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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.

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  1. Investigation into the Reactivity of Metals.

    The Group II elements are all metals, which form 2+ ions and have similar properties such as they all have the same number of electrons in their outer shell. When compared amongst themselves, Calcium is more reactive than Magnesium and Magnesium is more reactive than Beryllium. The reason for this is because Calcium has four shells and the outer electrons are far away from the proton. Due to the distance between the electrons and the proton, there is a less attraction between them and so it will lose these electrons more easily.

    • Word count: 1388
  2. An essay to discuss the relationship between the position of a metal in the Reactivity Series and the method of extraction of that metal from its ore

    It was also found native in streams and is hard, which made it good for tools those years ago. However copper is scarce so it can also be extracted from its ore, malachite, which is a copper carbonate. Copper was extracted in this way quite by accident, many years ago, when clay pots were heated over a fire. The fire was covered by soil, to prevent air entering and the malachite had accidentally fallen in. Afterwards carbon had formed, in the form of charcoal and the copper metal was formed from the malachite. After this, people improved the fires to produce more copper.

    • Word count: 1314
  3. Let us investigate the electrolysis of molten sodium chloride.

    Therefore, to maintain a fair test I will have to control the rest of the variables above. Through pre-testing I have learnt of an effective method to record results. Here is the equipment I have selected: The anode will be weighed and the result noted each time. Then the equipment will be set up as shown above and each value in the range shall be tested. I will start the stopwatch and then try and keep it at the correct current using the stopwatch. The electrodes will then be dried, and the anode weighed once more, noting the result.

    • Word count: 1915
  4. The Reactivity of Metals

    Iron is extracted using a blast furnace. The iron ore, coke and limestone are added to the blast furnace that has been heated to 1500oC, the coke burns and produces carbon dioxide the carbon dioxide then reacts with the unburnt coke to form carbon monoxide then reduces the iron ore to iron. In the other cases of metals the most common way of extracting the metal from its ore is by chemical reaction and through electrolysis. The more reactive the metals are; such as magnesium the harder they are to extract from the ore state that they are found.

    • Word count: 1657
  5. To investigate Electrolysis affecting amounts of substances at Anode+ and Cathode-

    * A power pack to supply the electricity for the experiment to take place. * Wires to make a complete circuit. * Two pieces of copper to be the anode and cathode * A holder to hold the anode and cathode * A bulb to use to set up the circuit with How to do the experiment: 1. First of all the equipment has to gathered as shown in the list above. 2. Measure out the ionic solution into the 400ml beaker. 3. Scrub down the anode and cathode to make it a fair test.

    • Word count: 1652
  6. Extraction of chlorine and iodine

    Or gain electrons to become more negatively charged ions or form electrons (reduced like hydroxide ions). It is necessary to keep apart the products liberated from aqueous sodium chloride at the anode and those which are formed at the cathode in order to prevent them reacting and to obtain higher purities of the products formed. Placing some sort of barrier between the two electrodes does this. In the mercury cathode to keep apart the products of the electrolysis of brine chlorine is simply produced in a different container from the hydrogen and sodium hydroxide.

    • Word count: 1097
  7. My aim of this experiment is to find out if the number of coulombs affects the amount of copper produced.

    We will use 250ml of copper sulphate solution at 1 mole concentration. I will use a stopwatch and change the time by two minutes each time, and do it 7 times and we will do the experiment three times for each different time, which makes a total of 21 parts to the experiment. We are going to do it three times, so we will be able to get an average result. We will be using 2 amps throughout the experiment so it will be a fair experiment. After the given time for each part of the experiment we do; we will swill it in propane to dry the piece of copper, with copper deposited on it, without taking the copper deposit on it off.

    • Word count: 1031
  8. The aim of this experiment is to discover how the rate of electrolysis is affected by the level of voltage.

    The voltages we shall use are 2, 4, 6, 8 and 10 volts. To make the test fair and accurate we shall take repeat results for each voltage so that we can find an average. Also, we shall use the same electrodes throughout the experiment. We shall use the same top pan balance that we get accurate weights. Additionally, the electrodes will be dried prior to them being weighed so that none of the copper sulphate solution is weighed with them. So that the experiment is safe we shall wear safety goggles throughout the experiment so that none of the harmful Copper Sulphate solution gets into our eyes.

    • Word count: 1723
  9. To investigate how voltage affects the amount of a copper (Cu) deposited during electrolysis of copper sulphate solution (CuSO4).

    The larger the electrode, the more copper can be deposited on it and faster. ELECTRODES (DISTANCE APART) - 5cm. The further apart the electrodes, the further the ions have to travel, and so it takes longer for the copper to be deposited and the less copper can be deposited in the given time period. Prediction I predict that the higher the voltage, the faster the ions in the copper sulphate solution will move and so deposit more copper at the cathode in the given time period. If I decrease the voltage less copper will be deposited. Below is some scientific theory to back up my prediction.

    • Word count: 1059
  10. Investigating a Factor Affecting Mass deposited at the Cathode during Electrolysis

    'Q' are the two electrons being added to 'Cu++' to form copper on the cathode if the charge is increased the mass deposited will increase. I will use the equation Cu++ + 2e- ( Cu if I keep Cu++ constant and increase 2e it will explain my hypothesis. Cu++ + 2e- ( Cu , Cu++ + 4e- ( Cu = Cu + 4e- My explanation for the increase in mass on the cathode is that the anode losses positive electrons because of the negative electrons passing through the circuit.

    • Word count: 1632
  11. Using Simple cells to find an order of reactivity in metals

    6. Repeat steps 1-5 testing all the metals as indicated in the results table 1 (N.B. If the voltmeter reads a negative value make a note of the sign.) DIAGRAM OF APPARATUS Fair Test I measured the voltage and sign the positive or negative value in order to find the reactivity series. The only variable in this practice is the type of metal used for METAL A and METAL B. The length of wire, amount of ammonium chloride, voltmeter settings and the surface area of metal in sodium chloride solution did not be changed in the practice.

    • Word count: 1236
  12. Describe the reactions which take place at the electrodes in the membrane cell and explain why they are redox reactions.

    + 2H2O(l) + 2e- H2(g) + 2Na+(aq) +2OH-(aq) the ionic equation is 2H2O(l) + 2e- H2(g) + 2OH-(aq) At the steel cathode, the Na+ ions are again supplied by the sodium hydroxide. The water comes from the reaction of the sodium hydroxide with the cathode. The water then gains electrons from the electrode and forms OH- ions and H2 gas. 223 words Suggest why it is necessary to keep the anode and the cathode products apart from each other in the electrolysis of aqueous sodium chloride, and describe how this is done in both the mercury cathode and the membrane cell in the chloro-alkali industry The products from the membrane cell have to be separated as

    • Word count: 1382
  13. Investigation to Find Out How the Amount of Electric Current Affects the Amount of Copper Deposited During the Electrolysis of Copper Sulphate Solution Using Copper Electrodes

    which will cause the mass of the cathode to rise. It is known that by passing a constant electric current through copper sulphate solution, when the ions pass through this solution, copper atoms get dissolved into the solution from the anode while positive copper ions (cations) being discharged at the cathode. Normally anions are discharged at the anode. The purpose of the experiment that I carried out was to monitor the quantity of Copper (Cu) metal deposited during the electrolysis of Copper Sulphate solution (CuSo4)

    • Word count: 1432
  14. An Investigation Into the Factors Which Effect the Electrolysis of Copper Sulphate Solution.

    I shall repeat this, but I do not feel that I shall have time to repeat it twice. To make sure that the amperage is set correctly as quickly as possible, I shall use the variable resistor. I shall watch the experiment continuously, to make sure that the anode and cathode do not touch, and in extreme circumstances, that the anode does not disintegrate due to electrolysis to the extent that it is no longer in the solution. To make it a fair test, I shall keep the amount of time the same for each, and try to set the amperage as quickly as possible.

    • Word count: 1336
  15. An Investigation Into the Electrolysis Of Copper Sulphate Solution

    It would seem easy enough to measure the mass of copper that has moved to the cathode, but what is the 'quantity of electricity.' In both the 'Hutchinson' and 'Collins' science dictionaries (Michael Upshell and D. McMonagle respectively), electricity is described as a ' flow of charges in a current.' However on the CD-ROM Electrochemistry (New Media), more depth and detail is found. It states electricity is a flow of electrons, and since electrons are negatively charged particles, electricity must be the flow of the charge.' When copper is deposited on the cathode, the equation is: Cu2+ + 2e- ?

    • Word count: 1728
  16. Electrolysis of aquatic salt solution

    This because non-metals have minus charges and are attracted to the positive anode to give electrons. Cl2- - 2e- Cl2 Br2- - 2e- Br2 I think this because opposites attract and positive element will go to the negative electrode and vice versa. Since the solutions are water based we will also get Hydrogen and Oxygen. This is because one molecule in every few million of water decides to be different and split up to give us Hydrogen and Oxygen atoms in the solutions, enough to give of a gas at anode and/or cathode. The equation for the water splitting up is this.

    • Word count: 1460
  17. Reactivity Series of Metals

    This is because the electrode potential of calcium is not quite as expected from its chemical reactivity. Also, the value given for Aluminium in the E.C.S. is for that value when its oxide layer has been removed. In practice or reality it is often less reactive than zinc or iron. Reaction of metals with Oxygen When metals are heated in air, if they react at all they usually react with the oxygen to form oxides. Some metals burn "completely" to form a high yield of their oxides but others react briefly to become coated with a layer of oxide which stops further reaction with the metal e.g.

    • Word count: 1176
  18. Electrolysis Investigation

    Variables. { [image001.gif] Material of the electrode. { Concentration. { Voltage. { Temperature. Independent { Surface area of the electrodes. Variables. { Distance between the electrodes. { Current. - Dependent variable. Apparatus. { Goggles. { Electrolysis Cell. { 6-Volt Power Pack. { Distilled Water. { Sodium Chloride. { Measuring Cylinder. { Ammeter. Diagram. Oval: A [image003.gif] [image004.gif] [image005.gif] Power Pack. [image006.gif] [image007.gif] [image008.gif] [image009.gif] [image010.gif] [image011.gif] Ammeter [image012.gif] [image013.gif] [image014.gif] [image005.gif] [image015.gif] [image016.gif] Anode Cathode. [image017.gif] [image018.gif] [image019.gif] [image014.gif] [image020.gif] [image021.gif] Beaker Sodium Chloride [image022.gif] Solution [image023.gif] Fair Test. To keep this experiment fair then I will only change one of the variables.

    • Word count: 1086
  19. Electrolysis Using Copper Sulphate And Copper Electrodes

    In industry the impure copper would be used as the anode and the pure copper used as the cathode. When the electrodes are connected to the battery the anode should be positively charged and the cathode negatively charged. Opposite charges attract so the positively charged ions would move towards the cathode and negatively charged ions would move towards the anode. Gallagher and Ingram say, "Cations go to the cathode. Anions go to the anode"2, therefore, metals such as copper that are positively charged are cations. Hill and Holman, who are talking about the electrolysis of sodium chloride, say, "when Na+ ions reach the cathode they combine with negative electrons from the battery forming neutral sodium atoms"3.

    • Word count: 1675
  20. Investigate whether changing voltage will affect the rate of Electrolysis.

    Instead Oxygen from the water (which the CuSO4 was dissolved) is separated, leaving hydrogen and oxygen. Because oxygen is a non-metal it has a minus charge. In this case it has a 2-. This mean it is attracted by the positive Anode, therefore the oxygen is an Anion. Quotes; A compound that conducts when molten or in solution is called an electrolyte. If a pair of electrodes is placed in a solution of an electrolyte, and a source of direct current is connected between them, the positive ions (cations)

    • Word count: 1031
  21. The effects of electrolysis of Copper Sulphate Solution and copper electrodes

    This is called Faraday's Law. So, because copper has a charge of 1+, we know that it takes a charge of 96500 coulombs to deposit just 1 mole of copper. The equation fro the charge is: Charge = Current X Time (In Coulombs) (In Amps) (In Seconds) PREDICTION: I predict that the Anode will lose mass and the Cathode will gain mass. I also think that the amount of weight lost at the Anode, will equal the amount of weight gained at the Cathode.

    • Word count: 1244
  22. How factors influence the energy change when metals are added to a metal salt solution?

    because the ferther away the electrons are from the nucleus, the more unreactive they are, thus energy is given off when the electrons are changed. Heats of reaction in solution are measured by allowing the heat from the reaction to be absorbed by or taken from the solution in an insulated container. My experiment is an exothermic reaction, the heat given out is absorbed by the solution, the temperature rises. Insulation reduces the amount of heat energy lost to the air which could cause my results to be not exactly wright.

    • Word count: 1471
  23. The Reactivity Series.

    Of course Calcium will be the highest and copper will be the lowest on the graph, but still, I think they will all rise and then slowly drop back to room temperature after a while - some may take longer than others. I will find out the order of reactivity, of these five metals, because of displacement. Displacement is when a more reactive metal pushes out a less reactive metal from its solution. I will know if this has happened by the temperature increase and maybe even if the reaction gives off hydrogen gas. Like this: Magnesium + Copper (ii)

    • Word count: 1933
  24. The Earth's Atmosphere and Air Pollution

    As the Earth cooled down, most of the water vapour condensed and formed the oceans. So then the atmosphere was mainly Carbon Dioxide [2] Over many millions of years the amount of carbon dioxide of the air decreased, while the amount of oxygen increased. The main reason for the increase of oxygen was due to the photosynthesis by plants. Although Photosynthesis isn?t the only reason that carbon dioxide decreased. Carbon Dioxide is locked away inside limestone, limestone is a sedimentary rock formed when layers of sand/mud and animal remains fall to the bottom of an ocean or lake, and slowly decompose and are crushed together by the weight of the water, forming a rock.

    • Word count: 1261
  25. Global Warming and Possible Solutions.

    Fossil fuels are not renewable. The earth population is growing and so do the need of transportation. The encreased usage of cars is leading to pollution. We also need more land for agriculture and therefore we cut down trees, this leads to deforestation which harms the environment. Deforestation is to cut down trees and reduce areas of woodland which again leads to carbon dioxide being released into the atmosphere. Since 50% of the trees are carbon, the storage of carbon dioxide will automatically be released. Between 25 and 30% of all the greenhouse gases that are being released into the atmosphere is caused by deforestation.

    • Word count: 1452

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