Topic 9: Chemistry of the Atmosphere Flashcards
How much of the Earth’s atmosphere is made up from nitrogen?
80%
How much of the Earth’s atmosphere is made up from oxygen?
20%
What are some other gases present in the Earth’s atmopshere? [3]
- Carbon dioxide
- Water vapour
- Noble gases
Why is the evidence for the early atmosphere limited?
Due to the time scale of 4.6 billion years
Describe the Earth’s early atmosphere
i) cause
ii) composition
iii) traces of?
i) Intense volcanic activity that released gases, forming the early atmosphere
ii) Atmosphere consisting mainly of carbon dioxide, little or no oxygen
iii) Traces of nitrogen, methane and ammonia
How were oceans formed?
Water vapour condensed to form oceans
What happened when the oceans were formed?
Carbon dioxide dissolved in the water and carbonates were precipitated producing sediments, reducing the amount of carbon dioxide in the atmosphere
Describe how the amount of oxygen in the atmosphere increased
Algae and plants produced the oxygen that is now in the atmosphere by photosynthesis (2.7 billion years ago)
Describe how the amount of carbon dioxide in the atmosphere decreased
Algae and plants decreased the percentage of carbon dioxide in the atmosphere by photosynthesis
Describe how deposits of coal, oil and gas (fossil fuels) were formed? [4]
- When plants, plankton and marine animals die, they fall to the seabed
- They get buried by layers of sediment
- Over millions of years, they become compressed and form sedimentary rocks (coal), oil and gas
- This traps the CO₂ within them
What is limestone made from?
Sedimentary rock - however it is mostly calcium carbonate deposits from the shells and skeletons of marine organisms
Describe the greenhouse effect and how it affects global temperature [4]
- The sun gives out short wavelength radiation
- This is reflected back by the Earth as thermal radiation
- The thermal radiation is absorbed by greenhouse gases in the atmosphere
- Greenhouse gases give out the thermal radiation in all directions including back towards Earth, causing the temperature to rise
Examples of greenhouse gases [3]
- Carbon dioxide
- Water vapour
- Methane
Describe how human activities are resulting in more CO₂ in the atmosphere [2]
- Deforestation means that there are less trees to remove CO₂ from the atmosphere via photosynthesis
- When we burn fossil fuels, the carbon that was ‘locked up’ in these fuels get released as CO₂
Describe how human activities are resulting in more methane in the atmosphere [2]
- There are more farm animals e.g. cows which release methane through their digestion processes
- More landfill sites and waste from agriculture means more methane released by decomposition of waste
Why is evidence peer-reviewed?
To check that the information is reliable
Why is it hard to fully understand the Earth’s climate? [2]
- Complex
- Too many variables to take into account
Consequences of climate change [4]
- Rising sea levels
- Changes in rainfall patterns
- Frequency and severity of storms
- Species may become extinct or migrate
Define ‘carbon footprint’
Total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event
Ways of reducing carbon footprint [3]
- Switching to renewable energy sources
- Using more efficient processes
- Carbon capture
State 2 things governments can do to try to reduce the greenhouse gas emissions of businesses
- Tax companies on how many greenhouse gases emissions they create
- Put a cap on the amount of greenhouse gas emissions companies can emit
Why is it hard to reduce greenhouse gases emissions? [3]
- Some renewables still in early development
- Many economies still based off fossil fuels
- Not everyone on board with plans to change
How are particulates made?
Produced during incomplete combustion
Problems with particulates [2]
- Can get into people’s lungs and cause respiratory problems
- Can cause global dimming
How is carbon monoxide made?
Produced during incomplete combustion
Problem with carbon monoxide
If breathed in, can starve our brain of oxgen and cause death
Properties of carbon monoxide [2]
- Colourless
- Odourless
How are is sulfur dioxide and nitrogen oxide made?
When impurities in hydrocarbons are oxidised when burnt
Problems with sulfur dioxide and nitrogen oxide [2]
- Can damage lungs and cause respiritory problems
- Can cause acid rain
