Materials from the Earth

Question 1

how are igneous rocks formed

Answer 1

igneous rocks are formed when magma or lava solidifies

Question 2

what are igneous rocks made of? what does this do?

Answer 2

they are made of interlocking crystals which makes them hard and resistant to erosion.

Question 3

how does the rate of cooling affect the size of igneous rocks

Answer 3

if the rock cools quickly they have small crystals (basalt). if the rock cools slowly they have large crystals (granite)

Question 4

give two examples of sedimentary rocks

Answer 4

chalk and limestone

Question 5

how are sedimentary rocks formed

Answer 5

formed when layers of sediment are compacted/squashed over a long period of time by being buried under more layers.

Question 6

give two features of sedimentary rocks

Answer 6

erode more easily than igneous and metamorphic rocks. and they may contain fossils

Question 7

give an example of a metamorphic rock

Answer 7

marble

Question 8

how are metamorphic rocks formed

Answer 8

formed from existing rocks by the action of heat (being being buried or from nearby magma) and pressure which causes new interlocking crystals to grow

Question 9

how is marble formed

Answer 9

marble is formed from chalk or limestone. it is a natural form of calcium carbonate

Question 10

what is limestone used for

Answer 10

making buildings, roads, railways.

Question 11

what is limestone mostly made of

Answer 11

calcium carbonate

Question 12

what is calcium carbonate used to make

Answer 12

it is used to make glass, cement and concrete

Question 13

how do we use limestone to make cement and glass

Answer 13

limestone is heated when making cement and glass

Question 14

describe the thermal decomposition of limestone(calcium carbonate)

Answer 14

the heat decomposes the calcium carbonate to from calcium oxide and carbon dioxide.

Question 15

give the word equation of the thermal decomposition of calcium carbonate

Answer 15

calcium carbonate > calcium oxide + carbon dioxide

Question 16

give 4 advantages of quarrying limestone

Answer 16

1) it is an important raw material
2) quarries provide jobs in the countryside
3) some limestone is exported to other countries, which helps the UK economy
4) jobs in quarries also help local economies, because the workers spend their money in local shops and businesses

Question 17

give 4 disadvantages of quarrying limestone

Answer 17

1) quarries produce dust and noise pollution
2) digging a quarry destroys habitats for wildlife
3) quarries spoil the scenery
4) lorries taking the limestone away cause extra traffic, noise and pollution

Question 18

Describe the ease of thermal decomposition of different metal carbonates

Answer 18

calcium carbonate (hardest to decompose), zinc carbonate, copper carbonate (easiest to decompose).

Question 19

give 3 features of atoms

Answer 19

1) atoms are the smallest particles of an element that can take part in chemical reactions
2) during chemical reactions, atoms are neither created nor destroyed
3) during chemical reactions, atoms are rearranged to make new products with different properties from the reactants

Question 20

Describe the effect of water on calcium oxide

Answer 20

heat is released. the mixture fizzes, steam is given off and the calcium oxide crumbles to a white powder of calcium hydroxide. if more water is added to the reactants, the calcium hydroxide dissolves to form a solution called limewater

Question 21

what happens when calcium hydroxide is dissolved in water

Answer 21

calcium hydroxide dissolves to form a solution called limewater

Question 22

what is a precipitate reaction

Answer 22

a precipitate reaction happens when two soluble substances react together to form a product that is insoluble. the insoluble product is the precipitate.

Question 23

what does a precipitation reaction in a sealed container show

Answer 23

it shows that the total mass before and after a reaction does not change.

Question 24

how can calcium oxide, calcium hydroxide and calcium

carbonate be used

Answer 24

they can all be used to neutralise acidic compounds. some soils are acidic. farmers use calcium compounds to neutralise the acidity so their crops will grow better.

Question 25

explain why gases emitted by coal-fired power stations need to be cleaned up, and how calcium carbonate can do this.

Answer 25

the waste gases from coal-fired power stations contain sulfur dioxide and nitrogen oxides, which are acidic gases. these gases cause acid rain if they get into the atmosphere. wet, powdered calcium carbonate is sprayed into the waste gases to neutralise them.