Name two natural materials from plants and two from animals and say where they come from.
plants: wood/paper from trees and cotton from cotton from cotton plant. Animals: Wool from sheep and/or silk from silkworm and/or leather from cows.
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Name materials made from humans (synthetic) and say why they're made by man.
1. Rubber- used to come from the sap of a rubber tree but now made in a factory because you can control the properties. 2. Paints are made from man made chemicals so that it doesn't fade. 3. Clothes made from man made materials to control properties.
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Whats the difference between tensile and compressive strength?
Tensile is how much a material can resist a pushing force where as compressive is how much a material can resist a pushing force
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What does density mean?
Mass per unit volume, (e.g. g/cm^3)
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Whats crude oil?
A mixture of hydrocarbons which vary in length.
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What are the two different bonds called that hold hydrocarbons together and what's the difference between them?
1. strong covalent bonds- between hydrogen and carbon within the molecules. 2. Intermolecular- attraction between different hydrocarbons in the mixture. Covalent are stronger than intermolcular.
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When a hydrocarbons length changes the properties also change. As it increases in length the...
Boiling point increases because there are more covalent bonds to break and they are stiffer.
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Whats fractional distillation?
hydrocarbons are separated into groups with different boiling points so that the chains of different lengths are separated. It's the separating of hydrocarbons which is called refining.
when monomers are joined together to make a polymer under high pressure to make a plastic. They are usually carbon based.
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whats a plasticiser?
they're added to a polymer to make it softer because the polymer chains can slide past each other easier.
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whats cross- linking?
adding links inbetween polymer chains to make them, stiffer, stronger and more heat resistant
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when you make a polymer more crystalline what happens?
density increases, melting point increases, stronger.
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what has a higher melting point, a polymer with strong or weak forces between the polymers?
strong
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how many nanometres is a nano particle?
1-100 nm
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Name 2 uses of nanoparticles and explain why they're used
sports equiptment- make it stronger and more durable without adding weight. Plasters- antibacterial property. Suncream- they cover a larger surface area with a smaller amount
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Other cards in this set
Card 2
Front
Name materials made from humans (synthetic) and say why they're made by man.
Back
1. Rubber- used to come from the sap of a rubber tree but now made in a factory because you can control the properties. 2. Paints are made from man made chemicals so that it doesn't fade. 3. Clothes made from man made materials to control properties.
Card 3
Front
Whats the difference between tensile and compressive strength?
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