Flashcards in How structure influences the properties and uses of substances Deck (18)
Why does pure water not conduct electricity? 
- no delocalised / free electrons
- no overall electric charge
- no ions
How does the size of a nanoparticle compare with the size of an atom? 
nanoparticles are larger
Suggest one reason why 1 g of cobalt oxide nanoparticles is a better catalyst than 1 g of cobalt oxide powder. 
nanoparticles have a larger surface area
Explain why metals can be bent and shaped. 
- layers of particles / atoms...
- ...slide over each other
Explain how copper conducts electricity. 
- it has delocalised electrons...
- ...and therefore can move through the structure
Explain why diamond is hard. 
- it's a giant structure...
- ...with strong bonds between carbon atoms
Explain why thermosetting polymers are better than thermosoftening polymers for saucepan handles. 
- thermosetting polymers do not melt (when heated)...
- ...due to cross-links (between chains)
Explain how electricity is conducted in a metal. 
- 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. 
- an alloy has different types / sizes of atoms...
- ...resulting in distorted layers
Why is Nitinol used in dental braces? 
it can return to its original shape
Suggest one reason why coins are not made of pure copper. 
pure copper is too soft
Aluminium is manufactured by the electrolysis of a molten mixture of cryolite and ________. 
How can the same reaction produce two different products? 
Give two reasons why instrumental methods of analysis are used to detect impurities in metals. 
- small sample
Suggest why carbon nanotubes are used as lubricants. 
- nanotubes can slide (over each other)...
- ...because there are no (covalent) bonds between the nanotubes
Explain why graphite can conduct electricity. 
- graphite has delocalised electrons...
- ...so that electrons can move through the graphite
- ...so that electrons can carry charge through the graphite
Describe, as fully as you can, the structure and bonding in diamond. 
- giant structure / lattice
- strong bonds (between carbon / atom)
- covalent (bonds)
- each carbon / atom forms 4 bonds