C20 - Making our resources (PAPER 2) Flashcards
What is corrosion
when a material reacts with substances in the environment and eventually wears away
What are the two ways corrosion can be prevented
- physical barriers
- sacrificial protection
How are physical barriers used to prevent corrosion
- the material is covered with a barrier such as grease or electroplated
- this outside layer will protect the material from corroding
How can aluminium be used as a physical barrier to prevent corrosion
the layer of aluminium around the metal reacts with oxygen in the air to form aluminium oxide.
- This layer protects the rest of the material from corroding
What is electroplating
covering a material with a thin layer of metal
How is sacrificial protection used to prevent corrosion
- a more reactive substance is placed on the material. The more reactive substance will react with the environment instead of the main metal
What is the term used for applying sacrificial protection to a substance
galvanising
What is rusting
iron corroding by reacting with oxygen and water from the environment
What is the use of alloys
allows us to tailor the properties of metals to specific uses
What is the
- composition
- properties
- use
of bronze
- copper and tin
- resistant to corrosion
- statues, decorative items, ship propellers etc.
What is the
- composition
- properties
- use
of brass
- copper and zinc
- very hard but workable
- door fittings, taps, musical instruments
What is the
- composition
- properties
- use
of gold alloys
- gold with copper, silver and zinc
- attractive, corrosion resistant, hardness depends on carat
- jewelley
How is the proportion of gold in a gold alloy measured
- What is the term for 100% gold
- What is the term for 75% gold
- carats
- 24
- 18
What is the
- composition
- properties
- use
of high carbon steel
- iron with 1-2% carbon
- strong but brittle
- cutting tools, metal presses
What is the
- composition
- properties
- use
of low carbon steel
- iron with <1% carbon
- soft, easy to shape
- extensive use in manufacture of cars, machinery, ships, containers, structural steel
What is the
- composition
- properties
- use
of stainless steel
- iron with chromium and nickel
- resistant to corrosion, hard
- cutlery, plumbing
What is the
- composition
- properties
- use
of aluminium alloys
- many different alloys possible
- low density, properties depend on composition
- aircraft, military uses
What are ceramics
materials with versatile properties
How is soda-lime glass
- manufactured
- what are its properties
- what are its uses
- heating a mixture of sand, sodium carbonate, limestone
- transparent, brittle
- everyday glass objects
How is borosilicate glass
- manufactured
- what are its properties
- what are its uses
- heat sand and boron trioxide
- transparent, brittle, higher melting point than soda-lime glass
- oven glassware, laboratory glassware
How are clay ceramics (pottery + bricks)
- manufactured
- what are its properties
- what are its uses
- shape wet clay then heat it in a furnace
- hard, brittle, easy to shape before manufacture, resistant to corrosion
- crockery, construction, plumbing fixtures
What two factors do the properties of polymers depend on
- the monomers that make them up
- the conditions under which they are made
What does LDPE stand for
- how is it formed
- why does it have a low density
Low density poly(ethene)
- when the addition polymerisation reaction of ethene is carried out under high pressure and in the presence of a small amount of oxygen
- the branched polymer chains cannot pack together
What does HDPE stand for
- how is it formed
- why does it have a high density
High density poly(ethene)
- when the addition polymerisation reaction of ethene is carried out using a catalyst at 50*C
- polymer chains are straight and so they can pack tightly together
What happens when thermosoftening polymers are heated
- why
they soften when heated
- they do not have links between different chains
What happens when thermosetting polymers are heated
- Why
they do not melt
- they have strong covalent bonds between chains (cross-linking)
What are composites
- what is the main material called
- what are the fragments and fibres of other materials called
- what is the purpose of composites
- what are some examples of composites
a material with fibres from other materials added to it
- matrix
- reinforcements
- to make the material’s properties more useful
- plywood and reinforced concrete
What are fertilisers
- what is a vital component of most fertilisers
important chemicals used to improve the growth of crop plants
- ammonia
What is the name of the process of producing ammonia
the Haber process
What is the word and balanced symbol equation for the production of ammonia
nitrogen + hydrogen ⇌ ammonia
N2 + 2H2 ⇌ 2NH3
What are the 5 steps to the Haber process
- hydrogen from natural gas, and nitrogen from the air, are pumped in
- the nitrogen/hydrogen mixture is compressed to a pressure of 200 atm and heated to 450*C
- passes through reaction vessel containing iron catalyst
- the mixture of gases emerging from the reactor is cooled; ammonia liquifies and is separated
- unreacted nitrogen and hydrogen are returned to the reaction vessel via the compressor(step 2)
What are the three conditions used for the Haber process
- iron catalyst
- temperature of 450*C
- pressure of around 200 atm.
What effect would lowering the temperature in the Haber process do
- why
- increase the yield but decrease the rate of reaction
- the forward reaction is exothermic
What effect would increasing the pressure have in the Haber process
- Why
- Why isn’t the pressure increased
increase the yield and rate of reaction
- fewer gas molecules on the product side
- it is very expensive to increase the pressure
What catalyst is used in the Haber process
- what effect does it have on the reaction
iron
- increases the rate, does not affect the yield
What is the benefit of using fertilisers
they increase the amount of food obtained from crops
What are NPK fertilisers
fertilisers containing nitrogen (N), phosphorus (P) and potassium (K)
What is the word and symbol equation for the Haber process
N2 + 3H2 ⇌ 2NH3
nitrogen + hydrogen ⇌ ammonia
What is the word and symbol equation for the reaction between ammonia and nitric acid
ammonia + nitric acid -> ammonium nitrate
NH3 + HNO3 -> NH4NO3
What is nitric acid produced from
ammonia
What is phosphoric acid produced from
mined phosphate rock
what is the word and symbol equation for the reaction between mined phosphate rock and nitric acid
phosphate rock + nitric acid -> calcium nitrate
phosphate rock + HNO3 -> Ca(NO3)2
what is the word and symbol equation for the reaction between mined phosphate rock and sulfuric acid
phosphate rock + sulfuric acid –> calcium phosphate + calcium sulfate
phosphate rock + H2SO4 -> CA3(PO4)2 + CaSO4
What is the common name given to the product of mined phosphate rock and sulfuric acid
single superphosphate
What is the word and symbol equation for the reaction between ammonia and phosphoric acid
H3PO4 + 3NH3 → (NH4)3PO4
ammonia + phosphoric acid -> ammonium phosphate
What are the end products of combining potassium chloride and ammonium phosphate
NPK fertilisers
What is the word and symbol equation for the reaction between phosphoric acid and mined phosphate rock
phosphoric acid + phosphate rock -> calcium phosphate
phosphate rock + H3PO4 -> Ca3(PO4)2
What is the common name given to the product of phosphoric acid and mined phosphate rock
triple superphosphate
What is the word and symbol equation for the reaction between ammonia and sulfuric acid
ammonia + sulfuric acid -> ammonium sulphate
NH3 + H2SO4 -> (NH4)2SO4
