Extraction and Uses of Metals Flashcards
What are minerals?
individual compounds of metals found in the earths crust combined with other elements
What are ores?
a sample of rock that contains enough mineral for it to be able to extract the metal
What does native mean?
they exist naturally as a pure/uncombined element. often unreactive metals. eg. gold
How can you extract metals?
you must remove it from the metal oxide (reduction)
metal ions are positive so electrons must be added (reduction)
the method of extraction depends of the metals position inn the reactivity series and economic factors
What are the economic factors for choosing a method of extraction?
cost of energy and cost of reducing agent
How do you extract metals less reactive than carbon?
heat it with carbon, since carbon is more reactive it will displace and reduce the metal and take it away from its oxygen compound. it is a redox reaction and the carbon is oxidised. this reaction can be carried out in a blast furnace. common for the extraction of iron.
How do you extract metals more reactive than carbon?
cant be reduced at reasonable temperatures because theyre more reactive than carbon and carbon can’t displace it.
therefore theyre extracted through electrolysis but its expensive and requires lots of energy
Describe the extraction of Al2O3
extraction through electrolysis because its more reactive than carbon
cathode: Al3+ +3e- -> Al (reduction)
anode: 2O2- -> O2 + 4e- (oxidation)
What is an alloy?
a mixture of different types of metals or carbon
Why are allows harder than pure metals?
as the metals have different sized atoms it disrupts the regular repeating lattice structure so the layers can’t slide over each other.
What does malleable mean?
the substance can be hammered into shape (shaped upon force)
metals are malleable
What does ductile mean?
a materials ability to be drawn into wires and stretched out without breaking
Describe the uses and properties of aluminium alloys
pure aluminium is very weak so alloys used instead. aluminium resists corrosion (bc its thin and Al2O3 forms on surface), has a low density and is a good conductor of electricity which is why its good for planes. strengthened by adding silicon, copper or magnesium
Describe the uses and properties of mild steel
alloy of iron with 0.25% carbon
malleable and ductile
used for nails, car bodies
bc it keeps the car light so less fuel used
3x denser than aluminium
Describe the uses and properties of high carbon steel
alloy of iron with 0.6-1.2% carbon and sometimes manganese
hard and more resistant to wear
more brittle, not as malleable and ductile
used for cutting tools
Describe the uses and properties of stainless steel
alloy of iron with chromium and nickel
chromium forms strong oxide layer on surface to resist corrosion
used in cutlery, sins, pans, brewing beer, milk+cheese production
more expensive than milk steel
Describe the uses and properties of copper
good conductor of electricity and heat, ductile, antimicrobial properties (can kill microorganisms)
used in electrical wires, pots and pans, water pipes, hospital surfaces
