c1.2

a) Limestone, mainly composed of the compound calcium carbonate (CaCO₃), is quarried and can be used as a building material.

b) Calcium carbonate can be decomposed by heating (thermal decomposition) to make calcium oxide and carbon dioxide.

• CaCO₃ CaO + CO₂
• Calcium oxide is yellow when hot, but white when cold

c) The carbonates of magnesium, copper, zinc, calcium and sodium decompose on heating in a similar way.

d) Not all carbonates of metals in Group 1 of the periodic table decompose at the temperatures reached by a Bunsen burner.

e) Calcium oxide reacts with water to form calcium hydroxide, which is an alkali

• CaO + H₂O → Ca(OH)₂
• A lot of heat…