Nanoparticulate materials

• What is the size range of nanoparticles?

  1 nm to 100 nm
• Why do nanoparticulate substances have different properties compared to the same substance in bulk?

  Because of their tiny size and large surface area to volume ratios
• What is the definition of surface area?

  The total area of all sides on a 3D shape
• What is the definition of volume?

  The measure of the amount of space a 3D shape occupies
• What are some uses of nanoparticulate materials?

  • Medical treatments
  • Cosmetics, deodorants, and sunscreens
  • Electronics
  • Catalysts
• How do nanoparticulate sunscreens protect the skin?

  They block harmful ultraviolet light from the sun
• What is a property of bulk zinc oxide compared to nanoparticulate zinc oxide?

  Bulk zinc oxide is white, while nanoparticulate zinc oxide is invisible on the skin
• What is one disadvantage of nanoparticulate sunscreens?

  They tend to clump together, making them difficult to apply
• What is another disadvantage of nanoparticulate sunscreens?

  It may be difficult to tell where sunscreen has been applied if it is invisible
• Why do nanoparticulate materials act as effective catalysts?

  Due to their large surface area to volume ratios
• What is a catalyst?

  A substance that changes the rate of a chemical reaction without being changed itself
• What is an example of a practical application of nanoparticulate materials in self-cleaning technology?

  Self-cleaning window panes with nanoparticulate coatings
• What are some concerns regarding the use of nanoparticles?

  They may be inhaled or pass into cells, potentially causing harm
• What could happen if toxic substances bind to nanoparticles in the body?

  They could harm health if the nanoparticles enter the body
• Why is it difficult to determine the risks of modern nanoparticulate materials?

  Because they have only become common recently
• What is a possible environmental hazard of silver nanoparticles used in wound dressings?

  They could harm or kill useful bacteria when the dressings are discarded