Zinc - Essay Example

?INTRODUCTION TO ZINC: Zinc has its origin form the German word “Zin” which means Tin. Zinc is found in the group IIb in the periodic table. Zinc is a transition metal having a lustrous blue white appearance. At the ordinary room temperature, the appearance of zinc is crystalline and brittle. But it varies with different temperatures, as the appearance becomes ductile when heated at ranges 110-150 °C. Zinc is a reactive metal that was first discovered in 1746, and the person who discovered zinc was Andreas Marggraf. The symbol of zinc is denoted with “Zn”. Being in the group of transition metals, it is the property of zinc that it conducts electricity and heat. The valence electrons of zinc are present in more than one shell. Being placed in the transition metals, it has several oxidation states. Zinc has hexagonal crystalline structure. The atomic number of zinc is 30. It has the atomic mass of 65.39 a.m.u (atomic mass unit). Zinc has a melting point of 419.58 °C and it has a boiling point of 907.0 ° C. The density of zinc is 7.133 g/cm3. The numbers of neutrons are 30 and then numbers of protons/electrons are 35. ISOTOPES OF NEUTRON: The isotopes are the atoms containing different number of neutrons and same number of protons, responsible for altering total number of nucleons. There are ten isotopes of zinc that are shown in the table below. Half Life Zn-62 9.26 hours Zn-63 38.5 minutes Zn-64 Stable Zn-65 243.8 days Zn-66 Stable Zn-67 Stable Zn-68 Stable Zn-69m 13.76 hours Zn-70 Stable Zn-72 46.5 hours Zinc has two oxidation states and the valence electrons are in s shell. ATOMIC STRUCTURE OF ZINC:- The atomic structure gives us an idea about the structure of atoms and its arrangement. The atomic structure includes atomic radius, atomic size, covalent radius, cross section, and crystal structure. The atomic radius of zinc is 1.53 A°, the atomic volume is 9.2 cm3/mol, the covalent radius is 1.25 A°, cross section of 1.11, and the structure is hexagonal in nature. ELECTRONIC CONFIGURATION OF ZINC:- The electronic configuration tells us that how much electrons are placed in the specific shell. The electronic configuration of zinc is 1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4s2.This electronic configuration makes the process easier to remove 2 of 4s electrons and easier to form compounds like ZnO, Zncl2 and ZnSO4.  SOURCES OF ZINC:- The annual production of zinc is 5,020,000 tons. It is found in the minerals such as zincite (ZnO), zinc blende (sphalerite) (ZnS), calamine, and franklinite. CHEMICAL PROPERTIES:- Zinc has electronegativity of 1.65 Pauling, Heat of fusion of 7.322 kJ/mol, electron work function of 4.33 eV, it has an electrochemical equivalent of 1.22g/amp-hr, and a valence electron potential of 38.9. PHYSICAL PROPERTIES:- It is hard, brittle, bluish white transition metal. The enthalpy of fusion is 7.32 kJ/mol, enthalpy of atomization is 129.7 kJ/mol, average atomic mass of 65.39 and boiling point of 907° C. COMPOUNDS OF ZINC:- Many compounds of zinc are formed, but ten are discussed over here. 1. Zinc Borate: It is also called as fire brake ZB. Zinc borate has elements containing Zinc, Boron and oxygen. It has a chemical formula 3ZnO. 2B2O3. Its CAS number is 1332-07-6. Its casewell number is 909b. It is white powder. 2. Zinc carbonate: It is also called carbonic acid and zinc spar. It has a formula of ZnCo3, made up of zinc, carbon and oxygen. It has CAS number 3486-35-9. 3. Zinc sulphate: It has oxygen, sulphur and zinc. The formula is ZnsO4. The CAS number is 7733-02-0. Casewell number is 927. It is also called Bonazen having several other synonyms. 4. Zinc chloride: Is formula is ZnCl2. It has elements containing zinc and chlorine. Its CAS number is 7646-85-7. Its casewell number is 910. It is also called as butter of zinc. 5. Zinc Oxide: It has elements zinc and oxygen. Its chemical formula is ZnO2. Its CAS number is 1314-13-2. It casewell number is 920. It is also called as snow white. 6. Zinc stearate: Its formula is Zn(C18H35O2) 2. It has carbon, nitrogen, oxygen and zinc. Its CAS number is 557-05-1. Its casewell number is 926. 7. Zinc acetate: Its formula is Zn(O2CCH3)2. It has zinc, carbon and hydrogen in it. They are colorless solids having a CAS number 557-34-6. 8. Zinc molybdate: It has a formula (ZnMoO4). It has elements containing zinc, molybdenum and oxygen. Its CAS number is 13767-32-3. It has tetragonal structure and it is insoluble in water. 9. Zinc Chromate: It has the elements of zinc, chromium and oxygen. It has a chemical formula ZnCrO4. It has CAS number 13530-65-9. It is insoluble in water. 10. Zinc Phosphate: It has the elements contains zinc, oxygen and phosphate. It has CAS number 7779-90-0. It is inorganic in nature having chemical formula Zn3(PO4)2. USES OF ZINC:- 1. Coatings for steel: One of the most widely used applications for the zinc is that it is used for coating of steel. The reason that this application is widely used is because of the low corrosion rate of zinc compared to the steel. Zinc also gives corrosive protection to iron that is why it is widely used in immersed structure such as ships and pipe lines. Due to this reason, 4 million tons of zinc is used to protect 100 million tons of steel. 2. Buildings and construction: The 2/3 of the coated steel strips that are used in the buildings and construction mainly for roofing and industrial buildings are constructed from zinc use. The windows, doors, and domestic buildings use galvanized steel that are coated with zinc because of its good nature of corrosiveness. 3. Zinc recycling: Zinc is among the effective metals that can be recycled. That is the reason which is very important determining its worldwide usage in zinc plating and other coatings. The zinc scrap is priced according to the content of the zinc present and then it is recycled to be used again by the industries. 4. Zinc use in biology: Definite amount of zinc is very necessary for human as well animals. It is also necessary for bones growth and sexual maturation. And the body needs zinc for food processing as well as growth. 5. Other large scale usages: Zinc has a wide range of usage for which it is widely use. Among these uses includes agricultural applications, for making dry cell batteries, used in rubber industries, for making paints, it is used for making certain chemicals, and it is also use to make TV screens. 6. Copper alloys: Zinc is most widely used to make copper alloys and also in making brass. ZINC COMPOUNDS USES:- 1. Zinc borate: Zinc borate is widely used for wide range of plastics, papers, rubbers, as smoke suppressant and as flame retardant. It also replaces antimony oxide as a synergist. It is also widely used in ceramic industries and in making paints and pigments. 2. Zinc sulphate: It has granular and crystal powder appearance. Zinc sulphate is used as zinc additive in feed processing. It is also used as activator in latex paper. It is also an important fertilizer ingredient. 3. Zinc chloride: The zinc chloride is largely used in making of dry cell batteries. It is used in fluxing for soldering and tanning. It is also used as emulsion breaker in petroleum industry. It is also used as corrosion inhibitor in the cooling towers. 4. Zinc chromate: Zinc chromate is used as a corrosion resisting agent. It is used as anti corrosive barrier in the air craft industry. It is also used for making pigments and also used in paint industry. It is also use for UV resisting proposes. 5. Zinc phosphate: Zinc phosphate is used mainly for lubrication during cold forming, for corrosion resistance, to reduce break in wear on adjacent moving surfaces, it is used for bonding organic coatings to metals. REFERENCES: Stasosphere. (2010). 17. Uses of Zinc. Retrieved from http://chestofbooks.com/crafts/mechanics/Mechanical-Processes/17-Uses-Of-Zinc.html Kenneth L Barbalace (J.K. Barbalace, inc). (2011). Periodic Table of Elements - Common Compounds of Zinc. Retrieved from http://environmentalchemistry.com/yogi/periodic/Zn-compounds.html#Compounds AZoM™. (2011). Zinc and its Uses. Retrieved from http://www.azom.com/Details.asp?ArticleID=749 Lenntech Water treatment & purification Holding B.V. (2009). Zinc-Zn. Retrieved from http://www.lenntech.com/periodic/elements/zn.htm Yinon Bentor. (2009). Periodic Table: Zinc. Retrieved from http://www.chemicalelements.com/elements/zn.html Read More