C1.2.1 Calcium Carbonate
Limestone is a type of rock which is quarried and used as a building material. It is mostly calcium carbonate: CaCO3
Quicklime= clacium oxide, slaked lime= calcium hydroxide
- Raw material for cement, mortar, and concrete
- Neutralising rivers and acidic lakes
- As blocks and slabs for walls and pavements
- As aggregate (small lumps) for the base of roads and railways
Cement- heat limestone with clay
Mortar- mix cement with sand and water
Concrete- mix cement with sand, aggregate and water
- New jobs created
- Limestone a valuable building material
- Fewer tourists
- Extra traffic
- Noise, visual and atmospheric pollution
C1.2.1 Calcium Carbonate Chemistry
CaCO3 -> CaO + CO2
Carbonates of magnesium, copper, zinc and sodium decompose in the same way:
Metal carbonate -> metal oxide + carbon dioxide
Not all carbonates of metals in Group 1 decompose when heated with a bunsen flame.
Calcium oxide reacts vigorously with drops of water to make a white solid- calcium hydroxide. A lot of heat is given out in the reaction. Calcium hydroxide is an alkali which can be used to neutralise acids.
calcium oxide + water → calcium hydroxide
CaO + H2O → Ca(OH)2
Solution of calcium hydroxide in water, and is used as a test for CO2, which turns limewater cloudy.