2 4 bulk and surface properties

The three categories of particles based on their diameter are:

PM stands for Particulate Matter.

False. Nanoparticles are between 1 and 100 nanometres in size.

Fine particles have diameters between 100 and 2500 nm.

True. Nanoparticles usually contain only a few hundred atoms.

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

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

The surface area is: 3 x 3 x 6 = 54 cm2

The surface area is: 3 x 3 x 3 = 27 cm3

The surface area to volume ratio in 3:1.

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

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

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.

A potential risk of nanoparticles in medical applications could be:

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

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

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

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

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.