0620 w22 QP 42 Edit
0620 w22 QP 42 Edit
0620 w22 QP 42 Edit
*4909270147*
CHEMISTRY 0620/42
Paper 4 Theory (Extended) October/November 2022
1 hour 15 minutes
INSTRUCTIONS
● Answer all questions.
● Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
● Write your name, centre number and candidate number in the boxes at the top of the page.
● Write your answer to each question in the space provided.
● Do not use an erasable pen or correction fluid.
● Do not write on any bar codes.
● You may use a calculator.
● You should show all your working and use appropriate units.
INFORMATION
● The total mark for this paper is 80.
● The number of marks for each question or part question is shown in brackets [ ].
● The Periodic Table is printed in the question paper.
IB22 11_0620_42/3RP
© UCLES 2022 [Turn over
2
1 Diamond and graphite are different solid forms of carbon. The carbon atoms in diamond and
graphite are arranged in different ways.
(a) State the number of covalent bonds each carbon atom has in diamond.
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[Total: 8]
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(ii) State the colour of the flame seen when sodium burns.
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(iii) Write a chemical equation for the reaction which takes place when sodium burns in air to
form sodium oxide.
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(iv) Complete the dot-and-cross diagram to show the electron arrangement and charges of
the ions in sodium oxide.
....... .......
Na O
.......
Na
[3]
(c) Sodium reacts vigorously with water to form aqueous sodium hydroxide, NaOH, which is a
strong base.
....................................................................................................................................... [1]
....................................................................................................................................... [1]
....................................................................................................................................... [1]
= .............................. mol
= .............................. mol
(d) When NaOH(aq) is added to aqueous iron(III) chloride, FeCl 3(aq), a solid product is formed.
(i) Name the type of reaction where a solid is formed from two solutions.
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(iv) Write the ionic equation for the reaction. Include state symbols.
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[Total: 22]
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(b) Describe the process which converts metal ores to sulfur dioxide.
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(d) The reaction that produces sulfur trioxide is an equilibrium. The forward reaction is exothermic.
(i) State the temperature and pressure used to make sulfur trioxide.
temperature = .............................. °C
....................................................................................................................................... [1]
1 ..........................................................................................................................................
2 ..........................................................................................................................................
[2]
(iv) State the effect, if any, on the position of equilibrium when the following changes are
made.
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.............................................................................................................................................
[4]
(v) Explain, in terms of particles, what happens to the rate of reaction when the temperature
is increased.
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(e) Name the compound formed when sulfuric acid reacts with ammonia.
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[Total: 16]
4 A student prepares magnesium sulfate crystals, MgSO4, by adding excess magnesium to dilute
sulfuric acid.
.............................................................................................................................................. [1]
(b) Describe two observations which show the reaction has finished.
1 .................................................................................................................................................
2 .................................................................................................................................................
[2]
State the general name given to a solid separated from a solution by filtration.
.............................................................................................................................................. [1]
(d) The aqueous magnesium sulfate is heated until crystals begin to appear.
(i) Suggest the name for a solution in which no more solute can dissolve.
....................................................................................................................................... [1]
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(e) Magnesium sulfate crystals have the formula, MgSO4•xH2O, where x is a whole number of
molecules of water.
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(ii) The student heats a sample of MgSO4•xH2O and finds it has lost 0.140 moles of H2O and
has 2.40 g of MgSO4 remaining.
Mr = ..............................
x = ..............................
[3]
(f) If the student uses dilute nitric acid instead of dilute sulfuric acid, the salt formed is
magnesium nitrate, Mg(NO3)2.
Write the chemical equation for the reaction when solid magnesium nitrate is heated.
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[Total: 12]
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A
C2H6 + Cl 2
energy
B
C2H5Cl + HCl
progress of reaction
....................................................................................................................................... [1]
....................................................................................................................................... [1]
(iii) State how the energy profile diagram shows this is an exothermic reaction.
....................................................................................................................................... [1]
H H H H
H C C H + Cl Cl ! H C C Cl + H Cl
H H H H
bond energy
bond
/ kJ mol
C–H 410
C–C 350
Cl –Cl 240
C–Cl 340
H–Cl 430
Use the bond energies in the table to calculate the energy change in this reaction.
energy = .............................. kJ
● Calculate the energy released in making bonds.
energy = .............................. kJ
[Total: 10]
H C O H
.............................................................................................................................................. [1]
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(d) Complete the dot-and-cross diagram to show the arrangement of electrons in a molecule of
carboxylic acid Y.
H C O H
[3]
(e) Carboxylic acid Y will react with propan-1-ol, C3H7OH, to form ester Z and one other product.
name ..........................................................
structure
[3]
(ii) Name the other product formed when carboxylic acid Y reacts with propan-1-ol.
....................................................................................................................................... [1]
(iii) Name:
.............................................................................................................................................
.............................................................................................................................................
[2]
[Total: 12]