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Flashcards by Usman Rauf, updated more than 1 year ago
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Created by Josh Price
over 9 years ago
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Copied by Usman Rauf
over 9 years ago
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| Question | Answer |
| What are the materials we use made of? | Chemicals or mixtures of chemicals. |
| What examples of there of materials being obtained from living things? | Cotton, Silk, Paper, Wool. |
| What are synthetic materials? | Alternatives to materials from living things which are made by combining chemicals. and raw materials from the Earth's crust. |
| What does crude oil mainly consist of? | Hydrocarbons |
| What are hydrocarbons? | Chain molecules of vaying lengths made from carbon and hydrogen atoms only. |
| How does the petrochemical industry refine crude oil? | By fractional distilliation. |
| How does fractional distillation work? | Hydrocarbons are separated into fractions of different boiling points.The smallest molecules have the lowest boiling points, so the hydrocarbons are arble to be separated by size in this way. |
| What is polymerisation? | When some smalll loecules (monomers) join together to make very long molecules (polymers). |
| How do plasticisers modify the properties of a polymer? Why? | the polymer is softer, more flexible, and has a lower melting point. The polymer chains are further apart, so less energy is needed to break them. |
| How does cross-linking modify the properties of a polymer? Why? | The polymer is less flexible, stronger, harder, and has a higher melting point. More energy is needed to separate the molecules. |
| How does an increased chain length modify the properties of a polymer? | The polymer is stronger and has a higher melting point. The molecules are tangled together, so its harder to make them slide over each other. The forces between the molecules are stronger, so more energy is needed to break them. |
| How does increased crystallinity modify the properties of a polymer? | The polymer becomes stronger and denser. The forces between the molecules are stronger. |
| What examples are there of nanoparticles modifying the properties of materials? | Silver nanoparticles give fibres antibacterial properties. Nanoparticles in plastic sports equipment makes them stronger. Hydrophobic nanoparticles encourge water to flow more quickly. |
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