The Earth's atmosphere (unfinished)

Question 1

How old is the earth?

Answer 1

4.6 billion years old

Question 2

How do scientists tell what the atmosphere used to be like?

Answer 2

• Air bubbles trapped in ice
• Air trapped in ancient rocks
• Fossil fuels
• Animal shells forming into sedimentary rocks containing calcium carbonate

Question 3

What gases formed the early atmosphere?

Answer 3

• Carbon dioxide
• Water vapour
• Nitrogen

Question 4

How did gases get into the early atmosphere?

Answer 4

Volcanic activity

Question 5

How was oxygen put into the atmosphere?

Answer 5

Plants and algae photosynthesised, producing oxygen as a byproduct

Question 6

What is the equation for photosynthesis? (word and symbol)

Answer 6

• 6CO2+6H2O→C6H12O6+6O2
• Carbon dioxide+water→glucose+oxygen

Question 7

Why did some of the earliest microorganisms die out?

Answer 7

They couldn’t tolerate the high oxygen concentration

Question 8

What is the composition of Earth’s current atmosphere?

Answer 8

21% oxygen
78% nitrogen
about 1% other gases

Question 9

Why are greenhouse gases bad?

Answer 9

They absorb infrared radiation that the Earth emits, causing the planet to heat up.

Question 10

How do greenhouse gases get into the atmosphere?

Answer 10

• Burning fossil fuels
• Keeping cattle

Question 11

What is the equation for burning fossil fuels? (word and symbol)

Answer 11

• C3H8 + 5O2 —> 3CO2 + 4H2O
• Propane+oxygen—>carbon dioxide+water

Question 12

What is happening to the amount of greenhouse gases in the atmosphere?

Answer 12

Increasing

Question 13

What are examples of carbon dioxide sinks?

Answer 13

• Oceans
• Forests

Question 14

How much longer were winters 40 years ago?

Answer 14

2 weeks

Question 15

Why are rising sea levels bad?

Answer 15

Coastal towns and cities would flood

Question 16

Why is an increase in global temperature bad? (with examples)

Answer 16

• It will damage the weather system, such as more frequent and severe storms
• The distribution and timing of rain will change, meaning some places get drier and crop farmers may need to relocate.
• The distribution of wildlife will change, causing ecosystems to be under stress.

Question 17

What element is found in fossil fuels as an impurity?

Answer 17

Sulfur

Question 18

Why is sulfur bad to have in fossil fuels?

Answer 18

It becomes sulfur dioxide which is toxic and causes acid rain

Question 19

What is it called when there isn’t enough oxygen in the engine?

Answer 19

Incomplete combustion

Question 20

What is formed when incomplete combustion occurs?

Answer 20

Carbon monoxide (CO) instead of carbon dioxide (CO2)

Question 21

Why is carbon monoxide dangerous?

Answer 21

• It is toxic
• It is colourless and odourless

Question 22

How is carbon monoxide toxic?

Answer 22

It binds to the haemoglobin in red blood cells instead of oxygen , taking up spaces until there is no space left to carry oxygen. This starves the victim of oxygen until they lose consciousness.

Question 23

What is formed from high temperatures in the engine?

Answer 23

Nitrogen oxides

Question 24

Why are nitrogen oxides bad?

Answer 24

• They are toxic
• Can trigger asthma
• Cause acid rain