nanoscience

• What is the size range of nanoparticles?

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

  A few hundred atoms
• What is nanoscience?

  It is the study of structures between 1 and 100 nanometres in size.
• What are the sizes of different types of particles compared to nanoparticles?

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

  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 ratio gets 10 times bigger.
• 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?

  1,000 nm³
• What is the surface area to volume ratio of a cube-shaped nanoparticle with sides of 10 nm?

  0.6
• What does it mean if a substance is described as nanoparticulate?

  It consists of nanoparticles.
• 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 do sunscreens utilize nanoparticles?

  Zinc oxide nanoparticles block harmful ultraviolet light and are invisible on the skin.
• How do large surface area to volume ratios benefit nanoparticulate substances as catalysts?

  • They catalyse reactions more efficiently.
  • They can catalyse 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 some concerns regarding the use of nanoparticles?

  They may be inhaled or enter cells, potentially causing harmful reactions.
• Why is it difficult to determine the risks of modern nanoparticulate materials?

  They have only recently become common.