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• • • • • Ho Ka Ki Lee Ka Wing Lo Mung Ping Ngan Wan Ting Yeung Po Yee (25) (28) (31) (35) (40) • Introduction—Metals —Plastics • Metals : Aluminium • Plastics : Polystyrene • Comparison—Properties —Uses •From metal ores by chemical or electrolytic reduction •Are lustrous, ductile, malleable, and good conductors of heat and electricity. •Can be processed into alloys. •widely used in past & modern world. Made by raw materials from crude oil Major elements carbon & hydrogen Widely used in recent decades unique properties When being disposed of improperly environmental problems polystyrene polyethene • • • • Symbol: Al Silvery ,ductile,lightweight metals. Found primarily in bauxite ore The most abundant metal in earth crust • Used to manufacture a large variety of products • Very important to world economy It is colorless, hard with limited flexibility and a polymer made from styrene. Production Heat the mixture of styrene and kerosene pour it into methanol after cooling waxy, solid of polystyrene formed Danger Benzene, a material used to produce polystyrene, is human carcinogens. Materials Aluminium (Al) Polystyrene (PS) Conduct heat and electricity Yes No Burnable Yes No Strength lower Higher Transparent Density No Possible low low Shiny Yes Yes Recyclable Yes(e.g.Aluminium cans) Yes(e.g. Plastic cups) Resistant to corrosion Yes Yes ___:Differences ___:Similarities Materials Aluminium (Al) Polystyrene (PS) Household uses -Cooking appliances -Window frames Other uses -Aeroplanes -Cable -CDs $24000/ton -Lamps -Switches -Plastic cups -Medicine bottles -Expanded foams -Toys $12000/ton Price