C5

• How are metals extracted form ores through the use of Carbon?

  • Ore is an oxide of the metal
  • OXygen is removed through reduction using carbon
  • Reactivity series determines if it can be reduced
  • The metal has to be less reactive than Carbon
  • Zinc, Iron, Tin, Copper
  • Reduced in a blast furnace
• Through the use of electrolysis, how is metal ores extracted from their ores?

  > For metals more reactive than carbon

  > Electrolysis of molten compound

  1. Metals is melted - ions free to move
  2. Metal at cathode, non metal at anode Electrolysis is expensive
• Bioleaching


  > Use of bacteria

  > Bacteria + energy from bonds between atoms = separate metal from ore

  > Leachate- solution produced by the process, contains metal ions, extracted by electrolysis or displacement with a more reactive metal
• Phytoextraction 


  > Growth of plant in soil

  > Soil contains compounds

  1. built up in plant leaves
  2. Harvested, dried and burned in a furnace
  3. Ash full of metal compounds
  4. Extracted via displacement or electrolysis
• What is an alloy?

  A mixture of two or more metals (non metals)
• Alloy- Steel 


  Steel - Iron + Carbon> Steel is harder than iron

  > Steel is stronger than iron, as long as carbon is not greater than 1%

  > Iron on its own will rust (corrode) quickly, steel is less likely to rust

  > Grinders, bridges, engine parts
• Alloy- Brass


  Copper and zinc

  > Brass is harder

  > Used for making instruments and fixtures such as screws, springs
• Alloy- Bronze


  Copper and tin

  > Harder and stronger than tin

  > More resistant to corrosion
• Alloy- Solder


  Lead and tin

  > Solidifies as it cools down

  > Joins metal together
• Alloy- Duralumin 


  > Alloy composed of aluminium

  > 94% Al 4% Cu 1% Mg

  > Low density strong and light
• What is corrosion 


  Damaged/destroyed by a chemical process

  Rusting- Iron in contact with both water and oxygen

  Iron + Oxygen + water = hydrated iron (III) oxide

  > Redox reaction

  > iron loses 3 electrons - oxidised

  > Oxygen gains 2 electrons - reduced

  > Other metals corrode in presence of oxygen, water and metal oxide
• How to prevent Corrosion

  • Painting, Oiling, greasing
  • Tin plating - acts as a barrier
• More reactive metals prevent corrosion 


  > Sacrificial method- Water and oxygen reacts with more reactive metal first

  > Galvanising- Zinc over iron to prevent rusting. Zinc is sacrificial so it loses electrons first

  > Blocks of metal bolted to less reactive metals to prevent corrosion
• Haber process 


  > To produce ammonia

  N2+3H2 ⇌ 2NH3 

  Nitrogen- 78% of air

  Hydrogen- obtained from hydrocarbon from sources such as natural gas or crude oil

  > Reversible reaction

  > reaction reaches an equilibrium
• Conditions needed for haber process- Pressure

  Pressure 200 atm

  > Higher pressure favours forward reaction

  > High pressure to give the best yield capped at 200 atm as high pressure is too expensive
• Conditions needed for hater process- Temperature

  450 °C

  > Forward reaction exothermic

  > Increasing temperature shifts equilibrium position the wrong way away from ammonium

  > Lower temperatures, lower rate of reaction, higher yield

  450°C compromise between max yield and speed of reaction
• Conditions needed for hater process- efficiency 


  > Ammonia is formed as a gas but cools in condenser and liquifies and is removed

  > Unused hydrogen and nitrogen is recycled so nothing Is wasted
• Conditions needed for hater process- catalyst

  > Iron catalysts

  > Makes reaction faster

  > Doesn't affect position of equilibrium

  > Without catalysts the higher the temperature would have to raise
• What is a fertiliser

  Helps plants grow faster

  Essential: Nitrogen, Phosphorous, Potassium

  > absorbed nutrients from soil

  > If not acquired, growth and life process are affected

  > Fertiliser replace the missing element

  > Increase crop yield

  > Crops grow faster and bigger
• Ammonia used to produce fertiliser

  > Ammonia is a base that can be neutralised by acids to make ammonia salts

  > Key ingredient of fertilisers

  1. Nitric acid + Ammonia -> Ammonium nitrate
  2. Sulphuric acid + Ammonia -> Ammonium sulphate
  3. Nitric acid + Potassium -> Potassium hydroxide
• Practical Ammonium sulfate 


  Titration method

  1. set up apparatus (sulphuric acid solution, burette, solution- ammonia + universal indicator
  2. Slowly add sulphuric acid into ammonia until yellow -> red
  3. Methyl orange is alkali, red is acid. Once turned red, ammonia is neutralised
  4. Get pure solution using exact amount needed with no indicator
  5. Evaporate then let crystallise
• What is the contact process?

  Used to make sulfuric acid

  1. Sulphur add oxygen makes Sulfure dioxide
  2. sulfur dioxide is then oxidised to make sulphur trioxide
  3. Sulfur trioxide + water -> Sulfuric acid
• Conditions to make SO3 - Temperature

  • Oxidising sulfur dioxide to Sulfur trioxide is exothermic
  • 450 °C to get acceptable yield quickly
  • Reduced temperature slows rate of reaction
• Condition to make SO3 - Pressure

  • Two moles on product
  • Three moles of reactant
  • Increasing pressure is expensive/ not necessary
  • Just above atmospheric pressure
• Catalyst

  • Increases rate of reaction a vanadium pentoxide catalyst
  • Doesn't effect equilibrium
• Industrial process 


  Cost of raw materials- expensive

  Availability- non-renewable: run out, renewable and common is best

  energy lost- Associated to maintaining conditions required

  Rate- compromises yield

  Equilibrium- some are reversible controlling equilibrium maximises amount of products -> profit

  > lies on the left -> low yield
• What is the life cycle assessment

  • looks at each stage of the life of a product

  Material and manufacture

  • mined and extracted- energy and pollution increases, nonrenewable decreases
  • Manufacturing- energy and pollution increases (Co2 or HCl)
  • Waste to depose- recycle reduce waste

  Transport- energy increases, what is efficient?

  Product use- damage environment: Toxic fumes, Green house gases, damage ecosystem

  Disposal- landfill -> space -> pollutes -> incinerates, increase ai pollution
• Monomers

  • make up polymers
• Ceramics

  • made by baking a substance
  • produce brittle, stiff material
• Clay

  • mineral formed from weathered and decomposed rock
  • Soft when dug up
  • Hardened by firing at high temperatures
• Glass

  • transparent and strong
  • Moulded when hot and cab be brittle when thin
  • Made from soda-lime glass
  • made from heating limestone, sand and sodium carbonate that cools into glass
• What are composite materials

  • made from one material and embedded into another
• Composite material- Fibreglass

  • fibres of glass embedded in a matrix made of a polymer: Low density, very strong
• Composite material- Concrete

  • Aggregate embedded in cement
  • High compressive strength
• Composite material- KEVLAR- based composite

  • Made from kevlar (mad made polymer) embedded in another material
  • used as an ingredient
  • Adds strength without too much weight
• Composite material- Carbon fibre 


  carbon atoms bonded together

  Carbon fibres or nanotubes

  expensive to make but very strong and light
• Use of polymers

  • adaptable
  • flexible
  • Easily moulded
  • Cheap
  • less dense
  • Thermal and electrical insulator

  Advantage

  • Degradable- don't last as long
• uses of ceramics

  • insulators of heat and electricity
  • brittle and stiff
  • strong and hard wearing
  • Don't degrade or corrode
• Use of metals

  • Conductors of heat and electricity
  • Malleable
  • Some are corrosion resistant
  • less brittle
  • Can deform
• Uses of composites

  • designed for specific purpose
  • Depending on matrix/binder and reinforcement material
  • Expensive