C15 Using our Resources

Question 1

What is rusting

Answer 1

The corrosion of iron

Question 2

What is the word equation for rusting

Answer 2

Iron + Oxygen + Water = Hydrated iron oxide

Question 3

How can you prevent rust

Answer 3

Coat the iron or steel with:
Paint
Oil of grease
Plastic
A less/more reactive metal

Question 4

What is meant when iron or steel is galvanised

Answer 4

Coated in a thin layer of zinc
Zinc acts as a sacrificial metal
Any oxygen/water will react with the zinc

Question 5

Describe low density polyethene

Answer 5

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

Question 6

Describe high density polyethene

Answer 6

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

Question 7

What is a thermosoftening polymer

Answer 7

Will soften easily then will reset when cooled
Made from individual polymer chains that tangled together

Question 8

What is a thermosetting polymer

Answer 8

Do not melt when heated
Have strong covalent bonds forming crosslinks between their cross links

Question 9

How is soda lime glass produced

Answer 9

Sand, limestone and sodium carbonate are heated to 1500c, they melt and react to form molten glass
It is transparent, hard and brittle

Question 10

What is borosilicate glass

Answer 10

Sand and boron trioxide
Has higher melting point than soda lime glass
Used for oven glassware and test tubes

Question 11

What are composites, give examples

Answer 11

Made up of different materials which have been combined to improve their properties
Concrete
Plywood

Question 12

What are the 2 components in composites

Answer 12

Matrix
Reinforcement

Question 13

What are ceramics, give examples

Answer 13

Materials which have been made by heating clay or other compounds to high temperatures
Crockery

Question 14

Compare the physical properties of glass composites and ceramics

Answer 14

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)

Question 15

What is the Haber process

Answer 15

The method of turning nitrogen in the air into ammonia (Used to make fertilisers)

Question 16

What are the raw materials needed for the Haber process

Answer 16

Nitrogen from the air
Hydrogen from natural gas

Question 17

What are the steps of the Haber process

Answer 17

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

Question 18

How is ammonium phosphate made in school labs

Answer 18

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

Question 19

How is ammonium sulphate fertiliser manufactured on an industrial level;

Answer 19

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