cycle

• limestone cycle starts and ends with limestone
• limestone = calcium carbonate
• thermal decomposition = breaking down of a compound (two + atoms chemically combined together ) by heating
• calcium oxide = quicklime
• limestone cycle reaction 1:

  thermal decomposition of limestone to quicklime.

  limestone gives out an orange light ( glows and goes crumbly ) when strongly heated to show reaction is happening
• reaction 1 = calcium carbonate -> calcium oxide + carbon dioxide
• reaction 2:

  quicklime can react with excess water to form slaked lime .

  Calcium oxide (white solid ) crumbles and water boils -> exothermic (heat releasing ) reaction
• reaction 2 :

  quicklime + water (excess ) -> calcium hydroxide
• reaction 3:

  if carbon dioxide is bubbled through limewater , it turns milky / cloudy because the calcium carbonate formed is not soluble in water
• reaction 3 :

  limewater + carbon dioxide -> limestone+ water (excess)
• solution of calcium hydroxide = limewater
• label missing squares: with lime terms

  A) limestone

  B) quicklime

  C) limewater

  D) slacked lime

  
• slacked lime = calcium hydroxide
• limewater = a solution of calcium hydroxide
• reaction 1 produces calcium oxide (+carbon dioxide)
• reaction 2 produces calcium hydroxide as slacked lime
• reaction 3 produces calcium carbonate + water (in excess)
• reaction 1 equation = CaO + H20 -> Ca(OH)2
• reaction 2 equation = CaO + H2O -> Ca(OH)2
• reaction 3 equation = Ca(OH)2 + CO2 -> Ca(CO3) + H20