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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
- 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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* Make sure wires and power packs are working before you start * To change the electrolyte after each experiment * To use a stop watch instead of a clock as it is more accurate * To use a variable resistor to get the exact current you need Research: There are many factors that affect the rate of electrolysis: * The current * The dept of the electrodes * The distance between the electrodes * Time allowed for electrolysis * The concentration of the electrolyte The current effects electrolysis.
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(2-2-11, 27-01-2009 http://www.epa.gov/climatechange/science/images/co2-temp.gif) Scientific background Global warming What is it? Global warming is the rising average temperature around the world. It also includes the atmosphere and the oceans and may be due to the burning of fossil fuels such as coal, agriculture and industrialisation which are all part of human activities and also by natural observed occurrences. What causes it? (http://greenhouseeffectss.com/wp-content/uploads/2012/01/Cause-Of-Global-Warming.jpg) Global warming is basically caused when an increased amount of the suns solar radiation is absorbed into the atmosphere, thereby raising the global temperature.
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In this coursework, I aim to find out the different properties of gold and alloying and will analyse pieces of data pertaining to gold in particular
Its ability to reflect light well means that it can also be used for heat resistant suits and sun visors for spacesuits. Like all transition metals, the outer electrons in gold atoms are not bound to a particular atom but are free to move through the whole structure; this means that gold (including all other transition metals) make good electrical and thermal conductors. This is why it is widely used for electrical wiring. Sometimes, different metals are merged to produce an alloy, which possesses a combination of qualities found in both metals; for example, steel consists primarily of iron and 0.2% to 2.1% of carbon.
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with carbon and used as an electrode which can deposit metals forming a solid plate made of a thin sheet of pure metal e.g., copper metal. ELECTROLYTIC PURIFICATION In Today's age, there is high demand for very pure metals. Electrolysis can be used to purify metals, such as purification of copper. A pure bar of cathode attached to the cathode can have deposits of that metal from the impure metal electrode from the anode. ELECTRO-REPAIRING This is a techniques used for repairing of broken machinery.
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I am investigating which supermarkets have the strongest plastic bags; I have tested this out in an experiment. I will also be researching whether plastic bags are good or bad for the environment and how they can be replaced or used differently.
Polyethylenes are generic in that they include all ethylene that has been polymerized, but they may have other characteristics. Three polyethylenes are identified as being used in the manufacture of plastic bags because of their density, low-density polyethylene, linear low-density polyethylene, and high-density polyethylene. Branching, replacing the polymer chain with other forms or variations of the monomer can further change the characteristics of the plastic. Highly branched polymers make thinner plastic. Branching also affects tensile strength and clearness or crystallinity of the plastic. The more branched the plastic bag, the less ability there is to see through it, and the easier it tears.
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In 1852 an English chemist called Robert Angus smith was first known to notice the incidence of acid rain. In other words acid rain is a word that means rain with a ph level of 5-6. It is a form of air pollution that is currently a theme of huge debate due to its wide spread damage. It is held responsible for the shocking of thousands of lakes and streams in the United States, Canada and parts of Europe. Buildings damaged: Many major buildings are getting damaged my acid rain. Other historical buildings and land marks are also affected by chemical weathering.
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We can change the rate of reaction by changing the concentration of the following reactants: = Sodium thiosulphate = Water particles = Hydrochloric acid particles On the diagram, 1 particle is 5%. Lower concentration of Higher concentration of sodium thiosulphate sodium thiosulphate (20% concentration) (80% concentration) Equipment - Sodium thiosulphate - 2 Measuring cylinders - Hydrochloric acid - Black cross card - Water - Stopwatch - Conical Flask Results I want to take Fair test - I will change the concentration of sodium thiosulphate and make sure that I keep the same amount each time.
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Petroleum contains a great variety of saturated hydrocarbons and petroleum products consist principally of mixtures of paraffin hydrocarbons. Example2: 1. Ethane: C2H6 2. Propane: C3H8 3. Butane: C4H10 Alkenes: These are unsaturated compounds, denoted by the formula of CnH2n where n is the number of carbon atoms. Like the paraffin series, the higher you go in the series, the denser the compound becomes.3 1. Ethene: C2H4 2. Propene: C3H6 3. Butene(But-1-ene and But-2-ene): C4H8 Alkynes: Alkynes are also unsaturated hydrocarbons, which mean they will have at least one triple bond in their compounds. Alkynes are denoted by the formula CnH2n-2 where n is the number of carbon atoms. These hydrocarbons are also quite reactive by nature. Example: 1.
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Hence, crude oil is used in generating many forms of energy such as gasoline, diesel and other fuel oils. Products made from crude oil are mostly synthetic products which are far more costly than Natural products. If the industry takes a big change and decided to create synthetic items, the overall effect will be costly and may lead us into recession if we get out of this one. Since crude oil is starting to be scarce the prices of fuels are rising. Wars will be starting as soon as one country is scarce of oil as oil is needed for everything.
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This then creates a genetically modified plant which also produces the beneficial trait.3 The main reason for GM foods being produced was for crop protection. It would make plants resistant to diseases caused by insects, viruses or they would have increased tolerance to herbicides.4 One method used to genetically modify plants is called Biolistics. This involves shooting new genes into the potential host. Microscopic particles of gold or titanium are coated in the DNA sections which are to be introduced to the host.
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24% of uranium resources are in Australia and 9% in Canada. Disadvantages of Nuclear Power * Waste: High level radioactive waste is very dangerous. It lasts for tens of thousands of years before decaying to safe levels. If there is to be a "nuclear renaissance", a sophisticated method of storing the waste for this period of time must be designed. This point itself has sparked a surprising number of debates. For example, how do you write "danger" on a concrete box, when in 5,000 years the word "danger" may no longer exist?
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The destruction of the Amazon Rain Forest is an example that shows the deadly results of tampering with one of natures ecosystems. Methane gas emissions are trapped in the Earth's atmosphere and reflect light along with all other pollutants, adding to the destruction of the Ozone Layer. The energy burned to run automobiles, heat homes, factories and businesses is responsible for about eighty percent of society's carbon dioxide output. Global warming has been a concern for the past two decades with the increase of industrial pollution from major industrialised countries around the world.
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When they reach it, the negatively charged cathode provides the electrons to "reduce" the positively charged ions to metallic form and create the plating. Plating is used to coat metals to avoid corrosion or resist abrasion as well as plating for a cosmetic finish. Michael Faraday, an English chemist and physicist discovered two relationships between the mass of metal produced at the cathode and the voltage passed through the cell. His first law of electrolysis states that the mass of a substance produced at an electrode during electrolysis is proportional to the number of moles of electrons (the quantity of electricity)
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GNVQ/Vocational Science - Reduction of Copper including methods of extracting metals (copper) in industry
Then separate the copper from the waste by half filling the test tube with water and pouring the mixture into a beaker of cold water. 7. Leave for two minutes and then pour off the dirty water. 8. Keep adding cold water to the mixture and pouring off the dirty water till you see pink copper at the bottom of the tube. 9. Put the copper onto filter paper to dry it. Measure the mass of dried copper - this is your actual yield.
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At the anode however, gas is usually collected, and is passed into the surrounding air. In my experiment I have chosen the copper sulphate solution to electrolyze. In the experiment when the solution is being electrolyzed it starts to decompose and at the positive cathode copper is formed, and makes a thin plating around it. At the anode however, oxygen is formed, and is released. This comes about because of the chemical change that has happened, as a result of the electricity being passed through and disrupting the ions, making them mix and collect at different electrodes depending on the polarity of the ions.
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I will be measuring the current in amps because it is easier to measure and read. Prediction: I predict that as the current increases, the mass of copper collected will increase. This is because more energy is present so the amount of ions in the electrolyte- copper sulphate solution- will increase and also the rate of electrolysis will increase. Copper Sulphate (CuSO4) is made up of 4 ions; Copper (II) ions (Cu2+), Sulphate ions (SO42-), Hydrogen ions (H+) and Hydroxide ions (OH-).
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Distance between two electrodes - If the distance between the two electrodes is greater, the copper ions require to travel more from the anode to the cathode. If the distance between the two electrodes is smaller, the copper ions need less energy to flow from the anode to the cathode than when the distance between of the electrodes is far apart. 4). Surface area of electrodes- The surface area of the electrodes affected the number of ions that can be lost or gained at the same time.
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These will tend to stay close because they are attracted to the negative charge on the piece of metal. Some of them will be attracted enough that they will reclaim their electrons and stick back on to the piece of metal. A dynamic equilibrium will be established when the rate at which ions are leaving the surface is exactly equal to the rate at which they are joining it again. At that point there will be a constant negative charge on the magnesium, and a constant number of magnesium ions present in the solution around it. Simplifying the diagram to get rid of the "bites" out of the magnesium, you would be left with a situation like this: Don't forget that this is just a snapshot of a dynamic equilibrium.
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In such instances the alternative half equation is: 2Br- Br� + 2e- Electrolysis - How Does It Happen? A compound made from metal and non-metal has ions which cannot move freely. This means the compound cannot conduct electricity, nor can it move towards electrodes. This is why the electrolyte must be in liquid form - either by melting it or by dissolving it in water.
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Investigate the effect of the amount of sodium chloride, i.e. concentration gradient, in the aqueous solution on the electric current during electrolysis.
By keeping the factors controlled and equal, you can prove it is the concentration. The following factors/variables must be controlled or monitored during the experiment: 1. Temperature 2. Quantity of solution 3. Voltage 4. Size of electrodes 5. Distance between electrodes 6. Surface on the electrodes 7. Distilled water I plan to finish the experiment in one day, so the temperature won't change drastically and use a stop-clock to maintain the time duration for applying voltage to 10s. By using a volumetric flask and pipette, I can measure and control the quantity of solution for each test batch more accurately.
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If the metal surface of the cathode is chemically and physically clean, the discharged atoms of copper are deposited within normal inter atomic spacing of the atoms of the basis metal and attempt to become an essential part of it. If the basis metal is copper, the new copper atoms will frequently arrange themselves to continue the structure of the basis metal, the plate becoming more or less indistinguishable from and inseparable from the basis metal. Copper is a chemical element, extremely ductile to metal unusually good conductor of electricity and heat.
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An investigation to find out what factors affect the rate of electrolysis of a solution containing copper (II) ions.
This means that the more voltage flowing through the circuit the faster the reaction will take place. Concentration of a solution: For many reactions involving liquids or gases, increasing the concentration of the reactants increases the rate of reaction. In a few cases, increasing the concentration of one of the reactants may have little effect of the rate so changing the concentration could speed up the reaction or it could have no affect at all. Although, it is very common that when you increase the concentration the reaction does speed up.
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There are some other commonly used metals, such as nickel and copper that are scarce in the earth's crust, but are in high grade ores in a few locations. Element %mass O 49.5 Mg 1.9 Si 25.7 H 0.88 Al 7.5 Ti 0.58 Fe 4.7 Cl 0.19 Ca 3.4 P 0.12 Na 2.6 C 0.09 K 2.4 Mn 0.08 Key: Non-metals Metals Most compounds are found as oxides or sulphides, but the sulphides are usually converted to oxides before extraction.
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It is more expensive than carbon. It is only used for the extraction of tungsten. Gold and platinum are found naturally as elements and do not need to be reduced. Silver and copper are also naturally found. Extraction of Metals and Alloying Metal ores are found in the earth. They are rocks containing mineral or metal compounds or metals themselves and need to be extracted or removed from the rocks and the ground. To extract a metal from its ores you need to know its reactivity.
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