1. and its uses

2. LIME STONE
BY
S.DAYANA PRIYA

4. What is limestone?
• It is a sedimentary
rock
• It was formed mainly
from sea shells
• It is the compound
called calcium
carbonate
• It is a useful raw
material

5. What can limestone be used for?
• Building walls
• Building houses
• Limestone is also
used to make
cement and
concrete
• Neutralising
excess acid in
lakes or soils

6. More about limestone
• Limestone is dug up out of the ground in
quarries
• In Britain about 150 million tonnes of
limestone are quarried each year
• Limestone is the compound calcium
carbonate
• It’s formula is CaCO3
• Limestone can be chemically changed into
other things

7. Heating limestone
• When limestone (calcium carbonate) is
heated, it will break down (decompose)
• When something breaks down with heat we
call this reaction a ….
Thermal decomposition reaction
• Calcium carbonate will have broken down
into calcium oxide and carbon dioxide
• We call calcium oxide quicklime

8. A word equation for this reaction
Calcium heat calcium
carbon
Carbonate oxide dioxide

9. Reacting quicklime with water
• Calcium oxide (quicklime) is a strong alkali
• It reacts with water to form calcium
hydroxide
• Calcium hydroxide is also known as slaked
lime

10. A word equation for this
reaction
calcium + water calcium
oxide hydroxide

11. Uses for slaked lime
• To neutralise acidic
soils, and to break up
the soil so that plants
can grow well
• To neutralise lakes
which have been
polluted by acid rain

12. Another use for calcium
hydroxide
• Calcium hydroxide is also called limewater
• Limewater is used to test for the presence of
carbon dioxide gas
• We breathe out a lot of carbon dioxide
• If we blow through a straw into limewater it
will change from clear to milky-white
• The substance formed in this reaction is
insoluble calcium carbonate

13. A word equation for this
reaction
calcium + carbon calcium + water
hydroxide dioxide carbonate

14. The Limestone Cycle
These reactions all make up the
limestone cycle.

15. limestone
Slaked lime
quicklimelimewater
heat
watermore
water
carbon
dioxide
The limestone cycle

16. I WANT TO THANK
VIJAYAM
INSTITUTION&CORRESPON
DENT SIR FOR GIVING ME
THIS OPPURTUNITY
AND THEN I WANT TO THANK
PRASAD SIR AND NALINI
MADAM.

17. THANK YOU

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