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Ceramics
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- 1What are ceramics?Ceramics are non-metal solids with high melting points that aren't made from carbon based compounds
- 2Some ceramics can be made from what? How?Some ceramics can be made from clay. Clay is a soft material when it's dug up out of the ground, so can be moulded into different shapes. When it's fired at high temperatures, it hardens to form a clay ceramic
Its ability to be moulded when wet and hardened makes clay ideal for making pottery and bricks - 3Some ceramics can be made from ___Glass. Glass is generally transparent, can be moulded when hot and can be brittle when thin
- 4Soda-lime glassMost glass made is soda-lime glass, which is made by heating a mixture of limestone, sand and sodium carbonate (soda) until it melts. When the mixture cools it comes out as glass
- 5Borosilicate glassHas a higher melting point than soda lime glass. It's made in the same way as soda-lime glass, using a mixture of sand and boron trioxide
- 6What are composites?Made of one material embedded in another. Fibres or fragments of a material (known as the reinforcement) are surrounded by a matrix acting as a binder. The properties of a composite depend on the properties it is made from
- 7Examples of composites: FibreglassFibreglass consists of fibres of glass embedded in a matrix made of polymer (plastic). It has a low density (like plastic) but is very strong (like glass). It's used for things like skis, boats and surfboards
- 8Examples of composites: Carbon fibreCarbon fibre composites also have a polymer matrix. The reinforcement is either made from long chains of carbon atoms bonded together (carbon fibres) or from carbon nanotubes. These composites are very strong and light so are used in aerospace and sports car manufacturing
- 9Examples of composites: ConcreteConcrete is made from aggregate (a mixture of sand and gravel) embedded in cement. It's very strong. This makes it ideal for use as a building material, e.g. in skate parks
- 10Examples of composites: WoodWood is a natural composite of cellulose fibres held together by an organic polymer matrix
- 11What 2 things can influence the properties of a polymer?How it's made and what it's made from
- 12Polymers: Poly(ethene)The properties of poly(ethene) depend on the catalyst that was used and the reaction conditions (the temperature and pressure) that it was made under
Low density (LD) poly(ethene) is made from ethene at a moderate temperature under a high pressure. It's flexible and is used for bags and bottles
High density (HD) poly(ethene) is also made from ethene but at a lower temperature and pressure with a catalyst. It's more rigid and is used for water tanks and drainpipes - 13The monomers that a polymer is made from determine the type of bonds that form between the polymer chains. These weak bonds between the different molecule chains determine the properties of the polymer:Thermosoftening polymers contain individual polymer chains entwined with weak forces between the chains. You can melt these plastics and remould them
Thermosetting polymers contain monomers that can form cross-links between the polymer chains, holding the chains together in a solid structure. Unlike thermosoftening polymers, these polymers don't soften when they're heated. Thermosetting polymers are strong, hard and rigid - 14Uses of ceramics:Ceramics include glass and clay ceramics such as porcelain and bricks. They're insulators of heat and electricity, brittle (aren't flexible and break easily) and stiff
- 15Uses of polymers:Polymers are insulators of heat and electricity, they can be flexible (they can be bent without breaking) and are easily moulded. Polymers have many applications including in clothing and insulators in electrical items
- 16Uses of composites:Properties of composites depend on the matrix/binder and the reinforcement used to make them, so they have many different uses
- 17Uses of metals:Metals are malleable, good conductors of heat and electricity, ductile (can be drawn into wires), shiny and stiff. Metals have many uses, including in electrical wires, car body-work and cutlery
- 18What are alloys?Alloys are made by adding another element to the metal. This disrupts the structure of the metal, making alloys harder than pure metals
Most metals in everyday use are alloys - 19Alloys of iron called steels are often used instead of pure iron. How are steels made?Steels are made by adding small (specific) amounts of carbon and sometimes other metals to iron
- 20What are the different types of steel?Low carbon steel: Easily shaped, softer, used in car bodies
High carbon steel: Very strong, inflexible, brittle, used in bridges
Stainless steel (chromium added and sometimes nickel): Corrosion-resistant, hard, used in cutlery - 21How is bronze made?Bronze = Copper + Tin
Bronze is harder than copper. It's used to make medal, decorate ornaments and statues - 22How is brass made?Brass = Copper + Zinc
Brass is more malleable than bronze and is used in situations where lower friction is required, such as in water taps and door fittings - 23What are gold alloys used to make?Jewellery. Pure gold is very soft. Metals such as zinc, copper and silver are used to harden the gold
Pure gold is described as 24 carat, so 18 carats means that 18 out of 24 parts of the alloy are pure gold. 18 carat gold is 75% gold - 24What is corrosion?Where metals react with substances in their environment and are gradually destroyed
- 25IronIron corrodes easily: it rusts (rust is only used for the corrosion of iron, not other metals)
In order to rust, iron needs to be in contact with both oxygen and water, which are present in air
Rust = compound hydrated iron (III) oxide
Iron + Oxygen + Water -> Hydrated Iron (III) Oxide
Iron is oxidised - 26When does corrosion happen?Only happens on the surface of a material, where it's exposed to the air
- 27What happens after iron has rusted?Rust is a soft crumbly solid that soon flakes off to leave more iron available to rust again. Means that eventually all the iron in an object corrodes away even if it wasn't initially at the surface
- 28AluminiumAluminium also corrodes when exposed to air. Unlike iron objects, things made from aluminium aren't completely destroyed by corrosion. This is because the aluminium oxide that forms when aluminium corrodes doesn't flake away. It forms a protective layer that sticks firmly to the aluminium below and stops any further reaction taking place
- 29Experiment to show that both oxygen and water are needed for iron to rustIf you put an iron nail in a billing tube with just water, it won't rust. The water is boiled to remove oxygen and oil is used to stop air getting in
If you put iron nail in a boiling tube with just air it won't rust. Calcium chloride can be used to absorb any water from the air
If you put an iron nail in a boiling tube with air and water, it will rust - 30Preventing Rusting: Coat the iron with a barrierThe obvious way to prevent rusting is to coat the iron with a barrier to keep out the water and oxygen:
Painting/Coating with plastic - ideal for big and small structures alike. Can be decorative too
Electroplating - uses electrolysis to reduce metal ions onto an iron electrode. It can be used to coat the iron with a different metal that won't be corroded away
Oiling/Greasing - this has to be used when moving parts are involved, like on bike chains - 31Preventing Rusting: Sacrificial methodsInvolves placing a more reactive metal such as zinc or magnesium with the iron. Water and oxygen then react with the sacrificial metal instead of with the iron
- 32Preventing Rusting: Combination of techniquesAn object can be galvanised (coated) by spraying it with a coating of zinc. The zinc layer is firstly protective, but if it's scratched, the zinc around the site of the scratch works as a sacrificial metal
- 33What do human's use the Earth's resources for?To provide warmth, shelter, food and transport
- 34Natural resources, supplemented by agriculture provide what?Food, timber, clothing and fuels
- 35What are natural resources?Form without human input. Include anything that comes from the earth, sea or air. For example, cotton for clothing or oil for fuel
- 36Some of these natural resources can be replaced by synthetic products or improved upon by man-made processes. Give an exampleRubber is a natural product that can be extracted from the sap of a tree, however, man-made polymers have now been made which can replace rubber in uses such as tyres
- 37Agriculture provides conditions where natural resources can be enhanced for our needs. Give an exampleThe development of fertilisers have meant we can produce a high yield of crops
- 38Renewable resourcesRenewable resources reform at a similar rate to, or faster than, we use them
Timber is a renewable resource as trees can be planted following a harvest and only take a few years to regrow. Other examples of renewable resources include fresh water and food - 39Finite (non-renewable) resourcesFinite resources aren't formed quickly enough to be considered replaceable
Finite resources include fossil fuels and nuclear fuels such as uranium and plutonium. Minerals and metals found in ores in the earth are also non renewable materials - 40What happens after finite resources have been extracted?Undergo man made processes to provide fuels and materials necessary for modern life
Fractional distillation is used to produce usable products such as petrol from crude oil and metal ores are reduced to produce a pure metal - 41Extracting finite resources has risksMany modern materials are made from raw, finite resources, for example most plastics, metals and building materials
People have to balance the social, economic and environmental effects of extracting finite resources
E.g. mining metal ores is good because useful products can be made. It also provides local people with jobs and brings money into the area. However, mining ores is bad for the environment as it uses loads of energy, scars the landscape, produces lots of waste and destroys habitats - 42What is sustainable development?Chemistry plays an important role in improving agricultural and industrial processes to provide new products and in sustainable development, which is development that meets the needs of current generations without compromising the ability of future generations to meet their own needs.
- 43Extraction and Processing of MaterialsExtracting resources can be unsustainable due to the amount of energy used and waste produced. Processing the resources into useful materials, such as glass or bricks, can be unsustainable too, as the processes often use energy that's made from finite resources
- 44How can we reduce the use of finite resources?Use less. This doesn't just reduce the use of that resource but also anything needed to produce it
We can't stop using finite resources altogether, but chemists can develop and adapt processes that use lower amounts of finite resources and reduce damage to the environment
E.g. chemists have developed catalysts that reduce the amount of energy required for certain industrial processes - 45Copper and extractionCopper is a finite resource. One way to improve it's sustainability is by extracting it from low-grade ores (ores without much copper in)
- 46BioleachingBacteria are used to convert copper compounds in the ore into soluble copper compounds, separating out the copper from the ore in the process. The leachate (the solution produced by the process) contains copper ions, which can be extracted, e.g. by electrolysis or displacement with a more reactive metal, e.g. scrap iron
- 47PhyotominingInvolves growing plants in soil that contains copper. Plants can't use or get rid of the copper so it gradually builds up in the leaves. Plants can be harvested, dried and burned in a furnace. Ash contains soluble copper compounds from which copper can be extracted by electrolysis or displacement using scrap iron
- 48Copper extactionTraditional methods for copper mining are pretty damaging to the environment. These new methods of extraction have a much smaller impact, but the disadvantage is that they're slow
- 49Recycling MetalsMining and extracting metals takes lots of energy, most of which comes from burning fossil fuels
Recycling metals often uses much less energy than is needed to mine and extract new metal, conserves the finite amount of each metal in the earth and cuts down on the amount of waste getting sent to landfill
Metals are usually recycled by melting them and then casting them into the shape of the new product
Depending on what the metal will be used for after recycling, the amount of separation required for recyclable metals can change. For example, waste steel and iron can be kept together as they can both be added to iron in a blast furnace to reduce the amount of iron ore required
A blast furnace is used to extract iron from its ore at a high temperature using carbon - 50Recycling GlassGlass recycling can help sustainability by reducing the amount of energy needed to make new glass products and also the amount of waste created when used glass is thrown away
Glass bottles can often be reused with reshaping
Other forms of glass can't be reused so they're recycled instead. Usually the glass is separated by colour and chemical composition before being recycled
The glass is crushed and then melted to be reshaped for use in glass products such as bottles or jars. It might also be used for a different purpose such as insulating glass wool for wall insulation in homes - 51Life Cycle AssessmentsExtracting and processing raw materials
Manufacturing and packaging
Use and operation during its lifetime
Disposable at the end of its useful life, including transport and distribution at each stage - 52Getting the Raw MaterialsExtracting raw materials needed for a product can damage the local environment, e.g. mining metals. Extraction can also result in pollution due to the amount of energy needed
Raw materials often need to be processed to extract the desired materials and this often needs large amounts of energy. E.g. extracting metals from ores or fractional distillation of crude oil - 53Manufacturing and PackagingManufacturing products and their packaging can use a lot of energy resources and can also cause a lot of pollution, e.g. harmful fumes such as carbon monoxide or hydrogen chloride
You also need to think about any waste products and how to dispose of them. The chemical reactions used to make compounds from their raw materials can produce waste products. Some waste can be turned into other useful chemicals, reducing the amount that ends up polluting the environment - 54Using the ProductThe use of a product can damage the environment. For example, burning fuels releases greenhouse gases and other harmful substances. Fertilisers can leach into streams and rivers causing damage to ecosystems
How long a product is used for or how many uses it gets is also a factor - products that needs lots of energy to produce but are used for ages means less waste in the long run - 55Product DisposalProducts are often disposed of in landfill sites. This takes up space and pollutes land and water, e.g. if paint washes of a product and gets into rivers
Energy is used to transport waste to landfill, which causes pollutants to be released into the atmosphere
Products might be incinerated (burnt) which causes air pollution - 56Problems with LCAsThe use of energy, some natural resources and the amount of certain types of waste produced by a product over it's lifetime can be easily quantified. But the effect of some pollutants is harder to give a numerical value to. E.g. it's difficult to apply a value to the negative visual effects of plastic bags in the environment compared to paper ones
Producing an LCA is not an objective method as it takes into account the values of the person carrying out the assessment. Means LCAs can be biased
Selective LCAs which only show some of the impacts of a product on the environment can also be biased as they can be written to deliberately support the claims of a company in order to give them positive advertising - 57Potable waterPotable waster is water that's been treated or is naturally safe for humans to drink - it's essential for life
Not pure water. Pure water only contains H2O molecules, whereas potable water can contain lots of other dissolved substances
Important: levels of dissolved salts aren't too high, has a pH between 6.5 and 8.5 and also there aren't any bacteria or other microbes in it - 58Sources of WaterRainwater is a type of fresh water. Fresh water is water that doesn't have much dissolved in it
When it rains, water can either collect as surface water (in lakes, rivers and reservoirs) or as groundwater (in rocks called aquifers that trap water underground)
In the UK, the source of freshwater used depends on location. Surface water tends to dry up first, so inn warm areas, e.g. the south east, most of the domestic water supply comes from groundwater - 59Treating WaterEven though it only has low levels of dissolved substances, water from these fresh water sources still needs to be treated to make it safe before it can be used:
Filtration - a wire mesh screens out large twigs, and then gravel and sand beds filter out any other solid bits
Sterilisation - the water is sterilised to kill any harmful bacteria or microbes. This can be done by bubbling chlorine gas through it or by using ozone or UV light - 60Desalination: PracticalIn some very dry countries, e.g. Kuwait, there's not enough surface or groundwater and instead sea water must be treated by desalination to provide potable water
Distillation can be used to desalinate sea water:
Test the pH of the water using a pH meter. If the pH is too high or too low, you can neutralise it. You can do this with a titration, but use a pH meter to tellyou when the solution's neutral, rather than an indicator, as this won't contaminate the water
You should als test the water for the presence of sodium chloride (main salt in sea water). To test for sodium ions, do a flame test on a small sample. If sodium ions ar epresent the flame will turn yellow. To test for chloride ions, take another sample of your water and add a few drops of dilute nitric acid, followeed by a few drops of silver nitrate solution. If chloride ions are present, a white precipitate will form
To distil the water, pour the salty water into a distillation apparatus. Heat the flask from below. The water will boil - 61Reverse OsmosisSalty water is passed through a membrane that only allows water molecules to pass through. Ions and larger molecules are trapped by the membrane so separated from the water. Pressure on water means uses loads of energy like distillation, so very expensive and not practical for producing large quantities of fresh water
- 62Waste Water comes from lots of different sourcesUrban lifestyles and industrial processes produce large amounts of waste water that require treatment before being released into the environment. Sewage and agricultural waste water require removal of organic matter and harmful microbes. Industrial waste water may
require removal of organic matter and harmful chemicals
Agricultural systems also produce a lot of waste water including nutrient run off from fields and slurry from animal farms
Sewage from domestic/agricultural sources has to be treated to remove any organic matter and harmful microbes before it can be put back into freshwater sources like rivers or lakes. Otherwise it would make them very polluted and would pose health risks
Industrial processes such as the Haber process also produce a lot of waste water that has to be collected and treated
As well as organic matter, industrial waste water can also contain harmful chemicals, so it has to undergo additional stages of treatment before it is safe to release it into the environment - 63Sewage TreatmentScreening - involves removing any large bits of material, like twigs, or plastic bags as well as any grit
Allowed to stand in a settlement tank and undergoes sedimentation. Heavier suspended solids sink to the bottom to produce sludge, while the lighter effluent floats on the top
Effluent in the settlement tank is removed and treated by biological aerobic digestion. This is where air is pumped through the water to encourage aerobic bacteria to break down any organic matter - including other microbes in the water
Sludge from the bottom of the settlement tank is also removed and transferred into large tanks. Gets broken down here by bacteria in a process called anaerobic digestion
Anaerobic digestion breaks down the organic matter in the sludge, releasing methane gas in the process. The methane gas can be used as an energy sources and the remaining digested waste can be used as a fertiliser
For waste water containing toxic substances, additional stages of treatment may involve adding chemicals, e.g. to precipitate metals, UV radiation or using membranes - 64Sewage Treatment UsefulSewage treatment requires more processes than treating fresh water but uses less energy than the desalination of salt water, so could be used as an alternative in areas where there's not much fresh water. Singapore is treating waste water and recycling it back into drinking supplies
- 65Formulated FertilisersFarmers used to use manure to fertilise fields. Formulated fertilisers are better as they're more widely available, easier to use, don't smell and have just enough of each nutrient so more crops can be grown
- 66NPK FertilisersNitrogen, phosphorous and potassium
If plants don't get enough of these elements, their growth and life processes are affected. These elements may be missing from the soil if they've been used up by a previous crop
Fertilisers replace these missing elements or provide more of them. This helps to increase the crop yield, as the crops can grow faster and bigger. For example, fertilisers add more nitrogen to plant proteins which make the plants grow faster - increasing productivity
NPK fertilisers are formulations containing salts of nitrogen, phosphorous and potassium in the right percentages of the elements - 67Ammonia is Used to Produce Nitrogen Containing CompoundsAmmonia can be reacted with oxygen and water in a series of reactions to make nitric acid
You can also react ammonia with acids, including nitroic acid to get ammonia salts
Ammonia and nitric acid react together to produce ammonium nitrate - this is an especially good compound to use in a fertiliser because it hs nitrogen from two sources
Ammonia + Nitric Acid -> Ammonium nitrate
NH3 + HNO3 -> NH4NO3 - 68Ammonia + Nitric Acid -> Ammonium nitrate In IndustryThe reaction is carried out in giant vats, at high concentrations resulting in a very exothermic reaction. The heat released is used to evaporate water from the mixture to make a very concentrated ammonium nitrate
- 69Ammonia + Nitric Acid -> Ammonium nitrate In LabThe reaction is carried out on a much smaller scale by titration and crystallisation. The reactants are at a much lower concentration than in industry, so less heat is produced by the reaction and it's safer for a person to carry it out. After the titration, the mixture then needs to be crystallised to give pure ammonium nitrate crystals. Crystallisation isn't used in industry because it's very slow
- 70Phosphate and Potassium are Sourced from Mined CompoundsPotassium chloride and potassium sulphate can be mined and used as a source of potassium
Phosphate rock is also mined. However, because the phosphate salts in the rock are insoluble, plants can't use them as nutrients
Reacting phosphate rock with a number of different types of acids produces soluble phosphates:
Reaction with nitric acid produces phosphoric acid and calcium nitrate
Reaction with sulfuric acid produces calcium sulfate and calcium phosphate (this mixture is known as single superphosphate)
Reaction with phosphoric acid only produces calcium phosphate (the product of this reaction can be called triple superphosphate) - 71Production of nitric acidProduction of nitric acid from ammonia
Ammonia, NH3, is oxidised in the presence of a platinum/rhodium catalyst to form nitrogen monoxide:
4NH3 + 5O2 → 4NO + 6H2O
The nitrogen monoxide is then further oxidised to form nitrogen dioxide:
2NO + O2 → 2NO2
The nitrogen dioxide is then dissolved into water in the presence of oxygen to form concentrated nitric acid:
4NO2 + 2H2O + O2 → 4HNO3
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- Karteikarten am Ceramics , erstellt von Jasmine Sillence am 06/02/2022.
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