CHEMISTRY Unit 1a

Limestone:

- The limestone is quarried out of the ground

- It is made from crushed sea shells and fossils

- It is used to make blocks for buildings

- Insoluble in water

- Acid rain can affect it by dissolving Limestone away

Limestone is Calcium Carbonate (CaCO3)

When it is heated, it thermally decomposes (breaks down), to make Calcium Oxide and Carbon Dioxide.

Calcium Carbonate ---> Calcium Oxide + Carbon Dioxide

Limestone Quick Lime

CaCO3  ----------------------> CaO                 + CO2

QUICKLIME ---> SLAKED LIME Slaked Lime:

Quicklime + Water -----> Slaked Lime  An Alkali used to neutralise soils

CaO         + H2O   -----> Ca(OH)2      Slake Lime neutralises much faster

CEMENT: Limestone is heated in a kiln with powdered clay to make cement

MORTAR: Cement is mixed with sand and water to make mortar.

Mortar is used to stick bricks together.

CONCRETE: Mix cement with sand, water and gravel.

GLASS: Limestone is heated with sand, and sodium Carbonate.