Carbonates

Question 1

Describe the manufacture of lime (calcium oxide)
from calcium carbonate (limestone) in terms of
thermal decomposition

Answer 1

• Quicklime (calcium oxide) is made in a lime kiln (rotary lime kiln)
• Lumps of limestone are fed in at the top
• Then, strongly heated by a current of hot air
• Rotation helps limestone mix with hot air => decomposed to quicklime => removed at bottom of kiln

Question 2

Name some uses of lime

Answer 2

• Reacts with CO2 and hardens to form lime mortar

- Treat acidic soil

Question 3

Name some uses slaked lime (calcium hydroxide)

Answer 3

• Treat acidic soils
• Slaked lime + H20 => Ca(OH)2 which is limewater
• Mortar

Question 4

Uses of limestone

Answer 4

• For construction of roads, building
• Powdered form used to treat acidic soil
• Make glass
• Mixed with clay and heated in furnace, calcium sulfate => crushed => cement