1.6 Limestone

Cards (22)

  • Thermal decomposition
    Breaking down a compound to simpler compounds or elements using heat
  • As the calcium carbonate is heated
    It decomposes to form calcium oxide and carbon dioxide
  • how do you prove the gas produced is CO2
    • Bubbling it through limewater, which will turn milky if carbon dioxide is present
  • Stability of metal carbonates
    • More reactive the metal, the more stable the carbonate
    • Copper carbonate is fairly unstable and decomposes at a relatively low temperature
    • Sodium carbonate is very stable and does not decompose at the highest temperature which can be reached using a Bunsen burner flame
  • Uses of limestone
    • Manufacturing iron
    • Manufacturing steel
    • Road building
    • Making cement
    • Neutralising acidic soil
  • What is Limestone
    Calcium carbonate (CaCO3)
  • What is Quicklime
    Calcium oxide (CaO)
  • what is Slaked lime
    Calcium hydroxide (Ca(OH)2)
  • The limestone cycle
    1. Roast the limestone for 20 minutes
    2. Add drops of water to the quicklime
    3. Slaked lime can be converted back to calcium carbonate by adding carbon dioxide
  • During reaction 1 (roasting the limestone) we will observe the limestone shining orange
  • During reaction 2 (adding drops of water to the quicklime) we will observe whistling or hissing and the solid crumbling. This is an example of exothermic reaction
  • Advantages of quarrying for limestone

    • Provides materials for the construction industry
    • More local jobs
    • Creates more wealth for the community
    • Build better road systems
  • Disadvantages of quarrying for limestone

    • Dust from lorries and explosions
    • Spoils the landscape
    • Noise of explosions
    • Destruction of habitats
  • What is the chemical equation for calcium carbonate being heated?
    CaCO3 -> CaO + CO2
  • What is the chemical equation to produce quicklime?
    CaO + H2O -> Ca(OH)2
  • What is the chemical equation to produce slaked lime?
    Ca(OH)2 + CO2 -> CaCO3 + H2O
  • What is calcium hydroxide (slaked lime) used for?
    neutralises acidity in lakes and soil
  • What is observed when limestone is heated?
    orange glow
  • what type of reaction is it when limestone is heated?
    endothermic
  • what type of reaction is it when water is added to calcium oxide?
    exothermic
  • What is produced when calcium hydroxide dissolves in excess water?
    calcium hydroxide solution (limewater)
  • what happens when carbon dioxide reacts with calcium hydroxide (limewater)?
    white calcium carbonate is formed turning the limewater milky