Book 3A: Fossil Fuels and Carbon Compounds Flashcards
Fractional distillation of petroleum - fractions
- Refinery gas - Liquified petroleum gas (LPG) as domestic fuel and fuel for taxis (mainly butane); raw materials for manufacturing chemicals
- Petrol - motor car fuel
- Naphtha - raw materials for town gas
- Kerosene - jet plane fuel, domestic fuel
- Diesel oil - fuel for bus, lorries and factories
- Fuel oil - burnt to generate energy in power plants, fuel in power stations and factories
- Lubricating oil - lubricating oil for machines, candle waz
- Bitumen - surfacing roads and roofs
Describe the process of fractional distillation of petroleum
- Petroleum is heated in a furnace and led into a fractionating column
- Vapours of hydrocarbons rise up along the fractionating tower which is cooler at the top
- Vapours of fractions with higher boiling pints condense into liquids and flow to the bottom
- Vapours of fractions with lower boiling points go up the tower
Importance of fractional distillation of petroleum
Separates crude oil into different fractions
- fuels for different purposes
- raw materials for manufacturing different chemicals
Advantages and disadvantages of using nuclear power (non-renewable energy!!)
Advantages:
- small amount of radioactive source can produce a large amount of energy
- cheaper in the long run
- produces less air pollutants
- cleaner fuel
Disadvantages:
- difficult to treat the waste
- expensive to set up nuclear power plant
- leakage of radioactive source may cause cancer
Define cracking (HKCEE)
Breaking down of large hydrocarbon molecules into small hydrocarbon molecules by heat with the help of a catalyst
endothermic process
Why shouldn’t the glass wool soaked with the large hydrocarbon be heated directly in cracking?
- the large hydrocarbon is a fuel - may catch fire upon direct heating
- the large hydrocarbon may vapourize and directly pass into the delivery tube without being cracked
Why is broken unglazed porcelain, instead of a large piece of unglazed porcelain, used?
- surface area of broken unglazed porcelain > surface area of a large piece of unglazed porcelain
- higher surface area → higher rate of rxn
Why is the first tube of gaseous products not collected?
Mainly air from the boiling tube
Cracking: Why is there an oil layer?
- Liquid products formed by cracking
- Unreacted naphtha, kersene and paraffin, etc.
what should be done in cracking after no gas can be collected
remove the delivery tube before heating is stopped
(reason: to prevent cracking of the boiling tube due to sucking back of water)
importance of cracking
- produce extra petrol to meet the increasing demand of petrol
- source of alkene to make synthetic polymer
‘Tetrafluoroethene undergoes polymerization to form ‘Teflon. Using this example, describe this type of polymerization.
Additional polymerization
- Compounds with C-C double bonds / C=C bonds can undergo addition polymerization
- No small molecules will be eliminated
-** High temperature, high pressure and catalyst are used**d
- Structure of the monomer + the polymer
Alternative of broken unglazed porcelain as the catalyst in cracking
aluminium oxide (Al2O3)
Substitution reaction: definition
an atom / a group of atoms in a molecule is replaced by another atom/ group of atoms
What should be done if sunlight should be used to start a substitution reaction?
Use diffused sunlight instead of direct sunlight
Other vigorous reactions other than substitution will occur
Is substitution reaction a good method to priduce desired CHBr3 from CH4 and Br2?
No because the product is a mixture of different molecules (e.g. CH3Br, CH2Br2, C2H6)
