Topic 5 - Fuels Flashcards
How is crude oil extracted?
By drilling and pumping
How is crude oil formed?
It is formed from the remains of plants and animals which over millions of years with high temperature and pressure the remains turn into crude oil.
What are hydrocarbons
Something that only consists of hydrogen and carbon
How is crude oil separated into different fractions
Fractional distillation. The crude oil is piped in the bottom of the fractionating column. This is heated and the vaporised oil rises up the column on the various fractions are constantly tapped off at different levels where they condense
What compound is crude oil made of?
Mixture of Hydrocarbons
Are shorter or longer molecules more flammable
Shorter
Does the number of carbons increase or decrease as you go up the fractionating column
Decrease
What hydrocarbons are produced by fractionating column and what are their uses?
Gasses - used for cooking and heating
Petrol - fuel for cars
Kerosene - used as an aircraft fuel
Diesel - used as fuel for lorries, trains, and some cars
Fuel oil - fuel for ships and in some power stations
Bitumen - used to surface roads
Are shorter molecules less viscous or more viscous
Less viscous
Complete combustion only happens when ……?
There is plenty of oxygen
What is produced by complete combustion?
Carbon dioxide and water
What is oxidisation ?
When oxygen is added to an element
Incomplete combustion happens when….?
There isn’t enough oxygen
Is incomplete combustion safe?
No
What does incomplete combustion produce?
water and carbon monoxide
What colour flame is complete combustion?
Blue
What colour flame is incomplete combustion
Smoky yellow
Which type of combustion produces more energy
Complete combustion
What are the properties of carbon monoxide?
Colourless
Odourless
Very toxic
What is the symbol for carbon monoxide?
CO
What are the two main things that burn fossil fuels?
Power stations ( making electricity) Cars
What gas is put in the air by cars?
Sulphur impurities are in petrol and diesel so sulphur dioxide is put into the air.
What does sulphur dioxide cause?
Acid rain
What damage does acid rain do?
Acid rain cause lakes and rivers to become acidic which kills plants and animals.
It also damages limestone buildings and stone statues.
How does the earth control its temperature
The temperature of the earth is a balance between the heat from the sun and the heat it radiates back into space. Gases in the atmosphere such as carbon dioxide water vapour and methane act like a layer of insulation and stop some of the radiating into space.
What can be done to reduce the amount of damage by acid rain?
Remove sulphur from fuels so there is less acid rain
Acid gas scrubbers in power stations (limestone removes it)
Cars are fitted with catalytic converters to clean up exhaust gases.
Reduce the amount of fossil fuels we use.
How does human activity effect the temperature of the earth?
We affect the amount of greenhouse gases by deforestation, burning fossil fuels and other things. This increases the amount of green house gases, heating up the earth.
What can we do to slow down the build up of greenhouse gasses?
Stop chopping down trees
Reduce the amount of fossil fuels we burn
Iron seeding
Converting waste carbon dioxide into hydrocarbons.
What is iron seeding?
Plants need iron for photosynthesis. By injecting iron into the upper ocean you promote the growth of phytoplankton. These blooms of phytoplankton absorb carbon dioxide from the atmosphere for photosynthesis.
What kind of bonds Do alkanes have
Single
What kind of bonds do alkenes have
Double
Which type of hydrocarbon is saturated
Alkanes
Which type of hydrocarbon is more reactive
Alkenes
Which type of hydrocarbon creates polymers
Alkenes
How many bonds does a carbon have in a hydrocarbon
4
How many bonds does a hydrogen have in a hydrocarbon
1
What would the hydrocarbon methane (CH4) look like
H
|
H-C-H
|
HWhat would ethene (c2h4) look like
H H | | C=C | | H H
Why are alkenes more reactive?
Because they have a double bond there is a space bond so other elements can join
What is the ending to the name of a alkane for example prop____
PropANE
What is the ending to the name of an alkene for example prop____
PropENE
What is cracking?
Cracking is a from of thermal decomposition which just means breaking molecules down into simpler molecules by heating them. Using this method you can shorten hydrocarbons to make them into something more useful.
Why is cracking important
There is more of a demand for shorter hydrocarbons do we need to shorten some. Also it produces alkenes which can be used to make plastics.
What are some uses of polyethene
It’s stretchy and light so can be used to make plastic bags hose pipes and laminating paper
What are some uses of polypropene
It is tougher flexible so can be used to make thermal underwear, carpets and plastic containers.
What can poly(tetrefluoroethene) (PTFE) be used to make
It’s unreactive flame resistant and very resistant to wear. It can be used as a non stick coating for pans.
What are some uses of polychloroethene (PVC)
It’s flexible and resistant to wear so can be used for clothing electric cables and pipes
Why are plastics hard to get rid of
They are non-biodegradable which means they aren’t broken down by microorganisms so they don’t rot.
If you burn some plastics they give off toxic gases.
It’s best to recycle them as this conserves resources.
What are biofuels?
fuels used for transport such as bioethanol or biodiesel that are made from biomass materials. These fuels are usually blended with fuels made from crude oil but can be used on their own.
What are the advantages of biofuels?
Biodiesel burns in an ordinary diesel engine with them having to be modified.
Bioethanol burns cleanly and the waste from manufacturing can be used as food for livestock.
they are a renewable energy source.
they don’t contain sulfur so don’t cause acid rain.
Carbon neutral
What are the disadvantages of biofuels?
Petrol engines need to be converted.
Transporting it and using farm machinery to harvest them increases the net CO2 released.
Large areas of tropical forest are being cleared to grow crops.
An increase in the growth of biofuels means less land is available for food.
What are the properties of a good fuel
burning considerations, usage, supply, products
Exam mark scheme
Burning considerations
• ignite easily
• burn easily
• release a lot of /sufficient heat energy when it
is burnt
Usage considerations
• be safe to use
• be safe/easy to transport
• be {safe/easy/convenient} to store
• be reasonably cheap
Supply considerations
• readily available/good supply
• be renewable/sustainable/not finite
Products considerations
• not produce (much) solid/ash when burnt
• not produce much/any smoke
• contain little/no sulfur
• not produce {toxic/harmful} gases/fumes
• carbon neutral
• not produce too much carbon dioxide or other
named gas such as sulfur dioxide or greenhouse
gases
What is biogas made by?
microorganisms. They are used to decompose living organisms’ waste or dead plants to create biogas which can be used as a fuel.
How can biogas be used?
It can be burned to heat water, used in central heating systems, power a turbine, used as a fuel for cars and buses.
What is an advantage of biogas over fossil fuels?
It is renewable. The plants which are decomposed can be replaced quickly. Carbon neutral Clean fuel Cheap Readily available
What does ethanol produce when used as a fuel?
Carbon dioxide and water
How is ethanol produces?
using yeast to ferment sugars
What percentage of ethanol is in gasohol?
10%
Where are good places to use gasohol?
where there is plenty of fertile land and good weather for growing crops.
What are the advantages and disadvantage of using gasohol?
Advantage: less crude oil being used, carbon neutral
Disadvantage: lots of land needed to grow crops so not as much room for food. Uses a lot of energy.
What do hydrogen and oxygen react to produce?
water and energy
What is a fuel cell?
An electrical cell thats supplied with a fuel and oxygen and uses energy from the reaction between them to generate electricity.
What are the advantages of hydrogen-oxygen fuel cells?
80% efficient
FC: electricity generated directly from reaction.
Not much energy lost as heat.
No moving parts so energy isn’t lost through friction.
Doesn’t produce any conventional pollutants
What are the disadvantages of hydrogen-oxygen fuel cells
Hydrogen is a gas so takes up more space to store than liquid fuels.
Explosive
Hydrogen fuel is often made from hydrocarbons (from fossil fuels) or by electrolysis of water (which uses electricity that is often created by using fossil fuels)
