Crude oil is fractionally distilled to produce fractions - Edexcel - GCSE Chemistry - Question 5 - 2017 - Paper 1
Question 5
Crude oil is fractionally distilled to produce fractions.
These fractions have many uses.
Complete the sentence by putting a cross (✗) in the box next to your answe... show full transcript
Worked Solution & Example Answer:Crude oil is fractionally distilled to produce fractions - Edexcel - GCSE Chemistry - Question 5 - 2017 - Paper 1
Step 1
Complete the sentence by putting a cross (✗) in the box next to your answer.
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Answer
The fraction least likely to be used as a fuel is: A bitumen because it is a heavy residue and not typically used for combustion.
Step 2
Describe what is meant by cracking.
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Answer
Cracking is a process that involves breaking down larger hydrocarbon molecules into smaller, more useful ones through heat and pressure, often resulting in the formation of alkenes and alkanes.
Step 3
Draw the structure of a molecule of one of these hydrocarbons, showing all bonds.
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Answer
A common hydrocarbon produced from cracking butane is ethene (C₂H₄). Its structure can be represented as:
H H
\ /
C = C
/ \
H H
This shows that ethene has a double bond between the two carbon atoms.
Step 4
Use your knowledge of hydrogen and petrol to explain the advantages and disadvantages of using hydrogen rather than petrol as the fuel in cars.
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Answer
Advantages of using hydrogen as a fuel include:
Environmental Impact: Hydrogen produces only water vapor when burned, making it a cleaner alternative to petrol, which emits carbon dioxide and other pollutants.
Renewable Sources: Hydrogen can be produced from various renewable resources, potentially reducing reliance on fossil fuels.
Disadvantages of using hydrogen include:
Infrastructure: The current lack of hydrogen refueling stations limits accessibility compared to a well-established petrol infrastructure.
Production Costs: Generating hydrogen, especially using green methods, can be expensive and energy-intensive.
Storage and Transport Challenges: Hydrogen's low energy density presents challenges for safe and efficient storage and transport.
