C15: Using our resources

Question 1

how does corrosion occur

Answer 1

caused by chemical reactions between the metal and substances in the environment

Question 2

rusting

Answer 2

corrosion of iron

Question 3

what is the equation for rusting

Answer 3

iron + oxygen + water -> hydrated iron (III) oxide

Question 4

what can we coat iron in to prevent rusting ?

Answer 4

-paint with rust inhibitors
-oil or grease
-plastic
-more reactive metal
-less reactive metal

Question 5

how can we coat iron in different metals (2)?

Answer 5

dipping in molten metal
electroplating

Question 6

what is it called when iron is coated in zinc

Answer 6

galvanising

Question 7

how does galvanising work

Answer 7

the zinc is more reactive than the iron, the water or oxygen reacts with the zinc instead

Question 8

what is galvanising an example of

Answer 8

sacrificial protection (zinc is sacrificed to protect the iron)

Question 9

what metals can also be used for sacrificial protection

Answer 9

aluminium or magnesium

Question 10

what is an alloy

Answer 10

a mixture of metals created for a useful reason

Question 11

why are alloys harder to break

Answer 11

the different sized metal ions make it harder for the layers to slip

Question 12

copper and tin alloy

Answer 12

bronze

Question 13

copper and zinc alloy

Answer 13

brass

Question 14

what can aluminium alloys be used for

Answer 14

aircraft , armour plates (they are lightweight)

Question 15

how can we find the fraction of gold in the jewellery

Answer 15

divide the carat by 24

Question 16

what are steels an alloy of

Answer 16

iron and carbon and/ or other elements

Question 17

what are the simplest steels called

Answer 17

carbon steels
cheap to make
used in cars, ships ect.

Question 18

what’s useful about stainless steel

Answer 18

it is resistant to corrosion

Question 19

what do we mix with steel to make stainless steel

Answer 19

chromium and nickel

Question 20

high carbon steel

Answer 20

very hard but brittle

Question 21

what are the two types of poly(ethene)

Answer 21

high density (HD)
low density (LD)

Question 22

how is LD poly(ethene) formed

Answer 22

high pressure and a trace of oxygen.
polymer chains are random and cannot pack closely together

Question 23

how is HD poly(ethene) formed

Answer 23

catalyst at 50 degrees and a slightly raised pressure.
straighter poly(ethene) chains, packed closely together

Question 24

differences between LD and HD

Answer 24

-HD has higher softening temperature
-HD is stronger

Question 25

what are thermosoftening polymers

Answer 25

they soften easily when heated, and re-set when they cool down

Question 26

what are thermosetting polymers

Answer 26

they do not melt when heated, due to strong covalent bonds 'cross-linking'

Question 27

why do thermosoftening polymers melt

Answer 27

weak intermolecular forces between polymer chains

Question 28

what will happen to a thermosetting polymer if it gets too hot

Answer 28

it will char

Question 29

what is soda-lime glass made of (most common glass)

Answer 29

sand, limestone, sodium carbonate (soda)

Question 30

properties of ceramics

Answer 30

-hard -brittle -good electrical insulators -resistant to chemical attack

Question 31

what is clay made of

Answer 31

metals and non-metals with ionic bonding between ions, and covalent between non-metal ions

Question 32

what are the two materials a composite is made of

Answer 32

- a matrix that binds the other material -another material

Question 33

what do composites do

Answer 33

bind the two materials together (reinforcement) and improve a desirable property that neither original material can offer alone

Question 34

examples of composites

Answer 34

-glass-ceramic -fibreglass -plywood/MDF -concrete

Question 35

what is ammonia's formula

Answer 35

NH(3)

Question 36

why do plants need nitrogen

Answer 36

it helps them make proteins

Question 37

why do plants not get enough nitrogen

Answer 37

the nitrogen in the air is insoluble in water and cannot be absorbed

Question 38

what is the process that turns nitrogen gas into ammonia

Answer 38

the Haber process

Question 39

ammonia's most important use

Answer 39

fertilisers

Question 40

what is the Haber process:

Answer 40

-nitrogen and hydrogen purified, passed over an iron catalyst at about 450 degrees and 200 atmospheres -the reaction is reversible -ammonia removed by cooling gases so that it liquefies. -separated from unreacted nitrogen and hydrogen

Question 41

what happens to the unreacted nitrogen and hydrogen in the Haber process

Answer 41

recycled back into the reaction mixture, the process happens again

Question 42

why is nitrogen in the air not a free resource

Answer 42

we have to separate it using fractional distillation, requiring energy

Question 43

how is the hydrogen made for the Haber process

Answer 43

reacting methane gas with steam at high temperatures methane +steam -> hydrogen + carbon monoxide

Question 44

what is the main cost of the Haber process

Answer 44

buying methane gas, bought as a natural gas (fossil fuel)

Question 45

how else can methane create hydrogen

Answer 45

mixing with air and oxygen, leaving mainly nitrogen in the air

Question 46

increase in pressure will do what in the Haber process

Answer 46

shift the equilibrium to the right, producing more ammonia

Question 47

why do we use 200 atmospheres in the Haber process

Answer 47

need a pressure as high as possible, but also reasonably priced. this is a compromise

Question 48

what does lowering the temperature do in the Haber process

Answer 48

shift the equilibrium to the right and increase ammonia

Question 49

why do we use 450 degrees with the Haber process

Answer 49

we need a low temperature, but too low would mean the reaction happens slow and this would be expensive. this is a compromise too low a temp would reduce the iron catalyst's effectiveness

Question 50

what three fertilisers can ammonia solution create

Answer 50

ammonium nitrate ammonium sulfate ammonium phosphate ALL BY ADDING ACIDS

Question 51

is ammonia acid or alk

Answer 51

alk

Question 52

ammonia solution forming new fertilisers is an example of what

Answer 52

neutralisation reaction

Question 53

what three minerals do plants need

Answer 53

nitrogen, potassium and phosphorus

Question 54

what is a fertiliser that has all the minerals needed for a plant

Answer 54

the NPK fertiliser

Question 55

how to get phosphorus for NPK

Answer 55

dug out from rock, treated with nitric, sulfuric and phosphoric acid, making triple superphosphate in the end

Question 56

how do we get potassium for NPK

Answer 56

dug from the ground

Question 57

how do we get nitrogen for NPK

Answer 57

ammonium solution