Making crude oil useful

Question 1

Explain why fossil fuels are finite resources and are

non-renewable

Answer 1

• finite resources are no longer being made or
  being made extremely slowly
• non-renewable resources are used up faster than
  they are formed

Question 2

Describe crude oil

Answer 2

a mixture of many hydrocarbons

Question 3

Discuss the problems associated with the finite

nature of crude oil

Answer 3

• all the readily extractable resources will be used
  up in the future
• finding replacements
• conflict between making petrochemicals and
  fuels.

Question 4

Describe how fractional distillation separates crude oil

into fractions:

Answer 4

• crude oil is heated
  • use of a fractionating column which has a
  temperature gradient (cold at the top and hot at
  the bottom)
  • fractions containing mixtures of hydrocarbons are
  obtained
  • fractions contain many substances with similar
  boiling points
  • fractions with low boiling points ‘exit’ from the top
  of the fractionating column
  • fractions with high boiling points ‘exit’ at the
  bottom of the fractionating column.

Question 5

Explain some of the potential environmental problems

involved in the transportation of crude oil:

Answer 5

• damage to birds’ feathers causing death
• use of detergents to clean up oil slicks and
  consequent damage to wildlife.

Question 6

Describe cracking as a process that:

Answer 6

• converts large alkane molecules into smaller
  alkane and alkene molecules
• makes useful alkene molecules that can be used
  to make polymers.

Question 7

Explain in simple terms the political problems

associated with the exploitation of crude oil:

Answer 7

• UK dependent on oil and gas from politically
  unstable countries
• future supply issues.

Question 8

Explain how cracking helps an oil refinery match
its supply of useful products such as petrol with the
demand for them.

Answer 8

Cracking converts long alkane molecules into shorter alkanes and alkenes, which are more useful.

Question 9

Explain in terms of molecular size, intermolecular
forces and boiling point why crude oil can be
separated by fractional distillation.

Answer 9

Large molecules have high boiling points as they have stronger intermolecular forces holding one molecule to another.

Question 10

Understand that during boiling the intermolecular
forces between molecules break but covalent bonds
within the molecule do not.

Answer 10

• When a substance boils, the forces between molecules (intermolecular forces) are broken
• But the covalent bonds within each molecule (intramolecular bonds) are not broken

Question 11

what are fossil fuels?

Answer 11

crude oil, gas and coal

Question 12

Describe non-renewable fuels

Answer 12

ones which take a
very long time to make and are used up faster than
they are formed.