Making Resources Flashcards
What is corrosion?
When a material reacts with substances within the environment and eventually wears away
Rusting is the corrosion of iron in the prescience of oxygen and water
What are physical barriers?
Grease, paint, electroplating (coating in another metal)
Aluminium reacts with oxygen to make a very thin layer of aluminium oxide around the metal that acts as a physical barrier
This layer then protects the rest of the metal from corrosion
What is sacrificial protection?
A more reactive material is placed on the material e.g iron is galvanised in zinc
What is bronze?
Copper and tin
Resistant to corrosion
Statues/ decorative items/ ship propellers
What is brass?
Copper and zinc
Very hard but workable
Door fittings/ taps/ musical instruments
What are gold alloys?
Copper/ silver/ zinc added
Attractive, corrosion, hardness depends on carat
Jewellery
24 = 100%
18 = 75%
What is high carbon steel?
1-2% Carbon
Strong and brittle
Cutting tools/ metal presses
What is low carbon steel?
Iron, Less than 1% Carbon
Soft and easy to shape
Cars, machinery, ships, containers, structured steel
What is stainless steel?
Iron with chromium and nickel
Hard and resistant to corrosion
Cutlery, plumbing
What are aluminium alloys?
Over 300 different alloys
Low density, properties depend on composition
Aircraft/ military uses
What are ceramics?
Materials with versatile properties with many different uses
What is soda lime glass?
Heat sand, limestone, sodium carbonate
Transparent and brittle
Everyday glass objects
What is borosilicate glass?
Heat sand and boron trioxide
Higher melting point
Oven and laboratory glassware
What are clay ceramics?
Shape wet clay and heat in furnace
Hard, brittle, easy to shape, resistant to corrosion
Crockery/ construction/ plumbing
What do the properties of polymers depend on?
The monomers that make them up
The conditions in which they are made
What is low density polyethene?
LDPE is formed from addition polymerisation under high pressure and in the presence of a small amount of oxygen
Branched polymer chains cannot pack together
What is high density polyethene?
HDPE Addition polymerisation carried out using a catalyst at 50 degrees C
Polymer chains are straight and can pack tightly together
What are thermosoftening polymers?
Don’t have links between different chains and so soften when heated
What are thermosetting polymers?
Have strong cross links between polymers and so do not melt when heated
What are composites?
Main material (matrix) and fragments or fibres of other materials (reinforcements)
This means the materials properties can be made more useful
E.g plywood or concrete
What is the Haber process?
Ammonia is produced from nitrogen and hydrogen
How does the haber process work?
Hydrogen from natural gas and nitrogen from the air are pumped in
The nitrogen and hydrogen are compressed to 200atm at 450 degrees C
They are passed through a reaction vessel with an iron catalyst
In the cooling chamber, ammonia liquifies and the unreacted nitrogen and hydrogen are returned to the reaction vessel
What are the conditions for the Haber Process?
Temperature - lower temperature favours forward exothermic reaction but warmer temperatures increase rate
Pressure - increases yield but is expensive
Catalyst - increases rate, not yield
Compromise between yield, cost and rate
What are NPK fertilisers?
Increase the amount of food obtained from crops
Nitrogen , phosphorus, potassium
Formulations
Examples of composites
Metal-concrete
Glass-ceramic
Polymer-glass
Where does nitrogen come from?
Haber process -> ammonia and nitric acid -> ammonium nitrate/ ammonium sulfate found in leaves
Where does phosphorous come from?
Mining -> phosphate rocks and acids
Phosphate salts roots
Where does potassium come from?
Mining rocks
Potassium sulfate or potassium chloride
Growth of flowers and fruits
Laboratory
Small scale
Batches
Titration and crystallisation
Ammonia and sulfuric acid
Lower energy cost
Factory
Large scale
Continuous
Several steps
Raw materials
Higher energy cost
