Cambridge IGCS Chemistry Coursebook 2023 Chapter 14 知识点整理

这是一篇关于Metallic elements and alloys的思维导图，主要内容包括：Alloys，Uses of metals，The properties of metals。

Metallic elements and alloys

• The properties of metals
  • Physical properties of metals and non-metals
    • Non-metals
      • Are solids or gases at room temperature (except for bromine)
      • Low melting and boiling point
      • do not conduct electricity (except graephite)
      • Poor theirmal conductors (except diamond)
      • Not malleable; they are brittle and break easily when hit
      • Low densities
      • not sonorous
        • To describe a metallic substance that rings like a bell when hit with a hammer
      • Vary in colour
      • Dull surface when solid
    • Metals
      • Usually solids (except for mercury) at room temperature
      • conduct electricity
        • Electrical conductivity: The ability to conduct electricity
      • High melting and boiling point
      • thermal conductivity
        • The ability to conduct heat
      • malleability
        • The ability to be bent or beaten into shape
      • ductility
        • The ability to be drawn out into a wire
      • Strong and dense
      • Do not shatter (not brittle)
      • They are sonorous
      • Grey in colour (except gold and copper)
      • Can be polished
  • Chemical reactions of metals with air, water and dilute acids
    • sodium, calcium, magnesium
      • burn very strongly in air to form oxide
        • react with cold water to give hydrogen
          • reawct very strongly with HCl to give hydrogen
    • aluminium, zinc, iron
      • burn less strongly in air to form oxide
        • react with steam when heated to give hydrogen
          • react less strongly with HCl to give hydrogen
    • lead, copper
      • react slowly to form oxide layer when heated
        • do not react with water
          • donot react with HCl
    • silver, gold
      • do not react with air
        • do not react with water
          • do not react with HCl
    • If a metal reacts with cold water, a emtal hydroxide and hydrogen are formed
    • If a metal reacts only with steam, then a metal oxide is formed
    • Metal + hydrochloric acid → metal chloride + hydrogen
• Uses of metals
  • Uses of Iron
    • Cast iron
      • bridge
      • cooking pots and pans
      • Steel and strainless steel
  • Uses of aluminium
    • naval vessels
    • modern cars
    • aeroplanes
    • window frames
  • Uses of copper
    • roofing
    • Electrical cables
• Alloys
  • mixture of elements (usally metals)
  • Some important alloys
    • Brass
      • 70% copper + 30% zinc
      • harder than pure copper; gold coloured, musical instruments, ornaments, electrical connections
    • Bronze
      • 90% copper + 10% tin
      • harder than pure copper, statues bells, machine parts
    • Mild steel
      • 99.7% iron + 0.3% carbon
      • stronger and harder than pure iron, car bodies
    • Stainless steel
      • 74% iron + 18% chromium + 8% nickel
      • harder than pure iron, does not rust, cutlery, surgical instruments, reaction vessels in the chemical inductry
    • Solder
      • 50% tin + 50% lead
        • lower melting point than either tin or lead, making electrical connections
  • Structure of alloys
    • stronger than pure metals
    • more brittle than metals