Using Resources Flashcards
What are Ceramics?
Non-metal solids with high melting points that are not made from carbon-based compounds
What are the two types of glass?
Soda-lime glass
Borosilicate glass
What are composites?
Made of one material embedded in another. Fibres or fragments of a material called the reinforcement are surrounded by a matrix. The properties depend on the properties of the materials it is made from.
What are some examples of Composites?
Fibreglass
Carbon Fibre
Concrete
Wood
What influences the properties of a polymer?
The catalyst that was used
The reaction conditions
The monomers used
What is Low Density Poly(ethene)?
Made from ethene at a moderate temperature under a high pressure. Flexible and is used for bags and bottles
What is High Density Poly(ethene)?
Made from ethene at a lower temperature and pressure with a catalyst. More rigid and is used for water tanks and drainpipes
What are Thermosoftening Polymers?
Contain individual polymer chains entwined together with weak forces between the chains. You can melt these plastics to remould them.
What are Thermosetting Polymers?
Contain monomers that can form cross-links between the polymer chains, holding the chains together in a solid structure. These polymers don’t soften when heated but burn instead. Strong hard and rigid
What are Alloys?
Mixtures of metals. This disrupts the structure of the metal, making alloys harder than pure metals
What are some examples of Alloys?
Bronze - Copper + Tin
Brass - Copper + Zinc
Stainless Steel - Iron + Chromium (+ nickel sometimes)
What is corrosion?
When metals react with substances in the environment which can weaken them
What is Rust?
Iron + Water + Oxygen -> Hydrated Iron(III) Oxide
How does Aluminium corrode?
Corrodes when exposed to air
Aluminium Oxide doesn’t flake away but forms a protective layer that sticks to the Aluminium and stops further corrosion
How can you prevent Corrosion?
Physical Protection
Sacrificial Protection
Examples of Barrier Protection
Painting / Coating with plastic
Electroplating - coats with a different metal that won’t corrode away
Oiling / Greasing
Examples of Sacrificial Protection
Involves placing a more reactive metal such as zinc or magnesium with the iron which react instead of iron
Galvanisation
What is Galvanisation?
The metal is sprayed with a coating of zinc. The zinc is protective, but if it’s scratched, the zinc around the scratch works as a sacrificial method
What is the Haber Process?
An important industrial process which produces ammonia. This is used to make fertilisers
What is the Haber Process formula
N2 (g) + 3H2(g) <-> 2NH3(g) (+ heat)
Nitrogen + Hydrogen <-> Ammonia
What is the industrial process of the Haber Process?
1) Nitrogen is obtained from the air
2) Hydrogen mainly comes from reacting methane with steam to form hydrogen and carbon dioxide
3) The reactant gases are passed over an iron catalyst. A high temperature (450°C) and a high pressure (200 Atmospheres) are used
4) The reaction is reversible so some of the ammonia produced converts back into hydrogen and nitrogen again. Eventually it reaches a dynamic equilibrium
5) Ammonia is formed as a gas, but as it cools in the condenser it liquifies and is removed. The unused hydro hydrogen and nitrogen are recycled so nothing is wasted
6) The ammonia produced can then be used to make ammonium nitrate - a very nitrogen-rich fertiliser
What are the compromises of the Haber Process?
Lower temperatures have a greater yield but slower rate of reaction
Higher temperatures have a lower yield but faster rate of reaction
Higher pressures increase percentage yield and rate of reaction
Iron catalyst increases rate of reaction but doesn’t affect yield
What are NPK fertilisers?
Formulations containing salts of nitrogen, phosphorus and potassium in the right percentages of the elements
How can Ammonia be used to make fertilisers?
NH3 (aq) + HNO3 (aq) -> NH4NO3 (aq)
Ammonia + Nitric Acid -> Ammonium Nitrate
