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copper rich ores are in short supply:

  • the supply of copper rich ores is in short supply.
  • the demand for copper is growing and this may lead to shortages.

bioleaching:

  • this uses up bacteria to seperate copper from copper sulfide. the bacteria get energy from the bond between copper and sulfur, seperating out the copper from the ore in the process.
  • the solution produced by the process contains copper, which can be extracted by filtering.

phytomining:

  • this involves growing plants in soil that contains copper. the plant cant use up the copper so it gradually builds up. the plants can be harvested, dried and burned in a furnace and the copper can be collected from the ashes that remain.
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Impacts of extracting metals

  • mining is good because it means that useful products can be made, it also provides local people with jobs and that brings money to the area.
  • mining is bad though because it causes noise, scars the landscape and causes the losses in habitats.

recycling metals is important:

  • mining and extracting metal uses a lot of energy which comes from fossil fuels.
  • fossil fuels are running out and burning them contributes towards global warming, climate change and acid rain.
  • recycling uses little energy and helps to save money.
  • recycling also cuts down on the amount being sent to landfill, which means landfill doesn't take up as much space and pollutes the surroundings less.
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properties of metals

  • metals are strong, bendy and great conductors.

properties:

  • metals are strong, but they can also be bent or hammered into shape.
  • there great at conducting heat and electricity.

transition metals, found in the centre of the periodic table have loads of everyday uses.

copper:

copper is a good conductor of electricity, so its ideal for electrical wires. its hard and strong but can be bent. it doesn't react with water.

aluminium:

aluminium is corrosion resistant and has a low density, pure aluminium isn't that strong but it forms hard strong alloys.

titanium:

titanium is a low density metal, its very strong and is corrosion resistant.

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Alloys

  • pure iron is a bit too bendy. iron straight from the blast furnace is only 96% iron. the rest is impurities.
  • the impure iron is used as cast iron, its used for making railing but not much else because its too brittle.
  • so because of this all impurities are removed from most of the iron. the pure atom has a regular arrangement of atoms, this means that the atoms can slide over each other, this makes the iron soft and easily shaped. this iron is too bendy for most uses.

most iron is converted to steel (an alloy)

  • steel is formed by adding small amounts of carbon and sometimes other metals to the iron.
  • low carbon steel is easily shaped so used for car bodies.
  • high carbon steel is very hard and not ver flexible so its used for bridges and blades.
  • stainless steel is corrosion resistant so is used for cutlery and containers for corrosive substances.
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Alloys

Alloys are harder than pure metals:

  • different elements have different sized atoms, so when an element such as carbon i added to pure iron, the smaller carbon atom will disrupt the layers of the pure iron atoms.

many metals used today are alloys;

  • bronze is copper and tin and is good for statues and medals.
  • cupronickel is copper and nickel and is used for silver coins.
  • gold alloys are used to make jewellery, pure gold is too soft.
  • aluminium alloys are used to make aircrafts,
  • nowadays much more is known about the properties of metals so new alloys can be designed for specific uses.
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fractional distillation of crude oil

Crude oil is a mixture of hydrocarbons:

  • crude oil is a mixture of compounds, most of the compounds are hydrocarbon molecules.
  • hydrocarbons are basically fuels such as petrol and diesel. they're made of just carbon and hydrogen.

-there are no chemical bonds between the mixture, so the hydrocarbon molecules in crude oil aren't chemically bonded to each other.

  • this means that they all keep their original properties, such as their condensing points.
  • the parts of the mixture can be separated out. crude oil can be separated by fractional distillation. each fraction contains molecules with a similar number of carbon atoms.

The fractional distillation column works continuously, with heated crude oil piped in at the bottom. the vaporised oil rises up the column and the various fractions are constantly tapped off at levels where they condense.

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Properties and uses of crude oil

crude oil is mainly alkanes:

  • all the fractions of crude oil are hydrocarbons called alkanes. alkanes are made up of chains of carbon atoms surrounded by hydrogen atoms. different alkanes have chains of different lengths
  • the first four alkanes are methane, ethane, propane and butane.
  • carbon atoms form four bonds and hydrogen atoms one bond. the atoms try and form bonds with as many other atoms as they can so this makes the saturated. all alkanes have the same formula CnH2n+2, so if an alkane has 5 carbons, its got 2x5 + 2 = 12 hydrogens.

    basic trends:

  • the shorter the molecule the more runny the hydrocarbon is.
  • the shorter the molecule, the more volatile it is, this means it turns too a gas at lower temperature and the lower its boiling point is.
  • the shorter the molecule the more flammable the hydrocarbon is.
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Properties and uses of crude oil

crude oil is mainly alkanes:

  • all the fractions of crude oil are hydrocarbons called alkanes. alkanes are made up of chains of carbon atoms surrounded by hydrogen atoms. different alkanes have chains of different lengths
  • the first four alkanes are methane, ethane, propane and butane.
  • carbon atoms form four bonds and hydrogen atoms one bond. the atoms try and form bonds with as many other atoms as they can so this makes the saturated. all alkanes have the same formula CnH2n+2, so if an alkane has 5 carbons, its got 2x5 + 2 = 12 hydrogens.

    basic trends:

  • the shorter the molecule the more runny the hydrocarbon is.
  • the shorter the molecule, the more volatile it is, this means it turns too a gas at lower temperature and the lower its boiling point is.
  • the shorter the molecule the more flammable the hydrocarbon is.
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Uses of hydrocarbons

  • the gas fraction has the shortest molecules therefore it has the lowest boiling point and is a gas at room temperature, this makes it ideal for bottled gas, its stored under pressure as a liquid then vaporises as it flows into the burner.
  • the petrol fraction has longer molecules, so a higher boiling point. its ideal for use in cars.
  • the viscosity also helps decide how the hydrocarbons are used, the really viscous hydrocarbons are used for lubricating engine parts and covering roads.

using crude oil as a fuel:

  • crude oil fractions burn cleanly. most transport is fuelled by a crude oil fraction. eg cars, boats, trains. some crude oil is also burned in central heating in homes and power stations to provide electricity.
  • as well as fuels, rude oil provides the raw materials for making various chemicals like plastics.
  • crude oil fractions are often very reliable unlike wind and solar power were you need the right conditions.
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Using crude oil as a fuel

  • crude oil is a non-renewable fuel.
  • alternative fuel methods are renewable methods, e.g wind, solar and tidal power.

crude oil isn't good for the environment.

  • oil spills happen often and birds get covered in the oil and are then poisoned, other animals like sea otters and whales are also poisoned.
  • burning oil is a major cause to global warming, acid rain and global dimming.
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environmental problems

burning fossil fuels releases gases and particles:

  • power stations burn huge amounts of fossil fuels to make electricity.
  • most fuels, such as crude oil and coal contain carbon and hydrogen. during combustion, the carbon and hydrogen oxidises and carbon dioxide and water vapour are produced.
  • if the fuel contains sulphur impurities then sulphur dioxide will be produced. oxides of nitrogen will also form if the fuel burns at a high temperature. when there is lots of oxygen and all the fuels burn then its called complete combustion.
  • when there isn't enough oxygen the some of the fuel doesn't burn (partial combustion). because of this solid particles of carbon and unburnt fuel is released, carbon monoxide is also released.

sulphur dioxide causes acid rain:

  • when the sulphur dioxide mixes with the clouds it forms a dilute sulphuric acid and this then falls as acid rain.
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Environmental problems

sulphur dioxide causes acid rain:

  • oxides of nitrogen cause acid rain by forming dilute nitric acid in the clouds.
  • acid rain causes lakes to become acidic which causes wildlife and plants to die.
  • acid rain kills tress and destroy limestone buildings and statues.

you can reduce acid rain by reducing sulphur emissions:

  • most of the sulphur can be removed from the fuels before they're burnt but it costs a lot.
  • removing sulphur from the fuels usually requires more energy which requires more fossil fuels to be burnt which releases more carbon dioxide.
  • power station now have acid gas scrubbers.
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Environmental problems

  • the level of CO2 in the atmosphere is increasing, this has meant that the average temperature of the earth has increased - global warming. global warming is a type of climate change and it can cause flooding from the ice caps melting.

particles cause global dimming:

  • global dimming is being causes by the particles of soot and ash being produced by the burning of fossil fuels.

alternative fuels:

  • ethanol can be produced from plant material and is a biofuel. its made by the fermentation of plants and is used as well as petrol in some cars. its carbon neutral but its not widely available and car engines need to be modified for them to work, there is also fears that farmers may stop growing food crops and grow plants for fuel which would mean an increase in food prices.
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Environmental problems

alternative fuels:

  • biodiesel is another biofuel. its produced from vegetable oils, e.g rapeseed oil and soybean oil. can be mixed with diesel and used in engines. its carbon neutraland engines dont need to be changed. produces much less sulphur dioxide and particles than diesel or petrol.
  • however you can make enough biodiesel to replace diesel and its expensive to make.
  • hydrogen gas can be used to power engines. you get it from the electrolysis of water and the energy needed split it comes from a renewable source e.g solar. hydrogen just joins with oxygen in the air to produce water so its very clean, however you need a special and expensive engine and hydrogen isn't readily available. its also very hard to store.
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Cracking crude oil

cracking means splitting up long chains of hydrocarbons:

  • long chain hydrocarbons are thick liquids like tar which isnt that usefull.
  • longer molecules produced from fractional distillation are turned into smaller ones by a process called cracking.
  • some of the products are useful as fuels e.g petrol.
  • it also produces substances like ethene, which are needed for making plastics.

passing vapour over hot catalyst:

  • cracking is a thermal decomposition reaction, breaking molecules down by heating them.
  • first thing is to heat the long-chain hydrocarbons to turn it into a gas.
  • the vapour is then passed over a powdered alluminium oxide at a temperature of about 400- 700 degrees.
  • the long chain molecules then split apart or '"crack" on the surface of the specks of catalyst.
  • most of the products of cracking are alkanes. unsaturated hydrocarbons are alkenes.
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alkenes and ethanol

  • alkenes are hydrocarbons which have double bond between two of the atoms in their chain.
  • they are unsaturated because they can make more bonds and the double bond can open up, this allows the two carbon atoms to bond with other atoms.
  • the first two alkenes are ethene (2 carbon atoms) and propene (3 carbons)
  • you can test for an alkene by adding the substance to bromine water, an alkene will de- colourise the bromine water, turning it from orange to colourless. this is because the double bond has opened up and formed bonds with the bromine.

ethene can be reacted with steam to produce ethanol:

  • ethene can be hydrated with steam in the presence of a catalyst to produce ethanol.
  • at the moment this process is cheap because ethene's cheap and not much of it is wasted.
  • however ethene's produced from crude oil, this in non-renewable and could run out soon. this means soon making ethanol will become expensive.
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Ethenol

Ethanol can be produced from renewable sources:

  • the raw material in fermentation is sugar, this is converted into ethanol using yeast.
  • the process needs a lower temperature and more simple equipment than when using ethene.
  • sugar is a renewable source and the ethanol used can be used as a cheap fuel.
  • however the ethanol that you get from this process isn't very concentrated, so if you want it to be stronger then you would have to distill is and and it would need to be purified.
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Using alkenes to make polymers

alkenes can be used to make polymers:

  • you can join the smaller alkene molecules together to form very large molecules and these are called polymers.
  • e.g many ethene molecules can be joined up to produce polythene.

Different polymers have different physical properties:

  • the properties of polymers depend on what there made from. polyamides are usually stronger than polythene.
  • a polymers properties also depend on the temperature and pressure of the polymerisation. e.g polythene made at 200 degrees and 2000 atmospheres pressure is flexible and has a low density. but polythene made at 60 degrees and a few atmospheres pressure with a catalyst is rigid and dense.
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uses of polymers

  • light, stretchy polymers such as low density polythene are used to make plastic bags. elastic polymer fibres are used to make lycra for tights.
  • waterproof coatings for fabrics are made of polymers, polymers are used in resin for tooth fillings.
  • biodegradable bags made from polymers and cornstarch.
  • memory foam is a smart material. its a polymer that gets softer as it gets warmer. mattresses can be made from memory foam and they mould to your body shape.

polymers are cheap but there hard to get rid of:

  • most polymers are not biodegradable so they don't rot. its difficult to get rid of them and if you bury them in a landfill sit they will stay there for years. the best thing is to re-use them then recycle them if you can
  • thing made from polymers are usually cheaper than metal.however when crude oil starts to run out then crude oil products like polymers will start to get more expensive.
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plant oils

you can extract oils from plants:

  • some fruits and seeds contain oils. e.g olives and sesame seeds. these oils can be extracted used as food or fuels.
  • the plant material is crushed and then put between metal plates and crushed and then quashed.
  • the oil can be separated from the plant material by a centrifuge, or solvents can be used to separate it.
  • distillation purifies oil removing water, solvents and impurities.
  • vegetable oils are used in cooking because it has a higher boiling point than water. this means the foods can be cooked at a higher temperature and quicker.
  • using cooking oil increases the energy we take in from food.
  • vegetable oils such as rapeseed oil can be processed and turned into fuels. because the oils provide a lot of energy it means that they are suitable for fuels, biodiesel is made from vegetable oil and has very similar properties to regular diesel fuel, it burns the same way so can e used in a Diesel engine.
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plant oils

unsaturated oils contain a double carbon bond:

  • oils and fats contain long-chain molecules with lots of carbon atoms. oils and fats are either saturated or unsaturated.
  • unsaturated oils contain double bonds between some of the carbon atoms. so an unsaturated oil will de-colorise bromine water.
  • monounsaturated fats contain one double carbon bond somewhere in the carbon chains. polyunsaturated fats contain more than one carbon double bond.

unsaturated oils can be hydrogenated:

  • unsaturated oils are a liquid at room temperature.
  • they can be hardened by reacting the with hydrogen and a nickel catalyst at 60 degrees. this is called hydrogenation, the hydrogen reacts with the double bonded carbon and opens them up.
  • hydrogenated oils have a higher melting point than unsaturated oils, so they're more solid at room temperature. this makes them useful for spreads and baking. margarine is made from partially hydrogenated oils, turning all the double bonds in the oil to single bonds would make it too hard but only hydrogenating most of the bonds gives it a spreadable consistency.
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plant oils

  • margarine is usually used instead of butter in biscuits because it lasts a lot longer and is cheaper.
  • but partially hydrogenated vegetable oils means yo end up with a lot of trans fats which are bad for you.
  • natural unsaturated fats reduces cholesterol, partially hydrogenated oils increase the amount of cholesterol in the blood so eating a lot of these fats can increase the risk of heart disease.
  • saturated oils increase the amount of cholesterol in the blood.
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Emulsions

  • you can mix oil with water to make an emulsion. emulsions are made up of droplets of one liquid suspended in another liquid. you can have a water in oil emulsion or and oil in water emulsion.
  • emulsions are thicker than water or oil. the physical properties of an emulsion makes them suited to lots of uses in food e.g salad dressings or sauces.
  • the more oil you have in a oil in water emulsion the thicker it is, emulsions also have non-food uses as well, most moisturising creams are oil in water emulsions, the smooth texture of the emulsion makes the cream easy to rub into the skin.

some food contains emulsifiers to help the oil and water mix:

  • emulsifiers are molecules that have one part thats attracted to oil and the other part water.
  • the bit thats attracted to the oil is a hydrophobic.
  • the bit thats attracted to the water is a hydrophilic.
  • when you shake oil and water together with an emulsifier, oil droplets are repelled by the hydrophilic bit of the emulsifier, while water molecules latch on, so the emulsion wont separate out.
  • emulsifiers give you a longer shelf life and allow company's produce low in fat food but some people are allergic to these emulsifiers
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Plate tectonics

Alfred wagerer theory of continental drift:

  • he had noticed that similar fossils had been found on other sides of the ocean then realised that Africa and South America fit together, he wondered whether the two continents had one been together and had then split.
  • he found evidence that there was matching layers in the rock, in 1915 Wenger felt he had enough evidence and published his theory of continental drift.
  • wenger said that 300 million years ago, there had been one super continent and that it broke into smaller continents which moved apart. he said that these chunks were moving apart.

it wasn't accepted for many years:

  • his theory of how they were drifting wasn't very convincing, he thought that the continents were ploughing through the sea bed and that the movement was caused by the tides.
  • scientist worked out that the force needed for this too happen would have stopped the earth from rotating.
  • in the 1950s scientists were able to investigate the ocean floor and they found evidence that the main idea of what Wenger was saying was correct. by 1960 scientists were convinced and they now new that the earth was split into tectonic plates.
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The earths structure

the earth has a crust,mantle, outer and inner core.

  • the crust of the earth is very thin and is surrounded by a atmosphere. below is the mantle and it has all the properties of a solid but can flow very slowly. within the mantle, radioactive decay takes place and this produces a lot of heat, this causes the mantle to flow in convection currents.
  • at the centre of the earth is the core, which is thought to be made of iron and nickel.

the earths surface is made up of tectonic plates:

  • the crust and the upper part of the mantle is split up into large pieces called tectonic plates. because of convection currents in the mantle it causes the plates to drift.
  • most of the plates move a few cm a year.
  • volcanoes and earthquakes often occurs on the plate boundaries between two of the tectonic plates.
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The earths structure

scientists cant predict when earthquakes and volcanoes erupt:

  • tectonic plates stay still for a while then could suddenly move forward.
  • scientists are trying to find any clues for a possible eruption, even with clues though you can not defiantly say when it going to happen just that it might happen.
  • there are some clues for when an eruption might occur, molten rock might rise up into chambers before an eruption, causing the ground to bulge slightly, this causes mini earthquakes near the surface.
  • but sometimes molten rock cools down instead of erupting so these mini earthquakes can just be a false alarm.
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The evolution of the atmosphere

  • the earths surface was molten for many years and any atmosphere just boiled away. eventually it cooled down and a thin crust formed but volcanoes kept erupting.
  • the volcanoes gave out a lot of gas which likely helped form the oceans and the atmosphere. the early atmosphere was mainly co2 with virtually no oxygen. the oceans formed when water vapour condensed.

green plants evolved and produced oxygen:

  • a lot of CO2 was dissolved in the ocean and then taken in by the green plants and converted to O2 by photosynthesis.
  • plants and algae died and were buried under sediment along with skeletons of dead organisms. the carbon and hydrocarbons inside them had become locked up in sedimentary rocks as insoluble carbonates and fossil fuels. when you burn fossil fuels the locked up carbon gets released into the atmosphere and the concentration of CO2 increases.
  • the build up of oxygen in the atmosphere killed of early organisms, but allowed more complex ones to develop. the oxygen also created the ozone layer which blocks harmful rays from the sun and allowed complex organisms to evolve. there is no CO2 left.
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life resources and atmospheric change

  • the permodial soup is a theory of how life was created, millions of years ago a collection of gases in the atmosphere (nitrogen, hydrogen, ammonia, and methane), was struck by lightning and it caused a chemical reaction. causing amino acids to be formed.
  • the amino acids collected in a permodial soup and out life crawled. the amino acids gradually combined to produce organic matter which eventually evolved into simple living organisms.
  • a test was carried out with the collection of glasses which when heat and electricity applied did produce amino acids but not as many as on earth showing that the theory was along the right lines.

the earth has all the resources the humans need:

  • the earths crust, oceans and atmosphere has all the resources that humans need, e.g you can fractionally distill air to get a variety of products for use in industry.

1. air is filtered to remove dust. 2. it is then cooled to -200 degrees and it turns into a liquid. 3 during cooling water vapour condenses and is removed. 4. CO2 freezes and is removed. 5. the liquified air then enters the column and is heated slowly. the remaining gases are separated by fractional distillation, oxygen and argon come out together.

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