Bulk and surface properties

Question 1

What size of structures does nano science refer to

Answer 1

1-100nm

Question 2

Compare the diameter of fine particles and coarse particles

Answer 2

Fine particles: 100 — 2500nm

Coarse particles: 2500 — 10000nm

Question 3

convert ‘1 x 10^-6m’ into nanometers

Answer 3

1000nm

Question 4

What happens when the side of a cube decreases by a factor of 10 (e.g moves from 10cm to 1cm)

Answer 4

The surface area to volume ratio increases by a factor of 10 (e.g moves from 0.6:1 to 6:1)

Question 5

What type of particles are dust

Answer 5

Coarse particles

Question 6

Why are smaller quantities of nanoparticles needed to be effective than with materials with normal particle size

Answer 6

They have a high surface area to volume ratio

Question 7

Give 3 of 6 examples of industries where nanoparticles can be used

Answer 7

Any 3 of:
.Medicines
.Electronics
.Cosmetics
.Sun creams
.Deodorants
.Catalysts

Question 8

Why are the risks of nanoparticles difficult to determine

Answer 8

They haven’t been in use for very long

Question 9

Give 3 problems caused by nanoparticles in suncreams

Answer 9

1) Can enter cells and cause damage
2) May be harmful to environment
3) Could be more reactive of toxic than bulk materials