How structure influences the properties and uses of substances Flashcards
Why does pure water not conduct electricity? [1]
- no delocalised / free electrons
- no overall electric charge
- no ions
How does the size of a nanoparticle compare with the size of an atom? [1]
nanoparticles are larger
Suggest one reason why 1 g of cobalt oxide nanoparticles is a better catalyst than 1 g of cobalt oxide powder. [1]
nanoparticles have a larger surface area
Explain why metals can be bent and shaped. [2]
- layers of particles / atoms…
- …slide over each other
Explain how copper conducts electricity. [2]
- it has delocalised electrons…
- …and therefore can move through the structure
Explain why diamond is hard. [2]
- it’s a giant structure…
- …with strong bonds between carbon atoms
Explain why thermosetting polymers are better than thermosoftening polymers for saucepan handles. [2]
- thermosetting polymers do not melt (when heated)…
- …due to cross-links (between chains)
Explain how electricity is conducted in a metal. [4]
- giant structure / lattice…
- …made up of atoms / positive ions
- …with delocalised electrons…
- …so electrons can move through the metal
Describe how the structure of an alloy is different from the structure of a pure metal. [2]
- an alloy has different types / sizes of atoms…
- …resulting in distorted layers
Why is Nitinol used in dental braces? [1]
it can return to its original shape
Suggest one reason why coins are not made of pure copper. [1]
pure copper is too soft
Aluminium is manufactured by the electrolysis of a molten mixture of cryolite and ________. [1]
aluminium oxide
How can the same reaction produce two different products? [1]
different. ..
- conditions
- catalyst
- pressure
- temperature
Give two reasons why instrumental methods of analysis are used to detect impurities in metals. [1]
- accurate
- sensitive
- rapid
- small sample
Suggest why carbon nanotubes are used as lubricants. [2]
- nanotubes can slide (over each other)…
- …because there are no (covalent) bonds between the nanotubes
