Paper 2 C9 - Chemistry of the Atmosphere Flashcards
State the percentage of oxygen in the atmosphere
21%
State the percentage of nitrogen in the atmosphere
78%
Name the three gases that exist in small amounts (~1%) today
- Carbon dioxide
- Argon
- Water vapour
The proportion of gases in the atmosphere have been the same as today for about ________________ years
200 million
Give one reason why there limited evidence for theories about the Earth’s early atmosphere
Happened 4.6 billion years ago
Describe one theory for how the earth’s early atmosphere was formed
Intense volcanic activity released carbon dioxide , water vapour and nitrogen into the atmosphere
Describe the composition of the early atmosphere
Like Venus/Mars today
–> Mainly carbon dioxide
–> Little to no oxygen
–> Small amounts of ammonia and methane
Explain how oxygen levels increased in the early atmosphere
Algae began to produce oxygen through photosynthesis
–> Around 2.7 billion years ago
–> Allowed animal life to evolve
Give 4 ways that carbon dioxide levels decreased in the early atmosphere
- Trapped in fossil fuels
- Used by algae and plants for photosynthesis
- Dissolved in oceans as carbonates
–> These formed sedimentary rocks
Name 4 greenhouse gases
- Methane (CH₄)
- Carbon dioxide (CO₂)
- Nitrous oxide (N₂O)
- Water vapour (H₂O)
Explain the greenhouse effect
- Short wavelength radiation passes through the atmosphere to the earth’s surface and warms it up
- Long wavelength radiation is re-emitted from the surface
–> gets absorbed by the greenhouse gases in the atmosphere
—> increases the earth’s average temperature
Give 2 examples of human activities that increases carbon dioxide levels in the atmosphere
- Burning fossil fuels
- Deforestation
Give 2 examples of human activity that increases methane levels in the atmosphere
- Intense farming
- Decay of organic waste in landfill
Explain why the media use simplified models of climate change
Climate change is:
- Complex
- Hard to model accurately
The media let people speculate/give their own opinion on climate change, which results in a _________ presentation of it
Biased
State the type of evidence for climate change that is of a higher quality than media
Peer-reviewed evidence
Identify one major cause of climate change
Increasing average global temperatures
Give 4 potential effects of climate change
- Extinction of species
- Raised sea levels (due to melted ice caps)
- Decrease in crop yield
- Extreme weather (drought/flooding)
Define carbon footprint
The amount of greenhouse gases released over the full life cycle of a product/service/event
Give 3 ways of reducing carbon emissions/footprint
- Recycling
- Eating less meat (methane)
- Using less fuel
- Taxing greenhouse emissions
Give 2 reasons why reducing a carbon footprint is difficult
- Needs government support to work
- Can be expensive
Give the chemical term for burning
Combustion
Write the word equation for complete combustion
hydrocarbon + oxygen → carbon dioxide and water
True/False: complete combustion doesn’t require much oxygen
False
- Complete combustion requires plenty of oxygen
Write the word equation for incomplete combustion
hydrocarbon + oxygen → carbon/carbon monoxide + carbon dioxide + water
True/False: incomplete combustion needs a lack of oxygen
True
Name the three elements that most fuels we burn contain
- Sulfur
- Hydrogen
- Carbon
Name the three pollutants that can be released into the atmosphere from burning fuels
- Particulates (unburned hydrocarbon)
- Sulphur dioxdes
- Nitrogen oxides
Name the two pollutants produced as a result of incomplete combustion
- Carbon (soot)
- Carbon monoxide
Give two properties of carbon monoxide
- Colourless
- Odorless
Give one effect of carbon monoxide
Lowers the amount of oxygen that the blood can carry
Give two effects of sulfur dioxide and nitrogen oxides
- Acid rain
- Respiratory problems in humans
Give two effects of particulates
- Global dimming
- Heart and lung problems
