Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

gcse science > Science - Chemistry - Using resources - C10 > Flashcards

Science - Chemistry - Using resources - C10 Flashcards

You may prefer our related Brainscape-certified flashcards:
GCSE Geography - AQA flashcards GCSE Religious Studies - Edexcel Route B flashcards GCSE Religious Studies - Eduqas Route A flashcards GCSE Religious Studies - Edexcel Route A flashcards GCSE Religious Studies - Eduqas Route B flashcards Biology 101 flashcards
1
Q

what are ceramics ?

A

non-metallic solids with high melting points that aren’t made from carbon based compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are the properties of ceramics ?

A

good insulators of heat/electricity
brittle
stiff

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the 2 types of ceramics ?

A

clay ceramics
glass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is clay ?

A

a soft material when it is dug out of the ground so it can be moulded into different shapes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what happens when clay is fired at high temperatures ?

A

it hardens to form a clay ceramic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is clay useful for ?

A

making pottery / bricks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are properties of glass ?

A

generally transparent
moulded when hot
brittle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the most common type of glass ?

A

soda lime glass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how is soda lime glass made ?

A

by heating a mixture of limestone sand and sodium carbonate until it melts then cools

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

which glass has a higher melting point :
borosilicate glass
or
soda lime glass

A

borosilicate glass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how is borosilicate glass made ?

A

using a mixture of sand and boron trioxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are composites ?

A

made of one material embedded in another - fibres or fragments of a material are surrounded by a matrix acting as a binder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what does the properties of composites depend on ?

A

the matrix/binder and the reinforcement used to make them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the uses of composites ?

A
  • wood
    -fibreglass
    -carbon fibre composites
  • concrete
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how is wood made ?

A

cellulose fibres held together by lignin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

give uses of wood ?

A

building material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

give properties of wood

A

strong
versatile
attractive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is fibreglass made of ?

A

fibres of glass embedded in a matrix polymer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

give properties of fibreglass

A

low density
strong

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is fibreglass used for ?

A

skis
boats
surfboards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

how are carbon fibre composites made ?

A

from carbon nanotubes or long chains of carbon atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

give properties of carbon fibre composites

A

strong
light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what are carbon fibre composites used for ?

A

aerospace
sports car manufacturing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how is concrete made ?

A

from aggregate embedded in cement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

give properties of concrete ?

A

strong
rigid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

give uses of concrete

A

building material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are polymers ?

A

large molecules formed when many small molecules called monomers join together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

give properties of polymers ?

A

insulators of heat/electricity
flexible
easily moulded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

give uses of polymers

A

clothes
insulators in electrical items

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what are the 2 things which influence the properties of a polymer ?

A

the monomers its made from
the conditions under which it’s made

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what do the monomers a polymer is made from decide ?

A

what type of forces form between the polymer chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what are thermosoftening polymers ?

A

made of individual tangled chains of polymers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what are the properties of thermosoftening polymers ?

A

flexible
can be melted then remoulded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what kind of forces are between thermosoftening polymer chains ?

A

weak forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what are thermosetting polymers ?

A

have cross links between their polymer chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what happens to a thermosetting polymer when heated ?

A

it chars

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

what are the properties of thermosetting polymers ?

A

strong
hard
rigid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

give an example of how reaction condition affects properties of polymers ?

A
  • 2 types of poly(ethene) can be made :

Low density poly ethene
High density poly ethene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

how is low density poly ethene made ?

A

by heating ethene to a moderate temperature at high pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what are the properties of low density poly ethene ?

A

flexible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

what is low density poly ethene used for ?

A

bags
bottles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

how is high density poly ethene made ?

A

at lower temperature and a lower pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

give properties of high density poly ethene ?

A

rigid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

when is high density poly ethene used ?

A

water tanks
drain pipes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

give properties of metals ?

A

malleable
good conductors of heat and electricity
ductile
shiny
stiff
sonorous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what is copper used for and why ?

A

electrical wires - conducts electricity well, and is ductile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

what is an alloy ?

A

mixtures of 2 or more metals or a mixture of a metal and a non - metal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

why are alloys better than pure metals ?

A

man pure metals are too soft for uses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

why are pure metals soft ?

A

their layers of atoms slide easily past each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

why are alloys harder than pure metals ?

A

they are made from atoms of different elements which have different sized atoms so the layers are distorted so it is more difficult for atoms to slide past each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

give properties of iron ?

A

soft
easily shaped
bendy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

what is iron used to make ?

A

alloys called steels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

how are steels formed ?

A

by adding small amounts of carbon to the iron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

what are the properties of low carbon steel ?

A

easily shaped

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

what is low carbon steel used to make ?

A

car bodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

what are the properties of high carbon steel ?

A

strong
inflexible
brittle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

what is high carbon steel used to make ?

A

blades
bridges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

what are the properties of stainless steel ?

A

corrosion resistant
hard

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

what is stainless steel used for ?

A

cutlery
containers for corrosive substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

what is bronze an alloy of ?

A

copper and tin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

what are the properties of bronze ?

A

hard

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

what is bronze used for ?

A

statues
decorative objects
medals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

what is brass an alloy of ?

A

copper and zinc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

give properties of brass ?

A

gold like appearance
malleable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

what is brass used for ?

A

door fittings
water taps

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

why are gold alloys used ?

A

gold is too soft

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

what are gold alloys used for ?

A

jewelry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

what makes gold alloys ?

A

zinc
copper
silver

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

what are the benefits of a gold alloy ?

A

cheaper

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

what is the amount of gold in an item described in ?

A

carats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

what is pure gold described as ?

A

24 carat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

what is aluminium used for ?

A

aircraft manufacture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

why can’t pure aluminium be used ?

A

it is too soft
so it is alloyed with other metals to make it stronger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

what is corrosion ?

A

when a metal is gradually destroyed by reacting with substances in the environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

give an example of corrosion ?

A

iron rusting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

what needs to be present for corrosion ?

A

oxygen
water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

what is rust also known as ?

A

hydrated iron oxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

what is the word equation for iron rusting ?

A

iron + oxygen + water - hydrated iron oxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

where does corrosion happen in a material ?

A

at its surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

why does corrosion happen at the surface of a material ?

A

it is exposed to air there

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

why will iron that wasn’t initially at the surface eventually corrode away ?

A

the iron initially at the surface will crumble and flake off to leave more iron available to rust

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

why aren’t objects made from aluminium completely destroyed by corrosion ?

A

the aluminium oxide that forms when aluminium corrodes doesn’t flake away so a protective layer is formed preventing any further corrosion happening

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

explain a rust experiment which shows oxygen and water is required for rust to form ?

A
  • put an iron nail in a boiling tube with just water - it won’t rust
  • put an iron in a boiling tube with just air - it won’t rust
  • put an iron nail in a boiling tube with air and water it wil rust
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

why will the mass of a rusty nail increase as it rusts ?

A

iron atoms in the nail will have bonded to oxygen and water molecules resulting in a compound which is heavier than just iron

83
Q

why is preventing corrosion important ?

A
  • structures could become damaged and dangerous to use, e.g bridges
84
Q

what are the 2 ways to prevent corrosion ?

A

creating a barrier
sacrificial method

85
Q

how can creating a barrier prevent corrosion ?

A
  • it keeps out water and oxygen
86
Q

give an example of how barriers are created to prevent corrosion in small objects ?

A

paint
coating with plastic

87
Q

explain how barriers are created to prevent corrosion using electroplanting ?

A

it uses electrolysis to reduce metal ions onto an iron electrode

88
Q

give an example of when oil/greasing is used to prevent corrosion ?

A

bike chains

89
Q

what is the sacrificial method to prevent corrosion ?

A

placing a more reactive metal with the metal you want to protect because water and oxygen will then react with that metal instead of the less reactive metal

90
Q

give an example of when creating a metal and using the sacrificial method is used to prevent corrosion ?

A

an iron object can be galvanished by spraying with zinc which is protective and more reactive than iron

91
Q

how are natural resources formed ?

A

without human input

92
Q

what do natural resources include ?

A

anything that comes from
earth
sea
air

93
Q

what are natural resources used for ?

A

providing energy for things
building materials
food

94
Q

give an example of how a natural resource is used ?

A

wind generates electricity by wind turbines

95
Q

what does agriculture provide ?

A

conditions where natural resources can be enhanced

96
Q

what are renewable resources ?

A

materials which can be re-formed at a similar rate or faster than we use them

97
Q

give an example of a renewable resource ?

A

timber

98
Q

what is a non - renewable resource ?

A

materials which cannot be formed quickly enough to be considered replaceble

99
Q

give examples of finite resources ?

A

fossil fuels
nuclear fuels
minerals and metals found in ores

100
Q

what is sustainable development ?

A

an approach to development that takes account of the needs of present society while not damaging the lives of future generations

101
Q

why is using finite resources unsustainable ?

A

lots of energy is used
lots of waste is produced

102
Q

give a way of reducing the use of finite resources ?

A

using them less
recycling - uses less energy
reusing objects

103
Q

give examples of new, more sustainable methods to extract copper from its ores ?

A

bioleaching
phytomining

104
Q

what is bioleaching ?

A

using bacteria which convert copper compounds into the ore into soluble copper compounds - separating copper from the ore in the process

105
Q

describe bioleaching

A
  • leachate (solution produced) contains copper ions which can be extracted by electrolysis or displacement reactions
106
Q

why is scrap iron used to displace copper from solutions ?

A

cheap
reduces scrap going to landfill

107
Q

what is phytomining ?

A

growing plants in soil which has copper

108
Q

how does phytomining work ?

A

plants cannot use or get rid of copper so it gradually builds up in the leaves
plants are harvested dried and burned in a furnace
the ash contains copper compounds and can be displaced using electrolysis or more reactive metals

109
Q

what are the advantages or phytomining and bioleaching ?

A
  • requires less energy
  • low grade ores do not need to be mined in the same ways as high mined ores which protects habitats
  • earth does not need to be dug up
110
Q

what are the disadvantages of bioleaching and phytominig ?

A

slow

111
Q

what are the advantages of recycling ?

A
  • it uses waste materials to make new products
  • uses little energy
  • saves money
  • conserves finite resources
  • cuts down rubbish sent to landfill
112
Q

what does resusing mean ?

A

using a product more than once for the same or different purpose

113
Q

how are metals recycled ?

A

melted down
casted into the shape of the new product

114
Q

how is glass separated during recycling ?

A

by colour
chemical composition

115
Q

how is glass recycled ?

A

crushed down
melted to be reshaped before being recycled

116
Q

what are life cycle assessments ?

A

things that asses the environmental impact of the entire lifetime of a product

117
Q

what are the stages of a lifetime of a product ?

A
  • getting the raw materials
  • manufacturing and packaging
  • using the product
  • product disposal
118
Q

what needs to be considered during each stage of the lifetime of a product ?

A

how many other resources are used
energy needed
pollution produced
waster formed = how waste is disposed

119
Q

what can extraction of a raw material do ?

A

damage environment
pollution

120
Q

what can transportation of raw materials lead to ?

A

greenhouse gases from combustion of fossil fuels

121
Q

what can manufacturing products cause ?

A

uses lots of energy
pollution
waste products from reactions used to make compounds

122
Q

what is considered by life cycle assessments ?

A

how long a product is used for

123
Q

why can products which needs more energy to produce but have a long life be better ?

A

it may mean less waste and raw materials

124
Q

why can product disposal be harmful ?

A
  • energy used when transporting to landfill
  • waste takes up space
  • may pollute land/water
  • non -biodegradable products take a long time to degrade
125
Q

what is incineration ?

A

when waste is burnt at high temperatures

126
Q

what are the benefits of incineration ?

A

it cuts down waste going to landfill and can be used to generate electricity

127
Q

what is the issue with incineration ?

A

causes air pollution

128
Q

what are life cycle assessments used for ?

A

evaluating different products and allowing decisions to be made about which products has the least environmental impact

129
Q

what are the problems with life cycle assessments ?

A
  • effects of some pollutants is hard to give a numerical value
  • they can be biased as it uses an objective method
  • selective LCAs only show some of the impacts of a product on the environment which can be biased as they can be written to support the claims of a company
130
Q

give an example of a life cycle assessment used -

A

plastic vs paper bags

131
Q

what do life cycle assessments of paper vs plastic bags show ?

A

even though plastic bags aren’t biodegradable they take less energy and have a longer lifespan than paper bags so are less harmful

132
Q

what is potable water ?

A

water that has been treated or is naturally safe for humans to drink

133
Q

what is pure water ?

A

H20 molecules ONLY

134
Q

what things need to be in potable water to make it drinkable ?

A
  • levels of dissolved salts aren’t to high
  • pH between 6.5 and 8.5
  • there aren’t dangerous bacteria or microbes swimming around in it
135
Q

what does how potable water is produced depend on ?

A
  • climate
  • landscape
  • cost
136
Q

what is fresh water ?

A

water that doesn’t have much dissolved in it

137
Q

give an example of fresh water ?

A

rain water

138
Q

name 2 ways rain water can be collected

A

as surface water
as ground water

139
Q

in the UK what type of water is the majority of water we drink ?

A

fresh water

140
Q

what does the source of fresh water chosen depend on ?

A

location

141
Q

in warm areas where does most of the domestic water supply come from and why ?

A

ground water as surface water dries up from the heat

142
Q

why does fresh water need to be treated before we can drink it ?

A

so it is safe

143
Q

how is water treated ?

A

filtration
sterilisation

144
Q

what is filtration in water ?

A

a wire mesh screens filters out large things then gravel and sand beds filter out any solid bits

145
Q

why is water sterilised ?

A

water is sterilized to kill any harmful bacteria or microbes

146
Q

how is water sterilised ?

A

by bubbling chlorine gad through it
using ozone or ultraviolet light

147
Q

why do some dry countries have to use sea water ?

A

there isn’t enough surface or ground water

148
Q

how must sea water be treated to produce potable water ?

A

desalination

149
Q

how can desalination be done ?

A

distillation
process that use membranes, e.g reverse osmosis

150
Q

what happens to sea water during reverse osmosis ?

A

salty water is passed through a membrane that only allows water molecules to pass through
Ions and larger molecules are trapped from the membrane and separated by the water

151
Q

what are the disadvantages of distillation and reverse osmosis ?

A

expensive
uses lots of energy

152
Q

how is seawater checked before it is considered safe to drink ?

A

if it has high levels of salts it needs to be distilled

153
Q

how do you test water before distilling it ?

A
  • check the pH using a pH metre - if it is too high or low you need to neutralise it
  • test for presence of sodium chloride
154
Q

how can you change the pH level to neutralise the water ?

A

with a titration then test with a pH metre to see if it is neutral

155
Q

how do you test for sodium ions ?

A

flame test - if sodium ions are present sample will turn yellow

156
Q

how do you test for chloride ions ?

A

add dilute nitric acid to silver nitrate solution to water, if chloride is present a white precipitate will form

157
Q

how do you distill water ?

A

pour salty water into distillation apparatus
heat flask from below
water will boil and form steam leaving any dissolved salts in the flask
steam will condense back to liquid water and can be collected

repeat test for sodium chloride and pH to check water is safe

158
Q

consolidate the steps for how to test and distil water

A

1 - test pH
2 - test for sodium ions
3- test for chloride ions
4 - distill water
5- retest water for pH and sodium chloride to check it is safe to drink

159
Q

in the home what do we use water for ?

A

baths
toilet
washing up

160
Q

what happens when we flush water from our homes ?

A

it goes into the sewers and towards sewage treatment plants

161
Q

why does sewage from domestic or agricultural sources need to be treated ?

A

to remove organic matter or harmful microbes before it can be put back into fresh water sources

162
Q

what are the issues with using unclean water ?

A

it can pollute lakes
cause health risks

163
Q

what can industrial waste contain ?

A

organic matter
harmful chemicals

164
Q

what are the stages of waste treatment ?

A

screening
sedimentation
aerobic digestion
anaerboic digestion

165
Q

what is screening ?

A

sewage is screened - large bits of material is removed

166
Q

what is sedimentation ?

A

screened waste is put in settlement tank and heavier suspended solids sink to the bottom producing sludge while the less dense effluent floats to the top

167
Q

what is aerobic digestion ?

A

air is pumped through the water to encourage aerobic bacteria to break down any organic matter - including microbes

168
Q

what is anaerobic digestion ?

A

sludge from the bottom of the tank is removed and put into large tanks

sludge gets broken down - anaerobic digestion is breaking down the organic matter in sludge

169
Q

what does sludge release during anaerobic digestion ?

A

methane gas

170
Q

what is methane gas used for ?

A

energy

171
Q

what is digested waste used for ?

A

fertilisers

172
Q

how is waste water with toxic substances cleaned ?

A

they add chemicals
UV radiation
Membranes

are added to the other steps

173
Q

what is the advantage of sewage treatment ?

A

uses less energy

174
Q

when can retrieving potable water via sewage treatment be beneficial ?

A

in areas where there is not much fresh water

175
Q

what happens in the haber process ?

A

nitrogen and hydrogen gas are used to make ammonia

176
Q

where is nitrogen found ?

A

in the air

177
Q

where is hydrogen found ?

A

reacting methane with steam
crude oil

178
Q

what is the reversible reaction to form ammonia in the Haber process ?

A

nitrogen + hydrogen = ammonia
N2 + 3H2 = 2NH3

179
Q

how is forming ammonia a reversible reaction ?

A

ammonia is formed then breaks down into nitrogen and hydrogen again

180
Q

describe what happens in the reaction vessel during the Haber process ?

A
  • gas is cooled in a condenser and liquifies
  • liquid ammonia is removed
  • unused nitrogen and hydrogen are recycled
181
Q

how is nitrogen and hydrogen being recycled beneficial in the Haber process ?

A

it reduces waste
saves resources
reduces cost

182
Q

what conditions are being formed in the haber process ?

A

temperature at 450 C
Pressure - 200 atmospheres
catalyst - iron

183
Q

what is the forward reaction of the Haber process - exothermic or endothermic ?

A

exothermic

184
Q

why is it bad that the forward reaction of the Haber process is exothermic ?

A

it moves the equilibrium the wrong way - away from ammonia towards nitrogen and hydrogen

185
Q

at what temperature is the yield of ammonia best ?

A

lower temperatures

186
Q

why is it difficult that to get a better yield of ammonia a lower temperature is used ?

A

lower rate of reaction - so temperature is increased anyway

187
Q

why is higher pressure good for the Haber process in making ammonia ?

A

it moves the equilibrium towards ammonia so it increases the yield and rate of reaction

188
Q

why can’t the pressure be put too high during the Haber process ?

A

it is too expensive

189
Q

what is the advantage of having an iron catalyst during the Haber process ?

A

it makes the reaction go faster so reaches equilibrium faster

190
Q

why is a catalyst important during the Haber process ?

A

without it the temperature would be raised even more so the percentage yield would decrease even more
leading to
it being more costly
higher energy usage

191
Q

how does presenting experiments in different conditions through graphs help scientists ?

A

they can find the best conditions for a reaction to take place

192
Q

what are the 3 main element needed for growth ?

A

nitrogen
phosphorous
potassium

193
Q

why may nitrogen potassium and phosphorous be missing from the soil ?

A

if they have been used up by the previous crop

194
Q

what will happen if plants don’t get enough nitrogen phosphorous and potassium ?

A

stunted growth
life prcesses affected

195
Q

what do fertilisers do ?

A

replace the missing elements or provide more of them which helps to increase crop yield

196
Q

what are NPK fertilisers ?

A

formulations containing salts of nitrogen, phosphorous and potassium in the right percentage of the elements

197
Q

what can ammonia react with to help produce fertilisers ?

A
  • oxygen and water to form nitric acid
  • nitric acid - to form ammonium nitrate
198
Q

why is ammonium nitrate good for a fertiliser ?

A

it has a high proportion of nitrogen

199
Q

what is the equation wen reacting ammonia and nitric acidn?

A

NH3 + HNO3 - NH4NO3

200
Q

why are the processes of producing fertilisers different in the laboratory or in industry ?

A

scale and speed of the operation determines the methods used in the process -
industry - lots needs to be made quickly to keep up with demand
lab - smaller amounts in batches

201
Q

how is ammonium nitrate formed in industry ?

A
  • ammonia gas is added directly to giant vats containing highly concentrated nitric acid
  • this give an exothermic reaction
    heat released evaporates water making a very concentrated ammonium nitrate product
202
Q

how is ammonium nitrate formed in labs ?

A
  • carried out on a smaller scale by titration and crystallization
  • ammonia solution is used and the reactants are at a lower concentration than in industry so les heat is produced and it is safer
  • after the titration the mixture needs to be crystallised to give pure ammonium nitrate crystals
203
Q

why isn’t crystallization happening in industry to form ammonium nitrate ?

A

slow

204
Q

what can phosphate rock be reacted with to form fertilisers ?

A
  • nitric acid = phosphoric acid and calcium nitrate
  • sulfuric acid = calcium sulfate and calcium phosphate
  • phosphoric acid - calcium phosphate
205
Q

what can be mined as a source of potassium ?

A

potassium chloride
potassium sulfate

206
Q

can phosphate rock be a fertiliser on its own ?

A

no

gcse science (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions