AQA A-LEVEL CHEMISTRY PAPER 2
SCRIPT COMPLETE ANSWERS GRADED
A+
◉ the shorter the hydrocarbon chain...
Answer: the less viscous
the more volatile
the more flammable
lower boiling points
◉ complete combustion
Answer: happens in excess of oxygen
releases lots of energy
C and H from the hydrocarbon are oxidised
◉ complete combustion equation
Answer: hydrocarbon + oxygen = carbon dioxide + water
◉ crude oil
Answer: fossil fuel
formed from remains of plats and animals
remains turn to oil with time, temp, and pressure
,non-renewable
finite
mixture of lots of different hydrocarbons
◉ fractional distillation
Answer: used to separate hydrocarbon fractions
◉ uses of crude oil
Answer: fuel - kerosene, diesel etc
makes new compounds like polymers and solvents
◉ cracking
Answer: splitting up hydrocarbons
turns long chain hydrocarbons into shorter chains
◉ catalytic cracking
Answer: 1. vaporise hydrocarbon
2. pass over hot powered aluminium oxide catalyst
◉ steam cracking
Answer: 1. vaporise hydrocarbon
2. mix with steam
3. heat to a very high temperature
, ◉ thermal decomposition
Answer: breaking down molecules by heating them
◉ cracking products
Answer: shorter chain hydrocarbon + alkene
◉ alkene
Answer: hydrocarbons with a double bond between two carbons
in their chain
two fewer hydrogens than alkanes
◉ properties of alkenes
Answer: unsaturated
c=c bond can open to bond to other atoms
much more reactive than alkanes
◉ alkene formula
Answer: Cn H2n
◉ first alkene
Answer: ethene C2H4
◉ second alkene
SCRIPT COMPLETE ANSWERS GRADED
A+
◉ the shorter the hydrocarbon chain...
Answer: the less viscous
the more volatile
the more flammable
lower boiling points
◉ complete combustion
Answer: happens in excess of oxygen
releases lots of energy
C and H from the hydrocarbon are oxidised
◉ complete combustion equation
Answer: hydrocarbon + oxygen = carbon dioxide + water
◉ crude oil
Answer: fossil fuel
formed from remains of plats and animals
remains turn to oil with time, temp, and pressure
,non-renewable
finite
mixture of lots of different hydrocarbons
◉ fractional distillation
Answer: used to separate hydrocarbon fractions
◉ uses of crude oil
Answer: fuel - kerosene, diesel etc
makes new compounds like polymers and solvents
◉ cracking
Answer: splitting up hydrocarbons
turns long chain hydrocarbons into shorter chains
◉ catalytic cracking
Answer: 1. vaporise hydrocarbon
2. pass over hot powered aluminium oxide catalyst
◉ steam cracking
Answer: 1. vaporise hydrocarbon
2. mix with steam
3. heat to a very high temperature
, ◉ thermal decomposition
Answer: breaking down molecules by heating them
◉ cracking products
Answer: shorter chain hydrocarbon + alkene
◉ alkene
Answer: hydrocarbons with a double bond between two carbons
in their chain
two fewer hydrogens than alkanes
◉ properties of alkenes
Answer: unsaturated
c=c bond can open to bond to other atoms
much more reactive than alkanes
◉ alkene formula
Answer: Cn H2n
◉ first alkene
Answer: ethene C2H4
◉ second alkene
