C13 - The Earths Atmosphere Flashcards
What is the atmosphere?
The relatively thin later of gases that surround planet Earth
How long has the atmosphere been in its current state?
200 million years
What are the 5 most abundant gases in the atmosphere?
1) Nitrogen
2) Oxygen
3) Argon
4) Carbon Dioxide
5) Water Vapour and Group 0
What proportion of the atmosphere is Nitrogen?
78%
What proportion of the atmosphere is Oxygen?
21%
What proportion of the atmosphere is Argon?
0.9%
What proportion of the atmosphere is Carbon Dioxide?
0.04%
What proportion of the atmosphere is Water Vapour and Group 0?
Trace amounts
What released the gases that formed the early atmosphere?
Intense volcanic activity spewed out gases and water vapour, forming the early atmosphere. These mainly included Nitrogen, Water Vapour, Ammonia, and Methane
How old is the earth?
4.6 billion years old
What were the 5 most abundant gases in the earths first 1 billion years?
1) Carbon Dioxide
2) Water Vapour
3) Nitrogen
4) Ammonia
5) Methane
What 2 reasons have caused CO2 concentrations in the atmosphere to decrease over time?
- Plants and other photosynthetic organisms take in Carbon Dioxide during photosynthesis. During Photosynthesis, the CO2 reacts with water to form glucose
- Carbon Dioxide dissolves in seawater to produce carbonates. These carbonates are used by marine animals to help build up their shells and skeletons. When these marine animals die, they fall to the seabed and get buried by layers of sediment, this weight compresses them into sedimentary rocks, reducing levels of CO2 in the atmosphere
Why is the CO2 concentration in the atmosphere currently rising?
- Deforestation
* Burning Fossil Fuels
Why have theories about the evolution of the earths atmosphere changed over time?
Advancements in science and technology bring new evidence to light, causing scientists to consider new theories
Why did the water vapour in the earths atmosphere decrease?
As the earth cooled, the water vapour cooled and condensed, forming the oceans
What 2 reasons has caused the nitrogen concentration in the atmosphere increased?
- Ammonia in the Earth’s early atmosphere reacted with oxygen to form nitrogen (and water)
- Denitrifying bacteria produced nitrogen gas from nitrate compounds in the soil
What organism was first responsible for producing oxygen on Earth and when?
Algae, 2.7 billion years ago
What was the Earths atmosphere like prior to any volcanic activity?
Almost entirely Carbon Dioxide with no other gases or water vapour. Similar to current Mars / Venus
What is the chemical equation of the formation of Nitrogen from ammonia?
Why does the % of Nitrogen in the atmosphere remain so high?
Nitrogen is an inert, unreactive gas. Therefore, Nitrogen is very stable in the atmosphere and is not involved chemical reactions that occur.
What is the balanced chemical equation for photosynthesis?
How were fossil fuels formed?
- Coal is a sedimentary rock formed by thick deposits of plant material. The plant material was buried, in the absence of oxygen, and compressed over millions of years to form coal
- Crude oil and natural gas were formed from the remains of plankton deposited in the mud on the seabed. These remains were covered by sediments that became layers of rock when compressed over millions of years. The Crude oil and natural gas were trapped in the layers of rock
Why did levels of ammonia in the atmosphere decrease?
It reacted with oxygen to form nitrogen and water
Why did levels of methane decrease in the atmosphere?
The methane reacted with oxygen to form carbon dioxide and water
