Edexcel IGCSE Chemistry: Double Science

Topic Questions

IGCSEChemistry: Double ScienceEdexcelTopic Questions4. Organic Chemistry4.3 Alkanes

4.3 Alkanes

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Medium
Hard
1a4 marks
a)
There are three isomers with the molecular formula C5H12
 
One of these isomers is pentane.
 
The displayed formula for pentane is
 
pentane-displayed
 
i)
State what is meant by the term isomers.
 
(2)
 
ii)
Draw the displayed formula for another isomer of C5H12 
 
(2)

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1b3 marks
b)
Pentane reacts with bromine in the presence of ultraviolet radiation.
 
i)
Complete the equation for this reaction.
 
(2)
 
C5H12 + Br2 → .................... + ....................
 
ii)
Give the name of this type of reaction.
 
(1)

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11 mark

Which of these formulae is that of an alkane?

(1)

  ☐ A C6H11 
  ☐ B C8H16 
  ☐ C C10H22 
  ☐ D C12H28 

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2a6 marks

The table shows the molecular formulae of six organic compounds, A, B, C, D, E and F.

A B C D E F
C2H4 C2H6 C3H6 C3H8 C4H8 C4H10

a) i)
Explain which homologous series compound B belongs to.
 
(2)
 
ii)
Give the letter of the compound that has the same empirical formula as its molecular formula.
 
(1)
 
iii)
Compound F exists as two isomers.
 
Explain what is meant by the term isomers.
 
Include the structures of the two isomers of compound F in your answer.
 
(3)

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2b4 marks
b)
Describe how compound D can be obtained from crude oil using the industrial process of fractional distillation.
 
(4)

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2c4 marks
c)
Compound C can be used to make a polymer.
 
i)
State the type of polymer formed from compound C.
 
(1)
 
ii)
Name the polymer formed from compound C.
 
(1)
 
iii)
Draw the structure of this polymer.
 
Include the displayed formula of the repeat unit.
 
(2)

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31 mark

The table shows the displayed formulae of some organic compounds. 

hydrocarbons

Which two are not classed as alkanes?

(1)

  ☐ A R and S
  ☐ B S and T
  ☐ C P and Q
  ☐ D R and T

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4a6 marks

This question is about alkanes and alkenes.

a) i)
Complete the boxes by giving the missing information about the alkane with the molecular formula C2H6 
 
molecular formula C2H6 
name  
empirical formula  
displayed formula  
 
(3)
 
ii)
Complete the chemical equation for the complete combustion of the alkane C2H6
 
(1)
 
...........C2H6 + ...........O2 → ...........CO2 + ...........H2O
 
iii)
Incomplete combustion occurs when the air supply is limited.
 
Give the names of two products of incomplete combustion.
 
(2)

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4b4 marks
b)
An alkene with molecular formula C4H8 reacts with bromine to form a compound with molecular formula C4H8Br2
 
i)
What is the name of this type of reaction?
 
(1)
 
  ☐ A addition
  ☐ B decomposition
  ☐ C precipitation
  ☐ D substitution
 
ii)
Draw displayed formulae for two different alkenes with the molecular formula C4H8 
 
(2)
 
alkene 1
 
alkene 2
 
 
iii)
State the term used for compounds with the same molecular formula but different structural formulae.
 
(1)

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4c5 marks
c)
The alkene C3H6 can be polymerised to form the polymer poly(propene).
 
i)
Complete the equation for this polymerisation reaction.
 
(2)
 
   propene-polymerisation-starting-point
 
ii)
Two ways of disposing of polymers such as poly(propene) are:
 
  • burying them in landfill sites
  • burning them to release heat energy
 
Discuss the environmental problems caused by these two methods of disposal.
 
(3)

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51 mark

Ethane and bromine can react in the following reaction: 

4-3-q3-edexcel-igcse-chemistry

What name is given to this type of reaction?

(1)

  ☐ A Substitution
  ☐ B Addition
  ☐ C Dehydration
  ☐ D Thermal decomposition

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61 mark

Methane and bromine react to form bromomethane and hydrogen bromide. 

What does this reaction occur in the presence of? 

(1)

  ☐ A Infrared radiation
  ☐ B Visible light 
  ☐ C Untraviolet radiation
  ☐ D Ozone

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71 mark

What is the correct chemical formula of butane?

(1)

  ☐ A C3H6
  ☐ B C3H8
  ☐ C C4H8
  ☐ D C4H10

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