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125 Cards in this Set

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what is petrol obtained from?

crude oil

describe the texture of crude oil

thick, black sticky liquid

where is crude oil found?

sedimentary rocks

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

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

how is oil or gas formed?

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

what is crude oil?

a mixture of different hydrocarbon molecules

what is a hydrocarbon?

compound that contains only hydrogen and carbon atoms

what do different hydrocarbons in crude oil have?

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

what impurity does crude oil contain?

sulphur

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

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

how are most oils obtained?

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

why is crude oil not easy to use?

contains hydrocarbons which are mixed together

where is crude oil sent for fractional distillation?

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

what is the definition of distillation?

process used to separate mixtures of different liquids

how are fractions produced?

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

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

gases


petrol


naptha


kerosene


diesel


fuel oil


bitumen

what are gases used for?

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

what is petrol used for?

fuel for cars

what is naphtha used for?

fluid in chemical industry

what is kerosene used for?

used as an aircraft fuel

what is diesel used for?

diesel engines

what is fuel used for?

heating and lubricating oils

what is bitumen used for?

making roads

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

higher

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

shorter

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

top

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

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

what is combustion?

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

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

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

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

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

what is the equation for complete combustion?

hydrocarbon + oxygen > carbon dioxide + water




this shows the reaction has been oxidised

when all hydrocarbon fuel burn what do they produce?

carbon dioxide and water only if there is enough oxygen

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

methane + oxygen > carbon dioxide + water


CH4 + 202 > CO2 + 2H20

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

blue

why does incomplete combustion happen?

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)

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

methane + oxygen > carbon + water


methane + oxygen > carbon monoxide + water


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

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

how much oxygen is available

what does carbon appear as in a bonfire?

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

what are the problems associated with carbon monoxide?

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

what are the two ways we can prevent carbon monoxide?

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

what are the problems with soot?

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

what is the equation for incomplete combustion?

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

where does pollution come from?

factories and power stations

what are the problems with acidic rain?

it kills fishes and other aquatic life in rivers and seas

why is rainwater slightly acidic?

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

describe the process of rainwater becoming acidic

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

what are the effects of acid rain?

- 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

what are the solutions of acid rain?

- 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

what is the mean surface temperature of the Earth?

14 degrees

how is the temperature of the Earth balanced?

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

what are the three greenhouse gases?

carbon dioxide


methane


water vapour

how do greenhouse gases keep the Earth warm?

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

describe the process of the greenhouse effect

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

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

human activities such as burning fossil fuels and farming

how does human activity affect carbon dioxide levels?

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

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

1. iron seeding


2. converting carbon dioxide into hydrocarbons

describe the process of iron seeding

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

describe the process of converting carbon dioxide into hydrocarbons

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

what are biofuels obtained from?

living organisms or organisms that have recently died

what do biofuels contains to be used as a fuel?

wood and dried animal droppings

what can chemists manufacture biofuel from?

raw materials

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?

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

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

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

what is the word equation for ethanol?

glucose > ethanol + carbon dioxide


(enzymes)

what is a biodiesel?

fuel made from vegetable oils by chemical reactions.

how can biodiesel be produced?

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

what are the advantages of biofuel?

- 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

what do we mean by carbon neutral?

does not add or takeaway carbon dioxide from the atmosphere

what are the disadvantages of biofuel?

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

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

they form energy

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

a fuel cell

what does a hydrogen fuel cell produce?

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

why is hydrogen called a clean fuel?

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

name 5 non renewable fossil fuels:

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

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

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

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

sulphur dioxide

what 3 things make a good fuel?

- how easily it burns


- how much energy is produced


- how easy it is to store and transport

why are fuels that are easily burnt more dangerous?

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

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

trains or lorries

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

tankers or pipes

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

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

definition of a fuel cell

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

what do buses with hydrogen powered fuel cells produce?

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

why are cars not powered with hydrogen powered fuel cells?

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

what is an alkane?

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

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

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

what are alkanes used as and where are they found?

alkanes are used as fuels and are found in crude oil

what is the general formula for an alkane?

CnH2n+2

describe what an alkene is

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

what is the general formula for an alkene?

CnH2n

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

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

what is bromine water?

bromine dissolved in water

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

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

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

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

why is crude oil separated?

to produce useful fuels and other products

define what is meant by cracking

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

where does the energy to heat the alkanes come from?

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

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

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

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

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

what are alkanes used for?

for fuel

what are alkenes used for?

plastics

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

crack the longer molecules

describe the practical to show whether they are alkanes or alkenes

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

describe the polymerisation reaction for alkene

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

when ethane polymerises what does it form?

polyethene

when propene polymerises what does it form?

polypropene

when chlorine polymerises what does it form?

polychlorothene

when tetrafluorethene polymerise what does it form?

polytetrafluorethene

name two polymers which occur naturally

proteins and cellulose (found in plant cell walls)

explain how polymers are manufactured

polymers are manufactured from the products of cracking crude oil

what are manufactured polymers called?

plastics

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

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

when unsaturated polymers are made what happens to their bonds?

the double bonds will open up

describe the properties and uses of polyethene

-flexible, cheap and an good insulator


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

describe the properties and uses of polypropene

- flexible, shatterproof, high softening point


- used for buckets and bowls

describe the properties and uses of polychlorothene

- tough, cheap, long lasting, good insulator


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

describe the properties and uses of polytetrafluorothene

- tough, slippery, resistant to corrosion, good insulator


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



what is the definition of biodegradable?

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



why are manufactured polymers not biodegradable?

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

where does rubbish go?

landfill sites

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

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

toxic gases can be removed but what will this produce?

toxic ash which has to be safely disposed of

why are chemists trying to develop polymers which are biodegradable?

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

how can we reduce using plastics?

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

why is it difficult to recycle polymers?

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