Glass

  1. It is a mixture of two or more types of metallic silicates but the main component is silicon(IV) dioxide.
  2. Glass has the following properties:
    1. Transparent and not porous
    2. Inactive chemically
    3. Can be cleaned easily
    4. Good insulators of heat and electricity
    5. Hard but brittle
    6. Can withstand compression but not pressure

Soda lime,glass


Composition: SiO2 – 70%, Na2O – 15%, CaO – 10%, Others – 4%

Properties:
  1. Low melting point (700°C)
  2. Moldable into shapes
  3. Cheap
  4. Breakable
  5. Can withstand high heat

Uses: Glass containers, Glass panes, Mirrors, Lamps and bulbs, Plates and bowls Bottles

Lead glass (crystal)


Composition: SiO2 – 70%, Na2O – 20%, PbO – 10%

Properties:
  1. High density and refractive index
  2. Glittering surface
  3. Soft
  4. Low melting point (600°C)

Uses: Containers for drinks and fruit, Decorative glass and lamps, Crystal glassware, Lenses for spectacles



Borosilicate glass (Pyrex)


Composition: SiO2 – 80%, B2O3 – 13%, Na2O – 4%, AI203 – 2%

Properties:
  1. Resistant to high heat and chemical reaction
  2. Does not break easily
  3. Allows infra-red rays but not ultra-violet rays

Uses: Glass apparatus in laboratories, Cooking utensils



Fused silicate glass


Composition: SiO2 – 99%, Other - 1%

Properties:
  1. High melting point (1700°C)
  2. Expensive
  3. Allows ultraviolet light to pass through
  4. Difficult to melt or mould into shape

Uses: Scientific apparatus like lenses on, spectrometer, Optical lenses, Laboratory apparatus

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