Flashcards in C9 Chemistry of the atmosphere Deck (28)
What percentage of the Earth's atmosphere is made of carbon dioxide gas?
What percentage of the Earth's atmosphere is made of oxygen gas?
What percentage of the Earth's atmosphere is made of argon gas?
What percentage of the Earth's atmosphere is made of nitrogen gas?
For how long has the Earth's atmosphere consisted of approximately 78% nitrogen, 21% oxygen, 0.9% argon and 0.04% carbon dioxide?
200 million years
Approximately how old do scientists think the Earth is?
4.6 billion years
One theory suggests that the first gases were released by volcanoes during the first billion years of the Earth's existence. What gas was the most common gas at this time?
What happened to water vapour in the atmosphere as the Earth cooled?
It condensed into seas and oceans
Which planets' atmospheres are thought to be similar today to the early Earth's atmosphere?
Mars and Venus
What effect did the early oceans and seas have on the level of carbon dioxide in the atmosphere?
The level of carbon dioxide in the atmosphere reduced as it was dissolved by the seas and oceans.
Some of the carbon dioxide that dissolves into seas and oceans gets tied up in rocks, how does it get there?
Tiny sea creatures use carbon dioxide from the sea to form carbonates such as calcium carbonate in their shells. When they die these shells form layers at the bottom of the sea which become compressed into sedimentary rocks.
Why did levels of oxygen in the atmosphere eventually start to rise?
Algae and green plants evolved and began to photosynthesise. This produced oxygen from carbon dioxide in the atmosphere.
How long ago did algae begin to photosynthesise?
2.7 billion years ago
How long did it take plants to release enough oxygen into the atmosphere to allow animals to evolve?
about 1 billion years (from 2.7 billions years ago to 1.7 billion years ago)
How long ago did animals begin to evolve on Earth?
Approximately 1.7 billion years ago
Apart from going into production of plant material by photosynthesis and into sedimentary rocks at the bottom of seas and oceans, where else did carbon dioxide get tied up?
In fossil fuels (coal, oil and natural gas).
Name three greenhouse gases
Carbon dioxide, methane and water vapour
How do greenhouse gases trap heat around the Earth?
Short wavelength infra-red radiation from the sun enter the atmosphere. They hit the Earth and warm it up. The Earth emits longer wavelength infra-red radiation which is trapped by greenhouse gases rather than radiating out into space.
Why do many scientists believe that greenhouse gases are linked to climate change?
Peer-reviewed evidence (evidence provided by scientists and reviewed by other scientists to check how reliable their evidence is) suggests there is a direct link between levels of greenhouse gases in the atmosphere and the temperatures at the surface of the Earth which in turn have been linked to changes in the climate.
Why is it that not all reports agree about the effect of greenhouse gases on climate change?
It is difficult to model such complex systems as global climate change. This leads to simplified models, speculation and opinions presented in the media that may be based on only parts of the evidence and which may be biased.
List four potential effects of climate change.
1. Loss of habitat - whether it is the polar ice-caps melting or the amazon rainforest drying up there are changes to the habitat of many species on Earth
2. Species being driven to extinction - if habitats are lost the animals that live in them may be driven to extinction
3. Flooding in some areas and drought in others - warm air holds more water than cold air and can change the pattern of rainfall across the globe
4. Oceans and seas cannot hold so much carbon dioxide gas when they are warmer so they will not be such good carbon sinks - leading to further climate change.
What is a carbon footprint?
The carbon footprint is the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event.
How can carbon footprints be reduced?
The carbon footprint can be reduced by reducing emissions of carbon dioxide and methane.
Name five atmospheric pollutants that can be released by burning fossil fuels.
1. carbon monoxide
2. nitrogen oxides
3. particulates (soot - carbon particles)
4. sufur dioxide
5. carbon dioxide
What damaging effects can sulfur dioxide have?
It can cause acid rain and cause respiratory (breathing) problems for humans
What damaging effects can carbon monoxide have?
It is a deadly, colourless (you can't see it), odourless (you can't taste it) toxic gas.
What damaging effects can nitrogen oxides have?
They can cause acid rain and cause respiratory (breathing) problems for humans.