C1 Unit 4 Revision

Front 1

what is petrol obtained from?

Back 1

crude oil

Front 2

describe the texture of crude oil

Back 2

thick, black sticky liquid

Front 3

where is crude oil found?

Back 3

sedimentary rocks

Front 4

where are crude oil and natural gas found and what prevents the liquid and gas from rising?

Back 4

they are found underground and are trapped by layers of rocks that prevent the liquid and gas rising

Front 5

how is oil or gas formed?

Back 5

crude oil and natural gas are found in fossil fuels which are formed over millions of years from the remains of microscopic plants and animals that once lived in the sea. when they died they fell to the sea bed and were buried by sediments. the sediments kept oxygen away and stopped the remains decaying so as more sediments were built on top the heat and pressure increased gradually turning them into oil or gas

Front 6

what is crude oil?

Back 6

a mixture of different hydrocarbon molecules

Front 7

what is a hydrocarbon?

Back 7

compound that contains only hydrogen and carbon atoms

Front 8

what do different hydrocarbons in crude oil have?

Back 8

they have different numbers of carbon atoms in their molecules ranging from one carbon to many hundreds

Front 9

what impurity does crude oil contain?

Back 9

sulphur

Front 10

how many more years are left for the supply of crude oil and why?

Back 10

40-50 years because crude oil is a non renewable resource and we are pumping oil out of the ground much faster than it is being made

Front 11

how are most oils obtained?

Back 11

they are obtained by drilling wells, however as the oil from wells run out and as the demand for oil increases surface mining of oil sands will increase

Front 12

why is crude oil not easy to use?

Back 12

contains hydrocarbons which are mixed together

Front 13

where is crude oil sent for fractional distillation?

Back 13

crude oil is sent to the oil refinery where they seperate it into simpler mixtures which is done by fractional distillation

Front 14

what is the definition of distillation?

Back 14

process used to separate mixtures of different liquids

Front 15

how are fractions produced?

Back 15

mixture of liquids are boiled and the vapour is condensed. the simpler mixtures produced by fractional distillation are called fractions

Front 16

give the order of the fractions from the highest boiling point to the lowest

Back 16

gases

petrol

naptha

kerosene

diesel

fuel oil

bitumen

Front 17

what are gases used for?

Back 17

used for fuel in vehicles and for heating and cooking at home

Front 18

what is petrol used for?

Back 18

fuel for cars

Front 19

what is naphtha used for?

Back 19

fluid in chemical industry

Front 20

what is kerosene used for?

Back 20

used as an aircraft fuel

Front 21

what is diesel used for?

Back 21

diesel engines

Front 22

what is fuel used for?

Back 22

heating and lubricating oils

Front 23

what is bitumen used for?

Back 23

making roads

Front 24

does the top of the fractianting column have higher or lower boiling points?

Back 24

higher

Front 25

does the top of the fractionating columns have shorter or longer molecules than the bottom?

Back 25

shorter

Front 26

is the top or the bottom of the fractionating column easy to ignite?

Back 26

top

Front 27

describe what the viscosity is like for the top and the bottom of the fractionating column

Back 27

the top has a runny liquid viscosity whereas the bottom is harder to ignite and are thick and sticky liquids

Front 28

what is combustion?

Back 28

this is when hydrocarbon fuels burn and react with oxygen to release heat and light energy and this is also an oxidation reaction

Front 29

describe the practiacal we could use to detect the products of a complete combustion reaction

Back 29

1. the u-tube in the middle contains copper sulphate and this white substance turns blue when water is added

2. the limewater is used to test for carbon dioxide gas so limewater will turn cloudy/milky if carbon dioxide is bubbled through it

Front 30

how does the practical for combustion show waste gases are present?

Back 30

copper sulphate will turn blue and limewater will turn cloudy/milky which shows carbon dioxide and water are present as waste gases

Front 31

what is the equation for complete combustion?

Back 31

hydrocarbon + oxygen > carbon dioxide + water

this shows the reaction has been oxidised

Front 32

when all hydrocarbon fuel burn what do they produce?

Back 32

carbon dioxide and water only if there is enough oxygen

Front 33

write the word and symbol equation for the complete combustion of methane

Back 33

methane + oxygen > carbon dioxide + water

CH4 + 202 > CO2 + 2H20

Front 34

when there is enough oxygen for complete combustion what colour does the flame turn?

Back 34

blue

Front 35

why does incomplete combustion happen?

Back 35

this happens when there is not enough oxygen so the hydrogen atoms in the hydrocarbon will give water but there is not enough oxygen for carbon dioxide so to produce carbon dioxide we may have to form carbon monoxide and solid particles of carbon (soot)

Front 36

what are the three word equations when methane burns without enough oxygen?

Back 36

methane + oxygen > carbon + water

methane + oxygen > carbon monoxide + water

methane + oxygen > carbon (soot) + carbon monoxide + carbon dioxide + water

Front 37

what do the percentages of carbon, carbon dioxide and carbon monoxide depend on?

Back 37

how much oxygen is available

Front 38

what does carbon appear as in a bonfire?

Back 38

appears as a tiny particle that you can see as black smoke in a bonfire

Front 39

what are the problems associated with carbon monoxide?

Back 39

carbon monoxide is an odourless, colourless toxic gas which reduces the amount of oxygen that the haemoglobin part of the blood can carry around the body and many people die due to faulty gas boilers and fires and carbon monoxide is also produced by engines

Front 40

what are the two ways we can prevent carbon monoxide?

Back 40

1. make sure all fuel burning appliances are serviced regularly

2. install carbon monoxide detectors to warn you if an appliance has stopped working properly

Front 41

what are the problems with soot?

Back 41

soot produced in appliances such as boilers can clog up the pipes carrying the waste gases away. it can even cause fires in chimneys if enough of it builds up and soot is also produced by diesel fuel vehicles and small particles of soot can be collected in the lungs by breathing in sooty air and this can lead to lung disease and soot can also make buildings dirty

Front 42

what is the equation for incomplete combustion?

Back 42

4CH4 + 6O2 > 2CO + CO2 + C + 8H20

Front 43

where does pollution come from?

Back 43

factories and power stations

Front 44

what are the problems with acidic rain?

Back 44

it kills fishes and other aquatic life in rivers and seas

Front 45

why is rainwater slightly acidic?

Back 45

this is because carbon dioxide and other gases in the air dissolve in it and produce acid rain which has a pH of 5.2

Front 46

describe the process of rainwater becoming acidic

Back 46

fuel is burnt and it reacts with oxygen from the air to form sulphur dioxide gas which also mixes with the clouds producing sulphuric acid this then dissolves in rainwater making it more acidic and lowering the pH

Front 47

what are the effects of acid rain?

Back 47

- makes rivers, lakes and soils acidic killing microorganisms

- damages trees

- speeds up weathering of buildings made of limestone and marble

- leads to the corrosion of metal

Front 48

what are the solutions of acid rain?

Back 48

- reduce the amount of sulphur in petrol, diesel and fuel oil and removing acidic gases from power station emissions

- power stations use acid gas scrubbers which takes the harmful gases out before they're released into the atmosphere

- cars are fitted with catalytic converters to clean up exhaust gases

- reduce our usage of fossil fuels

Front 49

what is the mean surface temperature of the Earth?

Back 49

14 degrees

Front 50

how is the temperature of the Earth balanced?

Back 50

there is a balance between the heat it gets from the sun and the heat it radiates back out into space

Front 51

what are the three greenhouse gases?

Back 51

carbon dioxide

methane

water vapour

Front 52

how do greenhouse gases keep the Earth warm?

Back 52

they trap heat energy and help keep the Earth warm and without these gases the surface temperature of the Earth will be -18 degrees

Front 53

describe the process of the greenhouse effect

Back 53

1. the sun rays enter the atmosphere

2. the heat is reflected back onto the earth's surface

3. heat is absorbed by greenhouse gases such as carbon dioxide and becomes trapped in the Earth's atmosphere

4. as a result the Earth becomes hotter

Front 54

why has the concentration of carbon dioxide increased since the 1800's?

Back 54

human activities such as burning fossil fuels and farming

Front 55

how does human activity affect carbon dioxide levels?

Back 55

this is caused by cutting down trees for timbers and to clear land for farming and this increases carbon dioxide because:

1. carbon dioxide is released when trees are burnt to clear land

2. microorganisms feeding on bits of dead wood releases carbon dioxide as a waste product of respiration

3. trees use carbon dioxide for photosynthesis so removing the trees means less carbon dioxide is removed from the atmosphere

Front 56

what are the two ways chemists are trying to reduce carbon dioxide?

Back 56

1. iron seeding

2. converting carbon dioxide into hydrocarbons

Front 57

describe the process of iron seeding

Back 57

this is adding iron compounds to the sea.

iron is an essential nutrient for plant growth and is often short in supply so adding iron compounds makes microscopic plants grow. they use carbon dioxide as they photosynthesis and are eaten by sea creatures so when the sea creatures die and sink to the floor bed the carbonate in their shells are buried which removes carbon from the atmosphere

Front 58

describe the process of converting carbon dioxide into hydrocarbons

Back 58

we can capture carbon dioxide from fossil fuelled power stations and we can react it to make a hydrocarbon compound such as propane and butane. these hydrocarbons can then be used as fuels

Front 59

what are biofuels obtained from?

Back 59

living organisms or organisms that have recently died

Front 60

what do biofuels contains to be used as a fuel?

Back 60

wood and dried animal droppings

Front 61

what can chemists manufacture biofuel from?

Back 61

raw materials

Front 62

ethanol is a type of alcohol which can be used as a fuel but when it burns what are the two products it produces and what is it made of?

Back 62

carbon dioxide and water which is made processing wheat, sugar cane and sugar beet

Front 63

how can ethanol reduce the demand for petrol and conserve crude oil?

Back 63

ethanol can be mixed with petrol to use as a fuel for car engines which helps reduce the demand for petrol and conserve crude oil

Front 64

what is the word equation for ethanol?

Back 64

glucose > ethanol + carbon dioxide

(enzymes)

Front 65

what is a biodiesel?

Back 65

fuel made from vegetable oils by chemical reactions.

Front 66

how can biodiesel be produced?

Back 66

the oil can be produced from oil seed rape or soya beans or used cooking oil from restaurants so diesel engines can run on biodiesel or a mixture of normal diesel oil and biodiesel

Front 67

what are the advantages of biofuel?

Back 67

- trees are always growing so wood will never run out and crops are always grown continuously so they are renewable and plants take in carbon dioxide from the air when they photosynthesis and when plants are burnt the carbon dioxide is returned back into the atmosphere by combustion so a biofuel can be carbon neutral and manure is also cheap and available

Front 68

what do we mean by carbon neutral?

Back 68

does not add or takeaway carbon dioxide from the atmosphere

Front 69

what are the disadvantages of biofuel?

Back 69

energy is needed to fertilise, harvest and process them and transport them to where it is needed and the energy gained is from fossil fuels so it is not entirely carbon neutral when it is manufactured and distributed and if we grow too many crops to make biofuel there will be less farmland for growing food and may lead to forest being cleared for biofuel crops instead

Front 70

in a rocket hydrogen and oxygen burn. what do they produce/form?

Back 70

they form energy

Front 71

how can hydrogen and oxygen react without being burnt to form energy?

Back 71

a fuel cell

Front 72

what does a hydrogen fuel cell produce?

Back 72

it produces electricity to run an electric motor and water will be the only waste product

Front 73

why is hydrogen called a clean fuel?

Back 73

the only waste gas hydrogen forms is water which isn't a pollutant

Front 74

name 5 non renewable fossil fuels:

Back 74

methane, natural gas, kerosene, petrol and diesel which are obtained from crude oil

Front 75

what do non renewable fossil fuels produce when they burn and what will they produce if incomplete combustion occurs?

Back 75

they produce carbon dioxide and water when they burn and if incomplete combustion occurs they will produce carbon monoxide and soot

Front 76

if a fuel contains sulphur what will hit produce when it burns?

Back 76

sulphur dioxide

Front 77

what 3 things make a good fuel?

Back 77

- how easily it burns

- how much energy is produced

- how easy it is to store and transport

Front 78

why are fuels that are easily burnt more dangerous?

Back 78

it is dangerous if they are not stored or transported properly/ safely and because leaking natural gas can cause explosions

Front 79

what do coal and other solid fuels have to be transported by?

Back 79

trains or lorries

Front 80

what do liquid and gas fuels have to be transported by?

Back 80

tankers or pipes

Front 81

why do gases such as methane and hydrogen have to be stored at high pressures?

Back 81

to reduce the size of the tanks when needed to store them

Front 82

definition of a fuel cell

Back 82

electrical cell which is supplied with fuel and oxygen and uses energy from the reaction between them to generate electricity

Front 83

what do buses with hydrogen powered fuel cells produce?

Back 83

it is mainly produced from natural gas so it releases carbon dioxide

Front 84

why are cars not powered with hydrogen powered fuel cells?

Back 84

it has to be economically and easily available in filling stations which means the stations will have to convert to sell and store compressed hydrogen, petrol and diesel but hydrogen will cost more so people will not use cars util hydrogen becomes cheap

Front 85

what is an alkane?

Back 85

saturated hydrocarbons with single carbon bonds and each carbon atom can only bond with a maximum of 4 other atoms

Front 86

what do natural gas contain when it is extracted and how is it processed to houses?

Back 86

hydrocarbon compounds such as methane, ethane and propane, the gas in then processed so that the gas piped to the homes is all mainly methane

Front 87

what are alkanes used as and where are they found?

Back 87

alkanes are used as fuels and are found in crude oil

Front 88

what is the general formula for an alkane?

Back 88

CnH2n+2

Front 89

describe what an alkene is

Back 89

an alkene is an hydrocarbon which contains double carbon atom bonds so they are unsaturated carbon atoms because they have a double bond between the carbon atoms

Front 90

what is the general formula for an alkene?

Back 90

CnH2n

Front 91

describe what the bromine test is and why we do this practical

Back 91

bromine test is used to find out if the compound contains double or single bonds

1. bromine has an orange/brown colour

2. when it is mixed with a saturated hydrocarbon there will be no colour change

3. but if it is mixed with an unsaturated hydrocarbon it will decolorise and the colour will fade away

Front 92

what is bromine water?

Back 92

bromine dissolved in water

Front 93

show the word equation when the alkane ethane is reacted with bromine water

Back 93

ethane (colourless) + bromine water (orange/brown) > no colour change so it remains a orange/brown liquid colour

Front 94

show the word equation when the alkene ethene is reacted with bromine water

Back 94

ethene (colourless) + bromine water (orange/brown) > colourless liquid

Front 95

why is crude oil separated?

Back 95

to produce useful fuels and other products

Front 96

define what is meant by cracking

Back 96

this is when longer hydrocarbons can be split into shorter hydrocarbons by heating them (thermal decomposition) which are more useful

Front 97

where does the energy to heat the alkanes come from?

Back 97

the long chain alkanes are heated and broken up into smaller molecules and the energy to heat the alkanes comes from burning fossil fuels

Front 98

after the process describe what will happen to the numbers of hydrogen and carbon atoms

Back 98

we will have the same number of hydrogen and carbon atoms before and after cracking

Front 99

why are there not enough hydrogen molecules to go around the chain of molecules?

Back 99

this is because the carbon atoms are now in two seperate molecules so there is not enough hydrogen atoms to go around

Front 100

what are alkanes used for?

Back 100

for fuel

Front 101

what are alkenes used for?

Back 101

plastics

Front 102

what do oil companies do to make the supply match the demand?

Back 102

crack the longer molecules

Front 103

describe the practical to show whether they are alkanes or alkenes

Back 103

1. vaporised hydrocarbons are passed over a powdered catalyst at about 400 - 700 degrees and silicon oxide and aluminium oxide are used as catalysts. 2. heat the paraffin and then move the Bunsen burner to the porcelain chips and alternate between the two until the paraffin vaporises and the porcelain glows red. 3. the heated paraffin will then crack as it passes over the heated porcelain. 4. the smaller alkanes and alkenes pass through the delivery tube. 5. the smallest alkanes and alkenes are collected in a gas jar and you can tell if the jar contains an alkene if bromine decolorises

Front 104

describe the polymerisation reaction for alkene

Back 104

this means you join together lots of monomers (small molecules) to form large chain molecules and these large chain molecules are called polymers

Front 105

when ethane polymerises what does it form?

Back 105

polyethene

Front 106

when propene polymerises what does it form?

Back 106

polypropene

Front 107

when chlorine polymerises what does it form?

Back 107

polychlorothene

Front 108

when tetrafluorethene polymerise what does it form?

Back 108

polytetrafluorethene

Front 109

name two polymers which occur naturally

Back 109

proteins and cellulose (found in plant cell walls)

Front 110

explain how polymers are manufactured

Back 110

polymers are manufactured from the products of cracking crude oil

Front 111

what are manufactured polymers called?

Back 111

plastics

Front 112

when an polymerisation reaction occurs what happens to the monomer molecules?

Back 112

the monomer molecules react to form long chain molecules. a polythene can have thousands of carbon atoms so we can also write is short by using a subscript

Front 113

when unsaturated polymers are made what happens to their bonds?

Back 113

the double bonds will open up

Front 114

describe the properties and uses of polyethene

Back 114

-flexible, cheap and an good insulator

- used for plastic bags/bottles, cling film, and an insulator for electrical wires

Front 115

describe the properties and uses of polypropene

Back 115

- flexible, shatterproof, high softening point

- used for buckets and bowls

Front 116

describe the properties and uses of polychlorothene

Back 116

- tough, cheap, long lasting, good insulator

- used for Window frames, gutters, pipes and insulation for electrical wires

Front 117

describe the properties and uses of polytetrafluorothene

Back 117

- tough, slippery, resistant to corrosion, good insulator

- used for saucepans, containers which contain corrosive substances, stain proofing carpets, and an insulator for electrical wires

Front 118

what is the definition of biodegradable?

Back 118

they can rot because microbes can feed on them e.g. wood and paper

Front 119

why are manufactured polymers not biodegradable?

Back 119

this is because they last for a long time and do not rot away when they are thrown

Front 120

where does rubbish go?

Back 120

landfill sites

Front 121

what can be done to rubbish to get rid of them?

Back 121

they can be incinerated (burnt) and the energy released would produce electricity but carbon dioxide is also produced which adds to global warming and toxic gases are produced unless the polymers are burnt at high temperatures

Front 122

toxic gases can be removed but what will this produce?

Back 122

toxic ash which has to be safely disposed of

Front 123

why are chemists trying to develop polymers which are biodegradable?

Back 123

if more plastic materials are made of polymers they will rot but it will take time so we should reduce our usage of plastics

Front 124

how can we reduce using plastics?

Back 124

- recycling and reusing our plastics so they can be processed to make new objects and also so crude oil can last longer

Front 125

why is it difficult to recycle polymers?

Back 125

they need to be sorted into different types of polymers before it can be made into a new object and plastic bottles and packaging materials are marked with a symbol to show what type of plastic it is