Organic Chemistry Alkanes, Alkenes, Alcohols Crude Oil Polymers

44 Pages·2014·4.65 MB·English

Name: _______________________________________________

Organic Chemistry

Alkanes, Alkenes, Alcohols

Date:

Time: 1 hour 53 minutes

Total marks available: 113

Total marks achieved: ______

2011 to 2013
Q1.
(a) Explain what is meant by the term isomerism.
(2)
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(b) The displayed formula of heptane (C H ) is
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Which one of the displayed formulae below does not represent an isomer of heptane?
Place a cross ( ) in the box to indicate your answer.
(1)
(c) Heptane belongs to a homologous series of compounds called alkanes.
The general formula of the alkanes is C H
n 2n+2
(i) Heptene belongs to a homologous series of compounds called alkenes.
Give the general formula of the alkenes.
(1)
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(ii) Complete the following diagram to show the structural formula of heptene (C H ) by
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inserting lines to represent the covalent bonds between the carbon atoms.
(2)
(d) When heptene is added to bromine water, and the mixture is shaken, a reaction
occurs.
State the type of reaction and give the colour of the bromine water before and after the
reaction with heptene.
(3)
Type of reaction
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Colour before
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Colour after
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(e) Explain, in terms of the bonds present, why heptane is described as saturated and
heptene as unsaturated.
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(Total for Question = 11 marks)

Q2.
The table shows the displayed formulae of three unsaturated hydrocarbons.
(a) Explain the meaning of the term hydrocarbon.
(2)
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(b) Explain the meaning of the term unsaturated.
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(c) Compounds A, B and C belong to the same homologous series. One characteristic of
the compounds in a homologous series is that they have the same general formula.
(i) State the name of this homologous series.
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(ii) State the general formula of this homologous series.
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(iii) State two other characteristics of the compounds in a homologous series.
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(d) Compound C has several isomers.
(i) What is the name of compound C?
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(ii) What is the molecular formula of compound C?
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(iii) Explain the meaning of the term isomers.
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(iv) Draw the displayed formula of an isomer of compound C.
(1)
(e) Bromine water can be used to distinguish compound A from ethane.
(i) Complete the sentence to show the colour change when compound A is bubbled
through bromine water.
(1)
Bromine water changes from orange to .............................................................. .
(ii) Complete the chemical equation for the reaction between compound A and bromine
water.
(1)
C H + Br → ...........................................
2 4 2
(Total for Question = 14 marks)

Q3.
There are two important ways to manufacture ethanol.
Reaction 1 C H + H O → C H OH
2 4 2 2 5
Reaction 1 C H O → 2C H OH + 2CO
6 12 6 2 5 2
(a) (i) Identify one raw material that could be used as the source of C H O
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(ii) Reaction 2 uses a catalyst called zymase, which is present in yeast.
Identify the catalyst used in reaction 1.
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(iii) In both reactions it is important to control the temperature.
State why the temperature in reaction 2 is kept below 35 °C.
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(b) A manufacturing company plans to build a factory to produce ethanol on a large
scale. The factory will be near an
oilfield. The ethanol will be used as a solvent for perfume.
Suggest why the company should use reaction 1 rather than reaction 2.
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(c) In the future, it may be necessary to convert the ethanol (produced by reaction 2)
into ethene.
Write the equation for this reaction and state the type of reaction that occurs.
(2)
Equation
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Type of reaction
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(Total for Question = 8 marks)

Q4.
Fractional distillation and cracking are important steps in processing crude oil.
(a) Place ticks ( ) in the columns to show which statements apply to each step.
You may place a tick in one column, in both columns or in neither column.
The first one has been done for you.
(5)
(b) The formula CH CH CH CH CH represents one of the compounds in crude oil.
3 2 2 2 3
(i) Give the molecular formula of this compound.
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(ii) Give the displayed formula of this compound.
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(iii) Give the empirical formula of this compound.
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(iv) Give the name of this compound.
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(v) Give the general formula of the homologous series that contains this compound.
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(c) The products of the complete combustion of hydrocarbons are carbon dioxide and
water.
(i) Balance the equation to show the complete combustion of ethene (C H ).
2 4
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C H + ...................O → ...................CO + ...................H O
2 4 2 2 2
(ii) Draw a dot and cross diagram to show the bonding in an ethene molecule.
Show only the outer electrons in each atom.
(2)
(d) Ethanol can be manufactured by the hydration of ethene. The equation for this
reaction is
C H (g) + H O(g) → C H OH(g)
2 4 2 2 5
(i) Identify the catalyst and state the temperature used in this process.
(2)
Catalyst
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Temperature
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(ii) A 20 mol sample of ethanol was produced using this reaction.
Deduce the amount, in moles, of ethene needed and the volume, in dm , that this
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amount of ethene would occupy at room temperature and pressure.