn + 2H 2 SO 4 \u003d ZNSO 4 + SO 2 + 2H 2 O

The composition of nitric acid reduction products is determined by the solution concentration:

Zn + 4hno 3 (conc.) \u003d Zn (NO 3) 2 + 2NO 2 + 2H 2 O

3ZN + 8HNO 3 (40%) \u003d 3ZN (NO 3) 2 + 2NO + 4H 2 O

4ZN + 10HNO 3 (20%) \u003d 4ZN (NO 3) 2 + N 2 O + 5H 2 O

5ZN + 12HNO 3 (6%) \u003d 5ZN (NO 3) 2 + N 2 + 6H 2 O

4ZN + 10HNO 3 (0.5%) \u003d 4ZN (NO 3) 2 + NH 4 NO 3 + 3H 2 O

The temperature, the amount of acid, the purity of the metal, the reaction time is also affected by the direction of the process of proceedings.

Zinc reacts with alkalis solutions, and formed tetrahydroxyzinkata and hydrogen:

Zn + 2NaOH + 2H 2 O \u003d Na 2 + H 2

Zn + Ba (OH) 2 + 2H 2 O \u003d Ba + H 2

With anhydrous alkalis zinc when fusing forms cincatas and hydrogen:

In the strongshop medium, zinc is an extremely strong reducing agent capable of restoring nitrogen in nitrates and nitrites to ammonia:

4ZN + Nano 3 + 7NAOH + 6H 2 O → 4NA 2 + NH 3

Due to complexation, zinc is slowly dissolved in ammonia solution, restoring hydrogen:

Zn + 4NH 3 · H 2 O → (OH) 2 + H 2 + 2H 2 O

Also zinc reduces less active metals (right in a row of activity) from aqueous solutions of their salts:

Zn + Cucl 2 \u003d Cu + ZnCl 2

Zn + Feso 4 \u003d Fe + ZNSO 4

Chemical properties chromium

Chrome - Mendeleeva Table Group element VIB. The electronic configuration of the chromium atom is written as 1S 2 2S 2 2P 6 3S 2 3P 6 3D 5 4S 1, i.e. In the case of chromium, as in the case of copper atom, there is a so-called "deposit of an electron"

The most commonly manifested degrees of chromium oxidation are +2, +3 and +6 values. They should be remembered, and within the framework of the program of the Chemistry program, it can be considered that there are no other degrees of oxidation chrome.

Under normal conditions, chromium is resistant to corrosion in both air and water.

Interaction with non-metals

with oxygen

Reducked up to temperature more than 600 o with powdered metal chromium burns in pure oxygen forming chromium (III) Occid:

4Cr + 3O 2 \u003d o. t.\u003d\u003e 2Cr 2 O 3

with halogen

With chlorine and fluorine chromium reacts at lower temperatures than with oxygen (250 and 300 o C, respectively):

2CR + 3F 2 \u003d o. t.\u003d\u003e 2CRF 3

2CR + 3CL 2 \u003d o. t.\u003d\u003e 2CrCl 3

The bromine chromium reacts at a temperature of red cagine (850-900 o C):

2Cr + 3Br 2 \u003d o. t.\u003d\u003e 2CrBr 3

with nitrogen

With nitrogen, the metal chromium interacts at temperatures of more than 1000 o C:

2Cr + N 2 \u003d O.t.\u003d\u003e 2CRN.

with gray

With a gray chrome can form both chromium sulphide (II) and chromium sulphide (III), which depends on the proportions of sulfur and chromium:

CR + S \u003d o T.\u003d\u003e CRS.

2CR + 3S \u003d o T.\u003d\u003e CR 2 S 3

With hydrogen chromium does not react.

Interaction with complex substances

Interaction with water

Chromium refers to metals of medium activity (located in a number of metal activity between aluminum and hydrogen). This means that the reaction proceeds between chrome-hot crown and superheated water vapor:

2CR + 3H 2 O \u003d o T.\u003d\u003e CR 2 O 3 + 3H 2

Interaction with acids

Chromium under normal conditions is passivated by concentrated sulfur and nitric acids, however, dissolves in them when boiling, while oxidizing to the degree of oxidation +3:

CR + 6HNO 3 (conc.) \u003d t O.\u003d\u003e CR (NO 3) 3 + 3NO 2 + 3H 2 O

2CR + 6H 2 SO 4 (concluding) \u003d t O.\u003d\u003e CR 2 (SO 4) 3 + 3SO 2 + 6H 2 O

In the case of dilute nitric acid, the main product of nitrogen reduction is a simple substance N 2:

10CR + 36HNO 3 (RSC) \u003d 10CR (NO 3) 3 + 3N 2 + 18H 2 O

Chrome is located in a row of activity to the left of hydrogen, which means that it is able to extract H 2 from non-acid acid solutions. During such reactions, chromium (II) salts are formed in the absence of air oxygen.

CR + 2HCl \u003d CRCl 2 + H 2

CR + H 2 SO 4 (RSC) \u003d CRSO 4 + H 2

During the reaction in the open air, the bivalent chrome is instantly oxidized in the air in the air to the degree of oxidation +3. In this case, for example, an equation with hydrochloric acid will take the form:

4CR + 12HCl + 3O 2 \u003d 4CrCl 3 + 6H 2 O

When fusing metal chromium with strong oxidizers in the presence of alkalishes, chromium is oxidized to the degree of oxidation +6, forming Chromat:

Chemical properties of iron

Iron FE, chemical element located in the VIIIB group and having sequence number 26 in the Mendeleev table. The distribution of electrons in the iron atom is the following 26 Fe1S 2 2S 2 2P 6 3S 2 3P 6 3D 6 4S 2, that is, iron refers to D-elements, since the D-sublayer is filled in it. It is most characteristic of two degrees of oxidation +2 and +3. The FEO oxide and hydroxide Fe (OH) 2 prevail basic properties, in oxide Fe 2 O 3 and FE hydroxide (OH) 3 are noticeably expressed amphoteric. So the oxide and hydroxide of iron (LLL) to some extent dissolve when boiling in concentrated solutions by alkalis, and also react with anhydrous alkalis when fusing. It should be noted that the degree of oxidation of iron +2 is very unstable, and easily passes into the degree of oxidation +3. Also known iron compounds in a rare degree of oxidation is +6 - ferrats, salts of non-existing "iron acid" H 2 FeO 4. These compounds are relatively resistant only in a solid state or in strongly alkaline solutions. In case of insufficient alkalinity, the ferrates are quite quickly oxidized even water, highlighting oxygen from it.

Interaction with ordinary substances

With oxygen

When combustion in pure oxygen, iron forms the so-called, iron okalinahaving the FE 3 O 4 formula and actually represents a mixed oxide, the composition of which can be conventionally possible to represent the FEO ∙ FE 2 O 3 formula. Iron combustion reaction is:

3Fe + 2O 2 \u003d t O.\u003d\u003e Fe 3 O 4

With gray

When heated iron reacts with gray, forming a bivalent iron sulfide:

Fe + S \u003d t O.\u003d\u003e Fes.

Or with an excess of sulfur disulfide Iron:

Fe + 2S \u003d t O.\u003d\u003e Fes 2

With halogen

All halogens, in addition to iodine, metal iron is oxidized to the degree of oxidation +3, forming iron halides (LLL):

2fe + 3F 2 \u003d t O.\u003d\u003e 2FEF 3 - iron fluoride (LLL)

2fe + 3Cl 2 \u003d t O.\u003d\u003e 2FeCl 3 - iron chloride (LLL)

The same as the weak oxidizer among halogens, oxidizes iron only to the degree of oxidation +2:

Fe + i 2 \u003d t O.\u003d\u003e Fei 2 - Iodide Iron (LL)

It should be noted that the compounds of trivalent iron easily oxidize iodide ions in aqueous solution to free iodine I 2 at the same time restoring to the degree of oxidation +2. Examples of similar reactions from FIPI Bank:

2FeCl 3 + 2Ki \u003d 2FeCl 2 + i 2 + 2KCL

2fe (OH) 3 + 6Hi \u003d 2Fei 2 + I 2 + 6H 2 O

Fe 2 O 3 + 6Hi \u003d 2FEI 2 + I 2 + 3H 2 O

With hydrogen

Iron with hydrogen does not react (with hydrogen from metals only alkaline metals and alkaline earth) react:

Interaction with complex substances

Interaction with acids

With non-acid acids

Since iron is located in a number of activity of the left of the hydrogen, it means that it is capable of exhibiting hydrogen from non-oxidant acids (almost all acids except H 2 SO 4 (conc.) And HNO 3 of any concentration):

Fe + H 2 SO 4 (RSC) \u003d FESO 4 + H 2

Fe + 2HCl \u003d FECL 2 + H 2

It is necessary to pay attention to such a trick in the assignments of the exam, as a question on how much oxidation is oxidized by iron under the action of dilute and concentrated hydrochloric acid. The correct answer is to +2 in both cases.

The trap here lies in the intuitive waiting for the deeper oxidation of iron (to C.O. +3) in case of its interaction with concentrated hydrochloric acid.

Interaction with oxidizing acids

With concentrated sulfuric and nitric acids under normal conditions, iron does not respond due to passivation. However, reacts with them when boiling:

2fe + 6h 2 SO 4 \u003d o T.\u003d\u003e Fe 2 (SO 4) 3 + 3SO 2 + 6H 2 O

Fe + 6hno 3 \u003d o T.\u003d\u003e Fe (NO 3) 3 + 3NO 2 + 3H 2 O

Note that dilute sulfuric acid oxidizes iron to the degree of oxidation +2, and concentrated to +3.

Corrosion (Rust) Iron

On the wet air, the iron is very rapidly subjected to rust:

4Fe + 6H 2 O + 3O 2 \u003d 4FE (OH) 3

With water in the absence of oxygen, iron does not react or under normal conditions, nor by boiling. The reaction with water proceeds only at temperatures above the temperature of the red casting (\u003e 800 o C). those..

I.V.Pigubchak

Chemistry Tutor Manual

Continued. Beginning, see No. 22/2005; 1, 2, 3, 5, 6, 8, 9, 11, 13, 15, 16, 18, 22/2006;
3, 4, 7, 10, 11, 21/2007;
2, 7, 11/2008

Lesson 24.

10th grade (first year of study)

Zinc and its connections

1. Position in Table D.I. Imendeeva, the structure of the atom.

2. The origin of the name.

3. Physical properties.

4. Chemical properties.

5. Finding in nature.

6. Basic methods of obtaining.

7. Oxide and zinc hydroxide - properties and methods of obtaining.

Zinc is located in a side subgroup of the II group of Table D.I. Mendeleev. His electronic formula 1 s. 2 2s. 2 p. 6 3s. 2 p. 6 d. 10 4s. 2. Zinc is d.-Element, manifested in compounds the only degree of oxidation is +2 (because the third energy level in the zinc atom is completely filled with electrons). Being an amphoteric element with a predominance of metal properties, in compounds zinc more often included in the composition of the cation, less often an anion. For example,

It is assumed that the name of the zinc comes from the ancient Germanic word "Qinko" (White, Belmo). In turn, this word dates back to the Arabic "Harasin" (metal from China), which indicates the place of development of zinc, brought to the Middle Ages to Europe from China.

F and Z and C and C and E S B O S T in A

Zinc - white metal; On the air is covered with an oxide film, and its surface fades. In the cold, this is a rather fragile metal, but at a temperature of 100-150 ° C, the zinc is easily processed, forms alloys with other metals.

Chemical properties

Zinc is a metal of medium chemical activity, however it is more active than iron. Zinc After the destruction of the oxide film, the following chemical properties manifest.

Zn + H 2 znh 2.

2ZN + O 2 2ZNO.

Metals (-).

Non-metals (+):

Zn + Cl 2 ZnCl 2,

3ZN + 2P Zn 3 P 2.

Zn + 2H 2 O Zn (OH) 2 + H 2.

Main oxides (-).

Acid oxides (-).

Basins (+):

Zn + 2NAOH + 2H 2 O \u003d Na 2 + H 2,

Zn + 2NAOH (melt) \u003d Na 2 ZnO 2 + H 2.

Acid non-oxidants (+):

Zn + 2HCl \u003d ZnCl 2 + H 2.

Acid-oxidizing agents (+):

3ZN + 4H 2 SO 4 (conc.) \u003d 3ZNSO 4 + S + 4H 2 O.

4ZN + 5H 2 SO 4 (conc.) \u003d 4ZNSO 4 + H 2 S + 4H 2 O,

4ZN + 10HNO 3 (Pts. Racks.) \u003d 4zn (NO 3) 2 + NH 4 NO 3 + 3H 2 O.

Salts (+/-): *

Zn + CuCl 2 \u003d Cu + ZnCl 2,

Zn + NaCl no reaction.

In PR and R o d E e zinc occurs in the form of compounds, the most important of which are sphalerite, or zinc destruction (ZNS), Smitstonitis, or zinc sword (ZnCO 3), red zinc ore (ZnO).

In the industry, the zinc is produced by zinc ore firing in order to obtain zinc oxide, which is then restored by carbon:

2ZNS + 3O 2 2ZNO + 2SO 2,

2ZNO + C2ZN + CO 2.

The most important compounds of zinc include its O to C and D (ZnO) and G and D R O K C and D (Zn (OH) 2). These are crystalline substances of white, manifests amphoteric properties:

Zno + H 2 SO 4 \u003d ZNSO 4 + H 2 O,

Zno + 2NaOH + H 2 O \u003d Na 2,

Zn (OH) 2 + 2HCl \u003d ZnCl 2 + 2H 2 O,

Zn (OH) 2 + 2NAOH \u003d Na 2.

Zinc oxide can be obtained by zinc oxidation, decomposition of zinc hydroxide or zinc debris flavors:

Zn (OH) 2 Zno + H 2 O,

2ZNS + 3O 2 2ZNO + 3SO 2.

Zinc hydroxide is obtained by the exchange reaction between zinc salt and alkali salt:

ZnCl 2 + 2NAOH (disadvantage) \u003d Zn (OH) 2 + 2NACL.

These compounds are n and t: zinc destruction (ZNS), zinc canopy (ZNSO 4 7H 2 O).

Test on the topic "Zinc and its connections"

1. The sum of the coefficients in the zinc reaction equation with a very diluted nitric acid:

a) 20; b) 22; c) 24; d) 29.

2. Zinc from the concentrated sodium carbonate solution displaces:

a) hydrogen; b) ditch gas;

c) carbon dioxide; d) methane.

3. Alkali solutions can react with the following substances (there are several correct answers):

a) copper sulfate and chlorine;

b) calcium oxide and copper;

c) sodium and zinc hydrosulfate;

d) zinc hydroxide and copper hydroxide.

4. The density of the 27.4% sodium hydroxide solution is 1.3 g / ml. The molar concentration of alkali in this solution is:

a) 0.0089 mol / ml; b) 0.0089 mol / l;

c) 4 mol / l; d) 8,905 mol / l.

5. To obtain zinc hydroxide, it is necessary:

a) dropped the sodium hydroxide solution to the zinc chloride solution;

b) dropped drops with zinc chloride solution to sodium hydroxide solution;

c) pour the excess solution of sodium hydroxide to the zinc chloride solution;

d) drops to add sodium hydroxide solution to zinc carbonate solution;

6. Exclude "superfluous" connection:

a) h 2 zno 2; b) ZnCl 2; c) zno; d) Zn (OH) 2.

7. The alloy of copper and zinc weighing 24.12 g was treated with an excess of diluted sulfuric acid. At the same time, there were 3.36 liters of gas (N.U.). The mass fraction of zinc in this alloy is equal to (in%):

a) 59,58; b) 40.42; c) 68,66; d) 70.4.

8. Zinc granules will interact with an aqueous solution (several correct answers are possible):

a) hydrochloric acid; b) nitric acid;

c) potassium hydroxide; d) aluminum sulfate.

9. Carbon dioxide with a volume of 16.8 liters (N.U.) was absorbed by 400 g of 28% of potassium hydroxide solution. The mass fraction of the substance in the solution is (in%):

a) 34.5; b) 31.9; c) 69; d) 63.7.

10. The mass of a zinc carbonate sample, which contains 4.816 10 24 oxygen atoms, is equal to (in g):

a) 1000; b) 33.3; c) 100; d) 333.3.

The key to the test

1	2	3	4	5	6	7	8	9	10
b.	but	a, B.	g.	but	b.	b.	a B C D	b.	g.

Tasks and exercises for amphoteric metals

Chains of transformations

1. Zinc -\u003e zinc oxide -\u003e zinc hydroxide -\u003e zinc sulfate -\u003e zinc chloride -\u003e zinc nitrate -\u003e zinc sulfide -\u003e zinc oxide -\u003e zincat potassium.

2. Aluminum oxide -\u003e Potassium tetrahydroxalulum -\u003e Aluminum chloride -\u003e Aluminum hydroxide -\u003e Potassium tetrahydroxide.

3. Sodium -\u003e sodium hydroxide -\u003e sodium bicarbonate -\u003e sodium carbonate -\u003e sodium hydroxide -\u003e hexagidroxchromate (III) sodium.

4. Chromium -\u003e chromium chromium (II) -\u003e chromium chromium (III) -\u003e hexagidroxchromate (III) potassium + bromine + potassium hydroxide -\u003e potassium chromat -\u003e Dichromate potassium -\u003e Chromium oxide (VI).

5. Iron sulphide (II) -\u003e x 1 -\u003e Iron oxide (III) -\u003e x 2 -\u003e iron sulfide (II).

6. Iron chloride (II) -\u003e A -\u003e B -\u003e B -\u003e G -\u003e D -\u003e chloride of iron (II) (all substances contain iron; in the scheme only three oxidative reaction reactions in a row).

7. Chrome -\u003e x 1 -\u003e chromium sulfate (III) -\u003e x 2 -\u003e Dichromate potassium -\u003e x 3 -\u003e chrome.

U r o v e n b a

1. To dissolve 1.26 g of magnesium alloy with aluminum used 35 ml of 19.6% sulfuric acid solution (density - 1.14 g / ml). Excess an acid reacted with a 28.6 ml of potassium bicarbonate solution with a concentration of 1.4 mol / l. Determine the composition of the initial alloy and the volume of gas (N.U.), which was distinguished when the alloy is dissolved.

Answer.57.6% MG; 42.4% Al; 1.34 L H 2.

2. A mixture of calcium and aluminum weighing 18.8 g was carried out without air access with an excess of graphite powder. The reaction product was treated with dilute hydrochloric acid, while 11.2 liters of gas (N.U.) were separated. Determine the composition of the initial mixture.

Decision

Reaction equations:

Let (CA) \u003d x. Mol, (AL) \u003d 4 y. mole.

Then: 40. x. + 4 27y. = 18,8.

Under the condition of the problem:

v (C 2 H 2 + SH 4) \u003d 11.2 liters.

Hence,

(C 2 H 2 + SH 4) \u003d 11.2 / 22.4 \u003d 0.5 mol.

By the reaction equation:

(C 2 H 2) \u003d (CAC 2) \u003d (SA) \u003d h. mole

(CH 4) \u003d 3/4 (AL) \u003d 3 y. mole

x. + 3y. = 0,5.

We solve the system:

x. = 0,2, y. = 0,1.

Hence,

(Ca) \u003d 0.2 mol,

(AL) \u003d 4 0.1 \u003d 0.4 mol.

In the original mixture:

m.(Ca) \u003d 0.2 40 \u003d 8 g,

(Ca) \u003d 8 / 18.8 \u003d 0.4255, or 42.6%;

m.(AL) \u003d 0.4 27 \u003d 10.8 g,

(AL) \u003d 10.8 / 18.8 \u003d 0.5744, or 57.4%.

Answer. 42.6% CA; 57.4% Al.

3. With the interaction of 11.2 g of metal VIII of the group of periodic system with chlorine, 32.5 g of chloride was formed. Determine the metal.

Answer. Iron.

4. When firing pyrite, 25 m 3 of sulfur gas was released (temperature 25 ° C and pressure 101 kPa). Calculate the mass of the solid formed at the same time.

Answer. 40.8 kg Fe 2 O 3.

5. When calculating 69.5 g of iron sulfate crystalline (II), 38 g of anhydrous salt is formed. Determine the formula of the crystallohydrate.

Answer. FESO 4 7H 2 O. heptahydrate

6. Under the action of an excess of hydrochloric acid per 20 g of a mixture containing copper and iron, gas was distinguished with a volume of 3.36 liters (N.U.). Determine the composition of the initial mixture.

Answer. 58% Cu; 42% FE.

U r o v e n b b

1. What volume of the 40% solution of potassium hydroxide (density - 1.4 g / ml) should be added to 50 g 10% of the aluminum chloride solution so that the initial precipitate is completely dissolved?

Answer. 15 ml.

2. The metal was burned in oxygen to form 2.32 g of oxide, to restore which it is necessary to spend 0.896 l (N.O.) of carbon monoxide to the metal. The reduced metal was dissolved in dilute sulfuric acid, the resulting solution gives a blue precipitate with red blood saline. Determine the formula of oxide.

Answer:Fe 3 O 4.

3. What volume 5.6 m of potassium hydroxide solution will be required for complete dissolution of 5 g of a mixture of chromium hydroxides (III) and aluminum, if the mass fraction of oxygen in this mixture is 50% equal to 50%?

Answer. 9.3 ml.

4. To a 14% solution of chromium nitrate (III), sodium sulfide was added, the resulting solution was filtered and boiled (without water loss), while the mass fraction of chromium salt decreased to 10%. Determine the mass fractions of the remaining substances in the resulting solution.

Answer. 4.38% Nano 3.

5. A mixture of iron (II) chloride with potassium dichromate was dissolved in water and acidified with a solution with hydrochloric acid. After some time, an excess solution of potassium hydroxide was added to the solution dropwise, the precipitate was filtered and pulled to constant mass. The mass of the dry residue is 4.8 g. Find the mass of the original mixture of salts, given that the mass fractions of iron (II) chloride and the potassium dichromate in it refer to as 3: 2.

Answer. 4.5 g

6. 139 g of iron vitrios was dissolved in water at a temperature of 20 ° C and a saturated solution was obtained. When cooling this solution to 10 ° C, the sediment of the Iron Epiphany. Find a mass of the precipitate and the mass fraction of iron (II) sulfate in the remaining solution (solubility of iron sulfate (II) at 20 ° C is 26 g, and at 10 ° C - 20 g).

Answer. 38.45 g FESO 4 7H 2 O; 16.67%.

Qualitative tasks

1. Silver-white light simple substance A, which has good heat and electrical conductivity, reacts when heated with another simple substance V. The sampled solid is dissolved in acids with the separation of gas C, with a transmittance of a substance V. Identify through a solution of sulfuric acid. Substances, write the equations of reactions.

Answer.Substances: A - Al, B - S, C - H 2 S.

2. There are two gas - a and B, whose molecules are tried. When each of them is added to the solution of potassium aluminate drops out. Offer possible formulas Gas A and B, given that these binary gases. Write the reactions equations. How can this gases be distinguished by chemical?

Decision

Gas A - CO 2; Gas B - H 2 S.

2kalo 2 + CO 2 + 3H 2 O \u003d 2AL (OH) 3 + K 2 CO 3,

2kalo 2 + H 2 S + 2H 2 O \u003d 2AL (OH) 3 + K 2 S.

3. Insoluble in water compound and brown color when heated decomposes with the formation of two oxides, one of which is water. Another oxide - B is restored by carbon with the formation of metal with, the second prevalence in nature among metals. Identify substances, write the equations of reactions.

Answer.Substances: A - FE (OH) 3,
B - Fe 2 O 3, C - Fe.

4. Salt A is formed by two elements, two oxide is formed in the air in the air: B is solid, brown, and gaseous. The oxide in react is reacting with silver-white metal with (when heated). Identify substances, write the equations of reactions.

Answer.Substances: A - FES 2, B - FE 2 O 3, C - Al.

* Sign +/- Indicates that this reaction proceeds not with all reagents or in specific conditions.

To be continued

Zinc alloy with copper - brass - was famous in ancient Greece, ancient Egypt, India (VII century), China (XI century). For a long time, it was not possible to allocate pure zinc. In 1746 A. S. Marggrant developed a method for producing pure zinc by calcining a mixture of its oxide with coal without access to clay refractory retorts, followed by condensation of zinc vapor in refrigerators. On an industrial scale, zinc gas began in the XVII century.
Latin zincum is translated as a "white flask". The origin of this word is definitely not established. Presumably, it goes from the Persian "Cheng", although this name refers not to the zinc, but in general to stones. The word "zinc" is found in the writings of paracetes and other researchers 16-17 centuries. And rises, perhaps, to the ancient German "Qinko" - raid, Belmo on the eye. The name "Zinc" became commonly used in the 1920s.

Finding in nature, receipt:

The most common zinc mineral is sphalerite, or zinc cheating. The main component of the mineral is zinc sulphide ZNS, and various impurities give this substance all sorts of colors. Apparently, for this mineral and is called a sniffer. The zinc deck is considered to be the primary mineral from which other minerals of element No. 30 were formed: Znco 3, ZnO cylint, Kalamin 2ZNO · SiO 2 · H 2 O. In Altai, it is often possible to meet the striped "burglar" ore - a mixture of zinc and brown spam. A piece of such ores made up really similar to the hidden animal.
The release of zinc begins with the concentration of ore by methods of sedimentation or flotation, then it is burned to the formation of oxides: 2ZNS + 3O 2 \u003d 2ZNO + 2SO 2
Zinc oxide is processed by electrolytic method or restore coke. In the first case, zinc leached from raw oxide dilute sulfuric acid solution, the intake of cadmium is precipitated with zinc dust and zinc sulfate solution is subjected to electrolysis. Metal 99.95% purity is deposited on aluminum cathodes.

Physical properties:

In its pure form - a rather plastic silver-white metal. At room temperature of the fragile, when the plate is bent, crackle from friction of crystallites is heard (usually stronger than the "tin cry"). At 100-150 ° C zinc plastic. Impurities, even minor, dramatically increase the fragility of zinc. Melting point - 692 ° C, Boiling point - 1180 ° C

Chemical properties:

Typical amphoter metal. Standard electrode potential is -0.76 V, in a number of standard potentials is located to iron. The zinc air is covered with a thin zno oxide film. With strong heating burns. When zinc heats up with halogens, with phosphorus, forming the phosphide Zn 3 P 2 and Znp 2, with gray and its analogues, forming various chalcogenides, ZNS, ZNSE, ZNSE 2 and ZNTE. With hydrogen, nitrogen, carbon, silicon and boron, zinc does not directly react. Zn 3 n 2 nitride is obtained by a zinc reaction with ammonia at 550-600 ° C.
Zinc conventional purity actively reacts with acid solutions and alkalis, forming in the latter case hydroxycycins: Zn + 2NaOH + 2H 2 O \u003d Na 2 + H 2
Very pure zinc solutions of acids and alkalis does not respond.
For zinc is characterized by compound with the degree of oxidation: +2.

Major compounds:

Zinc oxide - Zno, white, amphoterous, reacts with both acid solutions and alkalis:
Zno + 2NaOH \u003d Na 2 ZnO 2 + H 2 O (Flow).
Zinc hydroxide - It is formed in the form of a journalist white precipitate when adding alkali to aqueous solutions of zinc salts. Amphoteric hydroxide
Zinc salt. Colorless crystalline substances. In aqueous solutions, zinc ions Zn 2+ form an aquacomplexes 2+ and 2+ and are subjected to strong hydrolysis.
Cincatas They are formed by the interaction of oxide or zinc hydroxide with alkalis. When fusing, metacinates are formed (eg Na 2 ZnO 2), which dissolving in water are moving to tetrahydroxyzinkate: Na 2 ZnO 2 + 2N 2 O \u003d Na 2. When acidifying solutions, zinc hydroxide falls into the precipitate.

Application:

Production of anti-corrosion coatings. - Metal zinc in the form of bars is used to protect against corrosion of steel products in contact with sea water. Approximately half of the entire zinc produced is used to produce galvanized steel, one third - in hot galvanizing finished products, the rest is for strip and wire.
- Large-brass alloys (copper plus 20-50% zinc) have great practical importance. For injection molding, in addition to brass, a rapidly growing number of special zinc alloys is used.
- Another area of \u200b\u200bapplication is the production of dry batteries, although in recent years it has declined significantly.
- Zinc Telluride ZNTE is used as a material for photoresistors, infrared radiation receivers, dosimeters and radioactive radiation meters. - Zinc acetate Zn (CH 3 COO) 2 is used as a retainer when the fabrics are painted, wood preservative, antifungal agent in medicine, catalyst in organic synthesis. Zinc acetate is part of the dental cement, used in the production of glaze and porcelain.

Zinc is one of the most important biologically active elements and is necessary for all forms of life. Its role is mainly due to the fact that it is part of more than 40 important enzymes. The zinc function is established in proteins responsible for recognizing the base sequence in DNA and, consequently, regulating the transfer of genetic information during DNA replication. Zinc is involved in carbohydrate exchange with the help of a zinc-containing hormone - insulin. Only in the presence of zinc acts vitamin A. It is necessary to zinc and for the formation of bones.
At the same time, zinc ions are toxic.

Unhesive S., Stokes I.
HF Tyula, 571 Group.

Sources: Wikipedia: