C9 Chemistry Of the Atmosphere Flashcards
What are the proportions of the Earth Atmosphere?
- Nitrogen 78%
- Oxygen 21%
- Argon <1%
- CO2 0.04%
- Other Gases (inc. noble gases and water vapour) <1%
Why is Nitrogen needed for organisms?
Nitrogen is a key component of proteins, which are essential for growth
Whilst it is abundant in the atmosphere, the producers found at the base of food chains are not able to exploit this source
Instead, they must absorb nitrogen in the form of soluble nitrates from the soil
Why is Oxygen needed for organisms?
Oxygen is a reactant in respiration - a chemical reaction that takes place in all living cells
Why is Carbon Dioxide and Water vapour needed in the atmosphere?
Carbon dioxide and water vapour are greenhouse gases
Greenhouse gases absorb and then re-radiate heat energy that is reflected off the Earth’s surface. This is known as the greenhouse effect
What was early Early Earth Like?
For the first billion years of the Earth’s existence, highly active volcanoes populated the surface
What was the atmosphere of Earth like in early existence?
Volcanoes frequently erupted. This released lots of carbon dioxide
Scientists believe carbon dioxide dominated the early atmosphere in a similar way to modern-day Mars and Venus
How did volcanic activity create the oceans?
- The volcanic eruptions released water vapour
- The Water Vapour condensed and rained down, which eventually created the oceans
How did the formation of the Oceans remove Carbon Dioxide from the atmosphere?
The formation of oceans removed carbon dioxide from the atmosphere Some of the dissolved carbon dioxide reacted with seawater to produce carbonate precipitates. These were deposited as sediment
Which gases were released by volcanic activity into the Earth’s early atmosphere?
- Carbon Dioxide
- Nitrogen
- Water Vapour
- Methane
- Ammonia
How did photosynthetic organisms increase the atmospheric concentration of oxygen?
- Algae were the first photosynthetic organisms to evolve approximately 2.7 billion years ago
- Over the next billion years, photosynthesising plants began to evolve
- This led to an ever-increasing rate of oxygen accumulating in the atmosphere
Which 3 factors decreased the atmospheric concentration of Carbon Dioxide?
- Formation of Oceans
- Photosynthesis
- Marine Animals
How did oceans decrease atmospheric carbon dioxide?
When carbon dioxide is dissolved in the oceans, some of this carbon dioxide reacted with seawater to give carbonate precipitates
How did Photosynthesis decrease atmospheric carbon dioxide?
Carbon dioxide is one of the reactants for photosynthesis
So, the photosynthetic action of algae and plants removed carbon dioxide from the atmosphere
How did Marine Animals decrease atmospheric carbon dioxide?
Marine animals evolved. This removed carbonates from the oceans as the animals used these to build their shells and skeletons
Describe in detail the processes of the Greenhouse Effect?
- The sun emits short wavelength infrared radiation that enters the atmosphere and travels towards the Earth’s surface
- The Earth absorbs some of this radiation, but long wavelength radiation is reflected back into the atmosphere
- Greenhouse gases can’t absorb the frequency of radiation emitted by the Sun, but they can absorb the longer wavelength reflected radiation
- The gases then re-radiate this energy in all directions, including back towards Earth
- This increases the temperature at the Earth’s surface
