Bulk & Surface Properties

Question 1

What are the three categories of particles based on their diameter?

Answer 1

Coarse particles (dust)

Fine particles

Nanoparticles.

Question 2

What does PM stand for in PM2.5 and PM10?

Answer 2

PM stands for Particulate Matter.

Question 3

True or False?

Nanoparticles are between 1 and 100 micrometres in size.

Answer 3

False.

Nanoparticles are between 1 and 100 nanometres in size.

Question 3

What is the size range of fine particles in nanometres?

Answer 3

Fine particles have diameters between 100 and 2500 nm.

Question 4

True or False?

Nanoparticles usually contain only a few hundred atoms.

Answer 4

True.

Nanoparticles usually contain only a few hundred atoms.

Question 5

What is the size of atoms and simple molecules compared to nanoparticles?

Answer 5

Atoms and simple molecules are around 100 times smaller than nanoparticles.

Question 5

True or False?

Coarse particles (PM10) have diameters between 1 x 10-5 m and 2.5 x 10-6 m.

Answer 5

True.

Coarse particles (PM10) have diameters between 1 x 10-5 m and 2.5 x 10-6 m.

Question 6

True or False?

As particles decrease in size, their surface area decreases in relation to their volume.

Answer 6

False.

As particles decrease in size, their surface area increases in relation to their volume.

Question 7

A particle has a surface area of 24 cm2 and a volume of 8 cm3. What is the surface area to volume ratio?

Answer 7

The surface area to volume ratio in 3:1.

Question 8

Why do nanoparticles have different properties to the bulk material?

Answer 8

Nanoparticles have different properties to the bulk material because they have a higher surface area to volume ratio.

Question 9

How are fullerenes used in medicine?

Answer 9

Fullerenes are used in medicine and drug design as they are more easily absorbed than other particles and can deliver drugs to target areas more effectively.

Question 10

What is a potential risk of nanoparticles in medical applications?

Answer 10

A small amount of toxicity would be multiplied due to the high surface area to volume ratio.

They are not easily disposed of by the body.

Question 11

True or False?

The main industrial application of nanoparticles is in catalysis due to their high surface area to volume ratios.

Answer 11

True.

The main industrial application of nanoparticles is in catalysis due to their high surface area to volume ratios.

Question 11

True or False?

Nanoparticles are easily disposed of by the body.

Answer 11

False.

Nanoparticles are not easily disposed of by the body, which is a cause for caution in their medical application.

Question 12

How does titanium dioxide nanoparticle behave differently from its bulk form in sunscreens?

Answer 12

Titanium dioxide nanoparticles in sunscreens block UV light but leave no white marks on the skin.

Question 13

Why is 1 g of nanoparticles is a better catalyst than 1 g of cobalt oxide powder?

Answer 13

Nanoparticles are much smaller than coarse particles, so they have a higher surface area to volume ratio.

Question 14

True or False?

It is cheaper to use nanoparticles of platinum as opposed to coarse particles of platinum.

Answer 14

True.

It is cheaper to use nanoparticles of platinum as opposed to coarse particles of platinum.

Nanoparticles have a larger surface area to volume ratio, so less particles can be used to achieve the same effect.