The Earth's Atmosphere Flashcards
Rank the gases in the present-day atmosphere (200 million years until now) from the highest percentage to lowest:
1.
2.
3.
4.
- Nitrogen.
- Oxygen.
- Carbon dioxide.
- Other gases.
During the first billion years, there was intense ____________________.
Volcanoes __________________ that formed into the __________________.
volcanic activity
released gases
atmosphere
Volcanoes released water vapour.
As the ______________, the water vapour _____________________________.
Earth cooled
condensed to form the oceans
Volcanoes released huge amounts of ____________________.
So in the early stages, the Earth mainly consisted of __________________ with very little ____________________________.
carbon dioxide
carbon dioxide
nitrogen and oxygen
Volcanoes released nitrogen which ___________________ in the atmosphere because nitrogen is _______________.
gradually built up
unreactive
In the early stages, volcanoes released small amounts of other gases such as ____________ and _____________.
methane
ammonia
From 200 million years ago to present day,
carbon dioxide levels ______________.
oxygen levels ______________.
nitrogen levels ______________.
decreased
increased
increased
When water vapour condensed into oceans, carbon dioxide ___________________ to form a _______________ (_____________________________).
This is because carbon dioxide is a very _______________.
dissolved in oceans
weak acid
soluble carbonate compounds
soluble gas
The carbonate compounds __________ with ______________ in the sea to form _______________.
Over time, forming ________________________ on the ______________.
reacted
minerals
precipitates
carbon rock sediment
sea bed
Some carbon dioxide in the ocean was used to make __________ and _________________________.
When they die, the form the sedimentary rock:______________.
So carbon dioxide is ______________ from the atmosphere.
corals
shells of organisms
limestone
removed
Around 2.7 billion years ago, ___________________________.
Photosynthesis ____________________ and __________________________ from the atmosphere,
photosynthetic algae evolved
produced oxygen
removed carbon dioxide
Over billions of years, plants ___________.
_______________ the amount of oxygen in the atmosphere.
The level of oxygen reached the point where ____________________________.
evolved
Increasing
animals could evolve
True or false: Carbon is trapped in fossil fuels.
True.
What is coal formed from?
Remains of ferns and trees.
Give 2 reasons why coal cannot decompose in marshy wetlands:
- Lack of oxygen.
- Acidic conditions.
__________ cannot carry out _________________ in marshy wetlands, so plant remains are ________________________.
And under _________________ and _____________ coal is formed.
Bacteria
decomposition
compressed with sediment
high temperature
pressure
What is crude oil formed from?
Plankton.
When plankton _____ they settle in _____ on the sea bed.
If oxygen is not present, they __________________________ because oxidation cannot take place.
Over time, they are _______________________. __________________ converts plankton into _____________.
die
mud
do not decompose
compressed by sediment
Heat and pressure
crude oil
What does natural gas mainly consist of?
The hydrocarbon: methane.
What is natural gas formed from?
Plankton.
Where is natural gas mainly found?
On top of crude oil deposits.
All fossil fuels contain trapped carbon.
Which is part of the carbon dioxide taken in by what process?
Photosynthesis.
True or false: Oxygen levels decreased due to photosynthesis of plants.
False. Oxygen levels increased.
What are 2 indirect evidences of the composition of the Earth’s early atmosphere?
- Composition of rocks as old as the Earth.
- Fossilised remains of organisms alive at different times since the early atmosphere.
