This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
This document consists of 13 printed pages and 3 blank pages.
Section A For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 The table gives the successive ionisation energies for an element X.
8 Which row correctly describes the electrodes that can be used in a diaphragm cell for the production of chlorine, hydrogen and sodium hydroxide?
anode cathode
A steel graphite
B steel titanium
C titanium graphite
D titanium steel
9 Hexamine is a crystalline solid used as a fuel in portable stoves.
The diagram shows its skeletal structure.
N
NN N
What is the empirical formula of hexamine?
A CH2N B C3H6N2 C C4H8N4 D C6H12N4 10 A mixture of nitrogen and hydrogen gases, at a temperature of 500 K, was put into an evacuated
vessel of volume 6.0 dm3. The vessel was then sealed.
N2(g) + 3H2(g) 2NH3(g)
The mixture was allowed to reach equilibrium. It was found that 7.2 mol of N2 and 12.0 mol of H2 were present in the equilibrium mixture. The value of the equilibrium constant, Kc, for this
equilibrium is 6.0 × 10–2 at 500 K.
What is the concentration of ammonia present in the equilibrium mixture at 500 K?
11 Ammonia is made by the Haber process. The reactants are nitrogen and hydrogen.
N2(g) + 3H2(g) 2NH3(g) ∆H –ve
What will increase the rate of the forward reaction?
A adding argon to the mixture but keeping the total volume constant
B decreasing the temperature
C increasing the total pressure by reducing the total volume at constant temperature
D removing ammonia as it is made but keeping the total volume of the mixture the same 12 X is a Group II metal. The carbonate of X decomposes when heated in a Bunsen flame to give
carbon dioxide and a white solid residue as the only products. This white solid residue is sparingly soluble in water. Even when large amounts of the solid residue are added to water the pH of the saturated solution is less than that of limewater.
What could be the identity of X?
A magnesium
B calcium
C strontium
D barium 13 Rat poison needs to be insoluble in rain water but soluble at the low pH of stomach contents.
What is a suitable barium compound to use for rat poison?
A barium carbonate
B barium chloride
C barium hydroxide
D barium sulfate 14 Use of the Data Booklet is relevant to this question.
Which of the elements sodium, magnesium, aluminium, silicon, phosphorus, sulfur and chlorine
• has a lower first ionisation energy than the preceding element in the Periodic Table,
• conducts electricity and
• has a lower atomic radius than the preceding element in the Periodic Table?
15 The melting points of the Period 3 elements sodium to aluminium are shown in the table.
element Na Mg Al
mp / K 371 923 932
Which factor explains the increase in melting points from sodium to aluminium?
A the changes in first ionisation energy from sodium to aluminium
B the increase in electronegativity from sodium to aluminium
C the increase in the Ar of the elements from sodium to aluminium
D the increase in the number of outer electrons in each atom from sodium to aluminium 16 X is the oxide of a Period 3 element. X reacts with water to give an acidic solution.
A solution is prepared by reacting 0.100 g of X with excess water. This solution was neutralised by exactly 25.0 cm3 of 0.100 mol dm–3 sodium hydroxide solution.
What could be the identity of X?
A Al 2O3 B MgO C P4O10 D SO3 17 Which statement about bromine is correct?
A Bromine is insoluble in non-polar solvents.
B Bromine vapour is more dense than air.
C Bromine will not vaporise significantly under normal conditions.
D Gaseous bromine is purple. 18 The addition of aqueous silver nitrate to aqueous barium chloride produces a white precipitate
which dissolves in excess dilute aqueous ammonia to form a colourless solution.
The addition of excess dilute nitric acid to the colourless solution produces a white precipitate, Z.
22 Crude oil is a mixture of many hydrocarbons ranging in size from 1 to 40 carbon atoms per molecule. The alkanes in crude oil can be separated because they have different boiling points.
The table below shows the boiling points of some alkanes.
alkane boiling point
/ °C Mr
butane 0 58
pentane 36 72
hexane 69 86
2-methylbutane 28 72
dimethylpropane 10 72
2,3-dimethylbutane 58 86
What is the correct explanation for the difference in the boiling points of the three isomers with Mr = 72?
A Boiling point is dependent upon the length of the carbon chain only.
B Increased branching on a carbon chain increases the boiling point.
C Increased branching reduces the strength of the intermolecular hydrogen bonding.
D Increased branching reduces the strength of the intermolecular van der Waals’ forces. 23 Compound Q contains three double bonds per molecule.
CH2 CH2CH CH2C
O O
C OHX Y
Q
Which bond, X or Y, will be ruptured by hot, concentrated acidified KMnO4 and how many lone pairs of electrons are present in one molecule of Q?
Section B For each of the questions in this section, one or more of the three numbered statements 1 to 3 may be correct. Decide whether each of the statements is or is not correct (you may find it helpful to put a tick against the statements that you consider to be correct). The responses A to D should be selected on the basis of
A B C D
1, 2 and 3 are
correct
1 and 2 only are correct
2 and 3 only are correct
1 only is
correct
No other combination of statements is used as a correct response. 31 Which statements about orbitals in a krypton atom are correct?
1 The 1s and 2s orbitals have the same energy as each other but different sizes.
2 The third energy level (n=3) has three subshells and nine orbitals.
3 The 3d subshell has five orbitals that have the same energy as each other in an isolated atom.
32 The Group IV elements carbon, silicon and germanium can all exist in the giant molecular
structure which is also found in diamond. The bond lengths in these structures are given below.
The responses A to D should be selected on the basis of
A B C D
1, 2 and 3 are
correct
1 and 2 only are correct
2 and 3 only are correct
1 only is
correct
No other combination of statements is used as a correct response. 33 The salt NaCl O3 is used as a non-selective weedkiller.
On careful heating, this reaction occurs: 4NaCl O3 → NaCl + 3NaCl O4.
On strong heating this reaction occurs: NaCl O4 → NaCl + 2O2.
The overall reaction is 2NaCl O3 → 2NaCl + 3O2.
What do these equations show?
1 NaCl O3 can behave as an oxidising agent.
2 NaCl O3 can behave as a reducing agent.
3 The oxidation numbers of chlorine in the three compounds shown are +6, +8 and –1. 34 Which statements correctly describe an effect of a rise in temperature on a gas-phase reaction?
1 More particles now have energies greater than the activation energy.
2 The energy distribution profile changes with more particles having the most probable energy.
3 The activation energy of the reaction is decreased. 35 Which statements concerning the Group II elements magnesium, calcium and barium are
correct?
1 Their reactivity increases with increasing relative atomic mass.
2 The oxidation number exhibited in their stable compounds is +2.
3 On strong heating, their nitrates give off oxygen only. 36 Sulfur dioxide is used as a food preservative.
Which statements about sulfur dioxide, SO2, are correct?
37 An oxidising agent that can oxidise ethanal to ethanoic acid, or to ethanoate ions, will also oxidise methanoic acid, HCO2H, to carbon dioxide and water.
Which reagents, on heating, will react differently with HCO2H and CH3CO2H?
1 Na2CO3(aq)
2 Fehling’s reagent
3 dilute acidified KMnO4 38 Each of the compounds below is treated separately with excess NaBH4. The product of each
reaction is then heated with excess concentrated H2SO4.
In each case, one or more products are formed with molecular formula C7H10.
Which compounds give only one final product with the molecular formula C7H10?
1
O
O
2
O
O
3
O
O 39 Which reactions result in the formation of propanoic acid?
1 CH3CH2CO2Na with dilute H2SO4(aq)
2 CH3CH=CHCH3 with hot, concentrated H+ / MnO4
–(aq)
3 CH3CH2OH with H+ / Cr2O7
2–(aq) 40 The diagram shows the structure of propanamide.
H
H
H
C
H
H
H O
H
C C N
propanamide
Which statements about the hydrolysis of propanamide are correct?
1 Propanamide can be hydrolysed by heating under reflux with H2SO4(aq).
2 Propanamide can be hydrolysed by heating under reflux with NaOH(aq).
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
38 X is an organic compound. X gives a precipitate with aqueous silver nitrate. Some or all of this
precipitate remains undissolved when excess dilute aqueous ammonia is added.
What could be the identity of X?
1 2-chlorobutane
2 2-bromobutane
3 iodomethane
39 Which compounds, on heating with excess concentrated sulfuric acid, produce only one product
with molecular formula C7H10?
3
OH
OH
OH
OHOH
OH
1 2
40 Compound Z is heated with concentrated acidified potassium manganate(VII). This produces an
equimolar mixture of CO2 and CH3COCH2CH2CH(COCH3)CH2CO2H.
What could be the structural formula of Z?
1 2 3
16
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at
www.cie.org.uk after the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local
Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
Section A For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1 The table gives the successive ionisation energies for an element X.
8 Which row correctly describes the electrodes that can be used in a diaphragm cell for the production of chlorine, hydrogen and sodium hydroxide?
anode cathode
A steel graphite
B steel titanium
C titanium graphite
D titanium steel
9 Hexamine is a crystalline solid used as a fuel in portable stoves.
The diagram shows its skeletal structure.
N
NN N
What is the empirical formula of hexamine?
A CH2N B C3H6N2 C C4H8N4 D C6H12N4 10 A mixture of nitrogen and hydrogen gases, at a temperature of 500 K, was put into an evacuated
vessel of volume 6.0 dm3. The vessel was then sealed.
N2(g) + 3H2(g) 2NH3(g)
The mixture was allowed to reach equilibrium. It was found that 7.2 mol of N2 and 12.0 mol of H2 were present in the equilibrium mixture. The value of the equilibrium constant, Kc, for this
equilibrium is 6.0 × 10–2 at 500 K.
What is the concentration of ammonia present in the equilibrium mixture at 500 K?
11 Ammonia is made by the Haber process. The reactants are nitrogen and hydrogen.
N2(g) + 3H2(g) 2NH3(g) ∆H –ve
What will increase the rate of the forward reaction?
A adding argon to the mixture but keeping the total volume constant
B decreasing the temperature
C increasing the total pressure by reducing the total volume at constant temperature
D removing ammonia as it is made but keeping the total volume of the mixture the same 12 X is a Group II metal. The carbonate of X decomposes when heated in a Bunsen flame to give
carbon dioxide and a white solid residue as the only products. This white solid residue is sparingly soluble in water. Even when large amounts of the solid residue are added to water the pH of the saturated solution is less than that of limewater.
What could be the identity of X?
A magnesium
B calcium
C strontium
D barium 13 Rat poison needs to be insoluble in rain water but soluble at the low pH of stomach contents.
What is a suitable barium compound to use for rat poison?
A barium carbonate
B barium chloride
C barium hydroxide
D barium sulfate 14 Use of the Data Booklet is relevant to this question.
Which of the elements sodium, magnesium, aluminium, silicon, phosphorus, sulfur and chlorine
• has a lower first ionisation energy than the preceding element in the Periodic Table,
• conducts electricity and
• has a lower atomic radius than the preceding element in the Periodic Table?
15 The melting points of the Period 3 elements sodium to aluminium are shown in the table.
element Na Mg Al
mp / K 371 923 932
Which factor explains the increase in melting points from sodium to aluminium?
A the changes in first ionisation energy from sodium to aluminium
B the increase in electronegativity from sodium to aluminium
C the increase in the Ar of the elements from sodium to aluminium
D the increase in the number of outer electrons in each atom from sodium to aluminium 16 X is the oxide of a Period 3 element. X reacts with water to give an acidic solution.
A solution is prepared by reacting 0.100 g of X with excess water. This solution was neutralised by exactly 25.0 cm3 of 0.100 mol dm–3 sodium hydroxide solution.
What could be the identity of X?
A Al 2O3 B MgO C P4O10 D SO3 17 Which statement about bromine is correct?
A Bromine is insoluble in non-polar solvents.
B Bromine vapour is more dense than air.
C Bromine will not vaporise significantly under normal conditions.
D Gaseous bromine is purple. 18 The addition of aqueous silver nitrate to aqueous barium chloride produces a white precipitate
which dissolves in excess dilute aqueous ammonia to form a colourless solution.
The addition of excess dilute nitric acid to the colourless solution produces a white precipitate, Z.
22 Crude oil is a mixture of many hydrocarbons ranging in size from 1 to 40 carbon atoms per molecule. The alkanes in crude oil can be separated because they have different boiling points.
The table below shows the boiling points of some alkanes.
alkane boiling point
/ °C Mr
butane 0 58
pentane 36 72
hexane 69 86
2-methylbutane 28 72
dimethylpropane 10 72
2,3-dimethylbutane 58 86
What is the correct explanation for the difference in the boiling points of the three isomers with Mr = 72?
A Boiling point is dependent upon the length of the carbon chain only.
B Increased branching on a carbon chain increases the boiling point.
C Increased branching reduces the strength of the intermolecular hydrogen bonding.
D Increased branching reduces the strength of the intermolecular van der Waals’ forces. 23 Compound Q contains three double bonds per molecule.
CH2 CH2CH CH2C
O O
C OHX Y
Q
Which bond, X or Y, will be ruptured by hot, concentrated acidified KMnO4 and how many lone pairs of electrons are present in one molecule of Q?
Section B For each of the questions in this section, one or more of the three numbered statements 1 to 3 may be correct. Decide whether each of the statements is or is not correct (you may find it helpful to put a tick against the statements that you consider to be correct). The responses A to D should be selected on the basis of
A B C D
1, 2 and 3 are
correct
1 and 2 only are correct
2 and 3 only are correct
1 only is
correct
No other combination of statements is used as a correct response. 31 Which statements about orbitals in a krypton atom are correct?
1 The 1s and 2s orbitals have the same energy as each other but different sizes.
2 The third energy level (n=3) has three subshells and nine orbitals.
3 The 3d subshell has five orbitals that have the same energy as each other in an isolated atom.
32 The Group IV elements carbon, silicon and germanium can all exist in the giant molecular
structure which is also found in diamond. The bond lengths in these structures are given below.
The responses A to D should be selected on the basis of
A B C D
1, 2 and 3 are
correct
1 and 2 only are correct
2 and 3 only are correct
1 only is
correct
No other combination of statements is used as a correct response. 33 The salt NaCl O3 is used as a non-selective weedkiller.
On careful heating, this reaction occurs: 4NaCl O3 → NaCl + 3NaCl O4.
On strong heating this reaction occurs: NaCl O4 → NaCl + 2O2.
The overall reaction is 2NaCl O3 → 2NaCl + 3O2.
What do these equations show?
1 NaCl O3 can behave as an oxidising agent.
2 NaCl O3 can behave as a reducing agent.
3 The oxidation numbers of chlorine in the three compounds shown are +6, +8 and –1. 34 Which statements correctly describe an effect of a rise in temperature on a gas-phase reaction?
1 More particles now have energies greater than the activation energy.
2 The energy distribution profile changes with more particles having the most probable energy.
3 The activation energy of the reaction is decreased. 35 Which statements concerning the Group II elements magnesium, calcium and barium are
correct?
1 Their reactivity increases with increasing relative atomic mass.
2 The oxidation number exhibited in their stable compounds is +2.
3 On strong heating, their nitrates give off oxygen only. 36 Sulfur dioxide is used as a food preservative.
Which statements about sulfur dioxide, SO2, are correct?
37 An oxidising agent that can oxidise ethanal to ethanoic acid, or to ethanoate ions, will also oxidise methanoic acid, HCO2H, to carbon dioxide and water.
Which reagents, on heating, will react differently with HCO2H and CH3CO2H?
1 Na2CO3(aq)
2 Fehling’s reagent
3 dilute acidified KMnO4 38 Each of the compounds below is treated separately with excess NaBH4. The product of each
reaction is then heated with excess concentrated H2SO4.
In each case, one or more products are formed with molecular formula C7H10.
Which compounds give only one final product with the molecular formula C7H10?
1
O
O
2
O
O
3
O
O 39 Which reactions result in the formation of propanoic acid?
1 CH3CH2CO2Na with dilute H2SO4(aq)
2 CH3CH=CHCH3 with hot, concentrated H+ / MnO4
–(aq)
3 CH3CH2OH with H+ / Cr2O7
2–(aq) 40 The diagram shows the structure of propanamide.
H
H
H
C
H
H
H O
H
C C N
propanamide
Which statements about the hydrolysis of propanamide are correct?
1 Propanamide can be hydrolysed by heating under reflux with H2SO4(aq).
2 Propanamide can be hydrolysed by heating under reflux with NaOH(aq).
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
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 an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fl uid.DO NOT WRITE IN ANY BARCODES.
Answer all questions.Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.A Data Booklet is provided.
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.
CHEMISTRY 9701/21
Paper 2 Structured Questions AS Core October/November 2015
1 hour 15 minutes
Candidates answer on the Question Paper.
Additional Materials: Data Booklet
Cambridge International ExaminationsCambridge International Advanced Subsidiary and Advanced Level
(c) Aluminium reacts with chlorine to form a white, solid chloride that contains 79.7% chlorine and sublimes (changes straight from a solid to a gas) at 180 °C.
(i) Describe the structure and bonding in this compound. Suggest how it explains the low sublimation temperature.
(ii) Give the equation for the reaction for which the enthalpy change corresponds to the standard enthalpy change of formation of liquid sulfur trioxide, SO3. Include state symbols.
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
4 Some reactions involving ethanol are shown.
CH3CH2Cl CH3CH2OH Y
X
distil withCr2O7
2– + H+
reaction 1
reaction 2heat with NaOH
in ethanol
(a) (i) Give an equation for reaction 2 including the reagent needed for the conversion.
(ii) Explain, in terms of the properties of and intermolecular forces in CH3CH2OH and Y, why the chosen conditions for the reaction ensure that Y is the product.
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 an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fl uid.DO NOT WRITE IN ANY BARCODES.
Answer all questions.Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.A Data Booklet is provided.
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.
CHEMISTRY 9701/22
Paper 2 Structured Questions AS Core October/November 2015
1 hour 15 minutes
Candidates answer on the Question Paper.
Additional Materials: Data Booklet
Cambridge International ExaminationsCambridge International Advanced Subsidiary and Advanced Level
This document consists of 10 printed pages and 2 blank pages.
1 (a) Fill the gaps in the table for each of the given particles.
nameof isotope
typeof particle charge symbol electron
confi guration
carbon-13 1s22s22p2
–1 Cl3717
–
sulfur-34 atom 0
iron-54 cation 1s22s22p63s23p63d6
[5]
(b) One of the factors that determines the type of bonding present between the particles of a substance is the relative electronegativities of the bonded particles.
(i) Explain the meaning of the term electronegativity.
(b) The enthalpy change of hydration of anhydrous magnesium sulfate, ∆Hhyd MgSO4, can be calculated by carrying out two separate experiments.
In the fi rst experiment 45.00 g of water was weighed into a polystyrene cup and 3.01 g of MgSO4 was added and stirred until it was completely dissolved. The temperature of the water rose from 23.4 °C to 34.7 °C.
(i) Calculate the amount of heat energy transferred to the water during this dissolving process.
You can assume that the specifi c heat capacity of the solution is the same as that of water, 4.18 J g–1 K–1.
heat energy = .......................... J [1]
(ii) Calculate the amount, in moles, of MgSO4 dissolved.
(iii) Calculate the enthalpy change of solution, ∆Hsoln, of MgSO4(s).
You must include a sign with your answer.
∆Hsoln, of MgSO4(s) = .......................... kJ mol–1 [1]
In the second experiment, the enthalpy change of solution for the hydrated salt, MgSO4.7H2O(s), was calculated and found to be +9.60 kJ mol–1.
(iv) Use the equation below for the hydration of anhydrous magnesium sulfate to construct a suitable, fully labelled energy cycle that will allow you to calculate the enthalpy change for this reaction, ∆Hhyd MgSO4.
MgSO4(s) + 7H2O(l) → MgSO4.7H2O(s)
[1]
(v) Calculate the enthalpy change for this reaction, ∆Hhyd MgSO4. Include a sign in your answer.
(v) Draw and name the structures of the pair of geometrical isomers formed by reaction of 2-bromobutane with ethanolic sodium hydroxide.
name .............................................................
name .............................................................[2]
(vi) Name the third alkene produced by reaction of 2-bromobutane with ethanolic sodium hydroxide and explain why it does not show geometrical isomerism.
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
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 an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fl uid.DO NOT WRITE IN ANY BARCODES.
Answer all questions.Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.A Data Booklet is provided.
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.
CHEMISTRY 9701/23
Paper 2 Structured Questions AS Core October/November 2015
1 hour 15 minutes
Candidates answer on the Question Paper.
Additional Materials: Data Booklet
Cambridge International ExaminationsCambridge International Advanced Subsidiary and Advanced Level
(c) Aluminium reacts with chlorine to form a white, solid chloride that contains 79.7% chlorine and sublimes (changes straight from a solid to a gas) at 180 °C.
(i) Describe the structure and bonding in this compound. Suggest how it explains the low sublimation temperature.
(ii) Give the equation for the reaction for which the enthalpy change corresponds to the standard enthalpy change of formation of liquid sulfur trioxide, SO3. Include state symbols.
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
4 Some reactions involving ethanol are shown.
CH3CH2Cl CH3CH2OH Y
X
distil withCr2O7
2– + H+
reaction 1
reaction 2heat with NaOH
in ethanol
(a) (i) Give an equation for reaction 2 including the reagent needed for the conversion.
(ii) Explain, in terms of the properties of and intermolecular forces in CH3CH2OH and Y, why the chosen conditions for the reaction ensure that Y is the product.
Write your Centre number, candidate number and name on all the work you hand in.Give details of the practical session and laboratory where appropriate, in the boxes provided.Write in dark blue or black pen.You may use an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.
Answer all questions.Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.Use of a Data Booklet is unnecessary.A copy of the Periodic Table is printed on page 12.
Qualitative Analysis Notes are printed on pages 10 and 11.
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.
CHEMISTRY 9701/31
Paper 3 Advanced Practical Skills 1 October/November 2015
2 hours
Candidates answer on the Question Paper.
Additional Materials: As listed in the Confidential Instructions
Cambridge International ExaminationsCambridge International Advanced Subsidiary and Advanced Level
This document consists of 12 printed pages and 1 insert.
1 In this experiment you will determine the ionic equation for the reaction of acidified potassium manganate(VII) with potassium iodide. Excess potassium iodide is used and the reaction produces iodine. The amount of iodine produced is measured by titration with sodium thiosulfate.
FA 1 is 0.0180 mol dm–3 potassium manganate(VII), KMnO4. FA 2 is 1.00 mol dm–3 sulfuric acid, H2SO4. FA 3 is 0.500 mol dm–3 potassium iodide, KI. FA 4 is 0.100 mol dm–3 sodium thiosulfate, Na2S2O3. starch indicator
(a) Method
● Pipette 25.0 cm3 of FA 1 into a conical flask. ● Use the measuring cylinder to add 25 cm3 of FA 2 to the conical flask. ● Use the measuring cylinder to add 20 cm3 of FA 3 to the conical flask. ● Fill the burette with FA 4. ● Carry out a rough titration. When the colour of the mixture becomes yellow/orange, add a
few drops of starch indicator. Then titrate until the mixture goes colourless. ● Record all your burette readings in the space below.
The rough titre is ........................ cm3.
● Carry out as many accurate titrations as you think necessary to obtain consistent results. ● Make sure any recorded results show the precision of your practical work. ● Record in a suitable form below all of your burette readings and the volume of FA 4 added
in each accurate titration.
Keep FA 1 and FA 2 for use in Question 3 and FA 4 for use in Question 2.
[7]
(b) From your accurate titration results, obtain a suitable value for the volume of FA 4 to be used in your calculations.
Show clearly how you have obtained this value.
Volume of FA 4 required is ..................... cm3. [1]
Show your working and appropriate significant figures in the final answer to each step of your calculations.
(i) Calculate the number of moles of sodium thiosulfate in the volume of FA 4 calculatedin (b).
moles of Na2S2O3 = ............................. mol
(ii) Use the equation below to calculate the number of moles of iodine that reacted with the sodium thiosulfate in the titration.
I2 + 2Na2S2O3 → Na2S4O6 + 2NaI
moles of I2 = ............................. mol
(iii) Use information on page 2 to calculate the number of moles of potassium manganate(VII) in FA 1 used in the titration.
moles of KMnO4 = ............................. mol
(iv) From your answers to (ii) and (iii), calculate the number of moles of iodine produced by the reaction of 2.00 moles of potassium manganate(VII) with excess potassium iodide.
moles I2 = ............................. mol
(v) Using your answer to (iv), put a tick next to the ionic equation that represents the reaction between FA 1 and FA 3.
2 In this experiment you will investigate how the rate of reaction between sodium thiosulfate and hydrochloric acid is affected by the concentration of the acid.
When aqueous thiosulfate ions react with hydrogen ions, H+, in any acid, a pale yellow precipitate of sulfur is formed. The ionic equation for this reaction is given below.
S2O32–(aq) + 2H+(aq) → S(s) + SO2(aq) + H2O(l)
The rate of the reaction can be determined by measuring the time taken to produce a fixed quantity of sulfur.
FA 4 is 0.10 mol dm–3 sodium thiosulfate, Na2S2O3. FA 5 is 0.20 mol dm–3 hydrochloric acid, HCl.
(a) Method
Record all your measurements, in an appropriate form, in the space below.
Experiment 1
● Use the larger measuring cylinder to transfer 40 cm3 of FA 4 into the 100 cm3 beaker. ● Rinse the larger measuring cylinder thoroughly with water, then add 30 cm3 of FA 5 to the
beaker and start timing immediately. ● Stir the mixture once and place the beaker on top of the printed insert page provided. ● Look down through the solution in the beaker at the print on the insert. ● Stop timing as soon as the precipitate of sulfur makes the print on the insert invisible. ● Record the reaction time to the nearest second. ● Empty and rinse the 100 cm3 beaker. ● Dry the outside of the beaker ready for Experiment 2.
Experiment 2
● Rinse the larger measuring cylinder, then use it to transfer 40 cm3 of FA 4 into the 100 cm3 beaker.
● Use the smaller measuring cylinder to add 10 cm3 of distilled water to the beaker. ● Use the same measuring cylinder to add 20 cm3 of FA 5 to the mixture in the beaker and
start timing immediately. ● Stir the mixture once and place the beaker on top of the printed insert page provided. ● Stop timing as soon as the print on the insert becomes invisible. ● Record the reaction time to the nearest second. ● Empty and rinse the 100 cm3 beaker. ● Dry the outside of the beaker ready for Experiment 3.
Experiment 3
● Carry out the reaction using a mixture of 40 cm3 of FA 4, 20 cm3 of distilled water and 10 cm3 of FA 5.
● Measure and record the reaction time to the nearest second.
(iv) Predict how the reaction time measured in Experiment 1 would have been affected if the experiment had been carried out using 0.20 mol dm–3 sulfuric acid instead of 0.20 mol dm–3 hydrochloric acid.
(v) Predict how the reaction time measured in Experiment 3 would have been affected if the experiment had been carried out in a 250 cm3 beaker instead of a 100 cm3 beaker.
At each stage of any test you are to record details of the following.
● colour changes seen ● the formation of any precipitate ● the solubility of such precipitates in an excess of the reagent added
Where gases are released they should be identified by a test, described in the appropriate place in your observations.
You should indicate clearly at what stage in a test a change occurs. No additional tests for ions present should be attempted.
If any solution is warmed, a boiling tube MUST be used.
Rinse and reuse test-tubes and boiling tubes where possible.
Where reagents are selected for use in a test, the name or correct formula of the element or compound must be given.
(a) FA 6 is a sodium compound containing one anion listed on page 11.
Dissolve the FA 6 provided in about 15 cm3 of distilled water in a boiling tube. Carry out the following tests and record your observations in the table below.
test observations (i) To a 1cm depth of the solution
of FA 6 in a test-tube, add a few drops of aqueous barium chloride or aqueous barium nitrate, then
add dilute hydrochloric acid.
(ii) To a 1cm depth of the solution of FA 6 in a test-tube, add an equal volume of aqueous hydrogen peroxide, then
add a few drops of aqueous barium chloride or aqueous barium nitrate, then
(b) FA 7, FA 8, FA 9 and FA 10 each contain one cation from the list on page 10. You will attempt to identify the cations by testing with aqueous sodium hydroxide and aqueous
ammonia. In each case, use a 1 cm depth of the solution in a test-tube.
(i) Complete the table below.
testobservations
FA 7 FA 8 FA 9 FA 10
add sodiumhydroxide
add aqueousammonia
(ii) Use your observations to identify, as far as possible, the cation present in each solution. If alternative identities are possible, state this clearly.
FA 7 cation ....................................................
FA 8 cation ....................................................
FA 9 cation ....................................................
FA 10 cation ..................................................
(iii) Give the ionic equation for the reaction of one of your cations with a few drops of sodium hydroxide. State symbols are not required.
(iv) The precipitates obtained when alkalis are added to solutions of certain cations are sometimes difficult to see. Suggest how, using no additional apparatus, the experiment could be repeated in a way that would make these precipitates more visible.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Gro
up
140
Ce
Cer
ium
58
141
PrP
rase
odym
ium
59
144
Nd
Neo
dym
ium
60
PmP
rom
ethi
um61
150
SmS
amar
ium
62
152
EuE
urop
ium
63
157
Gd
Gad
olin
ium
64
159
Tb Terb
ium
65
163
Dy
Dys
pros
ium
66
165
Ho
Hol
miu
m67
167
Er Erb
ium
68
169
Tm Thul
ium
69
173
YbY
tterb
ium
70
175
LuLu
tetiu
m71
Th Thor
ium
90
PaP
rota
ctin
ium
91
UU
rani
um92
Np
Nep
tuni
um93
PuP
luto
nium
94
Am
Am
eric
ium
95
Cm
Cur
ium
96
Bk
Ber
keliu
m97
Cf
Cal
iforn
ium
98
EsE
inst
eini
um99
Fm Ferm
ium
100
Md
Men
dele
vium
101
No
Nob
eliu
m10
2
LrLa
wre
nciu
m10
3
1.0 H
Hyd
roge
n1
6.9 Li
Lith
ium
3
23.0
Na
Sod
ium
11
24.3
Mg
Mag
nesi
um12
40.1
Ca
Cal
cium
20
45.0 Sc
Sca
ndiu
m21
47.9 Ti
Tita
nium
22
50.9 V
Vana
dium
23
52.0 Cr
Chr
omiu
m24
54.9
Mn
Man
gane
se25
55.8 Fe Iron
26
58.9
Co
Cob
alt
27
58.7 Ni
Nic
kel
28
63.5
Cu
Cop
per
29
65.4
Zn Zinc
30
69.7
Ga
Gal
lium
31
27.0 Al
Alu
min
ium
13
10.8 B B
oron
5
12.0 C
Car
bon
6
14.0 N
Nitr
ogen
7
16.0 O
Oxy
gen
8
19.0 F
Fluo
rine
9
28.1 Si S
ilico
n14
31.0 P
Pho
spho
rus
15
32.1 S S
ulfu
r16
35.5 Cl
Chl
orin
e17
39.9 Ar
Arg
on18
20.2 Ne
Neo
n10
4.0
He
Hel
ium
2
72.6
Ge
Ger
man
ium
32
74.9
As
Ars
enic
33
79.0 Se
Sel
eniu
m34
79.9 Br
Bro
min
e35
83.8 Kr
Kry
pton
36
39.1 K
Pot
assi
um19
87.6 Sr
Stro
ntiu
m38
88.9 Y
Yttr
ium
39
91.2 Zr
Zirc
oniu
m40
92.9
Nb
Nio
bium
41
95.9
Mo
Mol
ybde
num
42
TcTe
chne
tium
43
101
Ru
Rut
heni
um44
103
Rh
Rho
dium
45
106
PdP
alla
dium
46
108
Ag
Silv
er47
112
Cd
Cad
miu
m48
115
In Indi
um49
119
Sn Tin
50
122
SbA
ntim
ony
51
128
TeTe
lluriu
m52
127 I
Iodi
ne53
131
Xe Xen
on54
137
Ba
Bar
ium
56
139
LaLa
ntha
num
57
*
178
Hf
Haf
nium
72
181
TaTa
ntal
um73
184 W
Tung
sten
74
186
Re
Rhe
nium
75
190
Os
Osm
ium
76
192
Ir Iridi
um77
195 Pt
Pla
tinum
78
197
Au
Gol
d79
201
Hg
Mer
cury
80
204 Tl
Thal
lium
81
207
Pb Lead
82
209 Bi
Bis
mut
h83
PoP
olon
ium
84
At
Ast
atin
e85
Rn
Rad
on86
Rf
Rut
herfo
rdiu
m10
4
Db
Dub
nium
105
SgS
eabo
rgiu
m10
6
Bh
Boh
rium
107
Hs
Has
sium
108
Mt
Mei
tner
ium
109
Uun
Unu
nnili
um11
0
Uuu
Unu
nuni
um11
1
Uub
Unu
nbiu
m11
2
Uuq
Unu
nqua
dium
114
Uuh
Unu
nhex
ium
116
Uuo
Unu
noct
ium
118
FrFr
anci
um87
Ac
Act
iniu
m89
9.0
Be
Ber
ylliu
m4
III
IIIIV
VV
IV
II0
85.5
Rb
Rub
idiu
m37
133
Cs
Cae
sium
55
Ra
Rad
ium
88 a Xb
a =
rela
tive
atom
ic m
ass
X =
atom
ic s
ymbo
l
b =
prot
on (a
tom
ic) n
umbe
r
Key
* 58-
71 L
anth
anid
es90
-103
Act
inid
es
The
Perio
dic
Tabl
e of
the
Elem
ents
*
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name on all the work you hand in.Give details of the practical session and laboratory where appropriate, in the boxes provided.Write in dark blue or black pen.You may use an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fl uid.DO NOT WRITE IN ANY BARCODES.
Answer all questions.Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.Use of a Data Booklet is unnecessary.
Qualitative Analysis Notes are printed on pages 10 and 11.A Periodic Table is printed on page 12.
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.
CHEMISTRY 9701/33
Paper 3 Advanced Practical Skills 1 October/November 2015
2 hours
Candidates answer on the Question Paper.
Additional Materials: As listed in the Confi dential Instructions
Cambridge International ExaminationsCambridge International Advanced Subsidiary and Advanced Level
1 The formula of hydrated copper(II) sulfate is CuSO4.xH2O where x is the number of moles of water of crystallisation in one mole of salt. You will determine the value of x by titration.
When aqueous copper(II) ions react with aqueous iodide ions, I–, iodine is produced.
2Cu2+(aq) + 4I–(aq) → I2(aq) + 2CuI(s)
The amount of iodine, I2, produced can be found by titrating it with aqueous thiosulfate ions, S2O32–.
2S2O32–(aq) + I2(aq) → S4O6
2–(aq) + 2I–(aq)
FA 1 is aqueous CuSO4.xH2O containing 26.2 g dm–3. FA 2 is 0.100 mol dm–3 sodium thiosulfate, Na2S2O3. FA 3 is aqueous potassium iodide, KI. starch indicator
(a) Method
● Pipette 25.0 cm3 of FA 1 into a conical flask. ● Use the measuring cylinder to add 15 cm3 of FA 3, an excess of KI, to the conical flask.
The solution will turn brown because iodine is formed. ● Fill the burette with FA 2. ● Add FA 2 from the burette until the colour of the mixture changes to pale brown. ● Add 10 drops of starch indicator. The mixture will turn blue-black. ● Continue adding FA 2 from the burette until the dark colour suddenly disappears to leave
an off-white solid. This is the end point of the titration. ● Carry out a rough titration and record your burette readings in the space below.
The rough titre is ............................. cm3.
● Carry out as many accurate titrations as you think necessary to obtain consistent results. ● Make certain any recorded results show the precision of your practical work. ● Record in a suitable form below, all your burette readings and the volume of FA 2 added
2 FA 4 is an impure sample of hydrated calcium chloride, CaCl 2.2H2O. On heating, hydrated calcium chloride loses its water of crystallisation.
CaCl 2.2H2O(s) → CaCl 2(s) + 2H2O(g)
You will determine the purity of FA 4 by measuring the loss in mass that occurs when it is heated. The impurity present in FA 4 is not decomposed on heating.
(a) Method
You should read the instructions carefully before starting any practical work and draw a table for your results in the space below.
● Weigh a crucible and record its mass. ● Add between 1.80 g and 2.00 g of FA 4 into the crucible. ● Reweigh the crucible and its contents and record the mass. ● Place the crucible on the pipe-clay triangle and heat gently for 1 minute and then strongly
for a further 2 minutes. ● Allow the crucible and its contents to cool. Reweigh the crucible and contents and record
the mass. ● Heat the crucible strongly for a further 2 minutes. Allow it to cool. Reweigh the crucible and
contents and record the mass. ● Repeat the heating, cooling and weighing until you are satisfied that all the water of
crystallisation has been removed. ● Calculate and record the mass of FA 4 used and the total mass of water lost.
While you are waiting for the crucible to cool, you may wish to start work on Question 3.
At each stage of any test you are to record details of the following.
● colour changes seen ● the formation of any precipitate ● the solubility of such precipitates in an excess of the reagent added
Where gases are released they should be identifi ed by a test, described in the appropriate place in your observations.
You should indicate clearly at what stage in a test a change occurs. No additional tests for ions present should be attempted.
If any solution is warmed, a boiling tube MUST be used.
Rinse and reuse test-tubes and boiling tubes where possible.
Where reagents are selected for use in a test, the name or correct formula of the element or compound must be given.
(a) (i) FA 5, FA 6 and FA 7 are aqueous solutions each containing one anion and one cation.
Carry out the experiments described below and record your observations for each solution in the table.
FA 5 FA 6 FA 7To a 1 cm depth in a test-tube, add a 1 cm depth of aqueous sodium carbonate.To a 1 cm depth in atest-tube, add a 1 cm depth of aqueous copper(II) sulfate.To a 1 cm depth in atest-tube, add a 1 cm depth of aqueousbarium chloride or aqueous barium nitrate.
(b) FA 8 contains two anions and two cations from the lists on pages 10 and 11.
• To a 5 cm depth of distilled water in a boiling tube, add all the FA 8. • Shake the boiling tube thoroughly for one minute to make sure that no more of the solid
will dissolve. • Filter the mixture into a clean boiling tube. • Place the filter funnel in a conical flask and wash the residue with a little distilled water. • Keep both filtrate and residue for tests (i) and (ii) below.
(i) Tests on the fi ltrate (the solution in the boiling tube)
Carry out the following tests and record your observations in the table below.
test observationsTo a 1 cm depth of the fi ltrate in a test-tube, add aqueous sodium hydroxide, then
add aqueous hydrogen peroxide.
(ii) Tests on the residue
Carry out the following tests and record your observations in the table below.
test observationsPlace the funnel containing the residue into a clean boiling tube. Pour approximately 5 cm3 of dilute nitric acid onto the residue. Collect a 1 cm depth of solution in the boiling tube. Remove the funnel and return it to the conical fl ask.To this solution in the boiling tube, add aqueous sodium hydroxide.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Gro
up
140
Ce
Cer
ium
58
141
PrP
rase
odym
ium
59
144
Nd
Neo
dym
ium
60
PmP
rom
ethi
um61
150
SmS
amar
ium
62
152
EuE
urop
ium
63
157
Gd
Gad
olin
ium
64
159
Tb Terb
ium
65
163
Dy
Dys
pros
ium
66
165
Ho
Hol
miu
m67
167
Er Erb
ium
68
169
Tm Thul
ium
69
173
YbY
tterb
ium
70
175
LuLu
tetiu
m71
Th Thor
ium
90
PaP
rota
ctin
ium
91
UU
rani
um92
Np
Nep
tuni
um93
PuP
luto
nium
94
Am
Am
eric
ium
95
Cm
Cur
ium
96
Bk
Ber
keliu
m97
Cf
Cal
iforn
ium
98
EsE
inst
eini
um99
Fm Ferm
ium
100
Md
Men
dele
vium
101
No
Nob
eliu
m10
2
LrLa
wre
nciu
m10
3
1.0 H
Hyd
roge
n1
6.9 Li
Lith
ium
3
23.0
Na
Sod
ium
11
24.3
Mg
Mag
nesi
um12
40.1
Ca
Cal
cium
20
45.0 Sc
Sca
ndiu
m21
47.9 Ti
Tita
nium
22
50.9 V
Vana
dium
23
52.0 Cr
Chr
omiu
m24
54.9
Mn
Man
gane
se25
55.8 Fe Iron
26
58.9
Co
Cob
alt
27
58.7 Ni
Nic
kel
28
63.5
Cu
Cop
per
29
65.4
Zn Zinc
30
69.7
Ga
Gal
lium
31
27.0 Al
Alu
min
ium
13
10.8 B B
oron
5
12.0 C
Car
bon
6
14.0 N
Nitr
ogen
7
16.0 O
Oxy
gen
8
19.0 F
Fluo
rine
9
28.1 Si S
ilico
n14
31.0 P
Pho
spho
rus
15
32.1 S S
ulfu
r16
35.5 Cl
Chl
orin
e17
39.9 Ar
Arg
on18
20.2 Ne
Neo
n10
4.0
He
Hel
ium
2
72.6
Ge
Ger
man
ium
32
74.9
As
Ars
enic
33
79.0 Se
Sel
eniu
m34
79.9 Br
Bro
min
e35
83.8 Kr
Kry
pton
36
39.1 K
Pot
assi
um19
87.6 Sr
Stro
ntiu
m38
88.9 Y
Yttr
ium
39
91.2 Zr
Zirc
oniu
m40
92.9
Nb
Nio
bium
41
95.9
Mo
Mol
ybde
num
42
TcTe
chne
tium
43
101
Ru
Rut
heni
um44
103
Rh
Rho
dium
45
106
PdP
alla
dium
46
108
Ag
Silv
er47
112
Cd
Cad
miu
m48
115
In Indi
um49
119
Sn Tin
50
122
SbA
ntim
ony
51
128
TeTe
lluriu
m52
127 I
Iodi
ne53
131
Xe Xen
on54
137
Ba
Bar
ium
56
139
LaLa
ntha
num
57
*
178
Hf
Haf
nium
72
181
TaTa
ntal
um73
184 W
Tung
sten
74
186
Re
Rhe
nium
75
190
Os
Osm
ium
76
192
Ir Iridi
um77
195 Pt
Pla
tinum
78
197
Au
Gol
d79
201
Hg
Mer
cury
80
204 Tl
Thal
lium
81
207
Pb Lead
82
209 Bi
Bis
mut
h83
PoP
olon
ium
84
At
Ast
atin
e85
Rn
Rad
on86
Rf
Rut
herfo
rdiu
m10
4
Db
Dub
nium
105
SgS
eabo
rgiu
m10
6
Bh
Boh
rium
107
Hs
Has
sium
108
Mt
Mei
tner
ium
109
Uun
Unu
nnili
um11
0
Uuu
Unu
nuni
um11
1
Uub
Unu
nbiu
m11
2
Uuq
Unu
nqua
dium
114
Uuh
Unu
nhex
ium
116
Uuo
Unu
noct
ium
118
FrFr
anci
um87
Ac
Act
iniu
m89
9.0
Be
Ber
ylliu
m4
III
IIIIV
VV
IV
II0
85.5
Rb
Rub
idiu
m37
133
Cs
Cae
sium
55
Ra
Rad
ium
88 a Xb
a =
rela
tive
atom
ic m
ass
X =
atom
ic s
ymbo
l
b =
prot
on (a
tom
ic) n
umbe
r
Key
* 58-
71 L
anth
anid
es90
-103
Act
inid
es
The
Perio
dic
Tabl
e of
the
Elem
ents
*
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name on all the work you hand in.Give details of the practical session and laboratory where appropriate, in the boxes provided.Write in dark blue or black pen.You may use an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fl uid.DO NOT WRITE IN ANY BARCODES.
Answer all questions.Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.Use of a Data Booklet is unnecessary.
Qualitative Analysis Notes are printed on pages 10 and 11.A Periodic Table is printed on page 12.
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.
CHEMISTRY 9701/34
Paper 3 Advanced Practical Skills 2 October/November 2015
2 hours
Candidates answer on the Question Paper.
Additional Materials: As listed in the Confi dential Instructions
Cambridge International ExaminationsCambridge International Advanced Subsidiary and Advanced Level
1 In this experiment you will determine the relative atomic mass, Ar, of magnesium by a titration method.
FB 1 is 2.00 mol dm–3 hydrochloric acid, HCl. FB 3 is 0.120 mol dm–3 sodium hydroxide, NaOH. magnesium ribbon bromophenol blue indicator
(a) Method
Reaction of magnesium with FB 1 ● Pipette 25.0 cm3 of FB 1 into the 250 cm3 beaker. ● Weigh the strip of magnesium ribbon and record its mass.
mass of magnesium = ................... g
● Coil the strip of magnesium ribbon loosely and then add it to the FB 1 in the beaker. ● Stir the mixture occasionally and wait until the reaction has finished.
Dilution of the excess acid ● Transfer all the solution from the beaker into the volumetric flask. ● Make the solution up to the mark using distilled water. ● Shake the flask to mix the solution before using it for your titrations. ● Label this solution of hydrochloric acid FB 2.
Titration ● Fill the burette with FB 2. ● Rinse the pipette out thoroughly. Then pipette 25.0 cm3 of FB 3 into a conical fl ask. ● Add several drops of bromophenol blue indicator. ● Perform a rough titration, by running the solution from the burette into the conical fl ask
until the mixture just becomes yellow. ● Record your burette readings in the space below.
The rough titre is ................... cm3.
● Carry out as many accurate titrations as you think necessary to obtain consistent results. ● Make sure any recorded results show the precision of your practical work. ● Record in a suitable form below all of your burette readings and the volume of FB 2 added
(v) In (a), you reacted 25.0 cm3 of FB 1 with your weighed piece of magnesium. After the reaction, the unreacted hydrochloric acid was used to prepare 250 cm3 of FB 2.
Use your answers to (iii) and (iv) to calculate the number of moles of hydrochloric acid that reacted with the magnesium ribbon.
moles of HCl reacting with Mg = ................... mol
(vi) Complete the equation below, for the reaction of magnesium with hydrochloric acid. State symbols are required.
Mg + HCl → MgCl 2 + ............................
Use your answer to (v) to calculate the number of moles of magnesium used.
moles of Mg = ................... mol
(vii) Use your answer to (vi) to calculate the relative atomic mass, Ar, of magnesium.
Ar of Mg = ...................[6]
(d) (i) State one observation that proves that the hydrochloric acid in FB 1 was in excess for the reaction with the magnesium ribbon.
(ii) A student carried out exactly the same experiment but used 1.00 g of magnesium ribbon. State and explain why the student’s experiment could not be used to determine the value
for the Ar of magnesium. Include a calculation in your answer.
2 In this experiment you will determine the relative atomic mass of magnesium by thermal decomposition of hydrated magnesium sulfate.
MgSO4.7H2O(s) → MgSO4(s) + 7H2O(g)
FB 4 is hydrated magnesium sulfate, MgSO4.7H2O.
(a) Method
Record all your weighings in the space below.
● Weigh the crucible with its lid. ● Transfer all FB 4 into the crucible. ● Weigh the crucible, lid and FB 4. ● Place the crucible on the pipe-clay triangle. ● Heat the crucible gently with the lid on, for about one minute. ● Then heat the crucible strongly, without the lid, for a further four minutes. ● Leave the crucible and its contents to cool with the lid on, for several minutes. ● While the crucible is cooling, begin work on Question 3. ● When the crucible has cooled, weigh it, with the lid and contents. ● Calculate and record the mass of anhydrous magnesium sulfate produced and the mass
of water lost.
[3]
(b) Calculations
(i) Calculate the number of moles of water lost during heating. (Use the data in the Periodic Table on page 12.)
moles of H2O = ................... mol
(ii) Use the equation above and your answer to (i) to calculate the number of moles of anhydrous magnesium sulfate produced.
At each stage of any test you are to record details of the following.
● colour changes seen ● the formation of any precipitate ● the solubility of such precipitates in an excess of the reagent added
Where gases are released they should be identifi ed by a test, described in the appropriate place in your observations.
You should indicate clearly at what stage in a test a change occurs. Marks are not given for chemical equations. No additional tests for ions present should be attempted.
If any solution is warmed, a boiling tube MUST be used.
Rinse and reuse test-tubes and boiling tubes where possible.
Where reagents are selected for use in a test, the name or correct formula of the element or compound must be given.
(a) FB 5 is a solution containing one cation and one anion. Carry out test-tube tests to fi nd out whether the cation in FB 5 is magnesium and whether the
anion is sulfate.
● State what reagents you used. ● Record the observations you made in a table. ● State your conclusions about which ions are present.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Gro
up
140
Ce
Cer
ium
58
141
PrP
rase
odym
ium
59
144
Nd
Neo
dym
ium
60
PmP
rom
ethi
um61
150
SmS
amar
ium
62
152
EuE
urop
ium
63
157
Gd
Gad
olin
ium
64
159
Tb Terb
ium
65
163
Dy
Dys
pros
ium
66
165
Ho
Hol
miu
m67
167
Er Erb
ium
68
169
Tm Thul
ium
69
173
YbY
tterb
ium
70
175
LuLu
tetiu
m71
Th Thor
ium
90
PaP
rota
ctin
ium
91
UU
rani
um92
Np
Nep
tuni
um93
PuP
luto
nium
94
Am
Am
eric
ium
95
Cm
Cur
ium
96
Bk
Ber
keliu
m97
Cf
Cal
iforn
ium
98
EsE
inst
eini
um99
Fm Ferm
ium
100
Md
Men
dele
vium
101
No
Nob
eliu
m10
2
LrLa
wre
nciu
m10
3
1.0 H
Hyd
roge
n1
6.9 Li
Lith
ium
3
23.0
Na
Sod
ium
11
24.3
Mg
Mag
nesi
um12
40.1
Ca
Cal
cium
20
45.0 Sc
Sca
ndiu
m21
47.9 Ti
Tita
nium
22
50.9 V
Vana
dium
23
52.0 Cr
Chr
omiu
m24
54.9
Mn
Man
gane
se25
55.8 Fe Iron
26
58.9
Co
Cob
alt
27
58.7 Ni
Nic
kel
28
63.5
Cu
Cop
per
29
65.4
Zn Zinc
30
69.7
Ga
Gal
lium
31
27.0 Al
Alu
min
ium
13
10.8 B B
oron
5
12.0 C
Car
bon
6
14.0 N
Nitr
ogen
7
16.0 O
Oxy
gen
8
19.0 F
Fluo
rine
9
28.1 Si S
ilico
n14
31.0 P
Pho
spho
rus
15
32.1 S S
ulfu
r16
35.5 Cl
Chl
orin
e17
39.9 Ar
Arg
on18
20.2 Ne
Neo
n10
4.0
He
Hel
ium
2
72.6
Ge
Ger
man
ium
32
74.9
As
Ars
enic
33
79.0 Se
Sel
eniu
m34
79.9 Br
Bro
min
e35
83.8 Kr
Kry
pton
36
39.1 K
Pot
assi
um19
87.6 Sr
Stro
ntiu
m38
88.9 Y
Yttr
ium
39
91.2 Zr
Zirc
oniu
m40
92.9
Nb
Nio
bium
41
95.9
Mo
Mol
ybde
num
42
TcTe
chne
tium
43
101
Ru
Rut
heni
um44
103
Rh
Rho
dium
45
106
PdP
alla
dium
46
108
Ag
Silv
er47
112
Cd
Cad
miu
m48
115
In Indi
um49
119
Sn Tin
50
122
SbA
ntim
ony
51
128
TeTe
lluriu
m52
127 I
Iodi
ne53
131
Xe Xen
on54
137
Ba
Bar
ium
56
139
LaLa
ntha
num
57
*
178
Hf
Haf
nium
72
181
TaTa
ntal
um73
184 W
Tung
sten
74
186
Re
Rhe
nium
75
190
Os
Osm
ium
76
192
Ir Iridi
um77
195 Pt
Pla
tinum
78
197
Au
Gol
d79
201
Hg
Mer
cury
80
204 Tl
Thal
lium
81
207
Pb Lead
82
209 Bi
Bis
mut
h83
PoP
olon
ium
84
At
Ast
atin
e85
Rn
Rad
on86
Rf
Rut
herfo
rdiu
m10
4
Db
Dub
nium
105
SgS
eabo
rgiu
m10
6
Bh
Boh
rium
107
Hs
Has
sium
108
Mt
Mei
tner
ium
109
Uun
Unu
nnili
um11
0
Uuu
Unu
nuni
um11
1
Uub
Unu
nbiu
m11
2
Uuq
Unu
nqua
dium
114
Uuh
Unu
nhex
ium
116
Uuo
Unu
noct
ium
118
FrFr
anci
um87
Ac
Act
iniu
m89
9.0
Be
Ber
ylliu
m4
III
IIIIV
VV
IV
II0
85.5
Rb
Rub
idiu
m37
133
Cs
Cae
sium
55
Ra
Rad
ium
88 a Xb
a =
rela
tive
atom
ic m
ass
X =
atom
ic s
ymbo
l
b =
prot
on (a
tom
ic) n
umbe
r
Key
* 58-
71 L
anth
anid
es90
-103
Act
inid
es
The
Perio
dic
Tabl
e of
the
Elem
ents
*
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name on all the work you hand in.Give details of the practical session and laboratory where appropriate, in the boxes provided.Write in dark blue or black pen.You may use an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fl uid.DO NOT WRITE IN ANY BARCODES.
Answer all questions.Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.Use of a Data Booklet is unnecessary.A copy of the Periodic Table is printed on page 12.
Qualitative Analysis Notes are printed on pages 10 and 11.
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.
CHEMISTRY 9701/35
Paper 3 Advanced Practical Skills 1 October/November 2015
2 hours
Candidates answer on the Question Paper.
Additional Materials: As listed in the Confi dential Instructions
Cambridge International ExaminationsCambridge International Advanced Subsidiary and Advanced Level
This document consists of 12 printed pages and 1 insert.
1 In this experiment you will determine the ionic equation for the reaction of acidifi ed potassium manganate(VII) with potassium iodide. Excess potassium iodide is used and the reaction produces iodine. The amount of iodine produced is measured by titration with sodium thiosulfate.
FA 1 is 0.0180 mol dm–3 potassium manganate(VII), KMnO4. FA 2 is 1.00 mol dm–3 sulfuric acid, H2SO4. FA 3 is 0.500 mol dm–3 potassium iodide, KI. FA 4 is 0.100 mol dm–3 sodium thiosulfate, Na2S2O3. starch indicator
(a) Method
● Pipette 25.0 cm3 of FA 1 into a conical fl ask. ● Use the measuring cylinder to add 25 cm3 of FA 2 to the conical fl ask. ● Use the measuring cylinder to add 20 cm3 of FA 3 to the conical fl ask. ● Fill the burette with FA 4. ● Carry out a rough titration. When the colour of the mixture becomes yellow/orange, add a
few drops of starch indicator. Then titrate until the mixture goes colourless. ● Record all your burette readings in the space below.
The rough titre is ........................ cm3.
● Carry out as many accurate titrations as you think necessary to obtain consistent results. ● Make sure any recorded results show the precision of your practical work. ● Record in a suitable form below all of your burette readings and the volume of FA 4 added
in each accurate titration.
Keep FA 1 and FA 2 for use in Question 3 and FA 4 for use in Question 2.
[7]
(b) From your accurate titration results, obtain a suitable value for the volume of FA 4 to be used in your calculations.
Show clearly how you have obtained this value.
Volume of FA 4 required is ..................... cm3. [1]
Show your working and appropriate signifi cant fi gures in the fi nal answer to each step of your calculations.
(i) Calculate the number of moles of sodium thiosulfate in the volume of FA 4 calculatedin (b).
moles of Na2S2O3 = ............................. mol
(ii) Use the equation below to calculate the number of moles of iodine that reacted with the sodium thiosulfate in the titration.
I2 + 2Na2S2O3 → Na2S4O6 + 2NaI
moles of I2 = ............................. mol
(iii) Use information on page 2 to calculate the number of moles of potassium manganate(VII) in FA 1 used in the titration.
moles of KMnO4 = ............................. mol
(iv) From your answers to (ii) and (iii), calculate the number of moles of iodine produced by the reaction of 2.00 moles of potassium manganate(VII) with excess potassium iodide.
moles I2 = ............................. mol
(v) Using your answer to (iv), put a tick next to the ionic equation that represents the reaction between FA 1 and FA 3.
2 In this experiment you will investigate how the rate of reaction between sodium thiosulfate and hydrochloric acid is affected by the concentration of the acid.
When aqueous thiosulfate ions react with hydrogen ions, H+, in any acid, a pale yellow precipitate of sulfur is formed. The ionic equation for this reaction is given below.
S2O32–(aq) + 2H+(aq) → S(s) + SO2(aq) + H2O(l)
The rate of the reaction can be determined by measuring the time taken to produce a fi xed quantity of sulfur.
FA 4 is 0.10 mol dm–3 sodium thiosulfate, Na2S2O3. FA 5 is 0.20 mol dm–3 hydrochloric acid, HCl.
(a) Method
Record all your measurements, in an appropriate form, in the space below.
Experiment 1
● Use the larger measuring cylinder to transfer 40 cm3 of FA 4 into the 100 cm3 beaker. ● Rinse the larger measuring cylinder thoroughly with water, then add 30 cm3 of FA 5 to the
beaker and start timing immediately. ● Stir the mixture once and place the beaker on top of the printed insert page provided. ● Look down through the solution in the beaker at the print on the insert. ● Stop timing as soon as the precipitate of sulfur makes the print on the insert invisible. ● Record the reaction time to the nearest second. ● Empty and rinse the 100 cm3 beaker. ● Dry the outside of the beaker ready for Experiment 2.
Experiment 2
● Rinse the larger measuring cylinder, then use it to transfer 40 cm3 of FA 4 into the 100 cm3 beaker.
● Use the smaller measuring cylinder to add 10 cm3 of distilled water to the beaker. ● Use the same measuring cylinder to add 20 cm3 of FA 5 to the mixture in the beaker and
start timing immediately. ● Stir the mixture once and place the beaker on top of the printed insert page provided. ● Stop timing as soon as the print on the insert becomes invisible. ● Record the reaction time to the nearest second. ● Empty and rinse the 100 cm3 beaker. ● Dry the outside of the beaker ready for Experiment 3.
Experiment 3
● Carry out the reaction using a mixture of 40 cm3 of FA 4, 20 cm3 of distilled water and 10 cm3 of FA 5.
● Measure and record the reaction time to the nearest second.
(iv) Predict how the reaction time measured in Experiment 1 would have been affected if the experiment had been carried out using 0.20 mol dm–3 sulfuric acid instead of 0.20 mol dm–3 hydrochloric acid.
(v) Predict how the reaction time measured in Experiment 3 would have been affected if the experiment had been carried out in a 250 cm3 beaker instead of a 100 cm3 beaker.
At each stage of any test you are to record details of the following.
● colour changes seen ● the formation of any precipitate ● the solubility of such precipitates in an excess of the reagent added
Where gases are released they should be identifi ed by a test, described in the appropriate place in your observations.
You should indicate clearly at what stage in a test a change occurs. No additional tests for ions present should be attempted.
If any solution is warmed, a boiling tube MUST be used.
Rinse and reuse test-tubes and boiling tubes where possible.
Where reagents are selected for use in a test, the name or correct formula of the element or compound must be given.
(a) FA 6 is a sodium compound containing one anion listed on page 11.
Dissolve the FA 6 provided in about 15 cm3 of distilled water in a boiling tube. Carry out the following tests and record your observations in the table below.
test observations (i) To a 1cm depth of the solution
of FA 6 in a test-tube, add a few drops of aqueous barium chloride or aqueous barium nitrate, then
add dilute hydrochloric acid.
(ii) To a 1cm depth of the solution of FA 6 in a test-tube, add an equal volume of aqueous hydrogen peroxide, then
add a few drops of aqueous barium chloride or aqueous barium nitrate, then
(b) FA 7, FA 8, FA 9 and FA 10 each contain one cation from the list on page 10. You will attempt to identify the cations by testing with aqueous sodium hydroxide and aqueous
ammonia. In each case, use a 1 cm depth of the solution in a test-tube.
(i) Complete the table below.
testobservations
FA 7 FA 8 FA 9 FA 10
add sodiumhydroxide
add aqueousammonia
(ii) Use your observations to identify, as far as possible, the cation present in each solution. If alternative identities are possible, state this clearly.
FA 7 cation ....................................................
FA 8 cation ....................................................
FA 9 cation ....................................................
FA 10 cation ..................................................
(iii) Give the ionic equation for the reaction of one of your cations with a few drops of sodium hydroxide. State symbols are not required.
(iv) The precipitates obtained when alkalis are added to solutions of certain cations are sometimes diffi cult to see. Suggest how, using no additional apparatus, the experiment could be repeated in a way that would make these precipitates more visible.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Gro
up
140
Ce
Cer
ium
58
141
PrP
rase
odym
ium
59
144
Nd
Neo
dym
ium
60
PmP
rom
ethi
um61
150
SmS
amar
ium
62
152
EuE
urop
ium
63
157
Gd
Gad
olin
ium
64
159
Tb Terb
ium
65
163
Dy
Dys
pros
ium
66
165
Ho
Hol
miu
m67
167
Er Erb
ium
68
169
Tm Thul
ium
69
173
YbY
tterb
ium
70
175
LuLu
tetiu
m71
Th Thor
ium
90
PaP
rota
ctin
ium
91
UU
rani
um92
Np
Nep
tuni
um93
PuP
luto
nium
94
Am
Am
eric
ium
95
Cm
Cur
ium
96
Bk
Ber
keliu
m97
Cf
Cal
iforn
ium
98
EsE
inst
eini
um99
Fm Ferm
ium
100
Md
Men
dele
vium
101
No
Nob
eliu
m10
2
LrLa
wre
nciu
m10
3
1.0 H
Hyd
roge
n1
6.9 Li
Lith
ium
3
23.0
Na
Sod
ium
11
24.3
Mg
Mag
nesi
um12
40.1
Ca
Cal
cium
20
45.0 Sc
Sca
ndiu
m21
47.9 Ti
Tita
nium
22
50.9 V
Vana
dium
23
52.0 Cr
Chr
omiu
m24
54.9
Mn
Man
gane
se25
55.8 Fe Iron
26
58.9
Co
Cob
alt
27
58.7 Ni
Nic
kel
28
63.5
Cu
Cop
per
29
65.4
Zn Zinc
30
69.7
Ga
Gal
lium
31
27.0 Al
Alu
min
ium
13
10.8 B B
oron
5
12.0 C
Car
bon
6
14.0 N
Nitr
ogen
7
16.0 O
Oxy
gen
8
19.0 F
Fluo
rine
9
28.1 Si S
ilico
n14
31.0 P
Pho
spho
rus
15
32.1 S S
ulfu
r16
35.5 Cl
Chl
orin
e17
39.9 Ar
Arg
on18
20.2 Ne
Neo
n10
4.0
He
Hel
ium
2
72.6
Ge
Ger
man
ium
32
74.9
As
Ars
enic
33
79.0 Se
Sel
eniu
m34
79.9 Br
Bro
min
e35
83.8 Kr
Kry
pton
36
39.1 K
Pot
assi
um19
87.6 Sr
Stro
ntiu
m38
88.9 Y
Yttr
ium
39
91.2 Zr
Zirc
oniu
m40
92.9
Nb
Nio
bium
41
95.9
Mo
Mol
ybde
num
42
TcTe
chne
tium
43
101
Ru
Rut
heni
um44
103
Rh
Rho
dium
45
106
PdP
alla
dium
46
108
Ag
Silv
er47
112
Cd
Cad
miu
m48
115
In Indi
um49
119
Sn Tin
50
122
SbA
ntim
ony
51
128
TeTe
lluriu
m52
127 I
Iodi
ne53
131
Xe Xen
on54
137
Ba
Bar
ium
56
139
LaLa
ntha
num
57
*
178
Hf
Haf
nium
72
181
TaTa
ntal
um73
184 W
Tung
sten
74
186
Re
Rhe
nium
75
190
Os
Osm
ium
76
192
Ir Iridi
um77
195 Pt
Pla
tinum
78
197
Au
Gol
d79
201
Hg
Mer
cury
80
204 Tl
Thal
lium
81
207
Pb Lead
82
209 Bi
Bis
mut
h83
PoP
olon
ium
84
At
Ast
atin
e85
Rn
Rad
on86
Rf
Rut
herfo
rdiu
m10
4
Db
Dub
nium
105
SgS
eabo
rgiu
m10
6
Bh
Boh
rium
107
Hs
Has
sium
108
Mt
Mei
tner
ium
109
Uun
Unu
nnili
um11
0
Uuu
Unu
nuni
um11
1
Uub
Unu
nbiu
m11
2
Uuq
Unu
nqua
dium
114
Uuh
Unu
nhex
ium
116
Uuo
Unu
noct
ium
118
FrFr
anci
um87
Ac
Act
iniu
m89
9.0
Be
Ber
ylliu
m4
III
IIIIV
VV
IV
II0
85.5
Rb
Rub
idiu
m37
133
Cs
Cae
sium
55
Ra
Rad
ium
88 a Xb
a =
rela
tive
atom
ic m
ass
X =
atom
ic s
ymbo
l
b =
prot
on (a
tom
ic) n
umbe
r
Key
* 58-
71 L
anth
anid
es90
-103
Act
inid
es
The
Perio
dic
Tabl
e of
the
Elem
ents
*
READ THESE INSTRUCTIONS FIRST
Write your Centre number, candidate number and name on all the work you hand in.Give details of the practical session and laboratory where appropriate, in the boxes provided.Write in dark blue or black pen.You may use an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fl uid.DO NOT WRITE IN ANY BARCODES.
Answer all questions.Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.Use of a Data Booklet is unnecessary.
Qualitative Analysis Notes are printed on pages 11 and 12.
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.
CHEMISTRY 9701/36
Paper 3 Advanced Practical Skills 2 October/November 2015
2 hours
Candidates answer on the Question Paper.
Additional Materials: As listed in the Confi dential Instructions
Cambridge International ExaminationsCambridge International Advanced Subsidiary and Advanced Level
1 You will investigate the rate of reaction between iron(III) ions, Fe3+, and iodide ions, I–.
2Fe3+(aq) + 2I–(aq) → 2Fe2+(aq) + I2(aq)
The iodine, I2, produced can be reacted immediately with thiosulfate ions, S2O32–.
I2(aq) + 2S2O32–(aq) → 2I–(aq) + S4O6
2–(aq)
When all the thiosulfate has been used, the iodine produced will turn starch indicator blue-black. The rate of the reaction can therefore be measured by fi nding the time for the blue-black colour to appear.
FB 1 is aqueous iron(III) chloride, FeCl 3. FB 2 is aqueous potassium iodide, KI. FB 3 is 0.0060 mol dm–3 sodium thiosulfate, Na2S2O3. starch indicator
You are advised to read the instructions before starting any practical work and draw a table for your results in the space on page 3.
(a) Method
Experiment 1
● Fill a burette with FB 1. ● Run 20.00 cm3 of FB 1 into a 100 cm3 beaker. ● Use the measuring cylinder to place the following in a second 100 cm3 beaker. ○ 10 cm3 of FB 2 ○ 20 cm3 of FB 3 ○ 10 cm3 of starch indicator ● Add the contents of the second beaker to the first beaker and start timing. ● Stir the mixture once and place the beaker on the white tile. ● The mixture turns brown and then yellow before turning a blue-black colour. Stop timing
when this blue-black colour appears. ● Record in your table the volume of FB 1 used, the volume of distilled water used and the
time to the nearest second for the blue-black colour to appear. ● Wash both beakers.
For each of Experiments 2-6 you should complete your results table to show the volume of FB 1 used, the volume of distilled water used and the time taken to the nearest second for the blue-black colour to appear.
Experiment 2
● Fill the other burette with distilled water. ● Run 10.00 cm3 of FB 1 into a 100 cm3 beaker. ● Run 10.00 cm3 of distilled water into the same beaker. ● Use the measuring cylinder to place the following in a second 100 cm3 beaker. ○ 10 cm3 of FB 2 ○ 20 cm3 of FB 3 ○ 10 cm3 of starch indicator ● Add the contents of the second beaker to the first beaker and start timing. ● Stir the mixture once and place the beaker on the white tile. ● Stop timing when a blue-black colour appears. ● Wash both beakers.
Carry out four further experiments to investigate the effect of changing the concentration of Fe3+(aq) by altering the volume of aqueous FeCl 3, FB 1, used.
You should not use a volume of FB 1 that is less than 6.00 cm3 and the total volume of the reaction mixture must always be 60 cm3.
The rate of reaction can be found by calculating the change in concentration of Fe3+(aq) that occurred when enough iodine was produced to change the colour of the indicator to blue-black.
Use your data and the equations on page 2 to carry out the following calculations.
Show your working and appropriate signifi cant fi gures in the fi nal answer to each step of your calculations.
(i) Calculate the number of moles of thiosulfate ions, S2O32– used in each experiment in (a).
moles S2O32– = ...................... mol
(ii) Calculate the number of moles of iodine, I2, that react with the number of moles of S2O32–
in (i).
moles I2 = ...................... mol
(iii) Calculate the number of moles of iron(III) ions, Fe3+, that were used to produce the number of moles of iodine in (ii).
moles Fe3+ = ...................... mol
(iv) When the moles of Fe3+ that you calculated in (iii) reacted, a change in the concentration of moles of Fe3+ occurred. Calculate this change in concentration.
change in concentration of Fe3+(aq) = ...................... mol dm–3
(v) The following formula can be used as a measure of the ‘rate of reaction’.
‘rate of reaction’ =change in concentration of Fe3+(aq)
reaction time × 106
Complete the table to show the volume of FB 1, the reaction time and the rate in Experiments 1-6. You should include units.
If you were unable to calculate a value for the change in concentration of Fe3+(aq) in (iv), you should assume it is 2.50 × 10–3 mol dm–3. (Note: this is not the correct value.)
(c) On the grid, plot the rate (y-axis) against the volume of FB 1 (x-axis). Draw a line of best fi t through the points. You should identify any points you consider anomalous.
(d) Using your graph, what conclusion can you reach about the effect of changing the concentration of FeCl 3 on the rate of the reaction between Fe3+(aq) and I–(aq)?
(e) A student wanted to investigate how changing the concentration of I– would affect the rate of reaction. Explain how this investigation could be carried out.
(f) It was found, by carrying out experiments similar to those used in (a), that increasing the concentration of I– increased the rate of the reaction.
The student suggested modifi cations to the method as used in (a). In each case, state what the effect would be on the reaction time in Experiment 1 and explain how these changes would affect the possible errors in the measurements.
Suggested modifi cation 1 The reaction was carried out using the same volumes of all reagents but with the concentrations
of FB 1 and FB 2 being double their original values.
At each stage of any test you are to record details of the following.
● colour changes seen ● the formation of any precipitate ● the solubility of such precipitates in an excess of the reagent added
Where gases are released they should be identifi ed by a test, described in the appropriate place in your observations.
You should indicate clearly at what stage in a test a change occurs. Marks are not given for chemical equations. No additional tests for ions present should be attempted.
If any solution is warmed, a boiling tube MUST be used.
Rinse and reuse test-tubes and boiling tubes where possible.
Where reagents are selected for use in a test, the name or correct formula of the element or compound must be given.
Half fi ll the 250 cm3 beaker with water and heat it to about 80 °C and then switch off the burner. This will be used as a water bath in (b).
Keep two clean, dry test-tubes for use in (b).
(a) FB 4 and FB 5 each contain two cations and one anion. One of the cations in FB 4 is the same as one of the cations in FB 5. The anion in FB 4 is the same as the anion in FB 5.
(i) Separately dissolve about half of each of your samples of FB 4 and FB 5 in about 5 cm depth of distilled water in a boiling tube.
Carry out the following tests and record your observations in the table.
testobservations
FB 4 FB 5To a 1 cm depth of solution in a test-tube, add a 1 cm depth of aqueous edta.
To a 1 cm depth of solution in a test-tube, add a 1 cm depth of aqueous potassium iodide.
(b) FB 6 is an aqueous solution of an organic compound.
(i) Complete the table below. The observation with 2,4-dinitrophenylhydrazine has already been made.
test observationsTo a 1 cm depth of FB 6 in a test-tube, a few drops of 2,4-dinitrophenylhydrazine were added.
orange precipitate formed
To a 1 cm depth of FB 6 in a test-tube, add a 2 cm depth of dilute sulfuric acid. Place the test-tube in the water bath. Then add two or three drops of acidifi ed aqueous potassium manganate(VII).
To a 1 cm depth of aqueous silver nitrate in a test-tube, add a few drops of aqueous sodium hydroxide. Then add aqueous ammonia until the brown precipitate just dissolves. To this, add a 1 cm depth of FB 6. Place the test-tube in the water bath and leave to stand.Care: rinse the tube as soon as you have completed this test.
(ii) What conclusion can you make about the identity of FB 6 from the observation of its reaction with 2,4-dinitrophenylhydrazine?
(iii) What conclusion can you make about the identity of FB 6 from the observation of its reactions with acidifi ed potassium manganate(VII) and silver nitrate in ammonia solution?
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
2 Reactions of anions
ion reaction
carbonate,CO3
2–
CO2 liberated by dilute acids
chloride,Cl –(aq)
gives white ppt. with Ag+(aq) (soluble in NH3(aq))
bromide,Br
–(aq)gives cream ppt. with Ag+(aq) (partially soluble in NH3(aq))
iodide,I –(aq)
gives yellow ppt. with Ag+(aq) (insoluble in NH3(aq))
nitrate,NO3
–(aq)NH3 liberated on heating with OH–(aq) and Al foil
nitrite,NO2
–(aq)
NH3 liberated on heating with OH–(aq) and Al foil;NO liberated by dilute acids(colourless NO → (pale) brown NO2 in air)
sulfate,SO4
2–(aq)gives white ppt. with Ba2+(aq) (insoluble in excess dilute strong acids)
sulfi te,SO3
2–(aq)SO2 liberated with dilute acids;gives white ppt. with Ba2+(aq) (soluble in excess dilute strong acids)
3 Tests for gases
gas test and test result
ammonia, NH3 turns damp red litmus paper blue
carbon dioxide, CO2 gives a white ppt. with limewater(ppt. dissolves with excess CO2)
chlorine, Cl 2 bleaches damp litmus paper
hydrogen, H2 “pops” with a lighted splint
oxygen, O2 relights a glowing splint
sulfur dioxide, SO2turns acidifi ed aqueous potassium manganate(VII) from purple to colourless
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 an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.
Section AAnswer all questions.
Section BAnswer all questions.
Electronic calculators may be used. You may lose marks if you do not show your working or if you do not use appropriate units.A Data Booklet is provided.
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.
CHEMISTRY 9701/41
Paper 4 Structured Questions October/November 2015
2 hours
Candidates answer on the Question Paper.
Additional Materials: Data Booklet
Cambridge International ExaminationsCambridge International Advanced Level
This document consists of 19 printed pages and 1 blank page.
(ii) Which of the following species can act as a ligand? Complete the table by placing a tick () in the appropriate column to indicate whether the
species can act as a ligand or not.
species can actas a ligand
cannot actas a ligand
NO3–
BF3
H2NCH2CH2NH2
NH4+
[2]
(c) Manganese ions, Mn2+(aq), show some similar chemical properties to those of copper(II) ions, Cu2+(aq).
Use this information and the Data Booklet to suggest the formula of the manganese species formed in each of the following reactions. State the type of reaction taking place in each case.
(a) The compound diborane, B2H6, can be used as a rocket fuel. It can be prepared by the reaction of boron trifluoride, BF3, with sodium borohydride, NaBH4.
(b) Primary and secondary alcohols can be formed by the reaction of carbonyl compounds with NaBH4, which is a source of hydride ions, H–.
Complete the mechanism for the reaction of butanone with hydride ions, H–, and draw the intermediate in the box. Include all necessary curly arrows and relevant dipoles.
CH2CH3
CH2CH3
O
C
intermediate
OH
Cstep 1 H+
H–
H3CH3C
H
[3]
(c) Borane, BH3, is used to synthesise alcohols from alkenes. The reaction occurs in two steps.
The BH2 group from BH3 bonds to the least substituted carbon atom of the double bond, and the remaining H from BH3 bonds to the other carbon.
(ii) In borazine, B3N3H6, the boron and nitrogen atoms alternate around the ring. Each ring atom has a single hydrogen atom bonded to it.
All boron-nitrogen bonds in borazine are 0.144 nm in length, whereas in simple compounds B–N and B=N bond lengths are 0.154 nm and 0.136 nm respectively.
(d) X-ray crystallography can be useful in obtaining information about the structures of large organic molecules, such as ATP. The technique involves X-rays interacting with the electrons within the molecule.
(i) Which element in the molecule of ATP will interact most strongly with the X-ray beam?
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
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 an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.
Section AAnswer all questions.
Section BAnswer all questions.
Electronic calculators may be used. You may lose marks if you do not show your working or if you do not use appropriate units.A Data Booklet is provided.
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.
CHEMISTRY 9701/42
Paper 4 Structured Questions October/November 2015
2 hours
Candidates answer on the Question Paper.
Additional Materials: Data Booklet
Cambridge International ExaminationsCambridge International Advanced Level
This document consists of 19 printed pages and 1 blank page.
(ii) Which of the following species can act as a ligand? Complete the table by placing a tick () in the appropriate column to indicate whether the
species can act as a ligand or not.
species can actas a ligand
cannot actas a ligand
NO3–
BF3
H2NCH2CH2NH2
NH4+
[2]
(c) Manganese ions, Mn2+(aq), show some similar chemical properties to those of copper(II) ions, Cu2+(aq).
Use this information and the Data Booklet to suggest the formula of the manganese species formed in each of the following reactions. State the type of reaction taking place in each case.
(a) The compound diborane, B2H6, can be used as a rocket fuel. It can be prepared by the reaction of boron trifluoride, BF3, with sodium borohydride, NaBH4.
(b) Primary and secondary alcohols can be formed by the reaction of carbonyl compounds with NaBH4, which is a source of hydride ions, H–.
Complete the mechanism for the reaction of butanone with hydride ions, H–, and draw the intermediate in the box. Include all necessary curly arrows and relevant dipoles.
CH2CH3
CH2CH3
O
C
intermediate
OH
Cstep 1 H+
H–
H3CH3C
H
[3]
(c) Borane, BH3, is used to synthesise alcohols from alkenes. The reaction occurs in two steps.
The BH2 group from BH3 bonds to the least substituted carbon atom of the double bond, and the remaining H from BH3 bonds to the other carbon.
(ii) In borazine, B3N3H6, the boron and nitrogen atoms alternate around the ring. Each ring atom has a single hydrogen atom bonded to it.
All boron-nitrogen bonds in borazine are 0.144 nm in length, whereas in simple compounds B–N and B=N bond lengths are 0.154 nm and 0.136 nm respectively.
(d) X-ray crystallography can be useful in obtaining information about the structures of large organic molecules, such as ATP. The technique involves X-rays interacting with the electrons within the molecule.
(i) Which element in the molecule of ATP will interact most strongly with the X-ray beam?
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
CHEMISTRY 9701/43
Paper 4 Structured Questions October/November 2015
2 hours
Candidates answer on the Question Paper.
Additional Materials: Data Booklet
Cambridge International ExaminationsCambridge International Advanced Level
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 an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.
Section AAnswer all questions.
Section BAnswer all questions.
Electronic calculators may be used. You may lose marks if you do not show your working or if you do not use appropriate units.A Data Booklet is provided.
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.
(c) Cobalt(II) ions, Co2+(aq), show some chemical properties similar to those of copper(II) ions, Cu2+(aq).
Use this information and the Data Booklet to suggest the formula of the cobalt species formed in each of the following reactions. State the type of reaction taking place in each case.
(ii) Some of the reactions of cyanogen, NC–CN, are similar to those of chlorine, Cl –Cl. On treatment with cold, aqueous sodium hydroxide, cyanogen disproportionates in a
(e) At room temperature, phosphorus atoms form P4 molecules rather than P2 molecules.
The phosphorus molecule, P4, has a cage-like structure containing only P–P single bonds. All the phosphorus atoms in P4 are trivalent.
(i) Suggest a structure for P4.
[1]
(ii) At a temperature of 1200 K P2 and P4 exist in equilibrium in the gas phase.
P2 molecules contain the P≡P bond.
The average bond energy of P–P is 198 kJ mol–1 while that of P≡P is 489 kJ mol–1.
Use the above bond energies to calculate the enthalpy change, ∆H, for the following reaction.
2P2(g) → P4(g)
[2]
(f) When phosphorus(V) chloride, PCl 5, is reacted with ammonium chloride, NH4Cl, hydrogen chloride gas, HCl, is released and a product with the molecular formula P3N3Cl 6 is formed.
(ii) P3N3Cl 6 has a cyclic structure containing alternating phosphorus and nitrogen atoms in the ring system. All the nitrogen atoms are trivalent and all the phosphorus atoms are pentavalent.
(c) DNA fingerprinting is based on the fact that all humans (apart from genetically identical twins) have different DNA base sequences. This is regularly used to help investigate serious crimes.
(i) The first stage of DNA fingerprinting requires a sample of DNA to be broken down into shorter fragments.
What could be used to carry out this fragmentation?
(iv) A sample of blood, thought to be from the suspect, was found at a crime scene. The DNA of the blood sample, and that of four possible suspects, was analysed.
bloodstain
suspect1
suspect2
suspect3
suspect4
Based on this evidence, circle the suspect who should be arrested.
8 (a) A mixture of volatile organic compounds X, Y and Z can be separated in a gas chromatograph. Their identities can be confirmed by measuring their different retention times and comparing to
known values. A gas chromatogram is shown.
absorptionX
Y
Z
5 10 15 20time / mins
(i) Suggest what is meant by the term retention time.
(iv) Explain a possible limitation of gas / liquid chromatography in separating two esters such as ethyl methanoate, HCO2CH2CH3, and methyl ethanoate, CH3CO2CH3.
(v) A student works out the areas underneath the three peaks in the chromatogram.
peak X Y Z
area / mm2 22 38 16
Assuming the areas underneath the peaks are proportional to the masses of the respective components, what percentage of the original mixture was made up of the organic compound, X?
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
9 Prodrugs are compounds that are inactive, but are easily converted in the body to the active drug by enzyme hydrolysis.
Compound W is a prodrug.
O
OO
NH2H2N
CH3
W
(a) Complete the molecular formula for W.
C H34N O[1]
(b) Compound W contains a benzene ring in its structure.
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 an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fl uid.DO NOT WRITE IN ANY BARCODES.
Answer all questions.Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.Use of a 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.
CHEMISTRY 9701/51
Paper 5 Planning, Analysis and Evaluation October/November 2015
1 hour 15 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
Cambridge International ExaminationsCambridge International Advanced Level
This document consists of 9 printed pages and 3 blank pages.
1 It is possible to determine the relative molecular mass, Mr, of a small sample of a volatile liquid by measuring its mass and then heating to vaporise it to obtain its volume as a gas.
(a) Explain how the relative molecular mass can be determined in this way.
(b) (i) The volume of the vaporised sample depends on its temperature and pressure.
In an experiment, a sample of volatile liquid of known mass was vaporised and its volume recorded. The pressure was correctly recorded as 101 kPa but the temperature was incorrectly recorded as 50 °C. The correct temperature was 60 °C.
By considering the effect of these different temperatures on the gas volume, explain how the value of the calculated Mr would be affected.
(ii) The temperature was maintained at 60 °C but the pressure was increased to 110 kPa. Would this have given an answer that was nearer to the true value of the relative molecular mass? Explain your answer.
In an experiment to determine the relative molecular mass of hexane, boiling point 69 °C, a specialist piece of apparatus called a Victor Meyer tube can be used. This consists of a long tube with a bulb at the base in which a sample can be vaporised. The tube has a side arm to allow the escape of gas from within the tube. The tube is surrounded by another which can be used to heat the contents of the fi rst tube.
A diagram of the apparatus is shown below.
Victor Meyer tube
sand
stopper
smallsample tube
hexane
A small sample tube containing the hexane is inserted at the top of the Victor Meyer tube. The sample tube is small enough to fi t inside the Victor Meyer tube and falls freely onto the hot sand below. The sand will cushion its fall so that the sample tube does not break. The stopper is then quickly replaced at the top of the Victor Meyer tube. The hot sand causes the hexane to vaporise and expel air contained in the Victor Meyer tube.
(c) Complete the diagram above to show:
● how the apparatus should be heated,
● a connection to further apparatus which would allow the air expelled from the Victor Meyer tube when the sample of hexane is vaporised to be collected and measured.
[2]
(d) Suggest one hazard associated with the use of hexane.
(e) (i) With the gas collection apparatus connected to the heated Victor Meyer tube, expelled air will be collected before the hexane is introduced. Explain why.
2 In an experiment, various masses of solid barium hydroxide are added to 60.0 cm3 of a solution of hydrochloric acid contained in a polystyrene cup.
In each experiment a fresh sample of the acid is taken and its initial temperature is measured. After the barium hydroxide has been added, the acid is stirred and the maximum temperature reached is noted.
The results of each experiment are recorded in the table below.
(a) Complete the table below to give the temperature rise obtained from each experiment to one decimal place and the amount of barium hydroxide used in mol to three signifi cant fi gures in each case.
The mass of 1 mol of barium hydroxide is 171 g.
initial temperature of HCl / °C
mass ofbarium hydroxide
added /g
maximum temperature reached / °C
temperaturerise / °C
barium hydroxide added / mol
21.0 0.500 22.2
20.6 1.00 23.0
21.2 1.50 24.9
21.8 2.00 26.5
20.5 3.00 27.8
21.4 4.00 31.1
21.2 5.00 31.6
21.0 6.00 31.4
20.8 8.00 31.2
[2]
(b) (i) Using the grid on page 7, plot a graph to show how the temperature rise varies with the moles of barium hydroxide added. [1]
(f) In another experiment, 60.0 cm3 of ethanoic acid is used instead of the 60.0 cm3 of hydrochloric acid.
If the ethanoic acid has the same concentration as the hydrochloric acid, draw on your graph another pair of lines to show the results you would expect to obtain.
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
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 an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.
Answer all questions.Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.Use of a 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.
CHEMISTRY 9701/52
Paper 5 Planning, Analysis and Evaluation October/November 2015
1 hour 15 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
Cambridge International ExaminationsCambridge International Advanced Level
This document consists of 9 printed pages and 3 blank pages.
1 It is possible to determine the relative molecular mass, Mr, of a small sample of a volatile liquid by measuring its mass and then heating to vaporise it to obtain its volume as a gas.
(a) Explain how the relative molecular mass can be determined in this way.
(b) (i) The volume of the vaporised sample depends on its temperature and pressure.
In an experiment, a sample of volatile liquid of known mass was vaporised and its volume recorded. The pressure was correctly recorded as 101 kPa but the temperature was incorrectly recorded as 50 °C. The correct temperature was 60 °C.
By considering the effect of these different temperatures on the gas volume, explain how the value of the calculated Mr would be affected.
(ii) The temperature was maintained at 60 °C but the pressure was increased to 110 kPa. Would this have given an answer that was nearer to the true value of the relative molecular mass? Explain your answer.
In an experiment to determine the relative molecular mass of hexane, boiling point 69 °C, a specialist piece of apparatus called a Victor Meyer tube can be used. This consists of a long tube with a bulb at the base in which a sample can be vaporised. The tube has a side arm to allow the escape of gas from within the tube. The tube is surrounded by another which can be used to heat the contents of the first tube.
A diagram of the apparatus is shown below.
Victor Meyer tube
sand
stopper
smallsample tube
hexane
A small sample tube containing the hexane is inserted at the top of the Victor Meyer tube. The sample tube is small enough to fit inside the Victor Meyer tube and falls freely onto the hot sand below. The sand will cushion its fall so that the sample tube does not break. The stopper is then quickly replaced at the top of the Victor Meyer tube. The hot sand causes the hexane to vaporise and expel air contained in the Victor Meyer tube.
(c) Complete the diagram above to show:
● how the apparatus should be heated,
● a connection to further apparatus which would allow the air expelled from the Victor Meyer tube when the sample of hexane is vaporised to be collected and measured.
[2]
(d) Suggest one hazard associated with the use of hexane.
(e) (i) With the gas collection apparatus connected to the heated Victor Meyer tube, expelled air will be collected before the hexane is introduced. Explain why.
2 In an experiment, various masses of solid barium hydroxide are added to 60.0 cm3 of a solution of hydrochloric acid contained in a polystyrene cup.
In each experiment a fresh sample of the acid is taken and its initial temperature is measured. After the barium hydroxide has been added, the acid is stirred and the maximum temperature reached is noted.
The results of each experiment are recorded in the table below.
(a) Complete the table below to give the temperature rise obtained from each experiment to one decimal place and the amount of barium hydroxide used in mol to three significant figures in each case.
The mass of 1 mol of barium hydroxide is 171 g.
initial temperature of HCl / °C
mass ofbarium hydroxide
added /g
maximum temperature reached / °C
temperaturerise / °C
barium hydroxide added / mol
21.0 0.500 22.2
20.6 1.00 23.0
21.2 1.50 24.9
21.8 2.00 26.5
20.5 3.00 27.8
21.4 4.00 31.1
21.2 5.00 31.6
21.0 6.00 31.4
20.8 8.00 31.2
[2]
(b) (i) Using the grid on page 7, plot a graph to show how the temperature rise varies with the moles of barium hydroxide added. [1]
(f) In another experiment, 60.0 cm3 of ethanoic acid is used instead of the 60.0 cm3 of hydrochloric acid.
If the ethanoic acid has the same concentration as the hydrochloric acid, draw on your graph another pair of lines to show the results you would expect to obtain.
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
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 an HB pencil for any diagrams or graphs.Do not use staples, paper clips, glue or correction fl uid.DO NOT WRITE IN ANY BARCODES.
Answer all questions.Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.Use of a 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.
CHEMISTRY 9701/53
Paper 5 Planning, Analysis and Evaluation October/November 2015
1 hour 15 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
Cambridge International ExaminationsCambridge International Advanced Level
This document consists of 9 printed pages and 3 blank pages.
1 The halogenoalkanes can react with hydroxide ions to form an alcohol and a halide ion.
(a) The rate at which the reaction occurs depends on which of the halogenoalkanes is chosen. The reaction is a nucleophilic attack by the hydroxide ion and the rate might depend on:
● the polarity of the carbon-halogen bond,
● the bond strength of the carbon-halogen bond.
For (i) and (ii), chlorobutane, bromobutane and iodobutane should be considered.
(i) If the rate of reaction was only controlled by the polarity of the carbon-halogen bond, the order of reactivity (most reactive to least reactive) would be
(ii) If the rate of reaction was only controlled by the bond strength of the carbon-halogen bond, the order of reactivity (most reactive to least reactive) would be
(b) An experiment can be carried out to compare the extent of the reaction between aqueous hydroxide ions and chlorobutane, bromobutane and iodobutane. Samples of the halogenoalkanes are reacted with sodium hydroxide for 2 minutes at 50 °C. After the reaction, addition of aqueous silver nitrate causes the formation of a silver halide precipitate.
Some hazards associated with the use of halogenoalkanes include:● very hazardous in case of skin and particularly eye contact,● very hazardous if inhaled or ingested,● fl ammable.
To carry out this experiment, the following would be supplied.
● usual laboratory apparatus ● laboratory reagents including a suitable aqueous solution of sodium hydroxide and
aqueous silver nitrate ● samples of each of the three liquid halogenoalkanes
(i) Identify the independent variable and the dependent variable in this experiment.
(ii) The amount of each halogenoalkane liquid to use is most practically measured by its volume. Usually equal volumes of the three halogenoalkanes are used.
Explain why this is not ideal and what change should be made to obtain a more reliable comparison between the halogenoalkanes.
(iv) Although the amount of silver halide formed can reasonably be obtained by measuring the height of the precipitate in the reaction tube, this is not very reliable.
Explain what should be done with the precipitate to obtain a more reliable measurement of the amount of silver halide produced.
(c) The use of halogenoalkanes is hazardous and both gloves and eye protection are necessary. State one other essential precaution which should be taken when carrying out the experiments.
2 At 25 °C, dinitrogen tetroxide, N2O4(g), forms an equilibrium mixture with nitrogen dioxide, NO2(g).
N2O4(g) 2NO2(g) ∆H = +57.2 kJ mol−1
As N2O4(g) is colourless and NO2(g) is brown, the composition of an equilibrium mixture can be determined by its colour.
(a) Write an expression for the equilibrium constant, Kc, for this equilibrium.
[1]
(b) In an experiment, quantities of N2O4 are left to reach an equilibrium which contains N2O4 and NO2. These are analysed to determine the concentrations of N2O4(g) and NO2(g) that are present. The results are listed in the fi rst two columns of the table below.
Complete the third column of the table to give the value of [NO2(g)]2 for each of the results of the experiment. Values should be given to three signifi cant fi gures.
(ii) Choose two suitable sets of values from your graph and use them to calculate a value for the equilibrium constant, Kc. Give your answer to three signifi cant fi gures and give its units.
co-ordinates of two points used ......................................... .........................................
Kc = ........................ units ........................[3]
(d) Identify the result which is most anomalous and suggest a reason, other than a calculation error, why this may have occurred.
(f) In the experiments, the results have been obtained by starting with pure N2O4(g) and then letting the equilibrium with NO2(g) form.
Calculate the starting concentration of pure N2O4(g) that would be required to produce the mixture of 0.900 mol dm–3 of N2O4(g) and 0.0729 mol dm–3 of NO2(g) once equilibrium had been established.
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge International Examinations Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cie.org.uk after the live examination series.
Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.