Metals and their uses

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  • Extracting Metals
    • Where do metals come from? What are (most) like when they are found?
      • The earth's crust, combined chemically with other elements, often oxygen.
    • What makes an ore worth extracting? How is it then separated from the rock?
      • If it has enough metal in the compound, and how easy it is to extract. Displacement, or electrolysis.
    • How are gold and silver found in the earth?
      • in their native state.
    • How are ores extracted in industry? What is the equation and reaction name?
      • Heated with carbon to displace metals less reactive than itself. Displacement reaction.
    • How are metals more reactive than carbon extracted?
      • By electrolysis.
    • How is iron extracted? What is this iron like?
      • In a blast furnace, iron oxide heated with carbon, iron contains carbon impurities, called cast iron.
    • How is pure iron made from cast iron? What are it's new properties?
      • It is treated to remove the carbon, it becomes soft and easily shaped.
    • What is steel?
      • An iron alloy; iron mixed with another substance such as carbon or another metal.
    • What are carbon steels? What are they used to make, what are the advantages and describe two types:
      • Iron with a little bit of carbon left from the blast furnace in them. Cheapest steel, used to make cars, knives, machinery etc. High carbon steel - strong and brittle, and mild steel- soft and easily shaped.
    • What are three other types of steel and their uses?
      • low alloy steel, contains small amount of other metals. high alloy steels, very expensive, lots of other metal, e.g. chromium-nickel steel (stainless steel) used for utensils and cutlery.
    • Why are aluminium and titanium often chosen for alloys?
      • Light, low density and non-corrosive.
    • What are the properties of aluminium and its uses?
      • light and low density, shiny metal. good conductor and ductile. does't corrode. used to make cans, foil, pans, cables, aeroplanes, bikes.
    • How is aluminium extracted and what are the problems with this?
      • electric current passed through molten aluminium oxide, aluminium goes to negative electrode. Expensive process, used lots of energy for high temperatures and electricity, environmental issues.
    • What are the properties and uses of titanium?
      • light and low density strong metal. does not rust, high melting point. used for race cars, hip joints, jet engines and nuclear reactors.
    • How is titanium extracted and what are the problems?
      • Displacement with carbon would make it brittle so it has to be displaced by a more reactive metal, sodium or magnesium, both must be extracted themselves by electrolysis first and titanium oxide must be converted to titanium chloride and distilled first, so expensive, high energy, long winded process.
    • What are the main methods used to extract copper?
      • Use sulphuric acide to produce copper sulphate, then use electrolysis to separate.
      • Smelting, heat strongly in a furnace with air to make crude copper.
    • Name a copper ore, and how it is extracted:
      • e.g. copper sulphide heated strongly with oxygen, makes copper and sulphur dioxide.
    • Describe the process of electrolysis: What is it used for regarding copper?
      • An electrical current is passed trough molten metals or copper sulphate solution to make the metal go to the negative electrode.
    • How is copper extracted from copper sulphate?
      • In industry, scrap iron is added to displace the copper sulphate.
    • What are transition metals? How are they (Copper) used?
      • Metals in the middle block of the periodic table, copper is used for pipes and wiring.
    • Describe bronze and brass:
      • Brass- copper and zinc alloy, harder than copper, musical instruments. Bronze- copper and tin, corrosion resistant and tough, ship propellers.
    • Why do we alloy gold?
      • to make it harder and to vary the shade.
    • What are the disadvantages of mining for metal ores?
      • Landscape scarred, noise and dust created, destroys habitats, leave heaps of waste rock, groundwater becomes acidic.
    • Describe the process of phytomining:
      • Plants are grown on copper rich soil (low grade ores) and they absorb copper irons as they grow. They are burnt and metals are extracted from ash by smelting.
    • Why should we recycle metals?
      • Recycling aluminium does not require electrolysis, cheaper, less energy, saves fossil fuels, conserves ores.
    • What are some benefits and drawbacks of using metals in construction?
      • Benefits: copper is unreactive, good for water pipes, aluminium is corrosion resistant, steel is strong.
      • Drawbacks: Iron and steel can rust, mining causes many problems, metals are expensive.
    • What is bioleaching?
      • Bacteria feed on low grade ores and a solution of metal irons called leachate is produced. This is then processed by electrolysis.

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