CHAPTER 1.1

Question 1

Nanoscience

Answer 1

the study of nanoparticles and nanotechnology

Question 2

Nanotechnology

Answer 2

the use of technologies that manipulate and investigate the properties of materials on the nanoscale

Question 3

examples of nanotechnology

Answer 3

• microchips in computers
• phones are made up of nanoscale transistors
• LEDs
• Lasers and light emitting diodes
• sunscreen ( absorbs ultraviolet radiations)

Question 4

what does the prefix ‘nano’ refer to?

Answer 4

one billionth or 10 to the power of -9m

Question 5

learn table 1.1.1

Answer 5

learn table 1.1.1

Question 6

How to convert into nanometres

Answer 6

1) convert to meters
2) write the length in scientific notation
3) multiply by 10 to the power of 9 to convert to nanometres

Question 7

what do opals and butterflies have in common

Answer 7

• opal is a nanometre made of tiny spheres of silica
• spheres diffract light to produce flashes of colour
• butterflies also get coloured patterns from nanostructures on the surface of their wings

Question 8

What are the two processes used to manufacture nanomaterials?

Answer 8

1) The bottom up method
2) The top down method

• although the two methods start at opposite ends of the scale, the bottom up and top-down approaches both produce materials that exist on the same nanoscale and rely on physical and chemical processes to achieve these nanomaterials

Question 9

What is the bottom up method?

Answer 9

uses specifically designed molecules or atoms in chemical reactions to gradually build up the new nanoparticle from the smaller atoms or molecular units.

Question 10

What is the top down method?

Answer 10

• uses the larger bulk material as the starting material

- the bulk material is broken down into nanoparticles by mechanical or chemical means.

Question 11

aDsorbtion

Answer 11

is used when a molecule attaches to surface of a solid or a liquid.

example: silica gel and activated charcoal can adsorb large amounts of liquids and gases.

Question 12

about activavted charcoal

Answer 12

• contains billions of nanoscale holes that trap unwanted molecules such as water and other gases.
• only small amount of activated charcoal is required to adsorb large number of gas molecules due to its numerous tiny holes.
• used in gas masks,
• invented in 1951 and were used in WW1

Question 13

How are nanomaterials engineered?

Answer 13

simple example = patterning of the surface of a CD rom

• information is encoded on the surface of the CD-ROM as a series of nanosized ‘pits’ or hollows.
• improvements in tech = smaller sized pits = more information stored = DVD

Question 14

what is a nanoparticles range?

Answer 14

from 1 to 100 nm

and are usually spherical

Question 15

what is the most important property of nanoparticles?

Answer 15

their large surface are compared to their volume

( surface area to volume ratio)

Question 16

why are surfaces (in chem and nanoparticles) important?

Answer 16

• surface areas are where chemical reactions take place

- substances made pf nanoparticles have very large surface areas because they are so small

Question 17

3 IMPORTANCE of large surface area to volume ratio.

Answer 17

1) aDsorbtion of particles- large surface area of nanop = small volume of nanop can aDsorb large number of molecules.
2) Transportation of molecules- nano p can be used to transport the molecules that are adsorbed onto the nanoparticles. The nanoparticles small size and large surface area mean they can transport chemical through the air, skin and cells
3) Catalysts

Question 18

difference between aDsorbtion and aBsorbtion

Answer 18

………………….

Question 19

what is meant by catalysts

Answer 19

the surface area of some nanoparticles can be used to increase the rate of particular chemical reactions

• acting as cataysts because they speed up the reactiosn but is not consumed ( used up) by the reaction.
• reactant molecules aDsorb onto surface of nanos which allows reactant molecules to combine to form the product.
• large surface area = reactions can take place at same time = increases rate of reaction significantly.

Question 20

three examples of composite nanomaterials

Answer 20

stain resistant cotton = water repellent
zinc oxide (sunscreen) = absorbs UV rays.

Question 21

what happens when a substance is processed into nanoparticles

Answer 21

physical
chemical
optical properties are changed.