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Obtaining and using metals
REACTIVITY
Metal + water → metal hydroxide + hydrogen
Very reactive metals (potassium/sodium/lithium/calcium) react vigorously & produce hydrogen bubbles
Metal + steam → metal oxide + hydrogen
Less reactive metals (magnesium/zinc/iron)
Experiment: mineral wool soaked in water + metal – in test tube with heat applied
Metal + acid → salt + hydrogen
More reactive: more hydrogen produced
louder squeaky pop in test for hydrogen
Faster production of bubbles
Faster reaction
Vigorous fizzing
Hydrogen always given off with metal (when it’s alone)
Oxidation:
Oxygen gain
Electron loss

Reduction:
Oxygen loss
Electron gain

Displacement reactions
Metal + metal salt solution → displacement
redox reaction
More reactive metal replaces less reactive metal from compound
More reactive: oxidised
Less reactive: reduced
Ionic equation
Magnesium + copper sulphate → magnesium sulphate + copper
Mg(s) + Cu2+(aq) + SO42-(aq)
→
Mg2+(aq) + SO42-(aq) +
Remove ‘Sulphates’ – spectator ions, don’t change in reaction
Mg(s) + Cu2+(aq)
→
Mg2+(aq) +
Cu(s)
Oxidation: Mg → Mg2+ – magnesium lost electrons, cation
Reduction: Cu2+ → Cu – copper gained electrons, anion

redox reaction
Cu(s)

Reactivity series of metals – how easy metal is oxidised
Test metal’s position in series by reacting it with water / dilute acid
Potassium
Sodium
calcium
magnesium
aluminium
carbon
zinc
iron
hydrogen – below hydrogen won’t react with dilute acids
copper
silver
gold
Higher up: more reactive – easily loses outer shell electron / easily oxidised / easily produces cation
Lower down: less reactive / more resistant to oxidation

EXTRACTION
Metal ore: rock containing enough metal for it to be economically worthwhile to extract from
most metals extracted from ores found in Earth’s crust
unreactive metals found in Earth’s crust as uncombined elements – can be mined straight from
ground but must be refined first
extraction of metals = reduction of ores = oxygen removed
why method used to extract metal from ore is related to reactivity series position & cost of
extraction process
carbon
Metal extracted by reduction using carbon: metal must be less reactive than carbon – can only take
oxygen away from metals less reactive than itself
Iron oxide: reduced in blast furnace to make iron
Electrolysis
Metals more reactive than carbon extracted by electrolysis of molten compounds
electric current passes through melted metal ore – has to be molten so ions are free to move
Metal: discharged at cathode
Non-metal: discharged at anode
More expensive: lots of electricity needed + costs for melting/dissolving metal ore so it can conduct
electricity
Aluminium:
Extracted from ore using electrolysis with carbon electrodes
Aluminium oxide: high melting point – dissolved in molten cryolite (aluminium compound with lower
melting point) to lower its melting point so ions free to move
During electrolysis: aluminium formed at cathode – Al3+ + 3e- → Al
Oxygen formed at anode – 2O2- → O2 + 4e2Al2O3 → 4Al + 3O2
Biological methods
Supply of some metal rich ores are limited
Demand for lots of metals growing – future shortages
Traditional methods of mining: damaging to environment – new methods have much smaller impact
Bioleaching: Bacteria to separate metals from ores
Bacteria get energy from bonds between atoms in ore, separating out metal & ore in process
Leachate (solution produced by process) contains metal ions – can be extracted with another method
Energy efficient
Slow
Phytoextraction: Growing plants in soil containing metal compound
Plants can’t use / get rid of metals – they build it up in their leaves
Plants: harvested / dried / burned in furnace
Metal extracted from ash by burning plant
Copper can be extracted by low grade ores
Avoids mining/moving rock
Less energy/heat/fuel/pollution
Slow – plants take time to grow
Cost: fertiliser – energy required

RECYCLING
Conserves resources and energy
Extracting raw materials uses lots of energy from burning fossil fuels: non-renewable & contribute to
climate change
Recycling material uses fraction of energy needed to extract/refine material
Metals: non-renewable
Economic benefits
Saving energy = saving money – energy is expensive
Some metals expensive to extract/buy – better to recycle
Creates jobs
Preserves environment
Extraction impacts environment: Mines damage environment & destroy habitats & ugly
Recycling = less mines
Recycling = less rubbish sent to landfill – takes space + pollutes surroundings
Recycling aluminium
4 tones of ore for 1 tone of metal
Mining makes mess of landscape
Lots of electricity used on transportation/extraction
Expensive to send used aluminium to landfill
1kg of recycled aluminium saves:
95% energy needed to mine fresh aluminium / 4kg of ore / lots
of waste
Life-cycle assessment: Measured on potential environmental impact
Choice of material
Metals must be mined/extracted from ores – needs lots of energy: causes pollution
Raw materials for chemical manufacture often from crude oil – non-renewable resource
manufacturing product
Uses lots of energy + other resources
Pollution
Waste products – some could be recycled into other useful chemicals: reduces amount polluting
environment
Most chemical manufacture uses water – can’t put polluted water back into environment
Product use:
Paint: toxic fumes
Burning fuels: releases greenhouse gases
Fertilisers: can leak into rivers – eutrophication
Disposal
landfill: Takes space + Pollutes land/water
Incineration: causes air pollution
Natural reserves of metal ores will last longer
Less need to mine ores – less noise/pollution
Less waste metal in landfill
Sulphur dioxide produced from sulphide ore extractions
Takes energy + money to collect, transport and sort metals for recycling
Some metals use more energy to recycle than to extract from ore

Reversible reactions and equilibria
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dynamic equilibrium
Both reactions occur at same time/rate
Concentrations/amount in moles of each product/reactant remain constant
Only in closed system: no reactant/product can escape
As reactants react, their concentrations fall – forward reaction slows down
As more product produced, their concentrations rise – backwards reaction speeds up
After while – both at same rate
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Haber process conditions:
450 °C temperature

200 atmosphere pressure

iron catalyst

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