Extraction And Uses Of Metals Flashcards
The extraction of metals depends on…
Its position in the reactivity series and cost
Electrolysis is used for metals…
More reactive than zinc
Heating with Carbon or carbon monoxide (as a reducing agent) is used to separate metals…
Up to zinc
Aluminium is extracted from an ore called…
Bauxite
Bauxite is…
Impure aluminium oxide
The half equations for the extraction of aluminium are…
Al(3+) + 3e- = Al
(Aluminium ions are attracted to the cathode and reduced)
2O(2-) = O2 + 4e-
(Oxide ions are attracted to the anode and oxidised)
Melting aluminium oxide requires…
Extremely high temperatures
To lower the melting point, aluminium oxide is…
Dissolved in an aluminium compound called cryolite as a flux to lower its melting point
Because of high temperatures in electrolysis the Carbon anodes will…
Burn with with the oxygen produced to form Carbon dioxide, so they have to be replaced regularly
One problem with electrolysis is…
The cost. The electricity requires cells with currents up to 100 000A
Properties that make aluminium good in aircraft:
It resists corrosion due to its aluminium oxide coat
It has a low density
It is strong
Properties that make aluminium oxide good for saucepans
It remains shiny
It is a good conductor of heat
It resists corrosion
It has a low density
Iron is extracted from … In a …
Haematite, which contains Iron (III) oxide, in a blast furnace
Coke is…
Impure Carbon
Coke burns to form…
Carbon dioxide
Coke burning is a … Reaction, which …
Strongly exothermic reaction which heats the blast furnace
The equation for Coke burning is…
C + O2 = CO2
Carbon monoxide is the main … In a blast furnace
Reducing agent
The equation for iron oxide reacting with Carbon monoxide is…
Fe2O3 + 3CO = 2Fe + 3CO2
The equation for iron (III) oxide being reduced by Carbon is…
Fe2O3 + 3C = 2Fe + 3CO
The heat of the furnace causes the limestone to…
Thermically decompose
Limestone thermos lily decomposes to form…
Calcium oxide and Carbon dioxide
The equation for limestone thermography decomposing is…
CaCO3 = CaO + CO2
A blast furnace is hottest at the top/bottom
Bottom. 400 oC at the top, 1800 oC at the bottom
One of the impurities found in haematite is…
Silicone dioxide SiO2
Calcium oxide on the blast furnace reacts with…
Silicone dioxide SiO2
When calcium oxide and silicone dioxide react they produce
Molten calcium silicate (slag)
The equation for slag forming is…
SiO2 + CaO = CaSiO3
Wrought iron is …% iron and is used for…
100% iron and is used for decorative work such as gates and railings as it is very soft
Mild steel is …% … And is used for
0.25% Carbon and is used for nails, car bodies and ship building as it is tough and malleable
High Carbon Steel is …% Carbon and is used for … As it is…
0.25 - 1.5% Carbon and is used for cutting tools as it is very hard
Cast iron is …% … And is used for … As it is …
About 4% Carbon and is used for manhole covers, guttering and engine blocks as it is very brittle but strong
Stainless steel is iron mixed with … And it is used for … As it is…
Chromium and nickel and is used for cutlery and cooking utensils as it resists rusting but is expensive
