Topic 5: Crude Oil, Fuels and Organic Chemistry Flashcards
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What is organic chemistry?
The chemistry of carbon-bases compounds.
What is crude oil?
A mixture of hydrocarbons formed from the remains of marine organisms over millions of years.
What are hydrocarbons?
Organic compounds containing only hydrogen and carbon.
What is fractional distillation?
A way of separating out different ‘fractions’ of the crude oil.
What is a fraction?
A component of crude oil, with its own particular molecular composition, weight and boiling point.
What are the 4 steps of fractional distillation? (summarised)
- Oil heated, gaseous mixture created.
- Put into fractional distillation column = very high temperatures.
- Extraction and condensing of gases/liquids.
What are the 4 properties of hydrocarbons at the top of the column?
Small molecules
Low B.P
Ignite easily
Less dense
What are the properties of hydrocarbons at the bottom of the column?
Large molecules
High B.P
Do not ignite easily
Viscous
What are 2 economic and political factors of crude oil?
Price of crude oil controlled by oil companies, which influences the economy
War in an oil-producing country restricts crude oil supplies (like Russia right now)
What are 4 social and environmental factors of crude oil?
Poorer countries deprived of oil - electricity and heat
Lots of jobs provided
Lots of CO₂ produced
oil spillages may kill habitats
What is cracking?
The breaking down of covalent bonds in large chain hydrocarbons to produce shorter chains.
What are 2 reasons why is cracking used?
Smaller chains have better properties as they are better fuels.
They can also produce monomers for plastic.
What are the conditions of cracking?
600-700°C
Catalyst - silica/aluminia
What is a fuel?
A combustable substance that reaction with oxygen (in the air) to release useful energy (exothermic).
What is the equation for complete combustion?
hydrocarbon + oxygen -> carbon dioxide + water
(eg) CH₄ + 2O₂ -> CO₂ + H₂O
What happens in incomplete combustion?
Carbon monoxide is produced as well.
It is poisonous and produces acid rain so we don’t want this.
What is the equation for measuring the energy released by fuel?
Energy transferred (J) = mass of water heated (g) x 4.2 x temperature rise (°C)
What is the benefit of hydrogen fuel?
Only produces water when burned:
2H₂ + O₂ -> 2H₂O
What are 3 disadvantages to hydrogen fuel?
Must be reacted with coal/neutral gas = not carbon neutral
Hydrogen = flammable
Must be stored in chilled + compressed conditions
What is the fire triangle?
The factors required to make fire: oxygen, heat, fuel.
How is oxygen removed from a fire?
Smothering the fire/ replacing O with CO₂
How is heat removed from a fire?
Water - not on oil/electric fires though
How is fuel removed from a fire?
Getting rid of it (like cutting down trees in a forest fire).
Or have material coated in non-flammable materials (like certain types of chemicals in clothes).
What is the 4 step method to calorimetry?
- Cold water measured into copper calorimeter (small metal can)
- Starting temperature of water recorded
- Water heated using Bunsen burner
- Final temperature of water recorded.
What is an alkane?
A saturated hydrocarbon - only single bonds.
What is the general formula for alkanes?
CₙH₂ₙ +₂
What are the first 5 first names for hydrocarbons?
Meth - 1 Eth - 2 Prop - 3 But - 4 Pent - 5
What is an alkene?
An unsaturated hydrocarbon - contain a double bond.
What is the general formula for alkenes?
CₙH₂ₙ
How do you name complex alkanes and alkenes?
- How many carbons in longest chain (meth, eth , prop)
- If/where double bond is (but-1-ene, but-2-ene)
- Number of carbon atoms in branch/branches (methyl, ethyl)
- More than one branch = use prefixes (di=2 tri=3)
- Position of branch (which carbon it is extending from)
What is the test for alkenes?
Bromide water = orange solution
Becomes colourless when shaken if alkene is present.
What are addition reactions?
A reaction in which the presence of a carbon double bond can allow other atoms to be added to the molecule.
What is isomerism?
Two or compounds can have the same molecular formula but different structural formulae, because the atoms are arranged differently.
What is a thermoplastic?
A plastic which soften when heated.
What is a thermoset?
A plastic resistant to heat and do not soften.
What are 3 examples of polymers?
Polythene, polypropene, polytetrafluoroethene (PTFE).
What is a plastic?
Any synthetic/semi-synthetic organic polymer.
What is a monomer?
Small molecules (like ethene) that are very reactive, containing a double bond.
What is a polymer?
A long chain of monomers joined together.
What are addition polymers?
Polymers made from 1 type of monomer.
What are condensation polymers?
Polymers made from 2 or more different types of monomers.
What is polymerisation?
The double bond of a monomer opens up and the units repeat themselves (and join together).
What is the environmental problems of plastics?
Non-biodegradable.
What are the advantages of plastics being reused?
Less plastic goes to landfill
Less oil used for plastic production (crude oil = finite)
Less energy consumed
What is an alcohol?
A homologous series of organic compounds (similar properties to alkanes and alkenes).
What is the general formula for alcohols?
C₂H₂ₙ ₊ ₁OH
What are some examples of alcohol abuse?
Cause of 10% of disease + death in UK
3rd most dangerous lifestyle factor
Alcohol misuse = cost £21 billion in healthcare, crime and lost productivity.
What is a benefit of alcohol?
It can be used in other industries other than the drinking industry too (especially ethanol).
What is fermentation and its equation?
The creation of ethanol from plant material.
C₆H₁₂O₆ -yeast+> 2C₂H₅OH + CO₂
glucose -yeast> ethanol + carbon dioxide
What are the conditions for fermentation?
Temperature - 25-50°C
Anaerobic
Sterile
What are biofuels?
Renewable fuels produced by natural products like plants containing carbohydrates.
What are 3 advantages of bioethanol?
Renewable
Less CO₂ produced than petrol
Less soot + CO
What are 4 disadvantages of bioethanol?
Less efficient
Modification of vehicles must be done
Lots of farmland needed
Process uses fossil fuels - not completely carbon neutral
How is vinegar made?
Ethanol forms ethanoic acid (found in vinegar) by oxidation.
C₂H₅0H -oxidation> CH₃COOH
What is the test for alcohols?
Solution: potassium dichromate + sulfuric acid
Add alcohol, gently heat
Solution=orange
Green colour change=alcohol present
