unit 5 Flashcards
(26 cards)
Can al3+ be oxidised to pure metal Al?
No
Can zone melting produce materials with a purity of up to 98% but no higher?
No
During zone melting when is the impurity ion most soluble
Liquid phase
What is the inert pair effect?
s orbitals penetrate the nucleus better than p orbitals and dont participate in bonding
Can aluminum powder react with air?
Yes
The lattice energy of Al203 is very high therefore…
Combustion creates a lot of heat
What structure can tin and germanium form?
Diamond structure
Which density of tin (diamond structure) or tin (FCC structure) has the higher density?
FCC
Is carbon the only group 13 that can form diamond structure?
No tin and germanium can too
How can you reduce the melting point of aluminia?
mixing it with other materials
Why is the melting point of Al203 higher than aluminium?
strong ionic bonds
Can silicon and oxygen form long chain molecules?
Yes
What can zeolites be described as?
Framework structures
What can zeolites be used for and why?
Catalysts as very small molecules can fit inside
Do zeolites have low melting points because they are ionic?
No
Why is diamond hard?
All the bonds are covalent
Why is graphite soft?
Its van der waal forces
What can diamond be made from?
Graphite under high pressure
how thick is a layer of graphene?
1 atom thick
What is lead azide?
Solid, sensitive Explosive, it can detonate to form nitrogen
How does mixing Cryolite and Al203 reduce melting point?
Ions can disturb the crystal structure of alumnia making it easier for the Al and O to move away from their lattice sites
How do group 3 exist?
Metalloid then rest are metals
What does amphoteric mean?
Reacts as both an acid and a base
Why does B3+ not form ionic compounds?
Very small radius which is so polarising electron density would be shared (covalent)
