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12/01/2014 C2 Material Choices OCR 21 st Century W Richards.

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Presentation on theme: "12/01/2014 C2 Material Choices OCR 21 st Century W Richards."— Presentation transcript:

1 12/01/2014 C2 Material Choices OCR 21 st Century W Richards

2 12/01/2014 C2.1 Properties of Materials Q. For each of the following materials describe what properties the material needs to have and why…

3 12/01/2014 Properties of materials Plastic (polythene) Light Flexible Easily moulded

4 12/01/2014 Properties of materials Plastic (polystyrene) Light Rigid Good insulation

5 12/01/2014 Properties of materials Nylon Light Tough Waterproof

6 12/01/2014 Properties of materials Polyester Light Tough Waterproof

7 12/01/2014 Properties of materials Unvulcanised rubbers Low tensile strength Soft Flexible

8 12/01/2014 Properties of materials Vulcanised rubbers High tensile strength Hard Flexible

9 12/01/2014 C2.2 Crude Oil

10 12/01/2014 Using Different Materials We use a variety of materials from a variety of different places: Cotton from plants Silk from silkworms Wood and paper from trees These are all natural materials – we can also use synthetic (man-made) ones like plastics – these are often made from materials from within the Earth like crude oil.

11 12/01/2014 Chemical formulae The chemical formulae of a molecule or compound is simply a way of showing the ratio of atoms in it. For example… NaCl = sodium chloride (NaCl) KI = potassium iodide (KI) KN OOO = potassium nitrate (KNO 3 )

12 12/01/2014 Chemical formulae Try drawing these: 1)Water H 2 O 2)Carbon dioxide CO 2 3)Calcium sulphate CaSO 4 4)Magnesium hydroxide Mg(OH) 2

13 12/01/2014 Simple chemical reactions Mg O H Cl Mg Cl H H O H Magnesium+Copper sulphate Mg O O Cu O O S Mg O O O O S Magnesium sulphate Copper + H2OH2OMgO+ WaterMagnesium oxide +Hydrochloric acid Magnesium chloride + 2HCl MgCl 2 + MgSO 4 Mg+CuSO 4 Cu + Notice that the number of atoms on each side of the equation is the same!

14 12/01/2014 Hydrocarbons and crude oil Increasing length Crude oil is a mixture of HYDROCARBONS (compounds made up of carbon and hydrogen). Some examples: Ethane C C H H H HH H Butane CC H H H HH H C C H H H H These different lengths are called _______ and most of them are used as _____. Some are used to make materials such as _______. Longer chains have higher _____ points. Words – boiling, fractions, plastics, fuels

15 12/01/2014 Fractional distillation Crude oil can be separated by fractional distillation. The oil is evaporated and the hydrocarbon chains of different lengths condense at different temperatures: Fractions with low boiling points condense at the top Fractions with high boiling points condense at the bottom

16 12/01/2014 Forces between molecules Weak force of interaction here Longer molecules = stronger force of attraction, leading to higher boiling points due to the molecules needing more energy to pull them away from each other.

17 12/01/2014 Polymers CC H H H H Ethene Heres ethene. Ethene is called a MONOMER because it is just one small molecule. We can use ethene to make plastics… Step 1: Break the double bond Step 2: Add the molecules together: This molecule is called POLYETHENE (i.e. polythene), and the process that made it is called POLYMERISATION

18 12/01/2014 C2.3 Molecular Structure

19 12/01/2014 Uses of addition polymers Poly(ethene)Poly(propene) Poly(chloroethene), PVCPoly(styrene)

20 12/01/2014 Structure of Plastics 1) Some plastics have ____ intermolecular forces between each molecule – these have __ melting points and can be ________ easily 2) Some plastics have _____ forces between each molecule. These have ____ melting points and are ____. Words – high, low, strong, weak, stretched, rigid

21 12/01/2014 Forces between molecules As weve already said, longer molecules have stronger forces of attraction between them. This tends to lead to longer chain plastics being: 1)Stronger 2)Stiffer 3)Harder 4)More difficult to melt (i.e. higher melting point)

22 12/01/2014 Modifying Plastics Polymers can be modified in a number of ways: 1)Increasing the chain length...making it stronger 2) Crosslinking...making it harder 3) Plasticizing...making it softer and more flexible 4) Packing more closely (a crystalline polymer)...making it stronger and more dense

23 12/01/2014 C2.4 Nanotechnology

24 12/01/2014 Nanotechnology Task: To find out what nanotechnology is and what it is used for 1)What is nanotechnology? 2)Define the terms nanoparticle and nanocomposite 3)Gives some examples of its uses 4)Describe some of the future uses of this technology 5)Describe some of the ethical concerns over this technology

25 12/01/2014 Nanotechnology Nanotechnology is a new branch of science that refers to structures built from a few hundred atoms and are nm big. They show different properties to the same materials in bulk, partly because they also have a large surface area to volume ratio and their properties could lead to new developments in computers, building materials etc. Definition:

26 12/01/2014 How nanoparticles are formed Nanoparticles can be formed by a number of methods: They can occur naturally in sea spray They can also be formed during combustion Or they can be formed by grinding down materials

27 12/01/2014 Two examples of nanotechnology The Nano Carbon Pro tennis racket uses nanoparticles to increase its strength. Silver nanoparticles can be used to give fibres antibacterial properties – look at what they do to e-coli bacteria: Normal e-coli E-coli affected by silver nanoparticles

28 12/01/2014 Nanoscience and health Nanoparticles are obviously very small and, as we have said, have a large surface area to volume ratio. This makes them useful but can also make them dangerous. Nanoparticles could easily pass through a cell membrane: How do these health concerns affect the development of nanotechnology? Im going to die…

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