Special materials

Question 1

What is graphene and its features?

Answer 1

• a form of carbon

a single layer of graphite

atoms arranged in a hexagonal structure

it is one atom thick

Question 2

What are the properties of graphene? (5)

Answer 2

• very strong
• a good thermal and electrical conductor (delocalised electrons)
• nearly transparent
• high melting point
• very light (it can be added to composite materials to improve their strength without adding much weight)

Question 3

What does graphene properties make them useful in?

Answer 3

electronic and composite materials

Question 4

Why is graphene strong?

Answer 4

because it has a network of covalent bonds

Question 5

what are fullerenes?

Answer 5

molecules of carbon atoms with hollow shapes.

they are shaped like closed tubes or hollow balls

Question 6

Describe the structure of fullerenes

Answer 6

made up of hexagons

they also contain rings with 5 or seven carbon atoms

Question 7

What was the first fullerene to be discovered and how was it like?

Answer 7

buckminsterfullerene

C60

had a spherical shape

Question 8

What were the features of the buckminsterfullerene

Answer 8

• made up of 60 carbon atoms
• joined together by strong carbon atoms in a series of hexagons and pentagons
• there are weak intermolecular forces between molecules so little energy is needed to overcome the bonds, therefore, it is slippery and has a low melting point

Question 9

What are carbon nanotubes?

Answer 9

cylindrical fullerenes with very high length to diameter ratios.

Their properties make them useful for nanotechnology, electronics and materials.

Question 10

What can fullerenes be used to do?

Answer 10

to deliver drugs in the body

can be used in lubricants

as catalysts

reinforcing materials

Question 11

What are polymers (describe it)?

Answer 11

long chains of repeating units that consist of very large molecules and are held together by strong covalent bonds

the intermolecular forces between the large polymer molecules are also quite strong

this makes it solid at room temperatures

Question 12

What are the properties of nanotubes?

Answer 12

Can conduct electricity and heat (delocalised electrons)

High tensile strength ( so strong in tension and can resist being stretched)

these properties allow nanotubes to be used for electronics or the strengthen materials without adding much weight

Question 13

What is the size of a coarse (dust) particle?

• in terms of diameter

Answer 13

have diameters between 2.5 x 10-6 m and 1 x 10-5 m

Question 14

What is the diameter of a fine particle?

Answer 14

100nm and 2500nm

OR

1 x 10-7m nd 2.5 x 10-6m

Question 15

What is the diameter of nanoparticles?

Answer 15

1–100 nm

OR

1 x 10-9m and 1 x 10-7m

Question 16

What happens as the particle size decreases by 10 times?

Answer 16

the surface area: volume increases by ten times

Question 17

Nanoparticles have a huge surface area: volume ratio.

What are the advantages of this?

Answer 17

smaller quantities are needed to be effective than for materials with normal particle sizes.

important for catalysts as having a large surface area improves their effectiveness

Question 18

What are nanoparticles used in?

Answer 18

medicine
in electronics 
in-cosmetics  
sun creams 
deodorants
catalysts

Question 19

Research into nanoparticles is important for the development of what?

Answer 19

• new drug delivery systems
• synthetic skin for burn victims
• computers and technology
• catalysts for fuel cells
• stronger and lighter construction materials
• new cosmetics and deodorants
• fabrics that prevent the growth of bacteria