C 15 Using our resources

Question 1

conditions for rusting

Answer 1

both air and water needed

Question 2

preventing rust

Answer 2

providing barrier between iron and air oxygen
1. paint
2. oil grease
3. plastic
4. less/more reactice metal

Question 3

protecting iron with zinc (more reactive)

Answer 3

iron galvanised, sacrificial protection fro zinc to ptotect iron, even when iron is exposed to water and air

Question 4

characteristics of alloys

Answer 4

harder than pure metals becasue layers are disorted by differently sized atoms, so they don’t slide.
mixture and formulation

Question 5

copper alloy

Answer 5

copper with tin. broze to make statues, resistant to corrusion
brass+copper= brass qhich is harder, used for musical instruments

Question 6

Al alloys

Answer 6

al low densities, many diff alloys can be made.
eg. aircraft

Question 7

gold alloys

Answer 7

gold+copper=jewellery
pure gold wears away to easily, varying proportions allows to get diff shades of gold

Question 8

percentage of gold in alloys

Answer 8

divide n carat by 24 x 100

Question 9

diff steels

Answer 9

High carbon steel
low carbon steel=soft easily shaped
stainless steel=chronium-nickel, don’t rust, hard resistant, eg cooking utensiles, cutlery, in chemical insustry

Question 10

what happens when you heat thermosetting polymers

Answer 10

don’t melt

Question 11

materials of sand

Answer 11

sand, limestone, sodium carbonate

Question 12

types of glass

Answer 12

soda-lime=sand,sodium carbonate, calcium carbonate
borosilicate= sand, boron trioxide, melt at higher p.
all mixet together at heated at high temp

Question 13

clay ceramics

Answer 13

hard, unreactive, resistant to heat
wet clay is baked in furnace
eg. briks, ceramig mugs, plates, crockery

Question 14

what are composites

Answer 14

made of 2 maerials.
have reinforcement (fibres, fragments) in Matrix (binds them together)

Question 15

fibre-glass composite

Answer 15

reinforcement= glass fibres
matrix=polymer
lighter,malleable.
cars

Question 16

natural wood composite

Answer 16

reinforcement=wood fibres
matrix=lignin

Question 17

Plywood

Answer 17

reinforcement=wood fibres
matix= grain (maybe)

Question 18

carbon fibre composite

Answer 18

reinforcement= C fibres/nanotubes
matrix= polymer
eg. sports equipment, tennis rackets

Question 19

raw materials for production of ammonia

Answer 19

nitrogen from air
hydrogen from natural gases(methane + steam)

Question 20

catalyst of haber process

Answer 20

iron

Question 21

temp + pressure haber process

Answer 21

200 atm
450 C

Question 22

uses of ammonia

Answer 22

85% fertilisers

Question 23

structure of NH3

Answer 23

covalent bonding

Question 24

reaction of haber process is

Answer 24

reversible

Question 25

how is ammonia removed

Answer 25

by cooling down the gases so that ammonia liquifies, unreacted nitrogen + H are recycled

Question 26

formula of haber process

Answer 26

N2 + 3h2 = 2NH3

Question 27

what would higher pressures cause in ammonia

Answer 27

produce more ammonia but it wold be too expensive to run as it favours the side with least amount of moles, equilibrium moves to the right

Question 28

effects high/low temp

Answer 28

equilibrium moves to tthe left as reaction favours endothermic reaction. Less ammonia would be made.
Low temp. would produce more ammonia but too slowly.

Question 29

what are the conditions in haber process

Answer 29

compromises

Question 30

what is ammonia aso used for

Answer 30

to make ammonium nitrate fertiliser, if added to nitric acid

Question 31

how can other solid fertlisers salts can be made

Answer 31

reacting ammonia (an alkali) with different acids)

Question 32

2 neutralisations of ammonia

Answer 32

ammonia +sulfuric acid-> ammonium sulfate (salt)
ammonia + phosphate -> ammoium phosphate(can be made using titration)

Question 33

why are fertlisers used

Answer 33

to supply nitrogen, phosphorus and potassium to plants

Question 34

what is NPK

Answer 34

mixtures of compounds so that N, P and K can be added to land at same time

Question 35

where does nitrogen come from and what is iy reacted with

Answer 35

from ammonia, reacted with acids to maked fertilisers
eg ammonium sulfate, ammonium nitrate

Question 36

source of phosphorus

Answer 36

phosphate rock, which is mined

Question 37

what happens to phosphate rock

Answer 37

treated with acids to form fertilisers
eg. ammonium phosphate, calcium phosphate

Question 38

where does potassium comes from

Answer 38

potassium salts which are mined

Question 39

potassium fertilisers examples

Answer 39

potassium chloride, potassium sulfate