Given are zinc copper zinc oxide. Zinc is a general characteristic of an element, the chemical properties of zinc and its compounds. Chemistry Tutor Benefit
1.2H 2SO 4 (conc.) + Cu = CuSO 4 + SO 2 + 2H 2O
copper sulfate
H 2SO 4 (dil.) + Zn = ZnSO 4 + H 2
zinc sulfate
2. FeO + H 2 = Fe + H 2O
CuSO 4 + Fe = Cu ↓ + FeSO 4
3. Let's compose the salts of nitric acid:
formula of nitric acid HNO3 acid residue NO3- - nitrate
Let's compose the salt formulas:
Na + NO3- According to the table of solubility, we determine the charges of the ions. Since the sodium ion and nitrate ion have charges "+" and "-", respectively, the subscripts in this formula are unnecessary. You get the following formula:
Na + NO3- - sodium nitrate
Ca2 + NO3- - According to the solubility table, we determine the charges of the ions. Let us arrange the indices according to the rule of the cross, but since the nitrate ion is a complex ion with a charge "-", it must be enclosed in brackets:
Ca2 + (NO3) -2 - calcium nitrate
Al3 + NO3- - According to the solubility table, we determine the charges of the ions. Let us arrange the indices according to the rule of the cross, but since the nitrate ion is a complex ion with a charge "-", it must be enclosed in brackets:
Al3 + (NO3) -3 - aluminum nitrate
further metals
zinc chloride ZnCl2
aluminum nitrate Al (NO3) 3
Zinc alloy with copper - brass - was known in Ancient Greece, Ancient Egypt, India (VII century), China (XI century). For a long time it was not possible to isolate pure zinc. In 1746, A.S. Marggraf developed a method for producing pure zinc by calcining a mixture of its oxide with coal without access to air in clay refractory retorts, followed by condensation of zinc vapor in refrigerators. IN industrial scale zinc smelting began in the 17th century.
Latin zincum translates as "white bloom". The origin of this word has not been precisely established. Presumably, it comes from the Persian "cheng", although this name does not refer to zinc, but in general to stones. The word "zinc" is found in the works of Paracelsus and other researchers of the 16th and 17th centuries. and goes back, perhaps, to the ancient Germanic "zinc" - a raid, an eyesore. The name "zinc" became commonly used only in the 1920s.
Being in nature, getting:
The most common zinc mineral is sphalerite, or zinc blende. The main component of the mineral is zinc sulfide ZnS, and various impurities give this substance all kinds of colors. Apparently, for this, the mineral is called blende. Zinc blende is considered the primary mineral from which other minerals of element No. 30 were formed: smithsonite ZnCO 3, zincite ZnO, calamine 2ZnO · SiO 2 · H 2 O. In Altai, you can often find striped "chipmunk" ore - a mixture of zinc blende and brown spar. A piece of such ore from a distance really looks like a hidden striped animal.
The separation of zinc begins with the concentration of ore by sedimentation or flotation methods, then it is roasted to form oxides: 2ZnS + 3О 2 = 2ZnО + 2SO 2
Zinc oxide is processed electrolytically or reduced with coke. In the first case, zinc is leached from the crude oxide with a dilute solution of sulfuric acid, the cadmium impurity is precipitated with zinc dust, and the zinc sulfate solution is subjected to electrolysis. Metal of 99.95% purity is deposited on aluminum cathodes.
Physical properties:
In its pure form, it is a rather ductile silvery-white metal. It is brittle at room temperature; when the plate is bent, a crackle is heard from the friction of crystallites (usually stronger than the "cry of tin"). Zinc is ductile at 100-150 ° C. Impurities, even insignificant ones, sharply increase the brittleness of zinc. Melting point - 692 ° C, boiling point - 1180 ° C
Chemical properties:
Typical amphoteric metal. The standard electrode potential is -0.76 V, in the series of standard potentials it is located before iron. In air, zinc is covered with a thin film of ZnO oxide. Burns out when heated up. When heated, zinc reacts with halogens, with phosphorus, forming phosphides Zn 3 P 2 and ZnP 2, with sulfur and its analogs, forming various chalcogenides, ZnS, ZnSe, ZnSe 2 and ZnTe. Zinc does not directly react with hydrogen, nitrogen, carbon, silicon and boron. Zn 3 N 2 nitride is produced by the reaction of zinc with ammonia at 550-600 ° C.
Zinc of normal purity reacts actively with solutions of acids and alkalis, forming in the latter case hydroxozincates: Zn + 2NaOH + 2H 2 O = Na 2 + H 2
Very pure zinc does not react with solutions of acids and alkalis.
Zinc is characterized by compounds with the oxidation state: +2.
The most important connections:
Zinc oxide- ZnO, white, amphoteric, reacts with both acid solutions and alkalis:
ZnO + 2NaOH = Na 2 ZnO 2 + H 2 O (fusion).
Zinc hydroxide- is formed in the form of a gelatinous white precipitate when alkali is added to aqueous solutions of zinc salts. Amphoteric hydroxide
Zinc salts... Colorless crystalline substances. In aqueous solutions, zinc ions Zn 2+ form aqua complexes 2+ and 2+ and undergo strong hydrolysis.
Zincats are formed by the interaction of zinc oxide or hydroxide with alkalis. Upon fusion, metazincates are formed (for example, Na 2 ZnO 2), which dissolve in water and transform into tetrahydroxozincates: Na 2 ZnO 2 + 2H 2 O = Na 2. When solutions are acidified, zinc hydroxide precipitates.
Application:
Production of anti-corrosion coatings. - Metallic zinc in the form of bars is used to protect against corrosion of steel products in contact with sea water... About half of all zinc produced is used for the production of galvanized steel, one third for hot-dip galvanizing of finished products, and the rest for strip and wire.
- Zinc alloys - brass (copper plus 20-50% zinc) are of great practical importance. For die casting, in addition to brass, a rapidly growing number of special zinc alloys are used.
- Another area of application is the production of dry batteries, although in last years it has dropped significantly.
- Zinc telluride ZnTe is used as a material for photoresistors, infrared detectors, dosimeters and radiation counters. - Zinc acetate Zn (CH 3 COO) 2 is used as a fixative for dyeing fabrics, wood preservative, antifungal agent in medicine, catalyst in organic synthesis. Zinc acetate is a component of dental cements and is used in the production of glazes and porcelain.
Zinc is one of the most important biologically active elements and is essential for all forms of life. Its role is mainly due to the fact that it is part of more than 40 important enzymes. The function of zinc in proteins responsible for the recognition of the sequence of bases in DNA and, therefore, regulating the transfer of genetic information during DNA replication has been established. Zinc is involved in carbohydrate metabolism with the help of a zinc-containing hormone - insulin. Vitamin A acts only in the presence of zinc. Zinc is also needed for the formation of bones.
At the same time, zinc ions are toxic.
Bespomestnykh S., Shtanova I.
KhF Tyumen State University, group 571.
Sources: Wikipedia:
Zinc is an element of a secondary subgroup of the second group, the fourth period of the periodic system chemical elements DI Mendeleev, with atomic number 30. It is designated by the symbol Zn (lat. Zincum). The simple substance zinc under normal conditions is a brittle transition metal bluish white(fades in air, becoming covered with a thin layer of zinc oxide).
In the fourth period, zinc is the last d-element, its valence electrons 3d 10 4s 2. In education chemical bonds only electrons of the external energy level are involved, since the d 10 configuration is very stable. In compounds for zinc, the oxidation state is +2.
Zinc is a chemically active metal, has pronounced reducing properties, and is inferior in activity to alkaline earth metals. Shows amphoteric properties.
Interaction of zinc with non-metals
When heated strongly in air, it burns with a bright bluish flame to form zinc oxide:
2Zn + O 2 → 2ZnO.
When ignited, it reacts vigorously with sulfur:
Zn + S → ZnS.
Reacts with halogens under normal conditions in the presence of water vapor as a catalyst:
Zn + Cl 2 → ZnCl 2.
Under the action of phosphorus vapors on zinc, phosphides are formed:
Zn + 2P → ZnP 2 or 3Zn + 2P → Zn 3 P 2.
Zinc does not interact with hydrogen, nitrogen, boron, silicon, carbon.
Interaction of zinc with water
Reacts with water vapor at red heat to form zinc oxide and hydrogen:
Zn + H 2 O → ZnO + H 2.
Interaction of zinc with acids
In the electrochemical series of metal voltages, zinc is found before hydrogen and displaces it from non-oxidizing acids:
Zn + 2HCl → ZnCl 2 + H 2;
Zn + H 2 SO 4 → ZnSO 4 + H 2.
Reacts with dilute nitric acid to form zinc nitrate and ammonium nitrate:
4Zn + 10HNO 3 → 4Zn (NO 3) 2 + NH 4 NO 3 + 3H 2 O.
Reacts with concentrated sulfuric and nitric acids to form zinc salts and acid reduction products:
Zn + 2H 2 SO 4 → ZnSO 4 + SO 2 + 2H 2 O;
Zn + 4HNO 3 → Zn (NO 3) 2 + 2NO 2 + 2H 2 O
The interaction of zinc with alkalis
Reacts with alkali solutions to form hydroxo complexes:
Zn + 2NaOH + 2H 2 O → Na 2 + H 2
when fusion forms zincates:
Zn + 2KOH → K 2 ZnO 2 + H 2.
Interaction with ammonia
Forms zinc nitride with gaseous ammonia at 550–600 ° C:
3Zn + 2NH 3 → Zn 3 N 2 + 3H 2;
dissolves into aqueous solution ammonia, forming tetraamminezinc hydroxide:
Zn + 4NH 3 + 2H 2 O → (OH) 2 + H 2.
Interaction of zinc with oxides and salts
Zinc displaces metals in the voltage row to the right of it from solutions of salts and oxides:
Zn + CuSO 4 → Cu + ZnSO 4;
Zn + CuO → Cu + ZnO.
Zinc (II) oxide ZnO
- white crystals, when heated, acquire a yellow color. The density is 5.7 g / cm 3, the sublimation temperature is 1800 ° C. At temperatures above 1000 ° C, it is reduced to metallic zinc by carbon, carbon monoxide and hydrogen:
ZnO + C → Zn + CO;
ZnO + CO → Zn + CO 2;
ZnO + H 2 → Zn + H 2 O.
Does not interact with water. Shows amphoteric properties, reacts with solutions of acids and alkalis:
ZnO + 2HCl → ZnCl 2 + H 2 O;
ZnO + 2NaOH + H 2 O → Na 2.
When fusion with metal oxides forms zincates:
ZnO + CoO → CoZnO 2.
When interacting with nonmetal oxides, forms salts, where it is a cation:
2ZnO + SiO 2 → Zn 2 SiO 4,
ZnO + B 2 O 3 → Zn (BO 2) 2.
Zinc (II) hydroxide Zn (OH) 2
- a colorless crystalline or amorphous substance. Density 3.05 g / cm 3, at temperatures above 125 ° C decomposes:
Zn (OH) 2 → ZnO + H 2 O.
Zinc hydroxide exhibits amphoteric properties, easily dissolves in acids and alkalis:
Zn (OH) 2 + H 2 SO 4 → ZnSO 4 + 2H 2 O;
Zn (OH) 2 + 2NaOH → Na 2;
also easily dissolves in aqueous ammonia to form tetraamminezinc hydroxide:
Zn (OH) 2 + 4NH 3 → (OH) 2.
It is obtained in the form of a white precipitate when zinc salts interact with alkalis:
ZnCl 2 + 2NaOH → Zn (OH) 2 + 2NaCl.
