The Earth's atmosphere (unfinished) Flashcards
(24 cards)
How old is the earth?
4.6 billion years old
How do scientists tell what the atmosphere used to be like?
- Air bubbles trapped in ice
- Air trapped in ancient rocks
- Fossil fuels
- Animal shells forming into sedimentary rocks containing calcium carbonate
What gases formed the early atmosphere?
- Carbon dioxide
- Water vapour
- Nitrogen
How did gases get into the early atmosphere?
Volcanic activity
How was oxygen put into the atmosphere?
Plants and algae photosynthesised, producing oxygen as a byproduct
What is the equation for photosynthesis? (word and symbol)
- 6CO2+6H2O→C6H12O6+6O2
- Carbon dioxide+water→glucose+oxygen
Why did some of the earliest microorganisms die out?
They couldn’t tolerate the high oxygen concentration
What is the composition of Earth’s current atmosphere?
21% oxygen
78% nitrogen
about 1% other gases
Why are greenhouse gases bad?
They absorb infrared radiation that the Earth emits, causing the planet to heat up.
How do greenhouse gases get into the atmosphere?
- Burning fossil fuels
- Keeping cattle
What is the equation for burning fossil fuels? (word and symbol)
- C3H8 + 5O2 —> 3CO2 + 4H2O
- Propane+oxygen—>carbon dioxide+water
What is happening to the amount of greenhouse gases in the atmosphere?
Increasing
What are examples of carbon dioxide sinks?
- Oceans
- Forests
How much longer were winters 40 years ago?
2 weeks
Why are rising sea levels bad?
Coastal towns and cities would flood
Why is an increase in global temperature bad? (with examples)
- 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.
What element is found in fossil fuels as an impurity?
Sulfur
Why is sulfur bad to have in fossil fuels?
It becomes sulfur dioxide which is toxic and causes acid rain
What is it called when there isn’t enough oxygen in the engine?
Incomplete combustion
What is formed when incomplete combustion occurs?
Carbon monoxide (CO) instead of carbon dioxide (CO2)
Why is carbon monoxide dangerous?
- It is toxic
- It is colourless and odourless
How is carbon monoxide toxic?
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.
What is formed from high temperatures in the engine?
Nitrogen oxides
Why are nitrogen oxides bad?
- They are toxic
- Can trigger asthma
- Cause acid rain
