Limestone

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Limestone

Thermal decomposition

Calcium carbonate breaks down when heated strongly. This reaction is calledthermal decomposition. Here are the equations for the thermal decomposition of calcium carbonate:

calcium carbonateright facing arrow with heat (http://www.bbc.co.uk/staticarchive/24ac5d1dcb82bc24e9ac3908069170de44a9b545.gif)calcium oxide + carbon dioxide

CaCO3right facing arrow with heat (http://www.bbc.co.uk/staticarchive/24ac5d1dcb82bc24e9ac3908069170de44a9b545.gif)CaO + CO2

Other metal carbonates decompose in the same way, including:

  • sodium carbonate
  • magnesium carbonate
  • copper carbonate

For example, here are the equations for the thermal decomposition of copper carbonate:

copper carbonate right facing arrow with heat (http://www.bbc.co.uk/staticarchive/24ac5d1dcb82bc24e9ac3908069170de44a9b545.gif)copper oxide + carbon dioxide

CuCO3right facing arrow with heat (http://www.bbc.co.uk/staticarchive/24ac5d1dcb82bc24e9ac3908069170de44a9b545.gif)CuO + CO2

Metals high up in the reactivity series (such as sodium, calcium and magnesium) have carbonates that need a lot of energy to decompose them. Indeed, not all the carbonates of group 1 metals decompose at the temperatures reached by a Bunsen burner.

Metals low down in the reactivity series, such as copper, have carbonates that areeasily decomposed. This is why copper carbonate is often used at school to show thermal decomposition. It is easily decomposed and its colour change, from green copper carbonate to black copper oxide, is easy to see.

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Limestone

Limestone is a rock which is made of calcium carbonate, CaCO3.

Its formed from the remains of tiny animals and plants that lived in the sea millions of years ago. We dig them from the ground using quarries. Which is ALL AROUND THE WORLD!!

LIMESTONE CAN be used for buildings and stuff. 

Many important buildimngs are made of LIMESTONE. 

wE CAN cut and shape the stone taken from the ground into blocks. These can be placed one top pf the otther, like bricks on the wall.

Powered Limestone can also be heated with powered clay to make a cement. When we mix cementpowder with water, sand and crushed rock, a slow chemical reaction takes place. The reaction produces a hard,stone-like building material called concrete.

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