Fuels Flashcards
What are hydrocarbons
Compounds containing hydrogen and carbon only
What are the six useful compounds that can be separated from crude oil called
Gases Petrol Kerosene Diesel oil Fuel oil Bitumen
How are the many useful compounds in crude oil separated
Fractional distillation
What is crude oil
A FINITE RESOURCE which is FOUND IN ROCK, produced from the REMAINS OF ANCIENT BIOMASS. It is a complex mixture of HYDROCARBONS and the molecules are ARRANGED IN CHAINS OR RINGS
How can crude oil be separated by fractional distillation
Because the hydrocarbons have different boiling points
What is used to separate crude oil into fractions
A FRACTIONATING COLUMN- a tall column in which the temperature decreases from bottom to top
What is it called when hydrocarbons have no double bonds
Saturated
What is a homologous series
A family of compounds with SIMILAR CHEMICAL PROPERTIES and GRADUAL VARIATION IN PHYSICAL PROPERTIES.
They have the SAME GENERAL FORMULA with successive members DEFERRING IN MOLECULAR FORMULA BY CH2
What is the general formula of an alkane
Cn H(2n+2)
What is complete combustion
When hydrocarbons burn in excess air to produce carbon dioxide and water ONLY
What is an oxidation reaction
When the hydrocarbons react with the oxygen in the air
What is the generic equation for complete combustion
Hydrocarbon + oxygen ————>carbon dioxide + water
When balancing an equation what order should you balance the elements
Carbon then…
Hydrogen then…
Oxygen
(Never change the little numbers)
Give the generic equation for incomplete combustion
Hydrocarbon + oxygen ————>carbon + carbon monoxide + carbon dioxide + water
What is INCOMPLETE combustion
Occurs when there is a limited supply oxygen
Water is still produced but carbon and carbon monoxide are formed as well as carbon dioxide
The greater the number of carbon atoms in a molecule…..
The greater the boiling point
The bigger the molecule…
The stronger the intermolecular forces
Give a use of GASES (a fraction from crude oil)
Domestic heating and cooking
Give a use of PETROL (a fraction from crude oil)
Fuel for cars
Give a use of KEROSENE (a fraction from crude oil)
Fuel for aircraft
Give a use of DIESEL OIL (a fraction from crude oil)
Fuel for some cars and trains
Give a use of FUEL OIL (a fraction from crude oil)
Fuel for large ships and power stations
Give a use of BITUMEN (a fraction from crude oil)
Surfacing roads and roofs
What is the test for the presence of an alkene
Bromine water:
If an alkene ISN’T present it stays orange
If an alkene IS present it goes colourless
What is the order of the alkanes
Methane
Ethane
Propane
Butane
What is cracking
The breaking down of longer chain hydrocarbons into shorter chain hydrocarbons
Are ALKANES saturated or unsaturated
Saturated and covalent
Are ALKENES saturated or unsaturated
Unsaturated and covalent
Describe the trend in number of atoms in molecules from GASES TO BITUMEN
Increases 
Describe the trend in boiling point from GASES TO BITUMEN
Increases
Describe the trend in ease of ignition from GASES TO BITUMEN
Becomes more difficult to ignite
Describe the trend in viscosity from GASES TO BITUMEN
Viscosity increases (flows with more difficulty)
What is the general formula of an ALKENE
CnH(2n)
Describe the trend in chain length from GASES TO BITUMEN
Chain length increases
What are the advantages of petrol as a vehicle fuel
Easily stored
Easily ignited
Combustion releases large amounts of energy
What are the advantages of hydrogen as a vehicle fuel
Environmental benefits
Easily ignited
What are the disadvantages of petrol as a vehicle fuel
High demand
Greenhouse gas
What are the disadvantages of hydrogen as a vehicle fuel
Difficult to store in large amounts as it has to be compressed
How does cracking work
Cracking involves breaking covalent bonds in hydrocarbon molecules.
Crude oil fractions are heated to evaporate them.
The vapours are passed over a catalyst containing aluminium oxide and heated to about 650°C
Smaller more useful hydrocarbon molecules form and these can be used as fuel or for making polymers
What is the functional group of Alcohols
O-H
What do the names of alcohols always end in
-anol
What are the two methods in which ethanol can be produced
Fermentation & hydration
What chemical substance do alcohols contain
Ethanol
What is the formula for ethanol
C(2) H(5) OH
How is ethanol created through the process of fermentation
Plant material containing sugars is mixed with water and yeast.
Enzymes in the yeast turn the sugars into ethanol and carbon dioxide
What is the general equation for the production of ethanol through the process of fermentation
glucose ——-> ethanol + carbon dioxide
What process increases the concentration of alcohol in a solution
Fractional distillation
Explain why the pH and temperature must be controlled carefully in the fermentation tank
It is important because the liquid needs to be at optimum temperature for enzymes to work and so does the pH
What are the pros of fermentation
Renewable
Only needs to be heated to 37°C

What are the cons of fermentation
Produces CO2
Slow reaction
A lot of workers needed
What are the pros of the method of hydration in producing ethanol
Only ethanol is produced (no waste products’
Few workers
What are the cons of the process of hydration
Non-renewable - cracked from crude oil
Requires more energy - steam (needs to be heated to 100° C)

