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| Questão | Responda |
| Why do materials need the right properties? | Otherwise they will be unsuited to the task, such as metal being a bad material for a feather duster. |
| What's the definition of a polymer? | A material made of very long molecules, formed by joining lots of small molecules (monomers) together. |
| There are both synthetic and natural polymers. Why are we using more synthetic polymers than 20 years ago. | There's now a lot more variety, so new materials are made more suited to our needs than natural alternatives. |
| A material can be strong in tension and/or strong in compression. What does this mean? | Tension: hard to pull apart. Compression: hard to buckle. |
| What is a stiff material? | The opposite of flexible, difficult to bend or stretch. |
| How can you tell if one material is harder than another? | The harder material will always scratch the softer one. |
| If a material is heavy for its volume, what is it? | Dense, as in a high density. |
| What is accuracy? | How close a measurement is to its true value. |
| What is repeatable and reproducible? | Repeatable: under the exact same conditions, the result wouldn't change. Reproducible: under different conditions the result wouldn't change. |
| Why do the factors not being tested have to be controlled, eg temperature? | To make it a fair test, so that the result is more accurate and not interfered with. |
| What are the properties of a material based upon? | Their atomic structure and the way the molecules line up. |
| How many nanometres in a metre? | 1,000,000,000,000 or 1 trillion |
| If a molecule such as wax has few atoms in each molecule, what's the effect? | The wax is brittle and easy to melt because the molecules are too small to tangle and can separate with ease. |
| On a molecular level what does vulcanisation cause? | Cross-links form between polymer chains, locking them in place. |
| What is plasticiser and what does it do? | An oily liquid with small molecules that sits between polymer chains, keeping them apart. This makes the polymer soft and flexible. |
| What is LDPE or a non-crystalline polymer? | Low Density Polythene, a form of polythene where there are branches on the polymer chains, making it irregular. |
| What is HDPE or a crystalline polymer? | High Density Polythene is made by forming polythene on a catalyst, so it forms packed and dense, without branches. |
| What is crude oil? | The unrefined oil recovered from the Earth's crust. Not very useful. |
| What can crude oil be used for? Name three. | Bottled gas, petrol for vehicles, chemicals, jet fuel, paraffin for heating, diesel fuels, fuel for central heating, lubricants, waxes, polishes, roads or roofing. |
| How is crude oil separated into groups of same-sized molecules? | By fractional distillation - the oil is heated, and then goes into a tower. The smaller molecules rise to the top because they take the least energy to become a gas. |
| What is nanotechnology? | The use and control of structures called nanoparticles, which are tiny, tiny particles. |
| Why do nanoparticles often have unusual or reactive properties? | The atoms on the surface are more reactive, and because nanoparticles are smaller they have more outer atoms. |
| Name three uses for nanoparticles. | Bus fuel, geckos' feet, bandages, proteins that control biological processes, sunscreen, tennis balls, electronic paper, clothing, self-cleaning windows. |
| Why are some doctors worried about nanoparticles? | They theorise that nanoparticles could be small enough to enter the brain through the blood, making normal chemicals toxic. |
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