GCSE Chemistry (AQA)

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Glass

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Using resources Using materials

Glass

3:38 Composition and Use of Different Materials
Spec 4.10.3.3
Previous Uses of Alloys Next Clay Ceramics
  • Glass is hard, transparent, and unreactive.
  • Used for windows, lenses, and wine glasses.
  • Does not soak up or react with liquids and allows visibility of contents.
  • Glass is brittle and can easily break.
  • Brittle objects snap or shatter rather than bend.
  • Reinforced glass is stronger than regular glass.
  • Chemistry behind glass making is important.
  • Glass is made from sand mixed with other substances.
  • Sand consists of silicon dioxide (silica) molecules.
  • Silicon atoms bond with four oxygen atoms to form a giant covalent structure.
  • The mixture is heated to form molten liquid and then cooled to form solid glass.
  • Molten substances have high melting points and are brought to a liquid state by raising their temperature.
  • Cooled mixture forms a sheet of glass.
  • Shaping glass involves pouring into molds or pumping air as it cools.
  • Other materials in the mixture depend on the type of glass being made.
  • Two types of glass for exams: soda lime glass and borosilicate glass.
  • Soda lime glass is cheap, easy to make, but breaks easily.
  • Made by heating a mixture of sand, sodium carbonate, and limestone (calcium carbonate).
  • Borosilicate glass is made by heating sand with boron trioxide.
  • Borosilicate melts at higher temperatures than soda lime glass.
  • Useful for lab equipment and cookware that need to withstand heat.
  • Heat and cold resistant, won't crack under extreme temperatures.
  • Harder and more expensive to produce and shape than soda lime glass.
  • Soda lime glass is used when heat resistance is not needed.

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