Mock Revision

Question 1

What do scientists believe about our early atmosphere?

Answer 1

Many scientists believe these gases would of been in our early atmosphere too. However, they cannot be certain how much of these gases early volcanoes produced.

Question 2

What has led to scientists thinking the Earth’s early atmosphere was mainly carbon dioxide?

Answer 2

Volcanoes on Mars and Venus but their atmospheres are mainly carbon dioxide.

Question 3

Limestone is what type of rock?

Answer 3

Sedimentary

Question 4

Limestone is a sedimentary rock. What is the main substance in Limestone?

Answer 4

Limestone is mostly calcium carbonate.

Question 5

What are two ways that carbon dioxide was removed from the early atmosphere?

Answer 5

1. As the Earth cooled, water vapour in the air condensed to form oceans.
2. Carbon Dioxide in the atmosphere then dissolved in oceans. Scientists think that about half of the carbon dioxide was lost from the atmosphere in this way

Question 6

Explain how the amount of oxygen in the atmosphere gradually increased.

Answer 6

Scientists believe that life started on Earth about 4 billion years ago. About 1 billion years ago, some organisms developed the ability to photosynthesise, which meant taking in carbon dioxide and releasing oxygen.

So it increased because over time more photosynthesising organisms evolved which sped up the rate at which carbon dioxide was removed and oxygen was added.

Question 7

What is the main gas in the atmosphere today?

Answer 7

Nitrogen is the main gas in the atmosphere today, it makes up 75% of the air.

Question 8

List the three main gases in air

Answer 8

Nitrogen, Oxygen, Argon

Question 9

How is an igneous rock formed?

Answer 9

They are formed by where molten rock cools down as it solidifies and becomes solid rock.

Question 10

What gases do volcanoes release?

Answer 10

Volcanoes on Earth today release mainly carbon dioxide and water vapour along with small amounts of ammonia, methane and nitrogen.

Question 11

Give one use of Limestone (1)

Answer 11

Limestone is cut into blocks to be used for constructing buildings

Question 12

The process of getting a metal from a compound in a rock by a chemical reaction is called what?

Answer 12

Extraction

Question 13

Some metals can be extracted by heating their compounds with what?

Answer 13

Carbon

Question 14

As the more reactive a metal is, what happens?

Answer 14

It becomes harder to extract

Question 15

What are the three most reactive metals?

Answer 15

Potassium - 1
Sodium - 2
Calcium - 3