Hannah Farbon
Flashcards by Hannah Farbon, updated more than 1 year ago
Hannah Farbon
Created by Hannah Farbon over 7 years ago



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EVOLUTION OF THE ATMOSPHERE The Earth's Atmosphere wasn't always like it is today
PHASE 1 - VOLCANOES GAVE OUT GASES Points (1,2,3) 1) The Earth's surface was originally molten for many millions of years. It was so hot that any atmosphere just 'boiled away' into space 2) Eventually everything cooled down a bit and a thin crust formed, but volcanoes kept erupting 3) The volcanoes gave out lots of gas, including Carbon Dioxide, Water vapour and Nitrogen. We think this was how the atmosphere was formed
PHASE 1 - VOLCANOES GAVE OUT GASES CONTINUED... Points (4,5) 4) According to this theory, the early atmosphere was probably mostly carbon dioxide CO2 and Water Vapour with virtually no oxygen 5) The oceans formed when the water vapour condensed when the Earth cooled
PHASE 2 - GREEN PLANTS EVOLVED AND PRODUCED OXYGEN 1) Green plants evolved over most of the Earth. They were quite happy in the CO2 atmosphere 2) A lot of the early CO2 dissolved into the oceans. The green plants also removed the CO2 from the air and produced Photosynthesis 3) When the plants died and were buried under layers of sediment, the carbon they had removed from the air (as CO2) became locked up in the sedimentary rocks as insoluble carbonates and fossil fuels
PHASE 3 - COMPLEX ORGANISMS EVOLVED 1) The build up of Oxygen in the atmosphere killed off some early organisms that couldn't tolerate it, but allowed other more complex organisms to evolve 2) There was virtually no CO2 left then
HUMAN ACTIVITY IS CHANGING THE ATMOSPHERE The concentration of nitrogen, oxygen and argon in the atmosphere are pretty much constant. But human activity is adding small amounts of pollutants to the air
5 MAIN POLLUTANTS - Carbon Dioxide C02 - Carbon Monoxide CO - Particulates (e.g. carbon) - Sulphur Dioxide S02 - Nitrogen oxides
WHERE DO THE POLLUTANTS COME FROM? - From burning fuels in power stations and vehicles - Gases and particulates can also be released by nature, e.g. volcanoes
DIRECT HARM FROM POLLUTANTS - Some pollutant gases are directly harmful to humans. They can cause disease or death if large quantities are inhaled, e.g. carbon monoxide, reduces the amount of oxygen that the blood can carry - leading to flu-like symptoms and eventually death
INDIRECT HARM FROM POLLUTANTS - Pollutants can also harm us indirectly by damaging our environment -e.g. Sulfur dioxide can cause acid rain, which pollutes river and lakes, killing the fish which people catch and eat - Other pollutants such as CO2 are leading to climate change e.g. leading to rising sea levels and disruption to farming
FOSSIL FUELS Fossil Fuels are Hydrocarbons - This means it is a compound which contains just Hydrogen and Carbon ONLY
COAL IS NOT A HYDROCARBON! Coal is NOT a hydrocarbon, it contains lots of impurities but it'd mostly just carbon
BURNING FUELS IS AN EXAMPLE OF OXIDATION - COMBUSTION Burning, also known as COMBUSTION is a type of chemical reaction
BURNING FUELS AND COMBUSTION 1)When a hydrocarbon burns, the hydrogen atoms in the fuel combine with oxygen atoms in the air to make hydrogen oxide (water) 2) and the carbon atoms in the fuel combine with oxygen atoms from the air to make carbon dioxide 3) When coal burns, you mostly get carbon dioxide
BURNING FUELS CONTINUED... Combustion is an example of an oxidation reaction 4) Any reaction where oxygen is added is called an oxidation reaction. Reactions where oxygen is lost are called reduction reactions 5) Reactions where oxygen is lost are called reduction reactions 6)The oxygen needed to burn hydrocarbons can come from the air, or it can be in the form of pure oxygen. Hydrocarbon fuels burn more rapidly in pure oxygen than they do in the air 7) Pure oxygen can be obtained from the atmosphere and kept in pressured cylinders
AIR POLLUTION - CARBON -All fossil fuels contain large amounts of the element carbon
COMPLETE AND INCOMPLETE COMBUSTION If the fuel is burnt when theres lots of oxygen available, then nearly all the carbon ends up as carbon dioxide COMPLETE COMBUSTION But if there's not much oxygen available, such as in a car engine, then small amounts of carbon monoxide and small particles of carbon are produced as well INCOMPLETE COMBUSTION
AIR POLLUTION - SULPHUR Sulphur comes from impurities in fuels as they are extracted straight from the Earth's crust and although many of the impurities are harmless some contain sulphur
SULPHUR AND HOW IT POLLUTES When the fuels burn, sulphur does too, and when sulphur atoms burn, they combine with oxygen in the air to produce the pollutant sulphur dioxide
ACID RAIN Acid rain is caused by sulphur pollution
AIR POLLUTION - NITROGEN Nitrogen pollution involves Nitrogen from the air
NITROGEN POLLUTION - Fossil fuels burn at such high temperature that nearby atoms in the air react with each other - Nitrogen in the air reacts with the oxygen in the air to produce small amounts if compounds known as nitrogen oxides - NO & NO2 - This happens in car engines - Nitrogen oxides are pollutants and are usually spewed straight out into the atmosphere
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