Bulk and surface properties of matter including nanoparticles

Question 1

Compare the size of nanoparticles to

atoms and molecules

Answer 1

Nanoparticles contain a few hundred
atoms and are between 1-100 nm
(nanometres) across.

Question 2

What are some of the risks associated with

nanoparticulate materials?

Answer 2

• Little is known about the effects of nanoparticles.
• May be harmful to health (they could enter the
  bloodstream or be breathed in).
• May catalyse harmful reactions inside the body.
• Large surface area to volume ratio may allow toxic
  substances to bind to them and enter the body.

Question 3

Why would nanoparticles be useful catalysts?

Answer 3

Nanoparticles have a very high surface area to volume ratio

Question 4

What is the equation to calculate the surface area to volume ratio?

Answer 4

Surface area to volume ratio= Surface area ÷ Volume

Question 5

Why might nanotubes be used to make electrical

circuits for computers?

Answer 5

• Can conduct electricity.
• Are very small so take up little space.
• Lightweight.

Question 6

Why might nanoparticles be used in sunscreen?

Answer 6

Some nanoparticles block UV light. Nanoparticles don’t leave white marks on skin

Question 7

What are the general properties of glass ceramics?

Answer 7

• Transparent.
• Strong but brittle.
• Easily moulded into shapes.
• Poor conductors.

Question 8

What are the general properties of clay ceramics?

Answer 8

• Opaque.
• Soft and malleable.
• Hardened with heat.
• Brittle once hardened.
• Poor conductors.

Question 9

What are the general properties of polymers?

Answer 9

- Properties can be adapted to suit the
purpose
- Usually tough and flexible
- Can be transparent or opaque
- Poor conductors

Question 10

What are the general properties of metals?

Answer 10

• Shiny
• Malleable
• Ductile
• Good conductors
• Can form alloys to produce more desirable properties

Question 11

What is a composite material?

Answer 11

Contains two or more materials with different
properties.
Typically, there are two components: the
reinforcement (makes up the bulk of the material)
and the matrix (binds the reinforcement together).

Question 12

Why do composite materials have a wide range of different properties?

Answer 12

As composite materials are made of several materials, the properties can be tailored to suit the need of the composite. Different composite materials contain different reinforcements and matrixes so the properties vary.

Question 13

What should be used to construct large buildings:

reinforced concrete or fibreglass? Why?

Answer 13

Reinforced concrete because it is strong
in compression and tension and slightly
flexible

Question 14

What should be used to make tennis rackets: timber

or fibre reinforced plastic? Why?

Answer 14

Fibre reinforced plastic because it has a
low density so is lightweight and is
flexible and strong in tension.