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Topic 5 - Metals - Coggle Diagram
Topic 5 - Metals
Displacement and redox
Metal displacement reactions
Magnesium is more reactive than copper, it will displace copper from a copper sulphate solution
Exothermic reaction
A more reactive metal will displace a less reactive metal from its salts solution
Redox reactions occur when electrons are ransferred between substances
Both reduction and oxidation occur at the same time
Displacement reactions are a type of redox
The less reactive metal gains electrons
The more reactive metal looses electrons
A more reactive element reacts to take the place of a less reactive one in a compound
Oxidation - The loss of electrons
Reduction - The gain of electrons
Extracting metals from their ores
A metal ore is a rock that contains enough metal to make it profitable to extract
An aluminium ore is bauxite, its aluminium oxide
Iron oxide is reduce to make iron, the oxygen is removed from the ore
Alloys
Pure metals are malliable
In alloys different sized atoms disrupt the layers
This makes it harder for the layers to slide over eachother
This makes an alloy stronger
Common alloys
Copper alloys
Brass - copper and zinc
Used in water taps and door fittings
Bronze - copper and tin
Statues and decorative objects
Gold alloys
Jewellery
Zinc, copper and silver are used to harden gold
Aluminium
Low density
Magnalium - aluminium and magnesium
Magnalium is stronger, lighter and corrodes less easily
Used in aeroplanes
Extracting metals with carbon
A metal below carbon in the reactivity series can be extracted from its ore by reducing it in a reaction with carbon
The ore is reduced as oxygen is removed
The carbon is oxidised as it gains oxygen
Metals more reactive than carbon have to be extracted using electrolysis which is expensive
Life cycle assessments
Getting raw materials
Extraction can reult in pollution and damage local environment
Transporting of materials reults in greenhouse gas emissions
Processing leads ot large amounts of waste
Manafacturing
Packaging uses alot of energy
Waste products produced
Water is required, which can be polluted during the process
Using
Use of a product can damage the environment
How long a procut getsused for
Disposing
Landfill takes up space and pollutes land and water
Incineration causes air pollution
If a product can be recycled, it will reduce landfill waste
Access the environmental impact of the entire lifetime of a product
The reactivity series
You can find the relative reactivity series of a metal by comparing its reactions with other metals
Reactions with water
Hydrogen is produced
In general, the more reactive the metal, the greater the rate of bubbling
Reactions with acids
Hydrogen us produced
In general, the more reactive the metal, the greater the rate of bubbling
Potassium, Sodium, Calcium, Magnesium, Aluminium, Carbon, Zinc, Iron, Hydrogen, Copper, Silver, Gold
Corrosion
Metals corrode in the presence of air and water
Oxidation of metals causes corrosion
Nail practical
Nail + boiled water and oil- no rust
Nail with water and air - rust
Nail + CaCl2 and air - no rust
Preventing corrosion
Electroplating
Uses electrolysis to coat the surface of one metal with another
The cathode is the object that is going to be electroplated
The anode is the metall that will end of coating the surface of the object
The electrolye is a solution containing the metal ions of the metal that is being plated on to the object
Uses
Stop corrosion
Decoration
Sacrificial protection
Placing a more reactive metal with iron
Water and oxygen will react with the sacrifical metal instead of the iron
Galvanising, a coat of zinc is put onto an iron object
Recycling
Sustainability
Extracting raw materials can take large amounts of energy
Recycling saves energy
Process only uses a small fraction on the energy needed to extract and refine the materials from scratch
Conserves resources
Environmetal benefits
Extracting metals damages the environment
Recycling reduces the needs for mines
Recylcing cuts down on the amount of rubbish that gets sent to landfill, which takes up space and pollutes the surrounding
Econonmic benefits
Recycling saves money
Massive industry and creates jobs
Extracting materials requires more energy than recycling them, energy is very expensive
Biological extraction
Phytoextraction
Uses plants
Metal compounds are absorbed by the roots
Plant concentrates metal compounds in its shoots
The plant is then burned
The ash contains metal compounds, which are extracted via displacement
Much cheaper
Very slow
Bioleaching
Uses bacteria
Bacteria convert metal compounds in the ore into soluble metal compounds
The leachate (solution produced) contains metal ions, which can be extracted
Smaller environmental impact