C15 Using our Resources Flashcards
What is rusting
The corrosion of iron
What is the word equation for rusting
Iron + Oxygen + Water = Hydrated iron oxide
How can you prevent rust
Coat the iron or steel with:
Paint
Oil of grease
Plastic
A less/more reactive metal
What is meant when iron or steel is galvanised
Coated in a thin layer of zinc
Zinc acts as a sacrificial metal
Any oxygen/water will react with the zinc
Describe low density polyethene
Using very high pressure a trace of oxygen forms low density polyethene
Polymer chains are randomly branched so cannot pack closely together therefore has a lower density
Describe high density polyethene
Using catalysts at 50c and a slightly raised pressure forms a high density polyethene
Made up of straighter polyethene chains therefore has a higher density
What is a thermosoftening polymer
Will soften easily then will reset when cooled
Made from individual polymer chains that tangled together
What is a thermosetting polymer
Do not melt when heated
Have strong covalent bonds forming crosslinks between their cross links
How is soda lime glass produced
Sand, limestone and sodium carbonate are heated to 1500c, they melt and react to form molten glass
It is transparent, hard and brittle
What is borosilicate glass
Sand and boron trioxide
Has higher melting point than soda lime glass
Used for oven glassware and test tubes
What are composites, give examples
Made up of different materials which have been combined to improve their properties
Concrete
Plywood
What are the 2 components in composites
Matrix
Reinforcement
What are ceramics, give examples
Materials which have been made by heating clay or other compounds to high temperatures
Crockery
Compare the physical properties of glass composites and ceramics
Soda lime glass-Hard, brittle, everyday glass objects
Borosilicate glass-Hard, brittle, higher melting point, oven glassware, test tubes
Clay ceramics-Hard, brittle, resistant to corrosion, easy to shape before manufacture, crockery
Composites-High melting points, usually very strong, construction (reinforced concrete, plywood)
What is the Haber process
The method of turning nitrogen in the air into ammonia (Used to make fertilisers)
What are the raw materials needed for the Haber process
Nitrogen from the air
Hydrogen from natural gas
What are the steps of the Haber process
1-Hydrgen and nitrogen are pumped in
2-The mixture is compressed to a pressure of 200atm and heated to 450c
3-It is pumped into a reaction vessel containing an iron catalyst
4-The mixture of gases emerging from the reactor is cooled, ammonia liquifies and is separated
5-Unreacted nitrogen and hydrogen are returned to the reaction vessel via the compressor
How is ammonium phosphate made in school labs
Low concentration solutions are used
Titration carried out slowly and carefully
Crystals of ammonium sulphate are slowly crystallised and collected to test effectiveness as fertilisers
How is ammonium sulphate fertiliser manufactured on an industrial level;
Ammonia and sulfuric acid undergo neutralisation to to make ammonium sulphate
In a continuous process the reactants are piped into large reaction towers where concentrated sulfuric acid is sprayed into ammonia gas at 60c
Pipes need to be strong stainless steel to withstand high pressures and corrosive materials
The energy from the exothermic reaction is passed on to a neighbouring tower where the ammonium sulphate is heated with air blown up from the base to make granules of fertiliser
