C2 - Material Choices

C2 - Material Choices

1. Material that is made of atoms of one element only:

   • Iron

2. Material that we use that comes from plants

   • Wood and paper from trees and cotton from cotton plant

3. Material that we need that comes from animals:

   • Wool comes from sheep. Silk is made by the silkworm larvae and leather comes from cows.

4. Advantes of synthetic rubber over natural rubber

   • With natural rubber, you can control its proprties making it suitable for different purposes eg wetsuits, as with synthtic rubbers, the properties of synthethetic fabrics can be controlled by the manufacturer. e.g you can make fabrics that are waterproof, super stretchy or sparkly
   • Difference between strength and stiffness
     • Strength is how good a material is at resisting a force and stiffness is good at not bending when a force is applied to it
   • How do plasticisers work?
     • Plasticisers work by getting in between the polymer chains and reducing the forces btween them

5. Whats the hardest material found in nature?

   • Diamond

6. What is density?

   • Density is a material mass per unit volume (g/cm3)

7. Two properties of each of the following materials that make them useful in manufacturing:

   • Plastic
     • Low density and mouldable
   • Rubber
     • Strong and mouldable
   • Nylon fibres
     • Soft and flexible and good tensile strength

8. What does crude oil contain?

   • Hydrocarbons which has carbon and hydrogen atoms only
   • Two important types of bond in crude oil
     • Strong covalent bonds and intermolecular forces

9. Why do big hyrocarbon molcules have higher boiling points than small ones.

   • The intermolecular forces break a lot more easily in small molecules than they do in bigger moleculess. Thats because the intermolecular forces of attraction are much stronger between big molecules than they ar between small molecules and so more energy is neededd for them to break out of a liquid and form a gas.

10. What happens when crude oil is refined?

    • Its done by fractional distillation. In this process hydrocarbons are separated into groups with different boiling points. Each group is called a fraction and hydrocarbons within a fraction have similar boiling points. Each fraction is made up of hydrocarbons with similar chain lengths
      • Five useful products of crude oil
        • Refinery gas
        • Petrol
        • Diesel
        • Lubricating oil
        • Naphtha
      • What most of the hydrocarbon fuels in crude oil used to produce?
        • Fuel

11. What happens during polymerisation?

    • Plastics are formed when lots of small molecules called monomers join together to make a very long molecule called a polymer. They're usually carbon based. Under high pressure many small moleculs join hands (polymerise) to form long chains called polymers

12. An example of a product where a polymer has replaced a natural material

    • Synthenthic fibres like nylon and polyester are often used to replace cotton, wool, or silk fabrics

13. How does the arrangement of polymer chains affect the density of a material?

    • If the polymer chains are packed close together, the material will have a high density. If the polymer chains are spread out, the material will have a low density

14. What are the arrangement of its molecule chains and the forces holding them together?

    • Chains held together by weak forces are free to slide over each other. This means the plastic can be stretched easily and will have a low melting point

15. What would you add to a polymer to make it stiffer and stronger?

    • Cross linking agents

16. What are the properties of a crystalline polymer?

    • Higher density, strongr and higher melting point

17. Nanotechnology is the branch of technology dealing with the making and use of nanoparticles

    • Give two examples of nanoparticles
      • Seaspray - The sea produces nanoscale salt particles which ar present in the atmosphere
      • Combustion - When fuels are burnt, nanoscale soot particles are produced