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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 The air around us is composed of 70% nitrogen, 29% oxygen and 1% other gases (mostly noble gases and 0.04% carbon dioxide)
- 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 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 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 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 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 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 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 Particulates, mainly found in car exhausts, get stuck in our lungs and cause cancer.
- 5 Low level ozone (O3) is incredibly dangerous, especially for people who have asthma.
What is global warming?
- 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 As well as carbon dioxide, other greenhouse gases include water and methane. They absorb the infrared radiation by making their bonds vibrate.
- 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 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 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
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.
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The solution is then heated and the water evaporates off leaving the molten ammonium nitrate/sulphate which is sprayed into a cooling chamber. Air is blown into the bottom of the cooling chamber to cool the ammonium nitrate/sulphate. The droplets of the molten ammonium nitrate/sulphate cool and harden to form pellets which are used in fertilisers.  The urea fertiliser is manufactured slightly differently. Urea is made from the reaction of ammonia and carbon dioxide. The ammonia and carbon dioxide are fed into a reactor at a high pressure and temperature.
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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.
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This is sometimes referred to as the 'enhanced greenhouse effect'. Carbon dioxide absorbs infrared (IR) radiation that is re-radiated by the Earth's surface. This process is vital in ensuring that the Earth does not lose too much heat and become a cold, lifeless planet. Too much carbon dioxide, however, leads to higher heat retention with consequent changes to the abiotic and biotic environment. Carbon monoxide Carbon monoxide is a lower-atmospheric pollutant. Road traffic emissions account for up to 90% of carbon monoxide emissions, although much of the remainder is generated during bushfires. Carbon monoxide is produced by the process of incomplete combustion.
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Fe2+: Fe3+: As Fe3+ has a half-filled 3d subshell, Fe3+ has extra stability over Fe2+. This can be reflected from the particularly low third ionization enthalpy. Fe2+ can readily be oxidized to Fe3+. Coloured ions and complex formation Complex is formed when ligands form dative covalent bonds with the central atom/ion. Transition metal ions like Fe2+ and Fe3+ can form complexes with ligands readily because they have large charge/radius ratio and low lying vacant d-orbitals available for accepting the lone-pair electrons of the ligands. After forming complexes, the d-orbitals of the transition metal ions split into two groups with slightly different energy levels.
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In fact, everyone can play a part in protecting our Earth from plastics by using biodegradable polymers as substituents. Problem caused by non-biodegradable polymers We have been using non-biodegradable plastics for so many years that we simply ignore their harmful effects. Plastics produce various problems in different areas, including ecological, environment and economical fields. A. Ecological problems Plasticizers and polychlorinated hydrocarbons used in the manufacture of plastics pose a health hazard and they may incorporate into the food chain, eventually getting into human body. Plastic wastes in the sea directly affect fishes. Small fishes have been found dead with their digestive tracts clogged by fragments of plastic foam they had ingested.
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However, it does contain ions (which are charged particles) fixed in a crystalline structure. When copper sulphate is dissolved, the copper sulphate solution becomes an electrolyte because the ions become free to move and they can conduct electricity. At the cathode, the copper ions, being more reactive than the hydrogen ions are deposited whilst the hydrogen ions remain in solution. At the anode, the copper atoms from the copper anode give up their two electrons to make them stable. The electron flow in the electric current back to the power supply and the anode dissolves.
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* 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)
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This will greater the current. Temperature- the ions will go quicker to the electrodes as the water will vibrate quicker when hotter. This will increase the current. Voltage- The current would be decreased because by ohm's law v=ir Surface area of the electrodes- if the surface area on the electrode increases there will be more space for the ions to go to and therefore the current will increase. Out of these 5 variables I am going to investigate how the change in concentration can affect the current flow.
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- How much the metal will be worth etc. What are the three methods of metal extraction? Given that most metals are only found locked up in their ores, but how do you go about getting them out? For a few metals, such as mercury, heat will do the trick. But for most ores the temperatures needed are far too high to make this a practical possibility. Another approach is needed. There are three methods of extracting metals from their ores, these are: - Electrolysis - Heating with carbon monoxide - Roasting in air Depending on the reactiveness of the metal, looking at the reactivity series, you can tell how each metal can be extracted.
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Whereas the 1.0 mol and 0.5 mol concentrations increases steadily at a slower rate. This obviously shows that if the voltage increase, the weight also increases. Hence I can conclude; the higher then voltage and concentration, the more copper is produced. The reason for this would be because we used electrolysis. This is used to separate metals from their ores and metal compounds. The electrolyte (solution) contains negative and positive ions. For electrolysis to work there must be the same amount of positive ions to negative ions so that the solution is electrically balanced.
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One of these reactions is the coke being burnt. The heat generated by this reaction increases the bottom of the furnace to a temperature near 19000� C. This reaction is represented in a chemical equation: C(s) + O2(g) (r) CO2(g) + heat The carbon dioxide generated rises halfway up the furnace, where it reacts with the hotter coke. This causes the carbon dioxide to reduce into carbon monoxide. This reaction absorbs some heat and lowers the temperature of the upper part of the furnace to roughly 1300� C. CO2(g)
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Concentration: The concentration of a mixture also effects the rate of reaction. An increase in concentration means there are more particles. More particles means there will be more collisions. This should increase the reaction rate. Concentration may be expressed in a number of ways. The simplest statement of the concentrations of the components of a mixture is in terms of their percentages by weight or volume. Apparatus List: Power Pack, Electrodes, Beakers, Sodium Chloride, Spatula, Water, Measuring Cylinder, Ammeter, Weighing Scales Diagram: Fair Test: This will be a fair test because I will be using the same electrodes, weighing machine; measuring cylinder and volume of water, and the same voltage (8)
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the solution gradually turned light blue, producing zinc sulphate. After flittering this solution copper was formed. We then weighed the copper. Results Sand = 1.91g Copper Ore = 3.09g Copper = 1.58g % Copper in Malachite = 1.58 5 100 = 31.6% %Copper on Copper Ore = 1.58 3.09 100 = 51.4 Theoretical % CuCO Cu(OH) H 0 2 Cu 63.5 2 = 127 6 O 16 6 = 96 4 H 1 4 = 4 1 C 12 1 =
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