In the periodic system of elements of D.I. Mendeleyev zinc is in the II group, the fourth period. It has serial number 30 and atomic mass 65.39. It is the transitional metal which is characterized by internal building of d-orbitals.
Instruction
1. On physical properties zinc – metal of bluish-white color. Under usual conditions it fragile, but when heating to 100-150˚C gives in to rolling. On air this metal grows dull, becoming covered by a protective thin layer of an oxidic film of ZnO.
2. In connections zinc shows the only oxidation level +2. In the nature metal meets only in the form of connections. The most important compounds of zinc – a zinc blende of ZnS and zinc ZnCO3 spar.
3. The majority of zinc ores contains a small amount of zinc therefore they are enriched at first before receiving a zinc concentrate. At the subsequent roasting of a concentrate receive ZnO zinc oxide: 2ZnS+3O2=2ZnO+2SO2. Pure metal is restored from the received zinc oxide by means of coal: ZnO+C=Zn+CO.
4. On the chemical properties zinc – quite active metal, but concedes to alkaline-earth. It easily interacts with halogens, oxygen, sulfur and phosphorus: Zn+Cl2=2ZnCl2 (zinc chloride), 2Zn+O2=2ZnO (zinc oxide), Zn+S=ZnS (zinc sulfide, or zinc blende), 3Zn+2P=Zn3P2 (zinc phosphide).
5. When heating, zinc reacts with water and hydrogen sulfide. In these reactions hydrogen is emitted: Zn+H2O=ZnO+H2 ↑, Zn+H2S=ZnS+H2 ↑.
6. At alloyage of zinc with waterless alkalis zincates – salts of zinc acid are formed: Zn+2NaOH=Na2ZnO2+H2 ↑. In reactions with water solutions of alkalis metal gives complex salts of zinc acid – for example, sodium tetrahydroxyzincate: Zn+2NaOH+2H2O=Na [Zn(OH)4] + H2 ↑.
7. In vitro zinc is quite often used for receiving hydrogen from the diluted hydrochloric HCl acid: Zn+2HCl=ZnCl2+H2 ↑.
8. In interaction with sulfuric acid ZnSO4 zinc sulfate is formed. Other products depend on concentration of acid. Hydrogen sulfide, sulfur or sulphurous gas can be them: 4Zn+5H2SO4 (it is strong razb.) =4ZnSO4+H2S+4H2O, 3Zn+4H2SO4 (razb.) =3ZnSO4+S+4H2O, Zn+2H2SO4 (konts.) =ZnSO4+SO2 ↑+2H2O.
9. Similarly there are reactions of zinc and with nitric acid: Zn+4HNO3 (konts.) =Zn(NO3)2+2NO2 ↑+2H2O, 4Zn+10HNO3 (razb.) =4Zn(NO3) 2+N2O+5H2O, 4Zn+10HNO3 (it is strong razb.) =4Zn(NO3) 2+NH4NO3+3H2O.
10. Zinc is applied to production of galvanic cells and galvanizing of iron and steel. The received anticorrosion coating protects metals from rust. The most important alloy of zinc – brass, the alloy of zinc and copper known to mankind since Ancient Greece and Ancient Egypt.