Chemistry 1 - Limestone

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Limestone

  • Limestone is quarried out of the ground and is used for making buildings. 
  • Limestone is mainly calcium carbonate - CaCO3. 
  • When it's heated it thermally decomposes to make calcium oxide and carbon dioxide. The equation for this is:

CaCO3 = CaO + CO2

(heat)

  • When magnesium, copper, zinc and sodium carbonates are heated they decompose in the same way. 
  • Calcium carbonate also reacts with acid to make a calcium salt, carbon dioxide and water. 

CaCO3 + H2SO4 = CaSO4 + CO2 + H20

When calcium carbonate reacts with an acid it always makes carbon dioxide and water.

When you add water to calcium oxide you produce calcium hydroxide. 

CaO + H20 = Ca(OH)2

  • Calcium hydroxide is an alkali so can be used to neutralise acidic soil in fields. 
  • Powdered limestone can also be used, the the advantage of using calcium hdroxide is that is works much faster.
  • Calcium hydroxide can be used to test for carbon dioxide too. If you make a solution of calcium hydroxide in water (limewater) and bubble gas…

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