Chemistry Of The Atmosphere Flashcards
(16 cards)
Describe the composition of the early atmosphere.
The composition of the early atmosphere would have been very high in carbon dioxide and water vapour. There would have been lots of volcanic activity, and a very high temperature.
Describe how the concentration of nitrogen in the atmosphere changed over time.
Nitrogen was emitted by volcanic activity. Since it is not greatly removed from the atmosphere by any natural processes, it’s concentration in the atmosphere simply continued to increase over time.
Describe how the concentration of carbon dioxide in the atmosphere changed over time.
Carbon dioxide was absorbed by the oceans to form carbonates that sea creatures used in their shells, as well as being removed from the atmosphere via photosynthesis by photosynthetic organisms and eventually green plants
Describe how the concentration of oxygen in the atmosphere changed over time.
The evolution of photosynthetic organisms and green plants caused oxygen to be released in great quantities into the atmosphere (which, incidentally, initially caused the extinction of many species on Earth: the ‘Great Oxidation Event’) via photosynthesis.
Describe how the concentration of water vapour in the atmosphere changed over time.
When the Earth cooled, the water vapour in the atmosphere condensed to form the world’s oceans (it rained for millions of years).
Describe the current composition of the atmosphere.
Our current atmosphere is approximately 21% oxygen, 78% nitrogen, 0.04% carbon dioxide and 0.96% argon, with trace amounts of other gases.
Give examples of greenhouse gases
Examples of greenhouse gases include water vapour, carbon dioxide and methane.
Describe the greenhouse effect.
The Sun emits short-wavelength radiation, which the Earth absorbs, heating its surface temperature. The Earth then emits long-wavelength radiation, which is then absorbed by greenhouse gas molecules in the atmosphere, causing the bonds in these molecules to stretch and squish, and the molecules themselves to vibrate, increasing the temperature of the atmosphere. The greenhouse gas molecules then re-emit IR radiation in random directions.
What forms of human activity affect the amount of greenhouse gases in the atmosphere.
Burning fossil fuels, deforestation, agriculture and the creation of waste all affect the amount of greenhouse gases in the atmosphere
What are climate change and global warming?
Global warming is the average increase in the surface temperature of the Earth caused by the human-enhanced greenhouse effect (whereby more greenhouse gas molecules are in the atmosphere). Climate change refers to the shifts in long-term weather patterns as a result of this
What are the consequences of climate change?
The consequences of climate change include the melting of the polar ice caps (leading to coastal flooding and erosion, as well as setting up a positive feedback cycle), changes in rainfall patterns leading to water shortages in some areas (and in turn potentially leading to food scarcity), the frequency and severity of storms and the extinction of wild species.
What are carbon footprints?
Carbon footprints are measures of the amount of carbon dioxide and greenhouse gases emitted throughout the lifetime of something (a product, service, event or even a human).
Why can carbon footprints be difficult to measure?
It can be difficult to calculate the carbon footprint of something since there are so many different factors affecting the amount of carbon dioxide that a product emits; e.g. in calculating the carbon footprint of a toaster, you would need to consider the extraction of the raw materials, transport, construction, the use of it and disposal.
How can carbon footprints be reduced?
Carbon footprints can be reduced by:
- Using renewable/nuclear energy.
- Using more efficient/sustainable processes.
- Governments taxing corporations in line with the amount of greenhouse gases they release, or capping the amount of greenhouse gases they can release.
- Carbon capture technologies.
Why is action on climate change not occuring?
Not enough is being done to address climate change due to various factors, including:
- The focus of governments on the short-term economic impacts of transitioning to renewables/nuclear.
- It is difficult to reach international agreements regarding tackling climate change.
- Renewable technologies still need work.
- Developing countries sometimes cannot afford to move to relying on renewables.
What are the different forms of air pollution, how are they formed and what do they do?
Greenhouse gases are formed when fossil fuels are burnt. They cause climate change.
Carbon monoxide is poisonous (it binds to the haemoglobin in red blood cells in the same way that oxygen does, which can be fatal) and it is released in incomplete combustion.
Particulates such as soot are also released in incomplete combustion and cause global dimming, as well as respiratory issues in humans.
Sulfur dioxide is formed when fossil fuels with sulfur impurities are burnt. It causes acid rain when they mix with clouds (forming dilute sulphuric acid), which can destroy limestone buildings, change the pH of soils and damage aquatic ecosystems.
Nitrogen oxides are formed when nitrogen reacts with the oxygen in the air in hot engines. They also cause acid rain when they mix with clouds, forming dilute nitric acid.
