c5 Flashcards
(12 cards)
1
Q
what shape is buckminsterfullerene? (1)
A
spherical
2
Q
give three uses of fullerenes
A
- (spherical fullerenes for) lubricants
- drug delivery around the body
- catalysts
- (cylindrical fullerenes for) strengthening materials
- antioxidants
3
Q
why is buckminsterfullerene a good lubricant? (2)
A
- molecules are spherical
- so will roll
4
Q
suggest why it is cheaper to use nano particles of silver rather than coarse particles of silver (2)
A
- larger surface area to volume ratio
- so use less silver for the same effect
5
Q
why should batteries not be put in household waste? (2)
A
- can be toxic
- could cause pollution in landfill sites
6
Q
name two factors which effect the voltage produced in a chemical cell (2)
A
- concentration of electrolyte
- temperature of electrolyte
7
Q
advantages of hydrogen fuel cells over rechargeable cells (3)
A
- no toxic chemicals to dispose of at the end of the cells life
- takes less time to refuel
- you can travel a longer distance before refuelling
8
Q
two half equations for the reactions in a hydrogen fuel cell
A
- H2 —> 2H+ + 2e-
- O2 + 4H+ + 4e- —> 2H2O
9
Q
disadvantages of hydrogen fuel cells
A
- made from fossil fuels
- made from non renewable resources
- difficult to store
- flammable/ explosive
- costs more to refuel and manufacture
- not many hydrogen filling stations
10
Q
why are hydrogen fuel cell trains called steam trains? (2)
A
- hydrogen is oxidised to produce water
- water is released as gas (steam)
11
Q
why do alkaline batteries eventually stop working? (2)
A
a reactant is used up so the reaction stops
12
Q
why can alkaline batteries not be recharged? (1)
A
reaction is not reversible
