Extracting metals

Question 1

Metal ore

Answer 1

rock which contains enough metal to make it economically worthwhile extracting metal from it
in many cases ore is just an oxide of the metal

Question 2

How can a metal be extracted from its ore?

Answer 2

chemically - by reduction
by electrolysis
using displacement reactions
using biological methods

Question 3

When metals are extracted from its ore by reduction, what does it use?

Answer 3

Carbon

Question 4

When ore is reduced what is removed?

Answer 4

Oxygen

Question 5

What determines if a metal in an ore can be extracted by reduction?

Answer 5

its position in the reactivity series

Question 6

Which metals are extracted using electrolysis?

Answer 6

metals higher than carbon in the reactivity series

Question 7

Which metals are extracted by reduction?

Answer 7

metals below carbon in the reactivity series

this is because carbon can only take away oxygen from metals which are less reactive than carbon itself

Question 8

Reactivity series

Answer 8

Potassium 
Sodium 
Calcium 
Magnesium 
Aluminium 
Carbon
Zinc 
Iron
Lead 
Hydrogen 
Copper 
Silver 
Gold

Question 9

Reactivity series mnemonic

Answer 9

Please 
Stop 
Calling 
Me 
A
Carless
Zebra
Instead 
Try 
Learning 
How 
Copper 
Saves 
Gold

Question 10

How are metals extracted from its ore by electrolysis?

Answer 10

once the metal is melted an electrical current is passed through it
metal is discharged at the cathode
non metal is discharged at the anode

Question 11

Which is more expensive electrolysis or reduction with carbon? why?

Answer 11

Electrolysis

electricity is expensive

Question 12

Why is electrolysis used on Copper?

Answer 12

Copper can be easily extracted by reduction with carbon - ore is heated in furnace (smelting)
however copper produced this way is impure
impure copper doesn’t conduct electricity very well - isn’t useful as copper is used to make electrical wiring
so electrolysis is also used to PURIFY it - even though its very expensive
this produces very pure copper - much better conductor

Question 13

When copper is electrolysed what is the:
cathode
anode
electrolyte

Answer 13

cathode - starts as a thin piece of pure copper and more pure copper adds to it
anode - big lump of impure copper which will dissolve
electrolyte - copper sulfate solution containing Cu2+ ions

Question 14

Biological methods

Answer 14

bioleaching

phytoextraction

Question 15

Bioleaching

Answer 15

uses bacteria to separate metals from their ores
bacteria gets energy from the bonds between the atoms in the ores - separating out the metal from the ore in the process
the leachate (solution produced by process) contains metal ions which can be extracted by electrolysis or displacement with more reactive metals

Question 16

Phytoextraction

Answer 16

involves growing plants in soil that contains metal compounds
the plants cant use or get rid off the metals - gradually builds up in the leaves
plant can be harvested, dried or burned in a furnace
ash contains metal compound - metal can be extracted using electrolysis or displacement reaction

Question 17

Advantage and disadvantage of biological methods

Answer 17

advantage - have smaller impact on the environment

disadvantage - slow