C1.2 Materials from the Earth Flashcards
What is magma?
Molten rock inside the Earth’s crust
What is lava?
Molten rock on the surface of the Earth
How are igneous rocks formed?
Through the solidification of magma or lava
What does the size of crystals within an igneous rock depend on?
The rate at which the magma or lava cools
When do igneous rocks form small crystals?
When they’re cooled quickly
When do igneous rocks form large crystals?
When they’re cooled slowly
What type of rock is granite?
Igneous
What type of rock is chalk?
Sedimentary
How can rocks be broken down into smaller pieces?
- through the expansion of water when it freezes
- erosion
How is sedimentary rock formed?
- weathering of rocks creates sediment which is deposited on the bottom of lakes or seas
- layers of sediment build up over a long period of time, causing compaction
- dissolved minerals cause cementation which binds the sediment together, forming sedimentary rock
What types of rock are marble and mylonite?
Metamorphic
What are metamorphic rocks?
Rocks that have been changed by heat or pressure
What type of rock is most susceptible to erosion?
Sedimentary
What type of rock can have fossil remains?
Sedimentary
Why are igneous and metamorphic rocks less likely to erode?
They have interlocking crystals which make them harder
What are the uses of limestone as a raw material?
The manufacture of cement, concrete and glass
What are the three natural forms of calcium carbonate?
Limestone, chalk and marble
What are the benefits of quarrying for limestone?
- creates jobs in the countryside where they might be difficult to find
- improves the economy when exported to other countries
What are the drawbacks of quarrying for limestone?
- dusty and noisy
- affect the quality of life of locals
- damage tourism industry
- the lorries that transport the limestone cause extra traffic, noise and pollution
- land taken up by the quarry can’t be used for other purposes like farming
- destroy the original landscape
What does the decomposition of calcium carbonate produce?
Calcium oxide + carbon dioxide
What is the thermal decomposition of limestone used to produce?
Cement and glass
What is thermal decomposition?
The breaking down of a substance by heat
How is cement made?
By heating limestone with powdered clay
How is concrete made?
By mixing cement with sand, gravel and water
How is glass made?
By heating limestone with sand and sodium carbonate
What is the test for carbon dioxide?
Passing it through limewater and seeing if it goes milky
What happens during a precipitation reaction?
Soluble substances react to form an insoluble precipitate
What is produced from the reaction of calcium oxide and water?
Calcium hydroxide
What is limewater?
Calcium hydroxide solution
How do you turn calcium hydroxide into limewater?
You add more water until it dissolves into a solution
What state is calcium hydroxide in?
Solid
Why does carbon dioxide turn limewater milky?
Its reaction with limewater produces an insoluble white precipitate of calcium carbonate
What happens to cloudy limewater when even more carbon dioxide is bubbled through it?
It goes back to being colourless
Why does limewater go back to being colourless when excessive carbon dioxide is bubbled through it?
- the carbon dioxide reacts with water to form an acidic solution because there are no more calcium atoms to react with
- this acid neutralises the calcium carbonate so there is no longer an insoluble precipitate
How do farmers neutralise the acidity of soil?
By spraying calcium carbonate, calcium oxide and calcium hydroxide on the soil to neutralise it
What gases cause acid rain?
- sulphur dioxide
- nitrogen oxides
How do power stations stop sulphur dioxide and nitrogen oxides from escaping?
They spray wet calcium carbonate into the chimeneys to neutralise the acidic gases
