UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate ...

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS

General Certificate of Education Advanced Subsidiary Level and Advanced Level

*4533287500*

9701/05

CHEMISTRY

Paper 5

Planning, analysis and evaluation

May/June 2008

1 hour 15 minutes

Candidates answer on the Question Paper.

No Additional Materials are required.

READ THESE INSTRUCTIONS FIRST

Write your Centre number, candidate number and name on all the work you hand in.

Write in dark blue or black pen.

You may use a soft pencil for any diagrams, graphs or rough working.

Do not use staples, paper clips, highlighters, glue or correction fluid.

DO NOT WRITE IN ANY BARCODES.

Answer all questions.

You are advised to show all working in calculations.

Use of Data Booklet is unnecessary.

At the end of the examination, fasten all your work securely together.

The number of marks is given in brackets [ ] at the end of each question or part question.

For Examiner¡¯s Use

1

2

Total

This document consists of 11 printed pages and 1 blank page.

SPA (DR/DR) T60103/4

? UCLES 2008

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1

The equations for the complete combustion of the first five members of the alcohol

homologous series are shown below.

CH3OH(l) + 1?O2(g)

methanol

CH3CH2OH(l) + 3O2(g)

2CO2(g) + 3H2O(l)

CH3CH2CH2OH(l) + 4?O2(g)

3CO2(g) + 4H2O(l)

CH3CH2CH2CH2OH(l) + 6O2(g)

4CO2(g) + 5H2O(l)

CH3CH2CH2CH2CH2OH(l) + 7?O2(g)

5CO2(g) + 6H2O(l)

ethanol

propan-1-ol

butan-1-ol

pentan-1-ol

CO2(g) + 2H2O(l)

You are to plan an experiment to determine the enthalpy change of combustion under

laboratory conditions, ¦¤Hc, for each of the five alcohols using the apparatus and information

below.

thermometer

copper can

water

spirit lamp containing

selected alcohol

[4.2 J of heat energy raise the temperature of 1 cm3 (1 g) of water by 1 ¡ãC.]

(a) Inspection of the products of the five equations shows that from ethanol to pentan-1-ol

each equation has one more mole of CO2 and one more mole of H2O produced per

mole of alcohol than the equation above it.

What difference between the structures of adjacent alcohols is responsible for these

additional combustion products?

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? UCLES 2008

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(b) There is a trend in ¦¤Hc for these five alcohols. Use your answer to (a) to sketch the trend

indicated by the equations.

number of carbon atoms in the alcohol

1

2

3

4

5

?Hc

[1]

(c) Identify each of the following variables in the experiment to determine the enthalpy

change of combustion of an alcohol using the apparatus in the diagram.

The independent variable is ¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­..

The dependent variable is

¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­¡­

Two variables to be controlled in this experiment are

1 .......................................................................................................................................

2 .......................................................................................................................................

[3]

? UCLES 2008

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(d) You are to plan a step-by-step method to determine the enthalpy change of combustion,

¦¤Hc, for each of the alcohols in turn. You should use the apparatus shown in the diagram

on page 2 and any other apparatus required that is normally found in a school or college

laboratory.

You need only explain how the method will be used for ethanol.

Your method should cover the following points.

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?

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the precision of the apparatus to be used

the way in which the independent variable is varied between experiments

measurement of the dependent variable

appropriate quantities to be used

the raw data to be collected

how this data is to be processed for ethanol

[4.2 J of heat energy raise the temperature of 1 cm3 (1 g) of water by 1 ¡ãC.]

Method

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? UCLES 2008

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Processing of raw data

[Mr: CH3CH2OH, 46]

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[6]

(e) Prepare a single table to show, for each alcohol, all of the measurements obtained

directly from the experiment and the information processed from these data.

Your table should show the correct units for each of the headed columns.

[2]

? UCLES 2008

9701/05/M/J/08

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For

Examiner¡¯s

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