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GCSE: Changing Materials - The Earth and its Atmosphere
Meet our team of inspirational teachers
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.
This will effect the experiment as the wider the beaker, the shallower the solution. This means that the electrodes will have less surface area in the solution and therefore less copper and less oxygen will be produced Yes, the beaker will be kept the same size (100 ml) The material of the electrodes If copper electrodes are used, then the electrodes will react with the solution and break down, causing a change in the mass of the electrodes and giving completely different results.
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However the voltage used will be a set a voltage i.e. I shall do the experiment on 12 volts. The temperature could also affect the experiment as well. It would affect the electrical wires because if the room was too hot then resistance would increase, but I shall keep temperature as a variable as I cannot do anything about it. If we look at the diagrams below: We see that the electrodes in (B) are further in than (A). Surface area can be a contributor that can affect the experiment. This is because if more of the electrodes are in the solution then this will mean that more electricity will be applied to the solution rather than (A).
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Investigate the factors that effect the current flowing during the electrolysis of an aqueous solution of sodium chloride.
* A beaker with clear and accurate measurements on it to keep the volume of water constant. * I will use an electrode holder that will hold the electrodes a set distance apart. * I will use the same power pack throughout the experiment, as not all power packs give out the same voltage. PREDICTION My hypothesis is that the more sodium chloride dissolved in the water the higher the current will increase. In a dilute solution, there are less sodium chloride particles. This means there is less chance of a sodium chloride particle hitting an electrode as compared with solution of a higher concentration.
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When this happens, heat energy is released, as the reaction is an exothermic one. The greater the difference in reactivity between the two metals, the more energy released. This fact allows us to measure the temperature rise and judge from that which metals are the most reactive and which the least. The reactivity series is a table of metals with the most reactive metals at the top of the table and the least reactive metals at the bottom. Look below for the reactivity series: A displacement reaction is an example of a redox reaction.
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I have chosen to do electrolysis of Copper Sulphate with copper electrodes rather than the alternatives, sulphuric acid with graphite electrodes, because then I would have to collect gas (which is more difficult) rather than a solid.
I also predict that a small amount of sludge will be deposited at the bottom of the beaker. Variables The following variables are ones that could possibly be used: * Time * Current * Temperature * Concentration of Copper Sulphate solution * Quantity of solution * Surface area of the copper electrodes in the Copper Sulphate solution * Distance between the copper electrodes I have chosen to vary the time and not the current because when varying the current the heat in the resistor changes, thus changing the resistance and the current. This would make the experiment akward because the current needs to be constant for each reading and do that the resistance may have to be altered throughout that particular reading.
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Investigating The Reactivity Of The Metals Iron, Magnesium, Zinc, Copper And Calcium And Their Reaction With Hydrochloric Acid.
The zinc will displace hydrogen from the acid. "If zinc can displace hydrogen fro H+ ions in acid, then it may be able to displace metals from solutions of various metal ions." (From Chemistry Counts by Graham Hill) From the table below I will show how I think the order of reactivity will be. This table is a secondary source of scientific evidence. Metal Used Mg (NO3) 2 ZnSO4 Pb (NO3) 2 CuSO4 AgNO3 Mg X Dark grey deposit of zinc Grey deposit of lead Red deposit of copper Black deposit of silver Zn X X Grey deposit of lead Red deposit of copper Black deposit of silver
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I have highlighted any anomalous results. Current (A) Average Increase at cathode (g) Average decrease at anode (g) 0.2 0.0503 0.0546 0.4 0.096 0.11 0.6 0.138 0.158 0.8 0.167 0.202 After finding these averages I am going to calculate the theoretical values, these will show what mass of nickel should be lost at the anode and gained at the cathode in theory. There is great room for error especially as the current increases because as the results become bigger there is more room for mistake. The unit for 'amount of charge' is Coulombs The amount of charge = current time (Coulombs)
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Therefore copper, being more reactive than hydrogen, is formed at the cathode. At the cathode (-): Cu+ ions near the cathode combine with electrons on the cathode forming neutral copper atoms: Cu+ + e? Cu It is considered that the following factors could affect the deposition of Copper metal on the cathode: 1. Time i.e. the duration of current discharge 2. Current i.e. the magnitude of current discharge 3. Concentration i.e. the molarity of the electrolyte 4. Temperature i.e. the temperature inside the electrolytic cell 5.
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E.g. Cu ? Cu2 ? + 2e- (at the Anode) Cu 2 + 2e- ? Cu (at the Cathode) Both of the above are half equations. Predictions: The current of 1 AMP (A) = 1 coulomb (c) per second One mole of electrons charge = 96500 coulombs (6.02 X 1023 X the charge of an electron) Hypothesis: Min (time) Current Coulombs Cu (g) lost at 5 0.5 150 0.05 10 0.5 300 0.10 15 0.5 450 0.15 20 0.5 600 0.20 25 0.5 750 0.25 30 0.5 900 0.30 35 0.5 1050 0.35 40 0.5 1200 0.40 300 X 0.5 = 150 (c) 600 X 0.5 = 300 (c) 900 X 0.5 = 450 (c)
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[image006.gif] [image007.gif] [image008.gif] [image009.gif] [image002.gif] Area of electrode where the ions can attract to. [image010.gif] 3. Strength of concentration: I predict that when the concentration of the solution is stronger then, the current will flow faster because there would be less water molecules in the solution therefore the travelling ions won't have such a battle. If the concentration is weak, then the ions will have to travel with many water molecules obstructing the way. Obtaining evidence These are the results I obtained from the 3 practical experiments carried out: Experiment 1: Distance between the electrodes Distance (cm) Repeat 1 (amps)
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When doing this experiment there are many variables which I could change which would affect the outcome. Here are the input variables which I could change: Surface area of electrode Temperature of electrode Time Voltage Strength of copper sulphate solution If I changed the surface area then it would affect the amount of copper deposited and lost by the copper electrodes. This is because when the electrode has a larger surface area there is more surface for the copper ions to dissolve into the solution from. It is important to keep the surface area of the electrodes the same because the greater the surface area the greater the loss in mass at the anode.
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To investigate the effect of the copper anode after electrolysing it in Copper Sulphate solution for certain periods of time
Copper, being extremely low down in the reactivity series is discharged at the cathode before all ions except silver. So in this experiment copper will be discharged. Since the anode will be copper as well, both the copper in the solution and from the metal will be attracted towards the negatively charged cathode. "During this process, the impure anode loses mass because the copper atoms lose electrons and become copper ions. Copper atoms copper ions + electrons Cu (s) Cu 2+ + 2e- The electrons released at the anode travel around the external circuit to the cathode. There the electrons are passed onto the copper ions from the CuSo4 solution and the copper is deposited on the cathode.
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electrodes * Current Only the mass or size of the electrodes, and the current are being investigated, therefore in order for this to be a fair test, the other factors must be kept constant. The temperature was monitored during the preliminary results, and the higher the current the higher the temperature change, which in the 1A reading was 5� C, therefore to keep it as constant as possible the current will be as low as possible, and monitored, so that it does not change during the experiment There will be a thermometer in the electrolyte so that the temperature can be monitored.
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Metal 2 Mg ------- Al x -------- Zn x 0.610 --------- Sn 1.470 0.030 x -------- Pb 0.720 0.230 x 0.050 -------- Cu 0.710 0.750 0.960 0.350 0.420 -------- Averages for sulphuric acid including anomalous results 1st results with H2SO4 (Volts) Metal 1 Mg Al Zn Sn Pb Cu 2nd results with H2SO4 (Volts) Metal 2 Mg ------- x x x x x Al 0.550 -------- x x x x Zn 0.130 0.470 --------- x x x Sn 1.075 0.100 0.380 -------- x x Pb 0.795 0.200 0.640 0.145 -------- x Cu 0.880 0.580 0.895 0.535 0.415 -------- Grapefruit Results
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* Concentration of Solution - The higher the concentration of the solution, the lower the resistance will be. A strong concentration which is made entirely of Copper Sulphate will be a lot better for electrolysis than a diluted solution, because the ions are able to move more freely. * Distance between electrodes - The further the distance between the electrodes, the further the ions have to travel, which would mean an increase in the resistance. The distance, which we place them apart, will be decided by to factors. a) If they are to close, the may touch and short circuit and b)
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The Chevrolet Volt is a plug-in hybrid electric vehicle that features a small gas-powered engine/generator. The Volt's battery can be charged by a standard household 120-volt outlet in approximately 10 hours. When the battery pack is empty, the Volt's gasoline engine turns on and generates energy that is converted to electricity, which extends the driving range by an additional 300 miles or so. The Honda FCX Clarity is a Fuel Cell Electric Vehicle that combines hydrogen with oxygen to make electricity.
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It is solid and made up of iron and nickel with temperatures of up to 5,500°C. With its immense heat energy, the inner core is like the engine room of the Earth. The outer core is the layer surrounding the inner core. It is a liquid layer, also made up of iron and nickel. It is still extremely hot, with temperatures similar to the inner core. Plate Tectonics and Continental Drift: Continental drift is the process that makes the Earth's plate's move. The Earth's crust and the upper part of the mantles are cracked into a number of large pieces called tectonic plates.
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Water Crisis. This term refers to the global problem of lack of access to clean water to the people of this earth.
The human body is 75% water and our blood is 90% water. Three-fourth of the Earth is also covered in water. If we lose 5% of the water in our body, we will faint and if 10%, we will die. We can survive a maximum of 3 days without water as it the most important substance for our body. The most important thing about water is that it helps the human body in so many ways. Water is a good medium for regulating the temperature of our body. It changes temperature slowly and so helps the body remain in the narrow range of temperature necessary for life and many other bodily functions.
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Some of the impacts of rising temperatures have already taken place; 1. Ice is melting worldwide, especially at the Earth?s poles. As well as mountain glaciers, ice sheets covering west Antarctica and Greenland, and artic sea ice. 2. Sea level rise became faster over the last century. 3. On average precipitation has increased across the globe. If warming continues these more serious effects could take place; 1. Sea levels are expected to rise between 7 and 23 inches by the end of the century. 2. Hurricanes, floods and droughts are likely to become more common.
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