AQA A Level Chemistry : Year 1 - Alkanes
What is a source of hydrocarbons? - Correct Answers-Crude oil (petroleum)
What is crude oil (petroleum) ? - Correct Answers-A mixture consisting mainly of alkane
hydrocarbons which can be separated by fractional distillation
How might blockage of the air vents in a combustion engine affect its performance? - Correct
Answers-Less energy given out by the fuel
Engine less powerful/efficient
What is fractional distillation? - Correct Answers-The continual evaporation and condensation
of a mixture causing the different components to separate because they have different boiling
points
Explain fractional distillation (4 steps) - Correct Answers-1. Crude oil is heated to a vapour
which passes into the column
2. The column is hotter at the bottom and cooler at the top
3. Vapours rise up the column and cool, condensing when they meet their boiling point
4. Short chain alkanes are collected near the top as they have lower boiling points
Give a use of alkanes - Correct Answers-Fuels
What is an alkane? - Correct Answers-A saturated hydrocarbon
What is cracking? - Correct Answers-The proceds where long chain hydrocarbon molecules are
broken into shorter chain molecules which are in high demand
What bond is broken during cracking? - Correct Answers-C-C
Why are high temperatures needed in both thermal and catalytic cracking? - Correct Answers-
The C-C bond is very strong
Requires high amount of energy to break
Why is it necessary to crack hydrocarbons? - Correct Answers-To produce short chain
hydrocarbons which are in high demand
What are the conditions for thermal cracking? - Correct Answers-1200K
What is a source of hydrocarbons? - Correct Answers-Crude oil (petroleum)
What is crude oil (petroleum) ? - Correct Answers-A mixture consisting mainly of alkane
hydrocarbons which can be separated by fractional distillation
How might blockage of the air vents in a combustion engine affect its performance? - Correct
Answers-Less energy given out by the fuel
Engine less powerful/efficient
What is fractional distillation? - Correct Answers-The continual evaporation and condensation
of a mixture causing the different components to separate because they have different boiling
points
Explain fractional distillation (4 steps) - Correct Answers-1. Crude oil is heated to a vapour
which passes into the column
2. The column is hotter at the bottom and cooler at the top
3. Vapours rise up the column and cool, condensing when they meet their boiling point
4. Short chain alkanes are collected near the top as they have lower boiling points
Give a use of alkanes - Correct Answers-Fuels
What is an alkane? - Correct Answers-A saturated hydrocarbon
What is cracking? - Correct Answers-The proceds where long chain hydrocarbon molecules are
broken into shorter chain molecules which are in high demand
What bond is broken during cracking? - Correct Answers-C-C
Why are high temperatures needed in both thermal and catalytic cracking? - Correct Answers-
The C-C bond is very strong
Requires high amount of energy to break
Why is it necessary to crack hydrocarbons? - Correct Answers-To produce short chain
hydrocarbons which are in high demand
What are the conditions for thermal cracking? - Correct Answers-1200K
