using resources Flashcards
what are the two things needed for rusting to occur
air and water
how can we prevent rust (5)
paint oil or grease plastic a less reactive metal more reactive metal
why is zinc used to protect iron
because the zinc is more reactive than the iron, so the iron is galvanised. the oxygen and water react with the zinc rather than the iron. This is called sacrificial protection.
when is sacrificial protection used
in harsh conditions where the surface may be scratched
why are alloys useful
because they are stronger as they have different sized metal ions which make it harder for the layers to slip
what is bronze and how is it made
bronze is a copper alloy and is made by mixing copper and tin.
what is brass and how is it made
brass is a copper alloy and is made by mixing copper with zinc
what are the different aluminium alloys like
aluminium alloys can either be very lightweight and used for aircrafts or heavy and used for tanks and military vehicles
what can gold be mixed with to make a stronger alloy
copper
what is steel made of
steels are an alloy of iron and carbon and other elements
what are the 2 different carbon steels
high carbon steels are very strong but are brittle and can shatter
low carbon steels are soft and easily shaped
what do the properties of a polymer depend on
the monomers used to make it
the conditions chose to carry out the reaction
what is a thermosoftening polymer
polymers which soften easily and then re-set when they cool down
what are thermosetting polymers
polymers which do not melt when you heat them due to their strong covalent bonds
what are two examples of composites
wood
concrete
what are the raw materials for the production of ammonia
nitrogen in the air, hydrogen from natural gas
what kind of reaction is the haber process
reversible reaction. the ammonia made can be converted back to hydrogen and nitrogen
how is ammonia made from nitrogen and hydrogen
- the nitrogen and hydrogen are purified
2. they are passed over an iron catalyst at a high temperature and high pressure
what is the chemical formula for ammonium nitrate and why is it used in fertilisers
NH2NO3 - it is used in fertilisers because plants need nitrates to grow
how is ammonia removed
by cooling the gases the ammonia liquifies. it can then be separated from the unreacted nitrogen gas and hydrogen gas
how is nitrogen separated from other gases in the air
fractional distillation of liquid air
how is the hydrogen made for making ammonia
methane + steam —> hydrogen + carbon monoxide
What will happen when pressure is added to the reaction
N2 + 3H2 —> 2NH3
equilibrium will shift to the right to produce more products
What will happen if you increase the temperature of the reversible reaction of nitrogen and hydrogen as it is an exothermic forward reaction
Increasing the temperature would shift the equilibrium to the left, making more reactants so lowering the temperature would result in more ammonium being produced.
