Crude oil, Fuels and Organic Chemistry Flashcards
What is Crude oil
A complex mixture of hydrocarbons
How was crude oil formed
From the remains of simple marine organisms over millions of years.
What are hydrocarbons
Compounds that contain carbon and hydrogen atoms only.
What does crude oil consist of
Dozens of hydrocarbons with carbon chains of varying lengths
Through what process are the fractions of crude oil separated?
Fractional distillation
Explain the process of fractional distillation (3)
1) Crude oil is boiled/vaporised before it enters the fraction in column
2) the hydrocarbons present condense at different heights in the column
3) The lower the boiling point, the higher in the column a compound is collected.
What are fractions (in fractional distillation)
Fractions are mixtures containing hydrocarbon compounds (alkanes) that have similar boiling points and therefore similar chain lengths.
What is the order of fractions collected in fractional distillation, highest to lowest, ()
1) petroleum gases
2) gas/petrol
3) naphtha
4) kerosine(paraffin)
5) diesel
6) lubricating oil
7) fuel oil
8) bitumen
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Use of petroleum gases
Bottled gas for portable burners
Use of gasoline/petrol
Fuel for cars
Use of naphtha
Used to make other chemicals, such as plastics
Use of kerosene
Fuel for aircraft
Use of diesel
Fuel for lorries and trains
Use of lubricating oil
Car oil
Use of fuel oil
Fuel for ships and heating buildings
Use of bitumen
Used as the ‘tar’ to make road surfaces
What are the trends in properties of fractions with increasing chain length? (5)
As chain lengths of hydrocarbons present in a fraction increase:
- boiling points increase
- viscosity increases
- ‘ease of ignition” decreases
- cleanliness of burn decreases
- the colour becomes darker
What happens to colour as average hydrocarbon chain length of a fraction increases?
It becomes darker. Colourless –> Yellow —> Brown
What are the environmental impacts of the oil industry? (2)
- Burning fuels causes global warming
- and acid rain
Why is there growing demand for crude oil?
Rapidly growing economies (e.g. in China and India) will consume greater amounts of energy year on year. Crude oil is used to supply that energy (but it is unsustainable in the long term).
What are the economic impacts of growing demand for crude oil? (3)
- It increases the price of crude oil
- it increases individual’s heating and travel costs
- it indirectly causes inflation (e.g. in food prices)
Is crude oil renewable?
No
What are some important uses of components of crude oil (other than fuel)? (3)
- plastics
- medicines
- products
What two options will people have to eventually decide on for the remaining reserves of crude oil?
- burning them
- using it for other purposes (e.g. products)
What element does the combustion of any fuel require?
Oxygen
What elements are produced in the combustion reaction of hydrocarbons? (2)
- Carbon dioxide
- water
Are all combustion reactions endothermic or exothermic?
Exothermic
Describe the steps of a simple experiment to determine the amount of energy released by a fuel? (6)
1) measure the initial mass of the fuel in the spirit burner with a digital balance
2) fill the calorimeter with a known volume of water
3) measure the starting temperature of the water with a thermometer
3) light the flame - burn the fuel
4) measure the final temperature of the water
5) measure the final mass of the fuel
6) record the mass change of the fuel and the temperature change of the water
What is the only product of the combustion reaction of hydrogen?
Water
What is hydrogen used as a fuel for?
It is rocket fuel
What are hydrogen fuel cells used to power nowadays?
Cars
What are the advantages of using hydrogen as a fuel? (2)
- renewable (produced from water)
- does not contribute to global warming or acid rain (water is the only product of its combustion)
What are the disadvantages of using hydrogen as a fuel? (4)
- It requires large amounts of electricity to produce hydrogen from water by electrolysis
- the electricity may be produced by non - renewable fuels that contribute to global warming and acid rain
- storage requires bulky and heavy pressurized containers
- it is potentially hazardous as it forms an explosive mixture with air
What is the fire triangle? (3)
The fire triangle shows the 3 factors required for combustion to occur. It includes:
- oxygen
- heat
- fuel
Where is the fire triangle used? (2)
- In firefighting
- and fire prevention
How can oxygen be removed in a fire? (3)
- fire blanket
- CO2 extinguisher
- sand
How can fuel be removed in a fire? (3)
- non flammable materials
- fuel breaks
- switch off gas
How can heat be removed in a fire? (2)
- water
- damp cloth
What is cracking?
The breaking down of some fractions of crude oil to produce smaller and more useful hydrocarbon molecules.
What is an example of a more useful product that can be made from cracking?
Breaking down larger fractions of crude oil to produce monomers (alkenes) that can be used to make plastics
What does the cracking process involve? (2)
Heating fractions obtained from crude oil to a high temperature in the presence of a catalyst.
Explain the cracking process? (3)
- A high temperature and catalyst are applied to the fraction (obtained from crude oil)
- this causes the hydrocarbon molecules present to decompose
- this forms smaller molecules, including an alkene
What hydrocarbons are the a greater demand for - smaller or larger?
Smaller
Why is there a greater demand for smaller hydrocarbons? (2)
There is a greater demand for smaller hydrocarbons because they are more useful and alkenes such as ethene are the starting material for the production of many plastics.
What is the general formula for alkenes?
CnH2n
(n represents the number of carbon atoms)
What is the general formula for alkanes?
CnH2n+2
(n represents the number of carbon atoms)
What is molecular formula
A formula that shows the number of each type of atom present in a molecule.
How many bonds must carbon atoms always have?
4
What is an alkane? (2)
A hydrocarbon that contains single bonds between the carbon atoms only (and is said to be saturated).
What is an alkene?
A hydrocarbon that contains a double covalent bond between two carbon atoms (and is said to be unsaturated)
How many carbon atoms does methane have?
1
How many carbon atoms does ethane have?
2
How many carbon atoms does propane have?
3
How many carbon atoms does butane have?
4
How many carbon atoms does pentane have?
5
What is the molecular formula for methane?
CnC2n+2
CH4
What is the molecular formula for ethane?
CnH2n+2
C2H6
What is the molecular formula for propane?
CnH2n+2
C3H8
What is the molecular formula for butane?
CnH2n+2
C4H10
What is the molecular formula for pentane?
CnH2n+2
C5H12
How many carbon atoms are in ethene?
2
How many carbon atoms are in propene?
3
What is the molecular formula for ethene?
CnH2n
C2H4
What is the molecular formula for propene?
CnH2n
C3H6
What is isomerism?
When compounds have the same molecular formula but different structural formulas.
What are all the isomers of C4H10?
- Butane
- 2-methyl propane
What are all the isomers of C5H12
- Pentane
- 2-methyl butane
- di-methyl propane
What is the basis of a hydrocarbon molecules’ name (e.g. pent) based on?
The longest continuous chain of carbon atoms
how do you decide what number an ‘ene’ is in hydrocarbons (e.g. but-1-ene or but-2-ene)?
the carbon atoms in the longest chain are numbered. You count from the side closest to the double bond (the double bond is the functional group). If the double bond is between 1 and 2 it is ‘1’. If it is between 2 and 3 it is ‘2’
what are the 2 alkyl’s that can be found in isomers of hydrocarbons?
- ethyl
- methyl
what is a ‘methyl’
CH3
- acts as a side chain/branch in hydrocarbon isomers.
what is an ‘ethyl’
C2H5
- acts as a side chain/branch in hydrocarbon isomers
What are the isomers of C4H8?
- But-1-ene
- But-2-ene
- 2-Methylprop-1-ene
what is the product of the addition reaction between an alkene and hydrogen?
an alkane
Write the balanced molecular formulae for the addition reaction of ethene and hydrogen?
C2H4 + H2 —> C2H6
What is the product of the addition reaction between an alkene and bromine?
A Bromoalkane
What colour is a bromoalkane?
Colourless
What is used to test for alkenes?
Bromine water
Why is bromine WATER used to test for alkenes? (2)
It is:
- safer and
- easier to handle
than bromine
What shows that a substance is an alkene in the bromine water test for alkenes?
The bromine water turns from orange/brown to colourless when added to an alkene
What happens in terms of structure in the addition reactions of hydrogen and bromine with alkenes? (2)
- one hydrogen or bromine atom is added to each of the carbon atoms across the C=C bond
- the unsaturated compound forms a saturated compound
what colour does an alkane turn when added to bromine water? (2)
- There is no change
- It stays orange/brown
What are monomers?
Small, reactive molecules that can be joined together to make a polymer
What is polymerization?
The process by which small, reactive molecules called monomers are joined together to make a polymer.
What is more reactive - an alkane or alkene?
Alkenes
Why are monomers (alkenes) reactive?
They have a double bond present between 2 carbon atoms.
How does polymerisation occur?
One of the bonds in the double bond between the two carbon atoms breaks in the monomer. This allows the molecule to join to another to form a polymer.
What does ethene polymerise to form?
Polythene
What does propene polymerise to form?
Poly(propene)
What does vinyl chloride polymerise to form?
Poly(vinyl chloride)
What does tetrafluoroethene polymerise to form?
poly(tetrafluoroethene)
What are the general properties of plastics? (6)
- flexible
- strong
- good thermal and electrical insulators
- resistant to corrosion
- low density
- do not rot.
What is polythene used for? (2)
- bags
- plastic bottles
What is poly(propene) used for? (2)
- Ropes
- Crates
What is poly(vinylchloride) used for? (2)
- Drainpipes
- Window frames
What is poly(tetrafluoroethene) used for?
Non - stick pans
Why is disposal of plastics in a landfill not ideal?
Landfill sites are rapidly being filled and any plastic items will not decompose for hundreds of years.
Why is burning plastics not a good method of disposing plastics?
Carbon dioxide gas and various toxic fumes are released when plastics burn.
Why is recycling waste plastic an ideal solution to disposal of plastics? (3)
- It reduces the amount of waste either ending up in landfill or being burned.
- because recycling uses less energy than production it reduces fossil fuel use,
- conserving crude oil reserves.
What are the environmental issues relating to the disposal of plastics? (2)
They are:
- non - biodegradable
- increasing pressure on landfill for waste disposal
What is the best way to address the issue of plastic disposal?
Recycling
By what processes is alcohol made from by sugars?
Fermentation
How does yeast assist in fermentation? (2)
It contains an enzyme that brakes down sugar (making ethanol and carbon dioxide)
What are the products of fermentation? (2)
- ethanol
- carbon dioxide
What are the reactants in fermentation?
Glucose (sugar)
Represent the fermentation reaction with a balanced symbol equation?
C6H12O6 —> 2C2H5OH + 2CO2
Represent the fermentation reaction with a balanced word equation?
glucose —> ethanol + carbon dioxide
What conditions are used in the fermentation process? (4)
- anaerobic conditions (no oxygen present)
- temperature kept at around 35o C
- Mixture of yeast and glucose in water
- pH in the range of 4-7 (weakly acidic)
How are spirits such as whiskey in the alcoholic drinks industry produced by fermentation products?
The fermentation products are distilled to produce spirits
What is done to the fermentation products to increase the concentration of ethanol?
They are distilled
is fermentation of sugars with yeast the most efficient method of producing ethanol for industrial uses? (2)
- No
- More efficient methods have been developed
What substance can be used to test for alcohols?
potassium dichromate(VI)
What colour does acidified potassium dichromate(VI) solution change from and to in the presence of an alcohol?
From orange to green
What colour does acidified potassium dichromate(VI) solution change from and to in the presence of no alcohol? (2)
- There is no change
- It remains orange
What was the reaction between potassium dichromate(VI) and alcohol previously used for?
it was the basis of a breathalyser test.
What is ethanol used in, in the consumer industry?
alcoholic drinks
What are the uses of ethanol, other than in alcoholic drinks? (2)
- fuel
- solvent
What is able to dissolve in ethanol?(2)
- Many substances
- including some that are insoluble in water
What is bioethanol produced from?
Plants such as sugar cane in some countries
What is an alternative fuel source similar to crude oil/petrol?
Bioethanol fuel
What are the benefits of bioethanol as an alternative fuel to fuels from crude oil? (3)
- renewable
- carbon neutral
- it releases less carbon monoxide and soot than fossil fuels when burned
What are the drawbacks of bioethanol as an alternative fuel to fuels from crude oil? (4)
- it decreases the amount of land available to grow food crops
- food poverty and deforestation
- sugar growth depends on the climate
- it releases less energy per gram than fossil fuels
What are the social and health problems associated with ‘binge drinking’? (5)
- aggressive behaviour
- domestic violence
- road accidents (drink-driving)
- memory loss
- increased strain on emergency services (other people suffer)
What are the social and health issues associated with misuse of alcohol over a long period? (5)
- liver/kidney damage
- heart disease
- depression
- cancer
- job loss
What is the current advice regarding ‘healthy’ limits about the maximum number of units of alcohol that should be consumed per week?
14 units a week for men and women
What is the economic advantage of alcoholic drinks?
Tax raised from the sale of alcoholic drinks generates significant revenue for the government
What is the economic disadvantage of alcoholic drinks?
a significant amount of public money is spent each year in treating alcohol-related illnesses and in dealing with various other issues, resulting from alcohol abuse.
What is the general formula for alcohols?
CnH(2n+1)OH
What are the names of alcohols derived from?
Their corresponding alkanes
What is the name of CH(3)OH?
Methanol
What is the name of C2H5OH?
Ethanol
What is the name of C3H7OH?
Propanol
What is the name of C4H9OH?
Butanol
What is the name of C5H11OH?
Pentanol
What is the functional group in an alcohol?
The -OH group
What is positional isomerism?
When the functional group of a molecule moves to a different position on the chain of carbon atoms
What is chain isomerism?
When the main carbon chain of a molecule is shortened and an alkyl side-chain (ethyl or methyl) is present as a branch from the main chain.
By what process is ethanol made into ethanoic acid?
microbial oxidation
What is a homologous series?
A group of organic compounds that share the same functional group/are represented by the same general formula/have similar properties
What homologous series does ethanoic acid belong to?
carboxylic acids
What is the pace of the microbial oxidation reaction of ethanol?
Slow - a few days
What is the result of the microbial oxidation of ethanol reaction in the alcoholic drinks industry?
It leads to beer and wine ‘going off’ once left exposed to the air for a period of a few days.
Can alcohols other than ethanol can be oxidised? (Give an example)
- yes
- e.g. propanol to propanoic acid
How does oxidation affect the formula of alcohols?
There is a greater proportion of oxygen and a lower proportion of hydrogen
What is the formula of ethanoic acid?
CH3COOH
What functional group do all of the carboxylic acids contain?
-COOH
What structural and molecular changes are made during microbial oxidation of alcohols?
- 2 hydrogens are removed from 1 carbon atoms
- 1 oxygen is added to this carbon atom (with a double bond)
How can the presence of certain bonds in organic molecules be identified?
Infrared spectroscopy
What does infrared spectroscopy enable us to do?
Identify whether molecules are alkanes, alkenes, alcohols or carboxylic acids based on the bonds present
Describe a method to determine the amount of energy released by a fuel? (8)
- Measure 100 cm3 of water into the conical flask.
- Clamp the flask at a suitable height so the spirit burner can be placed below it.
- Record the temperature of the water.
- Record the mass of the spirit burner (including the lid and alcohol).
- Place the spirit burner under the conical flask and light it.
- Allow the burner to heat the water until the temperature rises by about 40 °C. Record
the temperature of the water. - Extinguish the flame carefully and record the mass of the burner.
- Repeat steps 1-7 with each of the other alcohols.
What are the hazards in an experiment to determine the amount of energy released by a fuel (alcohol)? (2)
- Alcohols are highly flammable
- The hot flask could burn
What are the risks in an experiment to determine the amount of energy released by a fuel (alcohol)? (2)
- alcohol could ignite if left near a naked flame
- Burning could result if hot beaker handled
What are the control measures in an experiment to determine the amount of energy released by a fuel (alcohol)? (2)
- ensure spirit burners are kept away from lit bunsen burners
- allow hot beaker to cool before disassembling apparatus