Atmosphere

Question 1

How has the Chemistry of Earth’s atmosphere changed over time?

Answer 1

• During first billion years, there was lots of volcanic activity
• These volcanoes released lots of gases that formed the early atmosphere
• At this period our atmospheres may have been like Venus’ and Mars’
• Volcanoes produced Methane, Nitrogen and Ammonia
• Water vapour produced by volcanoes condensed to form oceans
• CO2 dissolved into oceans, reducing CO2 in atmosphere
• Carbonates were precipitated producing sediments, reducing CO2 in atmosphere
• Photosynthetic Algae 2.7 billion years ago took in CO2 and expired oxygen
• Billions of years later plants further reduced CO2 levels
• Until animals could evolve and survive on oxygen
• CO2 was decreased as fossils formed from carbon remains and sedimentary rock formed and limestone formed from shells of dead life

Question 2

How was crude oil and natural gas formed?

Answer 2

• Formed from simple plants and tiny animals
• Which died and their remains sank to the bottom of the sea
• Where they were buried under sediments
• The lack of O2 prevented oxidation from occurring

Question 3

How can pollutants damage the atmposphere?

Answer 3

• Oxides of nitrogen and sulphur dioxides can dissolve in rainwater to form acid rain
• Soot is a particulate made of unburned hydrocarbons and carbons
• Soot can increase risk of heart and lung disease
• Smog, Global dimming
• Affects rainfall patterns

Question 4

How is Sulphur dioxide formed?

Answer 4

• Impurity sulphur within fuel

- Oxidised with oxygen to form Sulphur Dioxide

Question 5

How are nitrous oxides formed?

Answer 5

• At really high temperatures
• Such as in the engines of cars
• Where nitrogen and oxygen react

Question 6

How can pollutants be damaging?

Answer 6

• Acid rain corrodes buildings
• Kills plants
• Global warming
• Cancer
• Respiratory problems from damaged lungs
• Corrode metals