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19 Cards in this Set
- Front
- Back
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What is the nano-size range? |
1 to 100 |
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As the size of the material gets smaller, what happens to the surface area? |
the surface area increases, the percentage of atoms on the surface increases |
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Atoms on the surface of any material tend to be more __________ than the ones in the centre. |
reactive |
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As the size of the solid pieces goes down, the reactivity of the material.... |
increases |
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Why would producing smaller solid particles of something like a catalyst be useful? |
It would be more efficient because each of the small particles would be more reactive |
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What have gold and silver nanoparticles been used as? |
colour pigments in stained glass windows and ceramics |
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Nano-sized gold will melt at a much ______ temperature than the solid metal |
lower |
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What property does nano-sized silver have? |
the property to kill bacteria |
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What is nano-sized silver used for? Give 3 examples |
1. Wound dressings 2. socks 3. antiseptic sprays |
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What can nano-sized titainium dioxide repel? |
repel water |
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What is nano-sized titainium dioxide used for? Give 3 examples |
1. Self-cleaning windows 2. sunscreen 3. cosmetics |
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Why is nano-sized titanium dioxide sometimes used in sunscreen? Give 2 reasons |
It can absorb and reflect UV light Appears transparent because particles are so small they can't be detected on the skin
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What are nanotubes made from? What is the structure? |
A single sheet of grapheme that has been rolled into a cylinder (one layer of carbon atoms bonded in hexagons) |
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Nano-tubes are ______ than steel but not as _______, so they can strengthen any material. |
stronger heavy |
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What is an example of what nano-tubes are used for? |
to strengthen tennis racquets and golf clubs |
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Carbon nano-tubes are from the class of compounds called.... |
fullerens |
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How are the carbon atoms bonded in a carbon nanotube? |
60 carbon atoms bonded together in pentagon and hexagon shapes |
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What is the small size a disadvantage of nano-sized particles and why? |
They have a large proportion of surface atoms, so there are many atoms that can react with oxygen in the air, so they tend to burn more easily |
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Give three other disadvantages of nanoparticles |
1. We have only just started to use them so can't be certain of their effects 2. Some scientists suggest that titanium dioxide nanoparticles can penetrate the skin and cause us damage 3. The existing safety measures may not be adequate |
