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GCSE: Changing Materials - The Earth and its Atmosphere

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Key things you need to know about the atmosphere

  1. 1 The air around us is composed of 70% nitrogen, 29% oxygen and 1% other gases (mostly noble gases and 0.04% carbon dioxide)
  2. 2 Two of the best ways now being used to reduce carbon dioxide emissions are: “capture and storage”- where we capture the CO2 and trap it in abandoned oil wells. And “sequestration”- where we react the CO2 with CaO to make CaCO3 (CaO + CO2 = CaCO3)
  3. 3 The layer of atmosphere that we live in is called the troposphere. Above that is the stratosphere, followed by the mesosphere, then the thermosphere and finally the exosphere. The ozone layer is located in the lower stratosphere.
  4. 4 The ozone layer is a layer of O3 molecules that absorb harmful ultraviolet radiation that would otherwise kill most human life on Earth (by giving us cancer).
  5. 5 Gases like CFC’s (chlorofluorocarbons) destroy the ozone layer. It takes decades for CFC’s to be removed from the atmosphere once they are up there- and all the time they are constantly destroying more ozone. There is currently a hole in the ozone layer caused by gases like CFC’s that is as big as the arctic (north) pole…and growing.

Five top tips on pollution

  1. 1 Carbon monoxide is a toxic gas as it blocks the haemoglobin in our blood from transporting oxygen around our body…if you take in too much carbon monoxide you will suffocate even if you keep on breathing!
  2. 2 Nitrogen oxide and nitrogen dioxide gases in the atmosphere cause acid rain. This destroys trees and makes lakes too acidic for fish to live in. It is also responsible for corroding buildings.
  3. 3 Carbon dioxide is the biggest cause of global warming and if its levels are not reduced, it could cause the melting of the polar ice caps. This will flood an estimated minimum of 30% of England. It is the biggest worry of atmospheric scientists of our time.
  4. 4 Particulates, mainly found in car exhausts, get stuck in our lungs and cause cancer.
  5. 5 Low level ozone (O3) is incredibly dangerous, especially for people who have asthma.

What is global warming?

  1. 1 Global warming is caused by greenhouse gases absorbing infrared radiation emitted from the Earth and scattering it back down to Earth. As infrared radiation is basically heat, this heats the surface of the Earth up.
  2. 2 As well as carbon dioxide, other greenhouse gases include water and methane. They absorb the infrared radiation by making their bonds vibrate.
  3. 3 As global warming causes the polar ice caps to melt, clathrate deposits (huge amount of trapped methane gas) are released. This causes further global warming in a positive feedback loop.
  4. 4 As the average temperature on land raises, many crops will not be able to grow. Almost all scientists agree that this will cause widespread famine on a scale never seen before. This will affect all countries, not just developing countries.
  5. 5 A common mistake students make is to confuse the greenhouse effect with the hole in the ozone layer. Ozone has nothing to do with the greenhouse effect. Keep these two topics clearly separated in your mind.

  • Marked by Teachers essays 6
  • Peer Reviewed essays 19
  1. Marked by a teacher

    How are products from oil obtained and used?

    4 star(s)

    The process begins in the oil refinery. In the oil refinery the crude oil is heated to turn the oil in to a vapour; it is then fed into the bottom of the fractionating column. Here several condensers are fitted at different heights. The column is hot at the bottom and cool at the top. The hydrocarbons with the lower boiling points turn into vapour easily compared to those with a higher boiling point. When the vapour reaches a height in the tower where the temperature of the column is equal to that substance's boiling point, it will condense to form a liquid.

    • Word count: 1778
  2. Marked by a teacher

    An investigation to see how voltage affects The electrolysis in a copper Sulphate solution using copper electrodes.

    4 star(s)

    We will then see how much copper is deposited after 3 and half minutes. The dependant variables for this test are the weight of the anode and the cathode. Prediction I believe the higher the voltage the more copper will be deposited on the cathode. This is because of the increase in voltage giving the electrons more push causing the Cu2+ atoms from the anode more of a push to the cathode which will cause a bigger build up as more atoms can get moved about faster.

    • Word count: 1825
  3. Peer reviewed

    Is Aluminium a Suitable Metal for Manufacturing Bicycles?

    5 star(s)

    * This forms a solution of sodium aluminate and sodium silicate, plus a residue of iron (III) oxide, which is removed. * CO2(g) is blown in and the sodium silicate remains in solution, but a precipitate if aluminium hydroxide is formed. * The mixture is then filtered, washed and heated to leave anhydrous aluminium oxide (alumina). * Al2O3 is left. Electrolysis This is how the aluminium and oxygen is separated, through reduction. First the aluminium oxide is added to cryolite (Na3AlF6)

    • Word count: 1034

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