C6-10 Spec Chemistry Flashcards

1
Q

what 4 things do humans use the earth’s resources for

A

warmth, shelter, food, transport

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2
Q

what 4 things do natural resources provide

A

food, timber, clothing fuels

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3
Q

what 2 things are finite resources from the earth, oceans and atmosphere processed to do

A

provide energy and materials

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4
Q

what is the role of chemistry for helping sustainable development

A

improving agricultural and industrial processes
to provide new products and promote sustainable development

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5
Q

what is the definition of sustainable development

A

meeting the needs of current generations without compromising the ability of future generations to meet their own needs

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6
Q

give 2 example of a synthetic product which supplements/replaces a natural one in agriculture

A

manure - natural fertiliser
replaced by haber process nitrogen fertiliser
rubber can be made naturally from sap but also can be produced synthetically

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7
Q

drinking water needs sufficiently low levels of what 2 things

A

dissolved salts
microbes

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8
Q

what is water safe to drink called

A

potable water

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9
Q

is potable water pure chemically

A

no - it contains dissolved substances

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10
Q

what 2 things can affect the method used to produce potable water

A

supplies of water
local conditions

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11
Q

what 3 places does rainwater collect?

A

ground, lakes, rivers

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12
Q

rain water is ____water

A

fresh

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13
Q

give the method of collecting the majority of potable water in the UK - 3 steps

A

choose appropriate freshwater source
pass water through filter beds
sterilising

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14
Q

give 3 examples of sterilising agents for potable water

A

chlorine
ozone
ultraviolet light

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15
Q

if supplies of freshwater are limited then what do you need to do

A

desalination of salty water or sea water

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16
Q

give 2 methods of desalination

A

distillation
processes using membranes such as reverse osmosis

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17
Q

why is water passed through filter beds

A

to remove insoluble particles

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18
Q

why is water sterilised

A

to kill microbes

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19
Q

how does reverse osmosis work

A

force water through a membrane which allows water through but prevents most ions travelling through

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20
Q

desalination requires lots of ____

A

energy

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21
Q

what colour is universal indicator if pH is 7

A

green

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22
Q

how do you test a substance has dissolved solids

A

weigh evaporating basin
use evaporating basin over gauze and tripod and bunsen burner
let the basin cool and then reweigh it
calculate the change in mass

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23
Q

explain how to purify a water sample by distillation

A

heat water gently using a bunsen burner, tripod, gauze and conical flask until it boils
connect the conical flask using a bung and tube to a test tube held in a clamp and in a beaker of ice and water

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24
Q

do alkanes have a double bond

A

nope - as A is single atm

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25
Q

what does saturation mean

A

max amount of hydrogens bonded to each carbon

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26
Q

what is crude oil made of

A

remains of ancient biomass consisting of mainly plankton that was buried in the mud

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27
Q

define hydrocarbon

A

compound with ONLY hydrogen and carbon atoms

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28
Q

crude oil hydrocarbons are mostly ___

A

alkanes

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29
Q

what is the homologous series for alkanes and what is the formula

A

Cn H2n+2
the family - alkanes

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30
Q

what are the first 4 alkanes

A

methane
ethane
propane
butane

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31
Q

there are many differernt hydrocarbons in crude oil which can be separated into what

A

fractions

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32
Q

each fraction contains a similar number of ___

A

carbon atoms

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33
Q

name 5 fuels from crude oil

A

heavy fuel oil
petroleum gases
kerosene
petrol
diesel

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34
Q

the petrochemical industry produces lots of useful materials for modern life such as what

A

solvents
lubricants
polymers
detergents

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35
Q

a vast array of natural and synthetic —- atoms occur due to the ability of — atoms to form similar compounds

A

CARBON
CARBON

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36
Q

describe how fractional distillation works - can do (can skip kind of)

A

fractionating column
with a temperature gradient
so the top is cooler than the bottom
vaporised crude oil enters the bottom
rises
longest chain hydrocarbons condense near the bottom as they have the highest boiling points
hydrocarbons condense at their boiling points further up
gases which still haven’t condensed at the top of the column leave as a waste product

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37
Q

how can hydrocarbons be broken down to produce smaller more useful molecules

A

cracking

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38
Q

what are the two ways of doing cracking

A

steam cracking
catalytic cracking

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39
Q

what are the general conditions for catalytic cracking

A

vaporise the hydrocarbon
pass it over an aluminium oxide catalyst

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40
Q

cracking breaks ___into ___ (although the products could still be ___

A

alkane
alkene
alkane

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41
Q

what type of reaction is cracking

A

thermal decomposition

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42
Q

what are the conditions for steam cracking

A

vaporise
mix with steam
heat to high pressures

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43
Q

what is more reactive - alkene or alkane

A

alkene

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44
Q

alkenes can react with ____ which is used to test for alkenes - what is the colour change?

A

bromine water
orange to colourless

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45
Q

why is cracking useful

A

there is a high demand for fuels with small molecules and so some of the products of cracking are useful as fuels

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46
Q

alkenes are used to produce what - (as starting materials for the production of many other chemicals)

A

polymers

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47
Q

properties of long chain hydrocarbons

A

not flammable
very viscous
high boiling points
burns with a smoky flame

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48
Q

properties of short chain hydrocarbons

A

flammable
runny - low viscosity
low boil points
burns without smoky flame

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49
Q

what 2 reasons are there for us producing lots of waste water that needs ___before being released into the environment

A

urban lifestyles
industrial processes

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50
Q

what needs removing from sewage and agricultural waste

A

organic matter
harmful microbes

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51
Q

what needs removing from industrial waste

A

organic matter and
harmful chemicals

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52
Q

give the 4 stages of sewage treatment

A

screening and grit removal
sedimentation to produce sewage sludge and effluent
anaerobic digestion of sewage sludge
aerobic biological treatment of effluent

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53
Q

what is the effluent in sewage treatment

A

the liquid that remains on top

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54
Q

how is sewage sludge digested

A

anaerobically

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55
Q

how is effluent digested

A

aerobically

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56
Q

what 2 things does sedimentation produce

A

sewage sludge and effluent

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57
Q

the earth’s metal ore stores are ___

A

limited

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58
Q

what ores are becoming scarce

A

copper ores

59
Q

give 2 ways of extracting copper from low grade ores

A

phytomining
bioleaching

60
Q

what are traditional mining methods of mining copper ore

A

digging
moving
and disposing of large amounts of rock

61
Q

what is phyotmining - don’t describe process

A

using plants to absorb metal compounds
P = plant

62
Q

what is the process of phytomining

A

plants harvested
burned to produce ash that contains metal compounds

63
Q

what is bioleaching

A

using bacteria to produce leachate solutions that contain metal compounds

64
Q

give 2 ways copper can be obtained from a copper compound

A

displacement using scrap iron
electrolysis

65
Q

what 4 stages to life cycle assessments take into account in measuring environmental impact

A

extracting and processing raw materials
manufacturing and packaging
use and operation during lifetime
disposal at end of useful life
transport and distribution at each stage

66
Q

why is life cycle assessment quantifying not purely objective

A

allocating numerical values to pollutant effects requires value judgements
HOWEVER
water, resources, energy sources and waste production can be fairly easily quantified

67
Q

give an example of how selective or abbreviated LCAs can be devised to evaluate a product and misused to reach pre-determined conclusions

A

advertising purposes

68
Q

give the LCA for a plastic bag

A

crude oil is finite + fractional distillation and cracking and polymerisation requires lots of energy
can be reused as stronger
can be recycled
don’t biodegrade
landfill - centuries there

69
Q

give LCA for a paper bag

A

can be made from recycled paper
less energy to make a paper bag
more expensive to make bags from paper as handles have to be glued on
short lifetime
can be recycled easily
biodegrade quickly

70
Q

give an example of a product that can be reused

A

glass bottles

71
Q

what can glass bottles be reused for

A

crushed and melted to make different glass products

72
Q

give 5 materials produced from limited raw materials

A

metals
glas
building material s
clay ceramics
most plastics

73
Q

how are metals recycled

A

melting
recasting or reforming into different products

74
Q

what doe the amount of separation required for recycling depend on

A

material and properties required of the final product

75
Q

give an example of a form of recycling to reduce the amount of iron that needs to be extracted from iron ore

A

add iron to scrap steel in a blast furnace

76
Q

what is corrosion

A

destruction of materials by chemical reactions with substances in the environment

77
Q

give an example of corrosion

A

rusting

78
Q

what 2 things are necessary for iron to rust

A

air and water

79
Q

give 4 ways of preventing corrosion

A

coating that acts as a barrier
such as greasing, painting or electroplating

80
Q

give an example of a metal that has a protective coating

A

aluminium has an oxide coating that protects the metal from further corrosion

81
Q

what is sacrificial protection

A

some coatings contain a more reactive metal to provide sacrificial protection

82
Q

give an example of using sacrificial protection

A

zinc is used to galvanise iron

83
Q

most metals in everyday use are___

A

alloys

84
Q

what is bronze an alloy of

A

copper and tin
b = c + t

85
Q

what is brass an alloy of

A

copper and zinc
s = z

86
Q

gold used in jewellery is usually an allow with what

A

silver, copper, zinc

87
Q

what is the proportion of gold in the alloy measured in

A

carats

88
Q

what is 18 carat gold

A

75%

89
Q

what are steels alloys of

A

iron - with specific amounts of carbon and other metal

90
Q

what are the 2 properties of high carbon steel

A

strong but brittle

91
Q

what are two properties of low carbon steel

A

softer and more easily shaped

92
Q

are do stainless steels contain

A

chromium and nickel
CNS

93
Q

give 2 properties of stainless steel

A

hard
resistant to corrosion

94
Q

give a property of aluminium alloys

A

low density

95
Q

give a use for high carbon steels

A

construction

96
Q

give a use for low carbon steels

A

car body panels - as malleable

97
Q

give a use of stainless steel

A

cutlery as doesn’t rust

98
Q

give a use of bronze

A

statues, bells, coins

99
Q

give a use of brass

A

musical instrument making, taps and door knobs

100
Q

what is most of the glass we use

A

soda lime glass

101
Q

how is soda lime glass made

A

heating a mixture of sand, sodium carbonate, and limestone

102
Q

what is borosilicate glass made of

A

sand and boron trioxide

103
Q

borosilicate glass melts at ___temperatures than soda lime glass

A

higher

104
Q

how are clay ceramics made

A

shaping wet clay
and then heating in a furnace

105
Q

give 2 examples of clay ceramics

A

pottery and bricks

106
Q

what 2 things do the properties of polymers depend on

A

what monomers made from
conditions under which they are made

107
Q

what do thermosoftening polymers do when heated

A

melt

108
Q

what do thermosetting polymers do when heated

A

don’t melt

109
Q

most composites are made of what 2 things

A

a matrix or diner
binding together fibres or fragments of the other material - the reinforcement

110
Q

give 3 examples of composites

A

reinforced concrete
fibreglass
chipboard

111
Q

what is the matrix for reinforced concrete and what is the reinforcement

A

matrix = concrete
reinforcement = steel

112
Q

what is matrix and reinforcement for fibreglass

A

reinforcement - glass fibres
matrix = polymer resin

113
Q

matrix and reinforcement for chipboard

A

matrix - resin glue
reinforcement - wood chips

114
Q

describe the difference between thermosetting and thermosoftening polymers in terms of structures

A

thermosoftening - no cross links (covalent bonds between between molecule layers) so molecules can move over each other when heated and therefore melt
thermosetting - cross links (strong covalent bonds between molecule layers - can’t melt when heated)

115
Q

how is low density poly(ethene) made

A

moderate temp
high pressure
with a catalyst

116
Q

how is high density poly ethene made

A

lower temp and pressure
different catalyst
compared to low density

117
Q

what is the haber process used for

A

manufacturing ammonia

118
Q

what can ammonia be used for

A

producing nitrogen based fertilisers

119
Q

what is nitrogen extracted from

A

the air

120
Q

what is hydrogen extracted from

A

natural gas

121
Q

what temp is haber process at

A

450 degrees celsius

122
Q

what pressure is the haber process done at

A

200 atmospheres

123
Q

the reaction in the haber process is ____and so some of the ammonia breaks down into ___and ___

A

reversible
nitrogen and hydrogen

124
Q

describe the process of the haber process

A

purified gases passed over an iron catalyst at high temp and pressure (450, 200)
cooled and ammonia is liquefied and removed
nitrogen and hydrogen remaining recycled

125
Q

what type of catalyst is used in haber process

A

iron

126
Q

how is ammonia removed from haber process

A

liquified

127
Q

what does equilibrium position on the right mean

A

there is more of the stuff on the right present in the mixture (as the rate of reaction on the left is higher)

128
Q

why is 200 atmospheres used in haber process

A

high pressure to increase ammonia yield - as equilibrium on side with least moles (ammonia side)
but not too high as maintaining that high pressure is expensive
N2(g) + 3H2(g) ⇌ 2NH3(g)

129
Q

why is the haber process completed at 450 degrees

A

increase rate of reaction
but trade off between yield and rate
as the forwards reaction is exothermic
so increasing temperature moves equilibrium to the side which is produced by an endothermic reaction (more of the reactants are produced)
decreasing yield of ammonia
N2(g) + 3H2(g) ⇌ 2NH3(g)

130
Q

how can the reaction being exothermic help reduce costs

A

excess heat can heat other parts of the process
and can generate electricity

131
Q

how can recycling hydrogen and nitrogen reduce cost

A

cost of obtaining raw materials reduced as less needed

132
Q

how does the catalyst affect reaction

A

increases rate - of both forward and backward reactions equally

133
Q

what are the 3 compounds in NPK fertilisers

A

nitrogen
potassium
phosphorus

134
Q

NPK fertilisers are formulations of ___

A

salts

135
Q

what can ammonia be used for

A

ammonium salts
nitric acid

136
Q

give 2 compounds of potassium that are obtained by mining

A

potassium chloride
potassium sulfate

137
Q

how is phosphate obtained

A

phosphate rock is mined - but it can’t be used directly as a fertiliser

138
Q

how is phosphate made to produce soluble salts that can be used as fertilisers

A

reacted with nitric acid and sulphuric acid

139
Q

what is reaction of phosphate rock plus nitric acid

A

calcium nitrate + phosphoric acid

140
Q

what is reaction of phosphoric acid and sulphuric acid

A

single superphosphate (mix of calcium phosphate and calcium sulphate)

141
Q

what is reaction f phosphoric acid and phosphoric acid

A

triple superphosphate - (calcium phosphate )

142
Q

give 2 ions from ammonia and how you can get them

A

ammonium - neutralisation
and nitrate - oxidation of ammonia

143
Q
A