Practise comparing diamond, graphite and C60 fullerene by linking their structures to hardness, conductivity and melting point behaviour.
Diamond and graphite are both giant covalent substances made up of carbon atoms.
- diamonds are used in cutting tools
- graphite is used in pencils to make marks on paper
Explain, with reference to structure and bonding, why each substance is suitable for its particular use.
Any explanation that links any three of the following points for diamond
M1 each (carbon) atom is (covalently) bonded to four other (carbon) atoms
M2 in a (giant) tetrahedral lattice /network / structure
M3 the (covalent) bonds are (very) strong
M4 (therefore) diamond is (very) hard (and so good for cutting tools)
Any explanation that links any three of the following points for graphite
M5 each (carbon) atom is (covalently) bonded to three other (carbon) atoms
M6 (the structure is) in layers
M7 weak forces (between layers)
M8 (the layers can) slide over each other/ rub off
M9 this makes graphite soft (so it can make marks on paper)
ALLOW each carbon has four bonds
ALLOW 3D/rigid in place of tetrahedral
ALLOW reference to lot of energy needed to break the (covalent) bonds
ALLOW there are lots of/many (covalent) bonds
ALLOW diamond is (very) strong
If mention of intermolecular forces in diamond MAX 2 for diamond
If mention of ions in diamond only M4 can be scored
ALLOW sheets
ALLOW slippery
If mention of intermolecular forces in graphite MAX 2 for graphite
If mention of ions in graphite only M9 can be scored