Department of Chemistry CHEM1020 General Chemistry *********************************************** Instructor: Dr. Hong Zhang Foster Hall, Room 221 Tel:

CHEM1020/General Chemistry _________________________________________ Chapter 11. (L20)-Chemistry of Earth Today’s Outline …Metals and ores Copper and bronze Iron and steel Aluminum Other important metals …Land pollution and solid wastes …Reduce, reuse, recycle

Chapter 11. (L20)-Chemistry of Earth Metals and ores …Human history in association with materals the Stone Age the Bronze Age the Iron Age …… the Steaming Engine age the Electricity Age the Nuclear Age the Computer Age …… the Information Age ……

Chapter 11. (L20)-Chemistry of Earth Metals and ores …Copper and bronze copper ores: blue to green Cu 2 S + O 2 + heat  2Cu(s) +SO 2 (g) Cu was known 5500 years ago bronze = 90% Cu + 10%Sn harder than Cu metal

Chapter 11. (L20)-Chemistry of Earth Metals and ores …Iron and steel Reactions to produce Fe: 2C(s) + O 2 (g)  2CO(g) Fe 2 O 3 (ore) + 3CO(g)  2Fe(s) + 3CO 2 (g) cast iron (easy to melt and to cast), brittle …Alloy A mixture of two or more elements with at least one of them being a metal.

Chapter 11. (L20)-Chemistry of Earth Metals and ores …Steel An alloy of Fe and C. High C steel is hard and strong W steel: high temperature strength Cr and Ni steel: stainless steel

Chapter 11. (L20)-Chemistry of Earth Metals and ores …Aluminum Al ore: bauxite, Al 2 O 3, Reaction for making Al metal: 2Al 2 O 3 + electricity  4Al + 3O 2 2 tons Al ore + 17,000 kWh of electricity gives rise to 1 ton Al metal (high energy consumption) Al corrodes much slower than many other metals. This is because of formation of a thin transparent film of Al 2 O 3 on the metal surface by reacting of Al with O 2 in the air.

Chapter 11. (L20)-Chemistry of Earth Environmental cost of iron and aluminum …Production of iron and aluminum generates many wastes besides consumption of huge amounts of energy The wastes released into waterways include lime, grease, oil, iron salts; The wastes released into airways include CO, nitrogen oxides, particular matter, and other pollutants.

Chapter 11. (L20)-Chemistry of Earth Other important metals …Other important metals (see Table 11.5) Cr, Au, Pb, Mg, Hg, Ni, Pt, Ag Na Sn W U Zn

Chapter 11. (L20)-Chemistry of Earth Land pollution and solid wastes …Municipal solid wastes (MSW) (Fig ) Landfills to hide and store pros and cons of landfills Incineration: another way to handle MSW (15%); this requires a lot of energy and releases a lot pollutants into the airways Wastes: Cannot be destroyed, the law of conservation matter. You can convert the wastes to other forms of matter or materials.

Chapter 11. (L20)-Chemistry of Earth The three R’s: Reduce, Reuse, Recycle …The best way: First of all, reduce the consumption and needs …Second, reuse, bottles, bags, many things can be reused more times and many times …Third, recycle, the materials can be recycled plastics, papers, metals, glass, and many more. …Do it, everyone oneself Recycle facilities in Cookeville (now near the cinema south of the I-40)

Chapter 11. (L20)-Chemistry of Earth The future of our spaceship, Earth …Limitation of natural resources …Non-renewable natural resources (e.g., fossil fuels like coal, petroleum, natural gas) …The economy based on limitless natural resources and energy …The economy based on limited natural resources and energy …The economy based on no wastes and pollution …The economy based on unavoidable generation of wastes and pollution …Our future: What path we should choose?

Chapter 11. (L20)-Chemistry of Earth Quiz Time TBA.