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1. KS4: Useful Materials FromMetal Ores
3. Getting metals from ores
4. Extraction of metals and energy changes The more vigorously an element forms compounds the harder it will be to get back that element from its compounds.
For example, magnesium gives out lots of heat when it combines with oxygen.
This means we will have to put lots of energy back to extract magnesium from magnesium oxide and so it will be hard to extract.
5. Extraction processes
6. Extracting methods Here is a list of the symbols of some metals in order of decreasing reactivity-
Li, Ce, Mn, Al, Zn, Cd, Sn, Pb, Cu, Pd
Use this to assign the most likely method of extraction: native (N), carbon(C), electrolysis (E).
7. Extracting Gold Because gold occurs native its extraction is a low-tech affair that simply involves finding it!
8. Iron Iron is a moderately reactive metal.
Iron ore is plentiful and relatively easily reduced to iron metal by heating with coal (carbon). It is therefore cheap.
It is strong and malleable (non-brittle).
Iron is the most commonly used metal.
10. Reactions - Reduction of iron ore
11. Reactions Removing impurities
12. Extraction of Iron A drag and drop activity
A drag and drop activity
13. Copper Copper is a metal of low reactivity.
It occasionally occurs native but more often occurs as copper compounds.
Heating copper compounds with carbon gives copper but this is not pure enough to use for electrical work.
14. Electrolytic purification The conductivity of copper is drastically reduced by tiny amounts of impurities.
Because of this most copper metal is further purified by electrolysis.
In this process impure anodes dissolve.
This dissolved copper is plated onto a cathode leaving behind impurities.
15. Copper atoms at the cathode Opposite charges attract.
Positive copper ions (Cu2+) move to the negative cathode.
At the cathode these ions gain electrons and turn into copper atoms.
So, during electrolysis a copper cathode gets thicker.
16. Copper ions form at the anode Impure copper is used as the anode of an electrolysis cell.
The battery pulls electrons off the copper atoms in the anode.
By losing electrons these atoms become copper ions and so the anode slowly dissolves away.
Impurities just sink to the bottom as anode mud.
17. Purification: The whole process
18. Purification: The half reactions
19. Copper is purified to improve its
NOT CIVIC DUTY
Copper is purified by
CELERY IS LOST
Pure copper forms at the
DO TEACH
Impurities form called
A ODD MENU
The anode will slowly
DIVE LOSS
At the cathode copper ions gain
CORN STEEL
20. Extracting platinum Platinum is a rare and expensive metal used in jewellery and also for plating the fuel nozzles in jet engines. It was first discovered by Europeans in 1735 but in South America the primitive pre-Columbian Indians had been using it for centuries.
21. Purifying copper and electricity Copper is purified using electrolysis.
Plan an experiment to investigate factors that might affect the rate of copper production.
Include:
Any factors that might affect rate.
The apparatus you would need.
A statement of how you would control variable in an investigation.
The number and range of readings.
The safety issues you would take into account.
22. Purifying copper: some answers (1) Some factors that might affect rate -
Concentration of solution.
Distance apart of electrodes
Electrical potential (volts) or current (amps).
Duration of electrolysis.
23. Control of variables
Basically only change one variable at a time!
Number and range of readings
Minimum of 8-10 different values
Repeat readings at least once
Attempt a range providing 10-fold change
Safety Issues
Check electrical, toxicity, corrosive, etc.
Take appropriate measures Purifying copper: some answers (2)
24. Aluminium: properties Aluminium is a reactive metal.
We might expect it to corrode easily but a strong coating of oxide on its surface prevents this in most everyday situations.
It has a low density which leads to its extensive use in the aerospace industry.
25. Aluminium: ores It occurs as bauxite ore which is a form of aluminium oxide.
Because aluminium is so reactive carbon is unable to pull away the oxygen from it.
It is extracted by electrolysis of molten bauxite. Early attempts at this failed because bauxite is so hard to melt.
If cryolite is added, the bauxite melts more easily. This is an essential step in the extraction process.
27. Aluminium formation Opposite charges attract.
And so positive aluminium ions move towards the negative cathode.
At the cathode these ions gain electrons and turn into aluminium atoms.
28. Oxygen formation Negatively charged oxide ions move to the anode.
Here they lose 2 electrons and so turn into neutral oxygen atoms.
These atoms rapidly join into pairs to form normal oxygen gas.
29. Carbon dioxide formation Remember the electrolysis is carried out at high temperature.
Under these conditions quite a lot of the oxygen reacts with the carbon anode.
Carbon dioxide is formed and the anode is rapidly eaten away and frequently has to be replaced.
32. Common aluminium ore
I axe tub
Added to reduce melting point
City role
The electrodes are made out of
Right ape
Extracting aluminium is a
Cretin duo
33. Aluminium the overall process
34. A Rotten Week in the State of Chemark Since the war of 2042 world trade
had been drastically reduced.
Many countries have a policy of using
home produced materials wherever
possible because imported materials
remain difficult to buy.
35. Chemsville The major town of Chemsville, in the state of Chemark, has 2 main industries:
-ChemCars manufacturing expensive cars
-ChemComm engaged in communications products such as newspapers, books, CDs and DVDs
It also had an 80% completed aircraft factory: ChemJet
-ChemJet has orders for 22 executive jets which they are committed to delivering to a tight schedule.
There are also several large farms within the borders of Chemsville producing crops and meat.
36. Chemsville
37. Monday Fire at ElectroSalt 1 The week starts badly! The company that electrolyses salt in Chemark has had a major fire. The ElectroSalt factory will not open again for at least 3 months.
The mayor of Chemsville phones. She urgently wants you to produce a brief report setting out:
What rock salt is used for?
How the factory close-down may affect companies, farmers and non-industrial activities in Chemsville
38. Monday: Useful products from rocksalt
39. Monday: answers about rocksalt
40. Monday: answers about rocksalt
41. Monday: Useful products from rocksalt
42. Wednesday: Price Rises by ElectroGen ElectroSalt had been one of the major customers of the only Electricity company.
Loss of ElectroSalts custom has taken ElectroGen into financial problems and they announce an emergency price rise of 50% for electricity.
The mayor phones. What effect will this have upon the cost of products made in Chemsville?
43. Wednesday: Report about ElectroGen Obviously there are normal running costs in all of the organisations but two vital products will be hit by the price rise and are difficult to get replace.
Copper for wiring of cars and aircraft. (Copper is refined by electrolysis which uses large amounts of electrical power.)
Aluminium for use in cars and especially in aircraft. (Aluminium is extracted by electrolysis of molten bauxite.)
44. Friday: Limestone shortage It seemed things could only get better - wrong!
The director of the unfinished aircraft factory phones saying the company providing cement has been unable to get supplies because of a strike at the limestone quarry.
The aircraft factory must be finished on time.
The director suggests using an old limestone wall and clay from the foundations of the new factory to make enough cement to finish the factory off.
Is this feasible / sensible?
45. The limestone wall could be heated to produce calcium oxide and this could be mixed with clay to make cement so this could solve the problem.
It might make more sense to ship the limestone to the existing cement factory to make a batch of cement as they already have the necessary equipment. This is my recommendation.
Friday: Answers to limestone shortage
46. The building of the ChemJet factory is not the only thing that will be affected by a limestone shortage.
The strike will affect manufacture of iron from which steel is made. This could have major effects on ChemCar as many car components are made of steel.
In the longer term it will also affect farmers who use limestone to neutralise their soil.
Friday: Answers to limestone shortage
47. Which of the following metals is most likely to occur native?
Sodium
Zinc
Iron
Gold
48. Which of the following metals has to be extracted by electrolysis?
Sodium
Zinc
Iron
Gold
49. Which of these happens in the purification of copper?
Copper cathode dissolves
Copper anode gets thicker
Copper atoms become ions at the cathode
Copper ions become atoms by gaining electrons.
50. Which of these happens in the extraction of iron?
Carbon oxidises the iron oxide
Combustion of carbon provides the energy for the extraction process.
Carbon monoxide reacts with acidic impurities in the iron ore.
The waste gas is mainly carbon monoxide