Edexcel IGCSE Chemistry (b) Crude oil Question Bank

Practise crude oil questions on fractions, boiling points, fuel combustion, acid rain, cracking and alkane or alkene formulae.

Exam points

explain fractional distillation using heating, column temperature gradient and condensation
link fraction position, chain length and intermolecular forces to boiling point
explain fuel combustion products, including CO toxicity and SO2 or NOx causing acid rain

Covered syllabus points

4.7 Crude oil as a hydrocarbon mixture 4.8 Fractional distillation of crude oil 4.9 Crude-oil fractions and uses 4.10 Trends in fraction properties 4.11 Fuels 4.12 Hydrocarbon combustion products 4.13 Carbon monoxide toxicity 4.14 Nitrogen oxides in engines 4.15 Sulfur impurities and sulfur dioxide 4.16 Acid rain 4.17 Catalytic cracking 4.18 Why cracking is necessary

[Maximum number: 7]

Crude oil is a mixture of hydrocarbons.

(a)

Name the process used to separate crude oil into fractions.

[ 1 ]

(b)

Give one use of the kerosene fraction.

[ 1 ]

(c)

Catalytic cracking is used to convert long-chain alkanes into shorter-chain alkanes.

[ 3 ]

(i)

Name the catalyst used in catalytic cracking.

[ 1 ]

alumina / silica

Accept:
- aluminium oxide
- silicon dioxide
- $\ce{Al2O3}$
- $\ce{SiO2}$
- zeolite(s)
- aluminosilicate(s)

(ii)

Explain why it is necessary to convert long-chain alkanes into shorter-chain alkanes.

[ 2 ]

(d)

Catalytic cracking also produces alkenes.
$\ce{C11H24}$ can undergo cracking to give pentane ( $\ce{C5H12}$ ) and two different alkenes.
Complete the equation for this cracking reaction.

$\ce{C11H24}$ -> $\ce{C5H12}$ + ................................ + ................................

[ 2 ]

$\ce{C11H24 -> C5H12 + C2H4 + C4H8}$

Marking guidance:
- Alkenes can be in either order.
- 1 mark for $\ce{C2H4}$ .
- 1 mark for $\ce{C4H8}$ .

Allow:
- $\ce{C6H12}$ / $\ce{2C3H6}$ / $\ce{C3H6}$ + $\ce{C3H6}$ for 1 mark
- correct displayed formulae

[Maximum number: 8]

Crude oil is an important source of organic compounds.

(a)

The diagram shows crude oil being separated into different fractions.

Figure for Question (a) — Edexcel IGCSE Chemistry

[ 6 ]

(i)

Name the process used to separate crude oil into different fractions.

[ 1 ]

(ii)

State what happens to the crude oil at X .

[ 1 ]

(iii)

Describe the differences between fraction B and fraction E.

In your answer, refer to
- size of the molecules
- boiling point
- colour
- viscosity

[ 4 ]

(b)

Crude oil often contains sulfur as an impurity.

Explain why this is a problem when using crude oil fractions as fuels.

[ 2 ]

An explanation which links the following two points:
- when sulfur burns, sulfur dioxide / $\ce{SO2}$ is formed
- this causes acid rain

Allow:
- sulfur trioxide / $\ce{SO3}$
- a specified harmful effect of acid rain
- references to causing / exacerbating respiratory problems
- greenhouse gas / causes global warming / climate change

Ignore:
- sulfur oxides

All question bank results loaded

Covered syllabus points

(b) Crude oil question 1

Question (a)

Question (b)

Question (c)

Question (i)

Question (ii)

Question (d)

(b) Crude oil question 2

Question (a)

Question (i)

Question (ii)

Question (iii)

Question (b)