Carbonates are bases but not alkali, so they turn universal indicator blue or purple. Carbonates react with acids to form salt, water and release carbon dioxide.
CaCO3 + 2HCl CaCl2 + H2O + CO2
All carbonates undergo thermal decomposition to form metal oxide and carbon dioxide.
MgCO3 > MgO + CO2
Calcium hydroxide produced in the limestone cycle is an alkali and can neutralize an acid. The products of a reaction are calcium salt and water:
Ca(OH)2 + 2HCl >CaCl2 + H2O
Mortar acts as a Binding material.
Ca(OH)2 + CO2 >CaCO3 + H2O
Limestone – calcium carbonate, CaCO3, is a solid material found naturally. It decomposes thermally to form calcium oxide – quicklime, CaO and carbon dioxide, CO2. When water added to quicklime it forms calcium hydroxide – slaked lime, Ca(OH)2. Slaked lime reacts further with carbon dioxide to form the calcium carbonate solid precipitate.
CaCO3 >CaO + CO2
CaO + H2O >Ca(OH)2
Ca(OH)2 > CO2+CaCO3
Uses of calcium carbonate
Cement – powdered limestone heated with powdered clay.
Concrete – mixture of cement, water, sand and crushed rock.
Glass – powdered limestone heated to high temperatures with a combination of sand and sodium carbonate.
Mortar – it holds other building materials together, it’s a mixture of calcium hydroxide, sand, and water. Lime in mortar reacts with carbon dioxide in the air producing limestone