Nanoparticles
Tiny particles which are between 1 and 100 nanometres (nm) in size. are structures, 1 to 100 nanometres (nm) in size, that usually contain only a few hundred The smallest part of an element that can exist.. This means that nanoparticles are larger than atoms and simple A collection of two or more atoms held together by chemical bonds..
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Small size
Some of the The characteristics of something. In chemistry, chemical properties include the reactions a substance can take part in. Physical properties include colour and boiling point. of nanoparticles depend on their very small size: 1 nm = 1 × 10-9 m (one billionth of a metre).
| Object | Approximate size (nm) |
| Hydrogen atom | 0.1 |
| Water molecule | 0.3 |
| Glucose molecule | 1 |
| Nanoparticle | 1 - 100 |
| Virus | 120 |
| Bacterial cell | 1000 |
| Object | Hydrogen atom |
|---|---|
| Approximate size (nm) | 0.1 |
| Object | Water molecule |
|---|---|
| Approximate size (nm) | 0.3 |
| Object | Glucose molecule |
|---|---|
| Approximate size (nm) | 1 |
| Object | Nanoparticle |
|---|---|
| Approximate size (nm) | 1 - 100 |
| Object | Virus |
|---|---|
| Approximate size (nm) | 120 |
| Object | Bacterial cell |
|---|---|
| Approximate size (nm) | 1000 |
Surface area to volume ratios
Some of the properties of nanoparticles depend on their large The total area of all sides on a 3D shape. to The volume of a three-dimensional shape is a measure of the amount of space or capacity it occupies, eg an average can of fizzy drink has a volume of 330 ml. ratios. For solid substances, the smaller its particles, the greater the surface area to volume ratio.
Question
A cube-shaped nanoparticle has sides of 10 nm. Calculate its surface area to volume ratio.
Surface area = 6 × 10 × 10 = 600 nm2 (remember that a cube has six sides)
Volume = 10 × 10 × 10 = 1000 nm3
\(surface\ area\ to\ volume\ ratio\ =\frac{600}{1000}\)
= 0.6
Question
A cube-shaped nanoparticle has sides of 1 nm. Calculate its surface area to volume ratio.
Surface area = 6 × 1 × 1 = 6 nm2
Volume = 1 × 1 × 1 = 1 nm3
\(surface\ area\ to\ volume\ ratio\ = \frac{6}{1}\)
= 6
