Nanoscience

• What is the size range of structures studied in nanoscience?

  1 to 100 nanometres (nm)
• How many atoms typically make up most nanoparticles?

  A few hundred atoms
• What are the size comparisons of different types of particles?

  • Atoms and small molecules: 0.1 nm
  • Nanoparticles: 1 to 100 nm
  • Fine particles (PM2.5): 100 to 2,500 nm
  • Coarse particles (PM10, dust): 2,500 to 10,000 nm
  • Thickness of paper: 100,000 nm
• If a zinc oxide nanoparticle has a diameter of 32 nm, how many times larger is it compared to a zinc atom with a diameter of 0.28 nm?

  About 100 times larger
• What does the symbol ≈ represent in calculations?

  It indicates that the answer is approximate
• How does the surface area to volume ratio change with particle size?

  • Smaller particles have a greater surface area to volume ratio.
  • If the length of a cube's side gets 10 times smaller, the surface area to volume ratio increases by 10 times.
• What is the surface area of a cube-shaped nanoparticle with sides of 10 nm?

  600 nm²
• What is the volume of a cube-shaped nanoparticle with sides of 10 nm?

  1000 nm³
• What is the surface area to volume ratio of a cube-shaped nanoparticle with sides of 10 nm?

  0.6
• What term describes a substance that consists of nanoparticles?

  Nanoparticulate
• What are the reasons for the different properties of nanoparticulate materials compared to bulk materials?

  • Tiny size of nanoparticles
  • Large surface area to volume ratios
• What are some uses of nanoparticulate materials?

  • Medical treatments
  • Cosmetics, deodorants, and sunscreens
  • Electronics
  • Catalysts
• How does zinc oxide in sunscreens differ in appearance when in nanoparticulate form compared to bulk form?

  Nanoparticulate zinc oxide is invisible on the skin, while bulk zinc oxide is white
• Why do nanoparticulate substances act as efficient catalysts?

  • Large surface area to volume ratios allow for:
  • More efficient catalysis of reactions
  • Catalysis of different reactions producing different products
• What is a practical application of nanoparticulate coatings on window panes?

  They catalyse the breakdown of dirt in the presence of sunlight
• What are the potential risks associated with nanoparticles?

  • Possible inhalation or cellular entry
  • Potential to catalyse harmful reactions
  • Toxic substances may bind to them, harming health
  • Difficulty in determining risks due to their recent common use