Chemistry of the Atmosphere Flashcards
What percentage of the modern atmosphere is oxygen?
About 20%
What percentage of the modern atmosphere is nitrogen?
About 80%
How long has the atmosphere been like like today’s?
200 million years
How was the early atmosphere first formed?
Volcanoes released carbon dioxide, water vapour, and nitrogen (and small amounts of methane and ammonia)
How did the oceans form?
Water vapour in the atmosphere condensed to fall as rain into hollows in the earth, forming oceans
What is the balanced chemical equation for photosynthesis?
6CO2 + 6H2O –> C6H12O6 + 6O2
How did oxygen appear in the atmosphere?
Algae and plants absorbed carbon dioxide through photosynthesis and released oxygen as a waste product. Over years oxygen levels increased until eventually animals could evolve
Why did the amount of carbon dioxide in the early atmosphere decrease?
Algae and plants took in carbon dioxide through photosynthesis
Formation of fossil fuels
Carbon dioxide dissolved into the oceans and reacted with metal oxides to form sediments (carbonates)
Which chemicals did volcanoes in the early atmosphere release?
Carbon dioxide
Water vapour
Nitrogen
Name three greenhouse gases
Carbon dioxide
Water vapour
Methane
What is the greenhouse effect?
- The Sun emits short-wave radiation towards Earth
- Some reflects back into space, but most passes through the atmosphere
- The Earth’s surface absorbs this short-wave radiation and emits it as long-wave radiation
- Some of this long-wave radiation is absorbed by the greenhouse gases in the atmosphere
- This causes the temperature of the atmosphere to increase
How is crude oil formed?
Dead marine organisms being crushed underground over millions of years under high temperatures and pressure
Why have carbon dioxide levels in the modern atmosphere remained fairly constant?
The carbon cycle
How is coal formed?
Plant material from land being crushed over millions of years
Which human activities increase greenhouse gas levels?
- Burning fossil fuels
- Cattle - growing amount of waste products decomposing
What are four effects of climate change?
- Rising sea levels
- Extreme weather events
- Temperature/rainfall levels changing
- Changes in wildlife distribution
Why is rising sea levels a problem?
Causes flooding and increased coastal erosion
Why is temperature / rainfall changes a problem?
Some places may become less suited to growing crops
Why is wildlife distribution changes a problem?
Some species may become extinct
Ecosystems put under stress
What is carbon footprint?
The total amount of carbon dioxide emitted over the full life cycle of a product, service, or event
What problems does carbon monoxide cause?
Toxic gas (starves the body of oxygen, causes drowsiness and eventually death)
Not easily detected as it’s colourless and odourless
What problems does sulphur dioxide cause?
Forms acid rain and causes respiratory problems
How is carbon monoxide produced from burning fuels?
When there is not enough oxygen in car engines, incomplete combustion occurs
How do particulates cause problems?
Global dimming - they reflect sunlight back into space
May damage lung cells or even cause cancer
