Using Resources Flashcards
(23 cards)
Ceramics production
Pottery: clay is fired so it hardens
Soda lime glass: sodium carbonate, limestone and sand fired until melted then hardens
Borosilicate glass: boron trioxide, sand
Composites production
Fibers are imbedded, this is reinforcement
matrix is often a polymer
Concrete: aggregate (sand and gravel) imbedded in cement
Polymers production
Addition polymers: monomers with same functional group, only produces the polymer
condensation polymers: different functional groups, produces the polymer and (normally) h2o
Polymer properties LD
Conditions: Moderate temperatures, high pressure, catalyst
Properties: More flexible but weaker
Uses: Carrier bags
Polymers, thermosoftening
thermosoftening contain individual chains entwined with weak forces between them. These break easily when heated, causing the polymer to melt. It can then be remoulded into a different shape and will harden again when cooled.
Corrosion (metals)
Iron and steel corrode easy
Iron + oxygen + water -> hydrated ironIII oxide
Rust flakes off exposing more iron to air and water
Aluminum forms aluminum oxide which does not flake away, this protects the underlying aluminum
Preventing rust (barrier )
Barrier:
Painting/plastic coating
Electroplating with another metal that won’t be corroded
Oiling / greasing, used when moving parts are involved
Preventing rust (sacrificial)
More reactive metal is used to react water and oxygen instead of the iron
Strength
Strength - the ability of a material to resist an applied force (it is hard to change the shape of a strong material).
Hardness
Hardness - how well a material can resist being scratched or indented (hard materials don’t scratch).
Polymer properties HD
Conditions: Low temperature/pressure, catalyst
Properties: More rigid but stronger
Uses: Drainpipes
Polymers, thermosetting
Thermosetting polymers are made from lots of polymer chains, held together by strong covalent bonds. These require lots of energy to break, so don’t soften when heated. These polymers are hard, strong and rigid.
corrosion definition
the process by which metals are slowly broken down by reacting with substances in their environment
reactivity series
haber process conditions
450 degrees at 200 atm with iron catalyst
making hydrogen
made from hydrocarbons like methane
haber process equation
N2 + 3H2 ⇌ 2NH3
Explain why a temperature of 450°C is used in the Haber process.
450°C is a compromise between percentage yield, rate of reaction, and cost.
The forward reaction is exothermic, and so the reaction should be done at a low temperature to get a high yield.
The reaction will be faster at higher temperatures because the particles will have more energy, and so will be more likely to collide with enough energy to react.
Generating high temperatures is expensive, so we can’t use a very high temperature.
formatting nitrogen in npk fertilisers
Ammonia can react with oxygen and water in a series of reactions to make nitric acid.
Ammonia can also react with acids (including nitric acid) to form ammonium salts.
What is the main reason plants need nitrogen?
To make amino acids that can be used to produce proteins
Producing phosphorus (P) fertiliser
Phosphate can be mined from the ground as insoluble phosphate rock.
react the phosphate rocks with acids to produce soluble salts:
Reaction with nitric acid produces phosphoric acid and calcium nitrate.
Reaction with sulfuric acid produces calcium sulfate and calcium phosphate (this mixture is known as single superphosphate).
Reaction with phosphoric acid only produces calcium phosphate (also called triple superphosphate).
Producing potassium (K) fertiliser
Potassium fertiliser is the simplest to produce. Potassium chloride and potassium sulphate can be both be mined from the ground and then used directly in fertilisers
