Uses of metals

• Alloy

  Mixture of 2 or more elements which at least one of them is a metal
• Copper alloys

  Bronze ( copper + tin)

  Brass (copper + zinc)
• Bronze


  Copper + tin

  Making statues, bells and coins

  First alloy made by humans ( 6000 years ago)
• Brass


  Copper + zinc

  Making musical instruments, door knobs, locks and taps
• Pure gold

  Very soft and malleable (changing shapes)

  Unreactive ( resists corrosion, stays shiny)

  Thin layer on space helmet to reflect sunlight
• Alloy

  A mixture of two or more elements, at least one of which is a metal
• Mixture

  Two or more substances that are not joined together. The substances can be elements, compounds, or both
• Element

  A substance made of one type of atom only
• Metal

  Shiny element that is a good conductor of electricity and heat, and which forms basic oxides
• Bronze


  • First alloy made by humans, around 6000 years ago, an alloy of copper and tin
• Uses of bronze

  • Statues
  • Bells
  • Coins
• Brass

  • An alloy of copper and zinc, used to make musical instruments, door knobs, locks and taps
• Malleable


  Capable of being hammered or pressed into a new shape without being likely to break or return to the original shape
• Unreactive

  A substance is unreactive or inert if it does not easily take part in chemical reactions
• Corrosion

  When chemicals in the water dissolve minerals in the rocks, causing them to break up (also called solution)
• The visors on space helmets are coated with a layer of gold
• The gold used for jewellery is gold alloyed with other metals, often silver, copper and zinc
• Percentage of gold in different gold alloys

  • 24 carat - 100%
  • 18 carat - 75%
  • 12 carat - 50%
  • 9 carat - 37.5%
• Calculating percentage of gold in 14 carat gold

  (14 ÷ 24) x 100 = 58%
• Alloy steel

  Alloy produced by mixing iron with one or more other metals
• Examples of alloy steels

  • High carbon steel - Strong, brittle
  • Low carbon steel - Softer, more easily shaped
  • Stainless steel - Hard, resistant to rusting
• High carbon steels are used for construction because of their strength
• Low carbon steels are used for making car body panels because they are malleable
• Stainless steel is used for cutlery because it does not rust
• Washing machines and dishwashers contain water


  Stainless steel does not rust
• Aluminium

  • Does not react with water, surface is protected by a natural layer of aluminium oxide that allows the metal to resist corrosion
• Density

  A measure of compactness and the ratio of mass to volume. It is usually measured in kilograms per metre cubed (kg/m 3 ) or grams per centimetre cubed (g/cm 3 )
• Magnalium

  • An alloy of aluminium and magnesium, stronger than aluminium alone but still has a low density, used to make aircraft parts
• Aluminium is used to make overhead electricity cables

  Aluminium is a good electrical conductor and has a low density