š¹topic 5 - Calculations And Electrolysis Flashcards
What is an ore?
A rock with enough metal compounds to be economical to extract the metal
In sodium chloride, whatās the electrolyte?
NaCl
Why donāt you need electrolysis to extract iron from iron oxide?
Itās less reactive than carbon so can be extracted by heating it with carbon
Why does electrolysis of calcium chloride have to happen to get calcium?
As calcium is more reactive that carbon do heating them wonāt work
Why does aluminium oxide have a high melting point in terms of bonding and structure?
As itās an ionic lattice structure with many strong electrostatic forces of attraction which require a lot of energy to overcome
How can graphite conduct electricity?
As each carbon atom in graphite is bonded to 3 others meaning there is a free electron which can carry a charge
Is electrolysis exothermic or endothermic?
Endothermic as it requires energy and more energy is taken in than released
Describe the uses of copper and itās properties that suit it to that use
Used in electrical wires as itās a good electrical conductor and is malleable
Used in pipes as itās good conductor of heat
Give 4 physical properties of transition metals
- hard and strong
- good electrical conductors
- good heat conductors
- have high melting points
Give two chemical properties of electrical conductors
- They form coloured compounds
- can act as a catalyst in reactions
How are bioleaching and phyto mining used to concentrate the amount of copper in ores.
Bioleaching is used as itās where bacteria concentrate copper ions which can be extracted
Phyto mining is used as itās where copper ions concentrated in plants are burned so ions can be extracted
Give some typical properties of a metal
Strong, conductor of electricity and high melting point
Why does magnesium conduct electricity?
s the sea of delocalised
What is magnesium becoming magnesium and oxygen an example of?
Thermal decomposition
What happens when lithium reacts with water?
It looses an electron to become a lithium ion
When comparing reaction of metals, why is it important to use the same acid?
As acid concentration may effect the rate of reaction
Why are some metals more reactive than others?
As they may loose electrons more easily
What is an ore?
A rock that contains enough metal compounds that itās economic to mine
Why should we be finding alternate methods of electrolysis when extracting metals?
As ore reserves are running out and electrolysis requires a lot of energy
What are the steps to phytomining
- Grow plants on or near the low grade ore
- Harvest the grown plants and burn them
- The ash contains metal compounds that can be purified during electrolysis
What are the steps to bioleaching?
- Bacteria are grown on or near low grade ore
- They they then produce a solution called leachate containing the metal compound which can be purified using electrolysis
What are the 4 stages of lifecycle assessments?
What should you consider within each stage?
- Obtaining and processing the raw material
(Renewable or not, how much land is used? deforestation in production? - Manufacturing and packaging the product
(Energy needed e.g. some need electrolysis while others require reduction with carbon) - Using the product
Some items can only be used once, lack of durability, efficiency - Disposal of the product
Can it be recycled or is it incinerated or disposed in a landfill e.c.t
Why is cryolite added to aluminium oxide?
To lower itās melting point
Give 2 properties specific to transition metals
Can act as a catalyst and form coloured compounds
What does it mean that transition metals have variable oxidation states?
They can form ions with different charges
Name 3 transition metals used in car parts
Platinum, palladium and rhodium
Why are nano particles good catalysts?
They have a high surface to volume ratio so there are a large number of active sites for the reaction to happen
Why are coins not made of pure copper?
As pure copper would be too soft and the coin would dent
