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Organic chemistry

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Question 29

The table below shows the percentage by mass of fractions obtained from a sample of crude oil and the percentage market demand for these fractions.

FractionPercentage by mass in crude oil (%)Market demand (%)
refinery gases37
petrol (gasoline)1238
kerosene (jet fuel)914
diesel (gas oil)1928
heavy fuel oil4511
bitumen / residue122
a.

Why is the market demand for the petrol fraction significantly greater than that for the heavy fuel oil fraction?

[2]
b.

Cracking is a process used in the petrochemical industry to convert heavier fractions into more useful shorter-chain hydrocarbons.

Complete the chemical equation to identify the other product formed when pentadecane (C15H32C_{15}H_{32}C15​H32​) is cracked.

C15H32→C12H26+……………… C_{15}H_{32} \rightarrow C_{12}H_{26} + \text{\dots\dots\dots\dots\dots\dots} C15​H32​→C12​H26​+………………
[1]
c.

Name a catalyst used in industrial catalytic cracking and state the temperature range used.

[2]
d.

Industrial ethanol can be manufactured either by the hydration of ethene (obtained from cracking) or by the fermentation of sugars.

State two advantages of manufacturing ethanol by the hydration of ethene rather than by fermentation.

[2]
e.

Suggest two reasons why a country might choose to produce ethanol via fermentation instead of from ethene.

[2]
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Organic chemistry Questions

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