Chemistry In Our World and materials from Earth

Question 1

What gases are released from volcanoes

Answer 1

Carbon dioxide, nitrogen, methane, ammonia, water vapour

Question 2

How did volcanoes lead to water

Answer 2

When they erupt water vapour is released and as the earth cooled the water vapour condensed and gradually formed oceans

Question 3

Why hasn’t Mars or venues atmosphere changed like ours

Answer 3

Life on Earth meant different gases were taken in and released, changing the atmosphere

Question 4

Why do scientists think there was almost no oxygen on earth billions of years ago

Answer 4

Some of the oldest iron compounds on earth can only form where there isn’t oxygen

Question 5

Where did most of the carbon dioxide in the early atmosphere gone after oceans formed

Answer 5

It was absorbed into the oceans. About half of it

Question 6

How is limestone formed

Answer 6

Sea creatures used the co2 in the water to make their shells out of calcium carbonate. When they died their shells sunk and formed layers, over time the heat and pressure turned the shells into limestone

Question 7

How was carbon dioxide removed using plants

Answer 7

Plants photosynthesis which removes the co2 and releases oxygen

Question 8

Gas percentages in the atmosphere

Answer 8

N 78.00
O 21.00
Argon 0.90
CO2 0.04
Other traces

Question 9

What are igneous rocks

Answer 9

Rocks from the cooling of lava

Question 10

What is molten rock called

Answer 10

Magma

Question 11

What is surface Magma called

Answer 11

Lava

Question 12

What determines the size of crystals in igneous rocks

Answer 12

Cools fast, smaller crystals

Cools slowly, larger crystals

Question 13

Example of an igneous rock

Answer 13

Granite

Question 14

What are sedimentary rocks made of

Answer 14

Sediment from other rocks caused by erosion or remains of organisms. Over millions of years, layers build up and pressure and heat forms the rock

Question 15

How are igneous rocks made

Answer 15

Through the cooling of magma/lava

Question 16

Example of sedimentary rock

Answer 16

Chalk, limestone

Question 17

What are metamorphic rocks made of and how are they made

Answer 17

Made up of other rock that has been put under lots of pressured and heat to form new crystals and morph into another rock

Question 18

Example of metamorphic rock

Answer 18

Marble, made from chalk or limestone

Question 19

What is the main compound in chalk and limestone

Answer 19

Calcium carbonate, from shell animals

Question 20

Why does sedimentary rock erode easier than igneous or metamorphic

Answer 20

Unlike igneous or metamorphic it doesn’t have interlocking crystals that help hold it together so they aren’t as hard

Question 21

Uses of limestone

Answer 21

Making glass
Cement
Buildings
Making alloys

Question 22

Advantages and negatives to quarries

Answer 22

Advantages:
Gives us useful materials
Gives people jobs in places where jobs are difficult to find
Negatives:
Lots of noise
Extra traffic from transport Lorries
Often built in pretty places like Peak District and they look ugly

Question 23

What usually happens to used up quarries

Answer 23

The owner often turns it into a nature reserve or farmland

Question 24

Thermal decomposition of Calcium carbonate

Answer 24

Calcium carbonate –> carbon dioxide +calcium oxide

Question 25

How is cement made

Answer 25

Heating limestone and powdered clay in a rotating kiln then grinding the mixture to make cement

Question 26

Uses of cement

Answer 26

Used to make mortar which is used to hold bricks together

Used to make cement after mixing it with water ,sand and rocks, used to make buildings and bridges

Question 27

How is glass made

Answer 27

Limestone is heated with sand and sodium carbonate to form molten glass

Question 28

How is limewater made

Answer 28

Calcium carbonate is heated to make calcium oxide and carbon dioxide
Water is added to calcium oxide which causes and hot reaction and forms a white compound called calcium hydroxide
More water is added to this compound and it dissolves to make lime water

Question 29

What is limewater called

Answer 29

Calcium hydroxide solution

Question 30

Why does limewater go cloudy when carbon dioxide is passed through

Answer 30

It reacts and calcium carbonate (a precipitate) is formed which is white. So it looks cloudy

Question 31

How can farmers neutralise acidic soil

Answer 31

Spraying powdered calcium carbonate/oxide/hydroxide onto the soil as it’s an alkali

Question 32

How do power stations stop acidic gases (sulphur dioxide and nitrogen oxides) from escaping and forming acidic rain

Answer 32

They are stored and powdered calcium carbonate is sprayed through them which neutralised them