Exam questions for Fractional Distillation, Cracking and Combustion

Exercise 11 Fractional Distillation, Cracking and Combustion

1. Petroleum is separated into its fractions by fractional distillation

a) What are fractions?
b) Explain how a fractionating column works in five key points.
c) Write a list of the fractions, in order of increasing boiling point, and give a
use for each.
d) Why is fractional distillation important?


2. Many of the fractions are then subjected to a process called cracking.

a) Name the two types of cracking. State the conditions required for each and
give one useful product of each process.
b) Why is cracking economically important?


3. Most of the fractions produced during fractional distillation are used as fuels.

a) Write an equation for the complete combustion of octane.
b) Write two equations for the incomplete combustion of octane.
c) Give two reasons why incomplete combustion is undesirable.


4. a) Identify five pollutants produced during the combustion of alkanes.
b) Explain why each is harmful.
c) Explain how two of these pollutants are removed from exhaust fumes.
Write an equation to illustrate your answer.




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