Flashcards in C1 - Rocks & Building Materials Deck (36)
What is limestone?
Limestone is mainly made of calcium carbonate.
What is limestone commonly used for?
What happens when limestone is heated?
The calcium carbonate breaks down to form CO2 and calcium oxide. This is thermal decomposition.
How is limestone used in building?
Powdered limestone with clay is used to make cement which is mixed with water, sand and crushed rock to make concrete.
What is the chemical formula for calcium carbonate?
Give the word equation for thermal decomposition of limestone.
calcium carbonate --heat--> calcium oxide + carbon dioxide
What is thermal decomposition?
Breaking down a chemical through heating.
How is calcium oxide produced industrially?
Using a lime kiln.
How does a rotary lime kiln work?
The kiln is filled with crushed limestone and heated using a supply hot air. The kiln is rotated to ensure the limestone is mixed with the hot air.
How do carbonates react with acids?
They form a salt, water and CO2.
What is the test for CO2 gas?
Limewater turns cloudy due to formation of insoluble calcium carbonate.
Give the symbol equation of the reaction of CO2 in limewater.
Ca(OH)2 + CO2 ----> CaCO3 + H2O
Give the symbol equation for the reaction of a carbonate with hydrochloric acid.
__CO3 + 2HCl ----> __Cl2 + H2O + CO2
Give the word equation of a metal carbonate decomposition.
_____ carbonate ----> _____ oxide + carbon dioxide
How is calcium hydroxide produced from calcium oxide?
Water added to calcium oxide produces calcium hydroxide.
Why is calcium hydroxide useful substance?
Calcium hydroxide is alkaline so can be used to neutralise acids.
What is the limestone reactions cycle?
The reactions of limestone and its products.
Give the order of the limestone cycle.
Calcium carbonate, calcium oxide, calcium hydroxide, calcium hydroxide solution.
What is given off when calcium carbonate is heated?
What is produced when a little water is added to calcium oxide?
What is produced when more water is added to calcium hydroxide and is filtered?
Calcium hydroxide solution
What is produced when carbon dioxide is added to calcium hydroxide solution?
How is mortar made?
Mortar is made by mixing cement and sand with water
How is concrete made?
Concrete is made by mixing aggregate, cement and sand with water.
Give a disadvantage of lime mortar.
It will not set at all where water prevents it from reacting with carbon dioxide.
How is cement made?
Heating limestone with clay in the kiln produces cement.
Give three advantages of concrete
-It is especially good at resisting forces which tend to squash or crush it.
-They can be made even stronger by pouring the wet mixture around steel rods or bars which makes reinforced concrete.
-This is also good at resisting forces that tend to pull it apart
Give one environmental social and economic effect of quarrying limestone.
-Quarrying limestone can damage or destroy animal's habitats.
-Blasting at quarry mines can disturb local residents.
-Limestone quarries can often bring jobs to the local economy.
How is limestone mined?
Explosive charges are used to dislodge limestone from the rock face.