OC03: nanomaterials

Question 1

nanomaterials

Answer 1

nano materials are materials which have at least one dimension in the size range between 1 to 100nm

Question 2

nano particles

Answer 2

nano particles are discrete particles with all 3 dimensions in the size range between 1 to 100 nm

Question 3

nano particles effect as catalyst

Answer 3

1. effectiveness:
   nanoparticles provide a large surface area to volume ratio. hence, there will be more reactive sites on the metal surface for reaction to take place.
   this increases the frequency of effective collision between particles and hence increasing rate of reaction
2. hence a smaller mass is needed and lowered cost

Question 4

nanoparticles effect on interactions between particles

Answer 4

millions of nanoparticles allow for large surface area to volume ratio
this large surface area gives rise to very extensive instantaneous dipole- induced dipole interactions between the feet of the gecko and the wall surface
the cumulative id-id interactions generates are translated to strong attractive forces capable of supporting large amounts if weight

Question 5

what are allotropes

Answer 5

allotropes are two or more different forms of an element in the same physical state, having different atomic arrangement
(eg. diamond vs graphite)

Question 6

properties of graphene

Answer 6

1. high electrical conductivity:
   due to p orbitals overlap to form an extensive pi electron cloud where electrons are delocalised in a sheet of graphene
2. high tensile strength:
   due to presence of very strong and extensive C—C bonds in its structure

Question 7

properties if carbon nanotubes (singular vs many)

Answer 7

singular:
1. strong and conduct electricity (same as graphene)

many:
1. not as strong because the carbon nanotubes are held together by weak id-id, poor conductors as absence of delocalised electrons (as electrons cannot move from one carbon nanotube to another)

2. they cab be used as a membrane due to low porosity

Question 8

fullerenes: nanometer sized hollow cages

Answer 8

1. low melting point (weak id-id between molecules)
2. slippery due to weak idid
3. insoluble in water
4. poor conductor of electricity
5. ball structure of fullerene enables it to carry small molecules like a cage

Question 9

potential harmful effects of nano particles (3) into humans

and environment

Answer 9

1. inhalation: as they are the same scale as cellular components (easy to enter lungs and bloodstream)
2. skin contact: permeable through skin into bloodstream
3. ingestion: efficiently absorbed into circulation system by the gastrointestinal tract

environment:
- through water bodies, land etc