Chemistry 5

simmyhall's version from 2015-06-08 17:11

Section 1

Question Answer
What changes place to place Water vapour amount
Most non metals are Miolecular -two atoms
Atoms in molecular substances are joined by Covalent bond
Covalent bonds come from The electrostatic attraction between the positive nuclei and negative electrons
Attractions between molecules are Weak intermolecular forces
What do intermolecular forces have effectLow melting points or bp when it melts or boils these forces break not strong covalent bonds
Covalent bonds forms when Two non metals share a pair of electrons

Section 2

Question Answer
Ionic When metals react with none metals -electrons are transferred from the metal atoms to non metals
Metal atoms become Positive
Non metals becomeNegative
Compounds like NaCl -lattice structure Strong electrostatic forces between them -lots of energy needed to separate the positive and negative ions -high melting and boiling point
Solid ionic compounds cannot conduct because Ions cannot move
When melted or dissolved in water solid ionic compounds canConduct electricity ions can move

Section 3

Question Answer
Silica is in a Giant covalent structure
Each silicon atom is Covalently bonded to four oxygens
Each oxygen is Covalently bonded to two silicon atoms
Ratio is SiO2
Properties Very hard ,high melting and boiling points ,insolvable in water ,doesn't conduct electricity - result of strong covalent bonds
Silicon is found in Granite -sand stone

Section 4

Question Answer
Diamond is made up of Carbon each covalently bonded to four carbon atoms by strong covalent bonds
Diamond is Used in drills because Hard
Graphite is made ofOne carbon joined to three others -forms layers
Bonds between layers are much Weaker than covalent bonds -slide over-making it soft -conduct electricity between layers
Graphite used in Pencil lead -due to layers

Section 5

Question Answer
One metals -present in their Ores as oxides
To extract metals from ores-Heat oxides with carbon
The metal oxide looses Oxygen -reduction
The carbon Gains Oxygen-oxidised
So metals such as aluminium are tooReactive -oxides cannot be reduced by carbon

Section 6

Question Answer
Electrolysis does what Breaks down ionic substances into their elements
For electrolysis to work -Ions have to be free to move
How do u get ions free Dissolved in water or melted ions are free to move
Negative electrode Cathode
Positive electrode Anode
Positive ions go to the Cathode -metal ions form here
Negative ions go to Anode -non metals form here e.g oxygen

Section 7

Question Answer
Extraction of aluminium done by Electrolysis
Aliminium ore Bauxite
Aluminium oxide has to be made Molten -high mp -so it is dissolved -reduces cost
Both electrodes made of Carbon
Al metal forms at negative electrodes Sinks to bottom -tapped of
Oxygen forms at positive ions Reacts with carbon -co2 -burns away -positive electrodes have to be replaced a lot-money

Section 8

Question Answer
Reaction at cathode Al 3+ + 3e- ---------Al
Reaction at anode 2O2 ----- O2 + 4e -

Section 9

Question Answer
Metal structure Held by positive ions surrounded by a sea of delocalised electrons
Can conduct electricity Electrons can move and carry current
Lots of emerygy needed to separate Strong electrostatic bond - high mp and bp

Section 10

Question Answer
Strip mining of metal ores Barren land
Waste materials Landfill
Toxic metal compulsions Pollute environment kill wildlife

Recent badges