C11- Earth's Atmosphere Flashcards
Describe the earth’s early atmosphere
Earth is 4.6 billion years old and so we are not certain about what it was like but there are 2 main theories. One theory is that volcanoes released carbon dioxide, CO2, water vapour, H2O, and nitrogen, N2 and that these gases formed the early atmosphere. Water vapour in the atmosphere condensed as the earth gradually cooled down, and fell as rain. Water collected in hollows in the crust as the rock solidified and the first oceans were formed. Another theory is that comets could also have brough water to earth. As icy comets rained down on the surface of the earth, they melted, adding to its water supplies. The atmosphere remained quite stable until life first appeared on earth.
How was oxyegn formed in the early atmosphere?
Bacteria and other simple organisms such as algae evolved. Algae could use energy from the sun to make their own food by photosynthesis, which produced oxygen as a waste product. Over the next billion years rose steadily as algae and bacteria thrived in seas. More and more plants evolved all photosynthesising removing carbon dioxide and making oxygen.
What is the composition of earth’s early atmosphere?
Carbon dioxide + water — glucose + oxygen
6CO2 + 6H2O — C6H12O6 + 6O2
—= energy from sunlight
Have the levels of carbon dioxide decreased or increased in the atmosphere?
Decreased
List the names and symbols of the gases in dry air
Nitrogen (N) Oxygen (O) Argon (Ar) Neon (Ne) Krypton (Kr) Xenon (Xe)
Where did ammonia and methane in the atmosphere come from?
Small proportions could have come from volcanoes.
How was the proportion of carbon dioxide from the early atmosphere removed?
It has gone mostly into living organisms and into materials formed from living organisms. Algae and plants decreased the percentage of carbon dioxide in the early atmosphere by photosynthesis.
What is the composition of dry air?
Nitrogen (78%) Oxygen (21%) Argon (0.9%) Carbon dioxide (0.04%) Neon, Krypton and xenon (less than (0.1%)
How can carbon dioxide form sedimentary rocks?
The layers of sediment are are pressured and deposited to form sedimentary carbonate rocks, such as limestone, containing mainly calcium carbonate, CaCO3.
Describe the greenhouse effect
The ground warms up and heat is emitted from the Earth’s surface. Some heat escapes into space but some is absorbed by greenhouse gases. It is re-emitted and does not escape.
Name 3 greenhouse gases
Carbon dioxide
Methane
Water vapour
State some human activities that will effect the proportion of greenhouse gases
Owning an increasing amount of grazing cattle
Increase in human population produces more waste to dispose of in landfill sites.
How do greenhouse gases increase the temperature of the earth?
The greenhouse gases let short-wavelength electromagnetic radiation ,e.g. ultraviolet light, pass through. The surface of the earth cools down by emitting longer wavelength infrared (thermal) radiation. However, greenhouse gases absorb infrared radiation. The radiation stimulates the bonds in these molecules to vibrate, bend, and stretch more vigorously, raising their temperature. So some of the energy radiated from the surface of the earth gets trapped in the atmosphere and the temperature rises. The higher the proportion of greenhouse gases in the air, the more energy is absorbed.
Why do scientists and the public disagree about the cause of climate change?
Because there is no ‘hard evidence’ of any theory or reason being correct. There are multiple different sources and reasons that could be but none of them are proven.
What is the difference between greenhouse effect and global warming?
Global warming is the long term change in climate that has happened cyclically throughout earth’s history, but is currently happening at a much faster rate than normal. This is usually associated with the greenhouse effect, which is a natural phenomenon that allows the Earth to trap heat.
What is the carbon footprint?
The carbon footprint of a product, service or event is the total amount of carbon dioxide and other greenhouse gases emitted over its full life cycle.
List some ways on how to reduce a carbon footprint
Carbon capture and storage. It would increase the cost of producing electricity by about 10%.
Eating less beef- Methane produced from cattle decreased.
Adding carbon taxes on cars that burn a lot of petrol or diesal
List the possible outcomes of climate change
Rising sea levels as a result of melting ice caps and expansion of the warmer oceans. For example, the arctic ice cap appears to be shrinking at a rate equivalent to the Netherland melting away each year. This may cause the flooding of low lying land and increased coastal erosion. Some islands could even disappear.
Increasingly common extreme weather events, such as more frequent and severe storms.
What are some of the problems in trying to reduce the greenhouse gas emissions?
People need inormation on global climate change and they need to understand that small actions like walking instead of driving make a big difference.
Poorer countries weren’t involved in negotiations of co-operation as they aren’t the main contributors to greenhouse gas emissions. However, restrictions could hinder their devloping industries.
List some atmospheric pollutants
Carbon dioxide
Carbon monoxide
Particulate carbon
Unburned hydrocarbons
Describe how carbon monoxide can be made from the incomplete combustion of fossil fuels
Instead of all the carbon in the fuel turning into carbon dioxide, carbon monoxide gas is also formed.
Describe the health impacts of atmospheric pollutants
A victim of carbon monoxide will die if the source of the gas is not removed
Nitrogen oxides are toxic and can trigger some people’s asthma
How are nitrogen oxides made when fossil fuels are combusted?
Oxidation of N2, gas in air at high temperatures in vehicle engines
How is sulphur dioxide made when fossil fuels are combusted?
Oxidation of sulfur impurities in fossil fuels
