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THIS IS A NEW SPECIFICATION




ADVANCED SUBSIDIARY GCE
CHEMISTRY A F322
Chains, Energy and Resources




Wednesday 3 June 2009
*OCE/T73768*




Candidates answer on the question paper

OCR Supplied Materials:
Morning
· Data Sheet for Chemistry A (Inserted)
Duration: 1 hour 45 minutes
Other Materials Required:
· Scientific calculator



* F…

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Answer all the questions.


1 Crude oil is a source of hydrocarbons which can be used as fuels or for processing into
petrochemicals.

Octane, C8H18, is one of the alkanes present in petrol.

Carbon dioxide is formed during the complete combustion of octane.

C8H18 + 12½O2 8CO2 + 9H2O…

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(d) Oil companies process hydrocarbons, such as octane, into branched and cyclic hydrocarbons
that promote efficient combustion in petrol.

Draw the skeletal formulae of a branched hydrocarbon and a cyclic hydrocarbon, each
containing eight carbon atoms.




[2]

(e) Some scientists believe that increased CO2 levels arising from the combustion…

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2 Enthalpy changes of combustion, Hc, are amongst the easiest enthalpy changes to determine
directly.

(a) Define the term enthalpy change of combustion.

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............................................................................................................................................ [2]

(b) A student carried out an experiment to determine the enthalpy change of combustion of
pentan-1-ol, CH3(CH2)4OH.

In the experiment, 1.76…

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(c) The standard enthalpy change of formation of hexane can be defined as:

The enthalpy change when 1 mol of hexane is formed from its constituent elements in
their standard states under standard conditions.

Hexane melts at ­95 °C and boils at 69 °C.

(i) What are standard conditions?…

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3 Alkenes are unsaturated hydrocarbons used in the industrial production of many organic
compounds.

(a) Complete the flowchart below to show the organic product formed in each addition reaction of
methylpropene.




H CH3
H2 / Ni Br2
C C

H CH3
HBr




mixture of isomers
[4]

(b) Curly arrows…

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(c) Alkenes can be prepared by the dehydration of alcohols with an acid catalyst.
Cyclohexene can be prepared by the dehydration of cyclohexanol, shown below.


OH
+ H2O



A student reacted 7.65 g of cyclohexanol, C6H12O, and obtained 0.0268 mol of cyclohexene.

(i) What is the molecular formula of…

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4 In the chemical industry methanol, CH3OH, is synthesised by reacting together carbon monoxide
and hydrogen in the presence of copper, zinc oxide and alumina which act as a catalyst. This is a
reversible reaction.

CO(g) + 2H2(g) CH3OH(g) H = ­91 kJ mol­1

(a) High pressures and low…

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(ii) Using the axes below, sketch an enthalpy profile diagram for an exothermic reaction to
show how a catalyst provides an alternative reaction route with a lower activation energy.
Include on your diagram labels for:

· enthalpy change, H;

· activation energy for the catalysed route, Ec;

· activation…

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5 Alcohols A, B, C and D are shown below.

CH3 CH3

CH3 CH2 OH H C OH CH3 CH2 CH2 OH H3C C OH

CH3 CH3

A B C D

(a) Compound A is ethanol, a very useful alcohol.

Identify the two main methods used in the industrial…

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