C2 – Material choices

Revision questions

  1. Hydrocarbons are made of …

Properties of Materials

  1. What’s the difference between natural and synthetic materials?
  1. Name 3 natural materials:
  1. Name 2 synthetic materials:
  1. “The melting point of chocolate is 30’C” What does that mean?
  1. The melting point of plastic is around 200’C. Why is it so much higher than chocolate?
  1. Match these properties to their meanings

Brittle / You can twist and draw this into wires or fibres
Tough / It doesn’t deform much before it breaks.
Stiff / You don’t need much force to change its shape
Flexible / You need a lot of force to change its shape
Ductile / Keeps a new shape when you deform it
malleable / It is strong and doesn’t change its shape.
plastic / Can be squeezed and bent into new shapes without breaking
  1. What key word means that a material will last a long time?
  1. What does it mean if a material is elastic?
  1. Name 2 properties of rubber.

Crude Oil

  1. How do we refine crude oil? By f______d______

  1. How does the temperature change as you go up the fractionating column?
  1. What are crude oil fractions used for? Give at least 3 uses.
  1. Where do short hydrocarbons come out of the column? Where do long hydrocarbons?

Polymers

  1. What do you call it when you put monomers together?
  1. Match each diagram of to its name. Then explain how that change affects the polymer.

/ Cross-linking / The bonds are weaker/stronger
because
/ Increasing the chain length / The bonds are weaker/stronger
because
/ plasticisers / The bonds are weaker/stronger
because
/ crystallization / The bonds are weaker/stronger
because
  1. Here are some ways you can change polymers. How does this affect their properties?

Stronger or weaker? / More or less flexible? / Higher or lower melting point?
Increase chain length (make the chain longer)
Increasing crystallinity
Add plasticisers
Increase cross-linking

Data handling

  1. Some students decided to test how much different materials can stretch.

Trial # / How much it stretched (cm)
nylon / wool
1 / 11 / 6
2 / 15 / 8
3 / 12 / 5
4 / 14 / 6
  1. Calculate the best estimate for each material

Wool:Nylon:

  1. What is the range for each material:

Wool:Nylon:

  1. Is there a real difference between the two materials? Yes/No

How do you know?

Nano Particles

  1. How big is a nano particle?

Between ___nm and ______nm in size.

  1. Give 3 examples of how nanoparticles are used

______

______

______

  1. Explain why nanoparticles have different properties to their macroscopic equivalents.
  1. Describe the risks associated with nanoparticles