C1.2- Limestone and building materials

Limestone is mainly calcium carbonate (CaCO3) This when heated breaks down into calcium oxide and carbon dioxide

Calcium oxide reacts with water to produce calcium hydroxide or lime water

Uses

Limestone has many uses such as being used in cement, mortar and concrete

Thermal decomposition

We break calcium carbonate down using thermal decomposition

Formula

calcium carbonate-----Heat----->calcium oxide + carbon dioxide CaCO3-----Heat----->CaO + CO2

For the Exam you need to know how you get calcium oxide

You get calcium hydroxide when reacting calcium oxide with water

Formula

calcium oxide + water → calcium hydroxide
CaO + H2O → Ca(OH)2

Alot of heat is produced in this reaction meaning it is exotermic

Limestone is a type of rock meaning it is good for buildings and statues.

Carbonates react with acids to produce carbon dioxide, a salt and water

This shows that calcium carbonate is a base

calcium carbonate + hydrochloric acid → carbon dioxide + calcium chloride + water
CaCO3 + 2HCl → CO2 + CaCl2 + H2O

How ever as it is mostly calcium carbonate it is effected by acid rain

calcium hydroxide is an alkali. Calcium hydroxide is used to neutralize excess acidity, for example, in lakes and soils affected by acid rain.

Cement is made by heating powdered limestone with clay. Cement is an ingredient in mortar and concrete

How it is obtained

Quarrying

Advantages: --------------------------------------------------------------------- 1) Limestone is a valuable natural resource, used to make things such as glass and concrete.-------------------------------------------------------------------------------------------------------------------------------2) Limestone quarrying provides employment opportunities that support the local economy in towns around the quarry.-----------------------------------------------------------------------------------------------------Disadvantages------------------------------------------------------------------Limestone quarries are visible from long distances and may permanently disfigure the local environment.----------------------------------------------------------Quarrying is a heavy industry that creates noise and heavy traffic, which damages people's quality of life.