C9 Crude oil and fuels Flashcards
What is crude oil?
A finite resource found in rocks from the remains of plankton. It is a mixture of many different compounds that boil at different temperatures
What are the liquids that are seperated by distillation called?
Fractions
What is a hydrocarbon?
A molecule that only contains hydrogen and carbon
What is the formulae of the first four alkanes?
CH4 (methane), C2H6 (ethane), C3H8 (propane), C4H10 (butane)
What is the general formula for alkanes?
CnH(2n+2)
What is meant by a saturated hydrocarbon?
It contains as many hydrogen atoms as possible
Why are fractions with smaller hydrocarbon molecules more useful as fuel? (4)
Because they have lower boiling temperatures, lower viscosities, very flammable and burn with clean fuels
How do you test for water?
Use blue cobalt chloride paper, which should turn pink in contact with water
What can incomplete combustion produce?
Carbon monoxide
What is cracking?
Large hydrocarbon molecules being broken down into smaller molecules
How can cracking be done? (2)
- Steam cracking - heating a mixture of hydrocarbon vapours and steam to a very high temperature
- Catalytic cracking - by passing hydrocarbon vapours over a hot catalyst
What is the difference between alkanes and alkenes?
Alkanes have a single covalent bond in their molecules, alkenes have a double covalent bond
What are more reactive, alkanes or alkenes?
Alkenes
How can you test for alkenes?
Alkenes react with bromine water turning it from orange to colourless
