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PREPARATORY EXAMINATION
2022
10842

PHYSICAL SCIENCES: CHEMISTRY

PAPER 2

TIME: 3 hours

MARKS: 150

16 pages + 4 data pages + 1 answer sheet

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INSTRUCTIONS AND INFORMATION:

1. This question paper consists of 9 questions. Answer ALL the questions in

the ANSWER BOOK.
Use the graph paper on the last page to answer QUESTION 5.3.1 and
QUESTION 5.3.3.

2. Start the answer to each question on a NEW page.

3. Number the answers correctly according to the numbering system used in

this question paper.

m
co
4. Leave ONE line open between sub-questions, for example, between
QUESTION 2.1 and QUESTION 2.2.

c s.
5. You may use a non-programmable calculator.

si
hy
6. You may use appropriate mathematical instruments.

7.
ep
You are advised to use the attached DATA SHEETS.
or
m

8. Show ALL formulae and substitutions in ALL calculations.

an

9. Round off your final numerical answers to a minimum of TWO decimal

st

places.
om

10. Give brief discussions, et cetera where required.

fr

11. Write neatly and legibly.

d
de
l oa
wn
do

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QUESTION 1: MULTIPLE-CHOICE QUESTIONS

Four options are given as possible answers to the following questions. Each question has only
ONE correct answer. Write only the letter (A – D) next to the question numbers (1.1 to 1.10) in
the ANSWER BOOK, e.g., 1.11 D.

1.1 Consider the condensed structural formula:

CH3COCH3

Identify the name of the functional group in this formula.

m
A Carboxylic acid

co
s.
B Carboxyl group

c
si
C Ketone

hy
D Carbonyl group (2)
ep
or
1.2 Which of the following is the empirical formula of 1,2-dichloroethane?
m

A CHCℓ
an

B
st

CH2Cℓ
om

C CHCℓ2
fr

D C2H4Cℓ2 (2)
d

1.3 Consider the structural formula of the organic compound below.

de
oa

H H
H C H H C H
l
wn

H H H
H
do

C C C C C H
H H
H C H
H

Which of the following statements about the above compound is CORRECT?

A 2,2,4-trimethylpent-2-ene

B 2,2,4-trimethylpent-3-ene

C 2,4,4-trimethylpent-2-ene

D 2,4,4-trimethylpent-3-ene (2)

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1.4 From the following options, choose the ONE that best explains why
catalysts are so extensively used in chemical reactions:

A Catalysts can be used to drive the equilibrium in the desired direction.

B Catalysts decrease the reverse reaction.

C Catalysts have no effect on the reverse reactions.

D Catalysts cause the forward and reverse reactions to proceed at a

faster rate. (2)

1.5 Study the following graph and match label X from the following choices.

400
X

300

200

100

A Activation energy

B Activated complex

C Activation complex

D Activated energy (2)

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1.6 The equation below represents a chemical reaction at equilibrium in a closed

container.

H2(g) + I2(g) ⇌ 2HI(g) H < 0

Which of the following changes will increase the yield of HI(g) in the above
reaction?

A Increase in the temperature

B Decrease in the temperature

C Increasing the pressure by decreasing the volume

D Decreasing the pressure by increasing the volume (2)

-3
1.7 Which of the following solutions, each of concentration 0,1 mol∙dm , has the
highest pH?

A HNO3(aq)

B NH4Cℓ(aq)

C Na2CO3(aq)

D CH3COOH (aq) (2)

1.8 A solution of ethanoic acid (acetic acid) is titrated against a standard sodium
hydroxide solution. Which of the following indicators would be the most
suitable for this titration?

Indicator pH range of the indicator

A Phenolphthalein 8,3 – 10
B Methyl orange 3,1 – 4,4

C Bromothymol blue 6,0 – 7,6

Changes colour over a wide range
D Universal indicator
of pH values (2)

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1.9 Which of the following correctly gives the direction, as well as the medium, in
which electrons move in a galvanic cell?

DIRECTION MEDIUM
A cathode to anode salt bridge
B anode to cathode external wire
C cathode to anode external wire
D anode to cathode salt bridge
(2)

1.10 Which of the following half-reactions occurs at the cathode during the
electrolysis of a solution of concentrated NaCℓ?

A 2H2O → O2(g) + 4H+ + 4e

B Na+ + e- → Na

C 2Cℓ- → Cℓ2 + 2e-

D 2H2O + 2e- → H2 + 2OH- (2)

[20]

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QUESTION 2 (Start on a new page.)

The following types of formulae represent organic compounds. Study the table below
and answer the questions that follow.

A B C

D CH3CHOHCH3 E 2,4-dimethylpent-1-ene F 2-methylpropan-2-ol

H
H C H
H H H H H

H C C C C C C H
G
H Br H H H
H C H
H

2.1 From the table above, consider compound B. Write down the:

2.1.1 Homologous series to which compound B belongs (1)

2.1.2 IUPAC name of compound B (2)

2.2 An alcohol and an acid are heated in the presence of concentrated sulphuric
acid to form compound B. Write down the:

2.2.1 Role of the concentrated sulphuric acid in this reaction (1)

2.2.2 Names of the alcohol and the organic acid used to prepare compound B (2)

2.2.3 Name of the type of the reaction that is taking place (1)

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2.3 From the table above, consider compound C.

2.3.1 Write down the name of the functional group of compound C. (1)

2.3.2 To which homologous group does compound C belong? (1)

2.3.3 Differentiate between the terms functional group and homologous

series. (2)

2.4 From the table above, consider compounds A, D and F.

2.4.1 Write down the homologous series to which they belong. (1)

2.4.2 Compound A and D are isomers. As what type of isomer will they be
classified? (1)

2.4.3 Draw the structural formula for compound F. (3)

2.5 Write down the:

2.5.1 IUPAC name of compound G (3)

2.5.2 Structural formula of compound E (2)

[21]

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QUESTION 3 (Start on a new page.)

3.1 Study the following two organic structures and answer the questions that
follow.

A B
H H H H O H H O H H

H C C C C C H H C C C C C H

H H H H H H
H H

3.1.1 Compound A and B are functional isomers. Define the term functional
isomer. (2)

3.1.2 Write down the IUPAC name of compound B. (2)

3.1.3 How does the boiling point of A compare to that of the

PENTAN-1-OL? Write down only GREATER THAN, EQUAL TO or
LOWER THAN. (1)

3.1.4 Explain your answer to QUESTION 3.1.3 fully, by referring to the

type of intermolecular forces present in each of these compounds. (3)

3.1.5 How will the vapour pressure of compound B compare to that of

PENTAN-1-OL? Write down only HIGHER THAN, LOWER THAN or
EQUAL TO. Explain the answer fully. (3)

3.2 Learners use compounds C to E to investigate ONE factor which influences

the boiling points of organic compounds.

C CH3CH2CH2CH3 -1 °C
D CH3CH2CH2CH2CH3 36,1 °C
E CH3CH2CH2CH2CH2CH3 69 °C

3.2.1 Define the term boiling point. (2)

3.2.2 Write down the independent variable for this investigation. (1)
3.2.3 Write down the type of Van der Waals force that occurs between these
organic compounds. (1)
3.2.4 Write down the conclusion that can be drawn about the boiling point
of straight chain alkanes. (2)
[17]

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QUESTION 4 (Start on a new page.)

Most organic compounds can undergo different reactions to produce a variety of

organic compounds. Some incomplete reactions are represented below.

2-bromopropane
+ HBr + HBr
C  D
propene E propane
A B hydrogenation

secondary alcohol
F

4.1 Consider reaction A. Write down the type of reaction that takes place. (1)

4.2 Reaction B represents a hydration reaction.

4.2.1 Define the hydration reaction. (2)

4.2.2 Write down the name or formula of the catalyst used for this reaction. (1)

4.3 During reaction C, a specific rule is followed to determine the major product
when HBr is added.

4.3.1 Write down TWO conditions for this reaction. (2)

4.3.2 Use structural formulae and write down the balanced equation for this
reaction. (3)

4.4 Identify the type of reaction taking place at:

4.4.1 Reaction D (1)

4.4.2 Reaction F (1)

4.5 Reaction E is a hydrogenation reaction.

4.5.1 Write down the TWO reaction conditions for this reaction. (2)

4.5.2 This reaction is widely used in industry. Name ONE use of

hydrogenation in the food industry. (1)
[14]

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QUESTION 5 (Start on a new page.)

5.1 The graph below shows the change in potential energy for the reaction where
limestone is changed into lime. The balanced equation for this reaction is:

CaCO3(s) → CaO(s) + CO2(g)

Potential energy (kJ.mol )

480
-1

0420

Reaction coordinate

5.1.1 Is the forward reaction exothermic or endothermic? (1)

5.1.2 Calculate the heat of reaction for the forward reaction. (2)

5.1.3 Write down the activation energy for the reverse reaction. (1)

5.2 The following graph represents the number of particles against a specific
amount of kinetic energy of the molecules. The data for samples R and S was
obtained at different temperatures which affects the rate of reaction.

R
Number of particles

S T

Kinetic energy of the molecules

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5.2.1 Define the term rate of reaction. (2)

5.2.2 What does the area to the right of line T represent? (1)

5.2.3 Which sample was at a higher temperature? Write down only

SAMPLE R or SAMPLE S. (1)

5.2.4 Explain the answer to QUESTION 5.2.3 by using the collision theory. (3)

5.3 11 g of magnesium ribbon reacts with a 0,25 mol.dm-3 hydrochloric acid solution
at a temperature of 25 C according to the following balanced reaction:

Mg(s) + 2HCl(aq)  MgCl2(aq) + H2(g)

A table of the results is given below:

Time elapsed Volume of H2(g)

(minutes) (cm3)
0 0
0,5 17
1,0 25
1,5 30
2,0 33
2,5 35
3,0 35

5.3.1 Use the graph paper that is printed on the last page of the question
paper. Plot a graph of these results. (2)

5.3.2 Use the graph and explain what happened with the reaction between
2 minutes and 3 minutes. (1)

5.3.3 In a second experiment, the concentration of the hydrochloric acid

changed from 0,25 mol.dm-3 to 1 mol.dm-3.
Draw a new curve on the same graph paper to show what effect it will
have. Label the new curve X. (2)

5.3.4 Assume the molar gas volume at 25 °C is 24,47 dm3mol-1. Calculate

the volume of acid that was used in the first experiment when the
reaction was completed. (4)
[20]

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QUESTION 6 (Start on a new page.)

6.1 The balanced equation below represents the reaction that reaches equilibrium
in a sealed container.

N2(g) + 3H2(g) ⇌ 2NH3(g) ∆H < 0

To increase the yield of ammonia, adjustments are made to the temperature,

pressure and concentration of the equilibrium mixture. The graph below
represents the results obtained.
Concentration (mol.dm-3)

Time (minutes)

Identify the changes made to the equilibrium mixture at each of the following
times.

6.1.1 t1 (1)

6.1.2 t2 (1)

6.1.3 t3 (1)

6.2 State Le Chatelier’s principle in words. (2)

6.3. The pressure of the reaction mixture in QUESTION 6.1 above is disturbed by
increasing the volume of the sealed container.

6.3.1 How will the change above affect the yield of NH3(g)? Write down only
INCREASES, DECREASES or REMAINS THE SAME. (1)

6.3.2 Use Le Chatelier’s principle to explain the answer to QUESTION 6.3.1. (3)

6.4 5 mol N2 and 5 mol H2 are now sealed into a 5 dm3 empty container. Equilibrium
is reached at 450 °C. Upon analysis of the equilibrium mixture, it is found that
the mass of NH3 is 20,4 g.

Calculate the value of the equilibrium constant (Kc) at 450 °C. (9)

6.5 The temperature is now increased to 700 °C. What will happen to the value of
Kc at this temperature once a new equilibrium was reached? Write down only
REMAINS THE SAME, INCREASE or DECREASE. (2)
[20]

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QUESTION 7 (Start on a new page.)

7.1 Define the term acid according to the Arrhenius theory. (2)

7.2 Consider the following acid-base reactions.

X: HF + H2O ⇌ H3O+ + F-
−
Y: HNO3 + NH3 ⇌ NH4+ + NO3

7.2.1 From reactions X and Y identify the reaction that illustrates the
Arrhenius theory. (1)

7.2.2 Write down a balanced equation for the hydrolysis of NH+

4 ions. (3)

7.2.3 Will the resultant solution from QUESTION 7.2.2 be acidic, basic or
neutral? Give a reason for your answer. (2)

7.3 A sodium hydroxide solution is prepared by dissolving 4 g of sodium hydroxide

in water to make a 500 cm3 solution.

7.3.1 Calculate the concentration of the sodium hydroxide solution. (3)

7.3.2 During a titration, 12,5 cm3 of sodium hydroxide solution neutralises

25 cm3 of a sulphuric acid solution according to the following balanced
chemical equation:

2NaOH(aq) + H2S04(aq)  Na2S04(aq) + H2O(ℓ)

Calculate the pH of the H2S04 solution. (7)

[18]

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QUESTION 8 (Start on a new page.)

The galvanic cell represented in the diagram below consists of a Ba electrode dipped
into a Ba(NO3)2 solution, and a Cu electrode dipped into a Cu(NO3)2 solution. Assume
that the cell operates under standard conditions.

Half-cell A Half-cell B

8.1 State TWO standard conditions under which this cell operates. (2)

8.2 Which half-cell, A or B is the cathode? Write only A or B. (1)

8.3 Write down the half-reaction that takes place in half-cell A. (2)

8.4 Write down the cell notation for this cell. (3)

8.5 Calculate the emf of this cell. (4)

8.6 How will each of the following changes influence the value of the cell's emf, as
calculated in QUESTION 8.5? Write down only INCREASES, DECREASES
or REMAINS THE SAME.

8.6.1 Ammonium sulfate is added to the barium nitrate solution. (1)

8.6.2 The temperature of the solutions is increased. (1)

[14]

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QUESTION 9 (Start on a new page.)

The diagram below shows an electrolytic cell used for the refining of copper in industry.

9.1 State the energy conversion that takes place in this electrolytic cell. (2)

9.2 What will be observed at the cathode? (1)

9.3 Write down the half-reaction that takes place at the anode. (2)

9.4 What will happen to the colour of the blue copper (II) sulfate solution as the
reaction progresses? (1)
[6]

TOTAL: 150

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DATA FOR PHYSICAL SCIENCES GRADE 12

PAPER 2 (CHEMISTRY)

GEGEWENS VIR FISIESE WETENSKAPPE GRAAD 12

VRAESTEL 2 (CHEMIE)

TABLE 1: PHYSICAL CONSTANTS/TABEL 1: FISIESE KONSTANTES

NAME/NAAM SYMBOL/SIMBOOL VALUE/WAARDE

Standard pressure
Standaarddruk p 1,013 x 105 Pa
Molar gas volume at STP
Vm 22,4 dm3∙mol-1
Molêre gasvolume by STD
Standard temperature
T 273 K
Standaardtemperatuur
Charge on electron
e- -1,6 x 10-19 C
Laai op elektron
Avogadro’s number
NA 6,02×1023
Avogadro se nommer

TABLE 2: FORMULAE/TABEL 2: FORMULES

m N
n n
M NA
n
c or/of c  m n
V
V MV Vm
ca Va n
 a pH = -log[H3O+]
cb Vb nb
Eθcell  Eθcathode  Eθanode / E θsel  Ekatode
θ
 E θanode

E θcell  E reduction
θ
 E θoxidation / E θsel  Ereduksie
θ
 E θoksidasie

E θcell  E θoxidisingagent  E θreducingagent / E θsel  E θoksideermiddel  E reduseermi

θ
ddel
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TABLE 3: THE PERIODIC TABLE OF ELEMENTS/TABEL 3: DIE PERIODIEKE TABEL VAN ELEMENTE
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
(I) (II) (III) (IV) (V) (VI) (VII) (VIII)
Atomic number/
KEY/SLEUTEL Atoomgetal
1 2
H He
2,1

1 29 4
Electro negativity/ Symbol/

1,9
3 4
Elektronegatiwiteit
Cu Simbool
5 6 7 8 9 10
Li Be B C N O F Ne
1,0

1,5

2,0

2,5

3,0

3,5

4,0
63,5
7 9 11 12 14 16 19 20
11 12 13 14 15 16 17 18
Na Mg
Approximate relative atomic mass/ Aℓ Si P S Cℓ Ar
0,9

1,2

1,5

1,8

2,1

2,5

3,0
23 24 Benaderde relatiewe atoommassa 27 28 31 32 35,5 40
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
0,8

1,0

1,3

1,5

1,6

1,6

1,5

1,8

1,8

1,8

1,9

1,6

1,6

1,8

2,0

2,4

2,8
39 40 45 48 51 52 55 56 59 59 63,5 65 70 73 75 79 80 84
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
0,8

1,0

1,2

1,4

1,8

1,9

2,2

2,2

2,2

1,9

1,7

1,7

1,8

1,9

2,1

2,5
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
86 88 89 91 92 96 101 103 106 108 112 115 119 122 128 127 131
55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tℓ Pb Bi Po At Rn
0,7

0,9

1,6

1,8

1,8

1,9

2,0

2,5
133 137 139 179 181 184 186 190 192 195 197 201 204 207 209

87 88 89
0,7

0,9

Fr Ra Ac
226
58 59 60 61 62 63 64 65 66 67 68 69 70 71
Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
140 141 144 150 152 157 159 163 165 167 169 173 175

90 91 92 93 94 95 96 97 98 99 100 101 102 103

Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr
232 238
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TABLE 4A: STANDARD REDUCTION POTENTIALS/

TABEL 4A: STANDAARD REDUKSIEPOTENSIALE
Half-reactions/Halfreaksies
E θ (V)
F2(g) + 2e ⇌ 2F + 2,87

⇌ Co2+
3+
Co + e + 1,81
H2O2 + 2H+ +2e ⇌ 2H2O +1,77

⇌
2+
MnO 4 + 8H+ + 5e Mn + 4H2O + 1,51

Cℓ2(g) + 2e ⇌ 2Cℓ + 1,36

2
Cr2O 7 + 14H+ + 6e ⇌ 2Cr3+ + 7H2O + 1,33

⇌
+
O2(g) + 4H + 4e 2H2O + 1,23
MnO2 + 4H+ + 2e ⇌ Mn2+ + 2H2O + 1,23
Pt2+ + 2e ⇌ Pt + 1,20
Br2(ℓ) + 2e ⇌ 2Br + 1,07
NO 3 + 4H+ + 3e ⇌ NO(g) + 2H2O + 0,96
2+
Hg + 2e 
⇌ Hg(ℓ) + 0,85
Ag+ + e ⇌

Increasing reducing ability/Toenemende reduserende vermoë

Ag + 0,80
NO 3 + 2H+ + e ⇌ NO2(g) + H2O + 0,80

⇌
Increasing oxidising ability/Toenemende oksiderende vermoë

3+
Fe + e Fe2+ + 0,77

⇌
+
O2(g) + 2H + 2e H2O2 + 0,68
I2 + 2e ⇌ 2I + 0,54
Cu+ + e ⇌ Cu + 0,52
SO2 + 4H+ + 4e ⇌ S + 2H2O + 0,45
2H2O + O2 + 4e ⇌ 4OH + 0,40
Cu2+ + 2e ⇌ Cu + 0,34
2
SO 4 + 4H+ + 2e ⇌ SO2(g) + 2H2O + 0,17

Cu2+ + e ⇌ Cu+ + 0,16


⇌ Sn2+
4+
Sn + 2e + 0,15

⇌
+
S + 2H + 2e H2S(g) + 0,14
2H+ + 2e ⇌ H2(g) 0,00
Fe3+ + 3e ⇌ Fe  0,06
Pb2+ + 2e ⇌ Pb  0,13
Sn2+ + 2e ⇌ Sn  0,14
Ni2+ + 2e ⇌ Ni  0,27
Co2+ + 2e ⇌ Co  0,28
Cd2+ + 2e ⇌ Cd  0,40
Cr3+ + e ⇌ Cr2+  0,41
Fe2+ + 2e ⇌ Fe  0,44
Cr3+ + 3e ⇌ Cr  0,74
Zn2+ + 2e ⇌ Zn  0,76
2H2O + 2e 
⇌ H2(g) + 2OH
 0,83
Cr2+ + 2e ⇌ Cr  0,91
Mn2+ + 2e ⇌ Mn  1,18
Aℓ3+ + 3e ⇌ Aℓ  1,66
Mg2+ + 2e ⇌ Mg  2,36
Na+ + e ⇌ Na  2,71
Ca2+ + 2e ⇌ Ca  2,87
Sr2+ + 2e ⇌ Sr  2,89
Ba2+ + 2e ⇌ Ba  2,90
Cs+ + e- ⇌ Cs – 2,92
K+ + e ⇌ K  2,93
Li+ + e ⇌ Li  3,05
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TABLE 4B: STANDARD REDUCTION POTENTIALS/

TABEL 4B: STANDAARD REDUKSIEPOTENSIALE

Half-reactions/Halfreaksies
E θ (V)
Li+ + e ⇌ Li  3,05
K +e+ 
⇌ K  2,93
Cs+ + e ⇌ Cs  2,92
Ba2+ + 2e ⇌ Ba  2,90
Sr2+ + 2e ⇌ Sr  2,89

Increasing reducing ability/Toenemende reduserende vermoë

Increasing oxidising ability/Toenemende oksiderende vermoë

Ca2+ + 2e ⇌ Ca  2,87

Na+ + e ⇌ Na  2,71
Mg2+ + 2e ⇌ Mg  2,36
Aℓ3+ + 3e ⇌ Aℓ  1,66
Mn2+ + 2e ⇌ Mn  1,18
Cr2+ + 2e ⇌ Cr  0,91
2H2O + 2e ⇌ H2(g) + 2OH  0,83
Zn2+ + 2e ⇌ Zn  0,76
Cr3+ + 3e ⇌ Cr  0,74
2+
Fe + 2e 
⇌ Fe  0,44
Cr3+ + e ⇌ Cr2+  0,41
Cd2+ + 2e ⇌ Cd  0,40
Co2+ + 2e ⇌ Co  0,28
Ni2+ + 2e ⇌ Ni  0,27
Sn2+ + 2e ⇌ Sn  0,14
Pb2+ + 2e ⇌ Pb  0,13
Fe3+ + 3e ⇌ Fe  0,06
2H+ + 2e ⇌ H2(g) 0,00
S + 2H+ + 2e ⇌ H2S(g) + 0,14
Sn4+ + 2e ⇌ Sn2+ + 0,15
Cu2+ + e ⇌ Cu+ + 0,16
2
SO 4 + 4H+ + 2e ⇌ SO2(g) + 2H2O + 0,17

⇌
2+
Cu + 2e Cu + 0,34
2H2O + O2 + 4e ⇌ 4OH + 0,40
SO2 + 4H+ + 4e ⇌ S + 2H2O + 0,45
Cu+ + e ⇌ Cu + 0,52
I2 + 2e ⇌ 2I + 0,54
O2(g) + 2H+ + 2e ⇌ H2O2 + 0,68
Fe3+ + e ⇌ Fe2+ + 0,77
NO 3 + 2H+ + e ⇌ NO2(g) + H2O + 0,80
Ag+ + e ⇌ Ag + 0,80
Hg2+ + 2e ⇌ Hg(ℓ) + 0,85
NO 3 + 4H+ + 3e ⇌ NO(g) + 2H2O + 0,96
Br2(ℓ) + 2e 
⇌ 2Br 
+ 1,07
Pt2+ + 2 e ⇌ Pt + 1,20
MnO2 + 4H+ + 2e ⇌ Mn2+ + 2H2O + 1,23
O2(g) + 4H+ + 4e ⇌ 2H2O + 1,23
2
⇌
3+
Cr2O 7 + 14H+ + 6e 2Cr + 7H2O + 1,33

Cℓ2(g) + 2e ⇌ 2Cℓ + 1,36


MnO 4 + 8H+ + 5e ⇌ Mn2+ + 4H2O + 1,51

⇌
+
H2O2 + 2H +2 e 2H2O +1,77
Co3+ + e ⇌ Co2+ + 1,81
F2(g) + 2e ⇌ 2F + 2,87
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PHYSICAL SCIENCES: 21
(Paper 2) 10842/22

Name: ________________________________________________________

5.3 Graph indicating the relationship between the volume of H2(g) and time

35

30

25
Volume (cm3)

20

15

10

0 0,5 1,0 1,5 2,0 2,5 3,0

Time (minutes)
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PREPARATORY EXAMINATION/
VOORBEREIDENDE EKSAMEN

2022
MARKING GUIDELINES/NASIENRIGLYNE

10842
PHYSICAL SCIENCES: CHEMISTRY/FISIESE WETENSKAPPE: CHEMIE

PAPER/VRAESTEL 2

12 pages/bladsye
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QUESTION/VRAAG 1

1.1 D  (2)

1.2 B  (2)

1.3 C  (2)

1.4 D  (2)

1.5 B  (2)

1.6 B  (2)

1.7 C  (2)

1.8 A  (2)

1.9 B  (2)

1.10 D  (2)
[20]

QUESTION/VRAAG 2

2.1 2.1.1 Ester/Ester  (1)

2.1.2 Methyl propanoate/ Metielpropanoaat (2)

2.2 2.2.1 Catalyst OR Speed up the reaction/ Katalisator OF Om die reaksie

te versnel
OR It lowers the activation energy / dit verlaag die aktiveringsenergie
Do not accept dehydrating agent. Not in this reaction.
Dehidrateringsmiddel word nie hier aanvaar nie. (1)

2.2.2 Propanoic Acid and Methanol/Propanoësuur en Metanol (2)

2.2.3 Esterification / Esterifikasie OR condensation / kondensasie (1)

2.3 2.3.1 Carboxyl group / Karboksielgroep (1)

2.3.2 Carboxylic acids / Karboksielsure (1)

2.3.3 Homologous series: A series of organic compounds that can be

described by the same general formula OR in which one member
differs from the next with a CH2 group.
Functional group: A bond or an atom or a group of atoms that
determine(s) the physical and chemical properties of a group of organic
compounds. 
As long as learners indicate difference between two.
(2)

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Homoloë reeks: ʼn Reeks organiese verbindings wat deur dieselfde

algemene formule beskryf kan word OF waarin die een lid van die
volgende verskil met ʼn CH2-groep. 
Funksionele groep: ʼn Binding of ʼn atoom of ʼn groep atome wat die
fisiese en chemiese eienskappe van ʼn groep organiese verbindings
bepaal.

2.4 2.4.1 Alcohols / Alkohole (1)

2.4.2 Positional (isomers) / Posisionele (isomere)  (1)

2.4.3
Marking criteria / Nasienkriteria
 methyl and alcohol both on 2nd C /
metiel en alkohol beide op 2de C
 main chain / hoofketting: 3 C 
 Structural formulae complete /
Volledige struktuurformule 

(3)

2.5 2.5.1 5-bromo-2,2-dimethylhexane /

5-bromo-2,2-dimetielheksaan

Marking criteria/Nasienkriteria
 Correct stem i.e. hexane / Korrekte stam d.w.s. heksaan
 All substituents: bromo and dimethyl  do not accept methyl only
/ Alle substituente: bromo en dimetiel moenie net metiel
aanvaar nie, moet dimetiel wees
 Completely correct numbering, sequence, hyphens, commas /
Heeltemal korrekte nommering, volgorde, koppeltekens,
kommas. 
(3)

2.5.2 H Marking
criteria/Nasienkriteria
H C H
 Whole structure correct /
H H H
Hele struktuur korrek 2/2
H C C C C C H  Only functional group
correct /Slegs
H H funksionele groep korrek
H H C H 1/2
  Additional functional
H groups / Addisionele
funksionele groepe 0/2
(2)
[21]

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QUESTION/VRAAG 3

3.1 3.1.1 Same molecular formula, but different functional groups.

/Dieselfde molekulêre formule maar verskillende funksionele
groepe.  (2 or 0) (2)

3.1.2 Pentan-3-one  / Pentan-3-oon (2 or 0)

Accept 3-pentanone / aanvaar 3-pentanoon (2)

3.1.3 LOWER THAN / LAER AS  (1)

3.1.4  Aldehydes have dipole-dipole forces  and alcohols have

hydrogen bonds. 
 Dipole-dipole forces are much weaker than hydrogen bonds. OR
The hydrogen bonds are stronger than Dipole-dipole forces.
OR
 Less energy is required to overcome the weak intermolecular
force. OR More energy is required to overcome the strong
intermolecular force.  (Third mark is split – either one of the
bullets)

 Aldehiede het dipool-dipool kragte en alkohole het

waterstofbindings. 
 Dipool-dipool kragte is baie swakker as waterstofbindings. OF
Waterstofbindings is sterker as Dipool-dipool kragte.
OF
 Minder energie word benodig om die swak intermolekulêre kragte
te oorkom. OF Meer energie word benodig om die sterker
intermolekulêre kragte te oorkom.  (Derde punt – enige een van
die laaste twee bullets) (3)

3.1.5 HIGHER THAN 

 Ketones have dipole-dipole forces and alcohols have hydrogen
bonds. 
 Dipole-dipole forces are much weaker than hydrogen bonds. 
OR
 Less energy is required to overcome the weak intermolecular
forces.

HOËR AS 
 Ketone het dipool-dipool kragte en alkohol het
waterstofbindings. 
 Dipool-dipool kragte is baie swakker as waterstofbindings. 
OF
 Minder energie word benodig om die swak intermolekulêre kragte
te oorkom.  (3)

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3.2 3.2.1 The temperature at which the vapour pressure equals the
atmospheric pressure. / Die temperatuur waarby die dampdruk van
die stof gelyk is aan die atmosferiese druk.  (2 or 0) (2)

3.2.2 Length of the chain / Molar mass / number of carbons in the chain /
surface area of molecule
Lengte van die ketting / molêre massa / aantal koolstowwe in die
ketting / kontakoppervlakte van molekule  (1)

3.2.3 London forces or dispersion forces or induced dipole forces /

Londonkragte of dispersiekragte of geïnduseerde dipoolkragte.  (1)

3.2.4 Positive marking from 3.2.2

As the chain length increases  the boiling point
increases.  If given as direct proportion (1/2)

Positiewe nasien vanaf 3.2.2

Soos die kettinglengte toeneem 
neem die kookpunt toe.  As direk eweredig (1/2) (2)
[17]

QUESTION/VRAAG 4

4.1 Elimination / Dehydration / Eliminasie / Dehidrasie  (1)

4.2 4.2.1 The addition of water to a compound  / Die addisie van water aan ʼn
verbinding (2 or 0) (2)

4.2.2 H2SO4 / H3PO4 (formula has to be correct) OR / OF

sulphuric acid / phosphoric acid / swaelsuur / fosforsuur  (1)

4.3 4.3.1  No water / No H2O / Geen water 

 (concentrated) strong acid as catalyst / (gekonsentreerde) sterk
suur as katalisator (as in CAPS on P113) (2)

4.3.2 H   H H H 
H
H C C C + H Br H C C C H
H H H H Br H
MARKING CRITERIA / NASIENKRITERIA (3)
 Whole structure of propene corrects – bromine must be on C 2
(rule of Markovnikov) / Die hele struktuur van propeen
korrek – broom moet op C 2 wees (reel van Markovnikov) 
Accept/Aanvaar HBr Ignore/Ignoreer: ⇌
 Condensed/semi-structural formulae/Gekondenseerde/
semi-struktuurformules Max/Maks: 2⁄3
 Molecular formula/Molekulêre formule 0⁄3

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Any additional reactant or Everything correct, wrong

products/Enige addisionele balancing/Alles korrek,
reactant of produkte: verkeerde balansering
Max/Maks.: 2⁄3 Max/Maks. 2⁄3

4.4 4.4.1 Substitution / Substitusie  (1)

4.4.2 Substitution / Hydrolysis / Substitusie / Hidrolise  (1)

4.5 4.5.1  Alkene dissolved in a non-polar solvent OR no water / Alkeen

opgelos in ʼn nie-polêre oplosmiddel OF geen water 
 (Catalyst) Pt / Pd / Ni / (Katalisator) Pt / Pd / Ni  (2)

4.5.2 Production of margarine / to harden unsaturated plant oils 

Produksie van margarien / om onversadigde plantolies te verhard 
There can be other options. Must be applicable to the food industry. (1)
[14]

QUESTION/VRAAG 5

5.1 5.1.1 Endothermic / Endotermies  (1)

5.1.2 ΔH = Eproducts - Ereactants / ΔH = Eprodukte - Ereaktante

ΔH = 420 – 0
ΔH = 420 kJmol-1  
If learner only writes the correct answer with unit – allocate 2 marks
No unit – only one mark
Slegs korrekte antwoord met eenheid – gee 2 punte
Geen eenheid – slegs een punt (2)

5.1.3 EA reverse = 60 (kJmol-1 )/ EA terugwaarts = 60 (kJmol-1 )  (1)

5.2 5.2.1 The change in concentration of reactants or products per unit time /
Die verandering in konsentrasie van reaktante of produkte per eenheid
tyd  (2 or 0) (2)

5.2.2 The number of particles with sufficient energy for effective collisions.
Or with enough energy for effective collisions /
Die hoeveelheid deeltjies met genoegsame energie vir effektiewe
botsings. Of met voldoende energie vir effektiewe botsings.  (1)

5.2.3 Sample S / Monster S  (1)

5.2.4  When the temperature is increased the particles gain kinetic

energy. 
 More particles will have sufficient energy/the number of effective
collisions will increase. 
 More particles will therefore have energy greater than the
activation energy, so the area under the graph to the right of line T
increases. 
(3)
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 Wanneer die temperatuur verhoog, verkry die deeltjies meer

kinetiese energie. 
 Meer deeltjies sal genoegsame energie hê / hoeveelheid
effektiewe botsings sal toeneem. 
 Meer deeltjies sal dus energie meer as die aktiverings energie hê
en die area onder die grafiek aan die regterkant van lyn T sal
toeneem. 

5.3 5.3.1 GRAPH INDICATING THE RELATIONSHIP BETWEEN THE

VOLUME OF H2(g) PRODUCED PER UNIT TIME/GRAFIEK WAT
DIE VERHOUDING AANDUI TUSSEN DIE VOLUME H2(g)
GEPRODUSEER PER EENHEIDSTYD
VOLUME (cm3)

TIME (minutes)/TYD (minute)

ON GRAPH PAPER/OP DIE GRAFIEKPAPIER

 All points correctly plotted/Alle punte korrek geplot
 Points connected into correct shape/Punte verbind en die vorm reg (2)

5.3.2 The reaction rate is decreasing because the reactants decrease.

The reaction rate is decreasing because the gradient of the graph is
decreasing.
The reaction has run to completion. The reactant has been used up. 
(any one)
Die reaksietempo neem af want die reaktante neem af.
Die reaksietempo neem af omdat dit gradiënt van die grafiek afneem.
Die reaksie is voltooi. Die reaktant is alles opgebruik.  (enige een) (1)

5.3.3 ON GRAPH PAPER/OP DIE GRAFIEKPAPIER

 Steeper gradient / Steiler gradiënt
 Reach completion earlier / Bereik gouer voltooiing (2)

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5.3.4 𝑉 0,035
𝑛(𝐻2) = 𝑉 = 24,47
𝑚 Marking criteria/Nasienkriteria
= 1,43 x 10-3 mol  Divide by / Deel deur 24,47 in
𝑉
𝑛(𝐻2) = 𝑉
n(HCℓ) = 2 𝑛(𝐻2) = 2,86 x 10-3 𝑚

mol  Ratio/Verhouding n(HCℓ) = 2 𝑛(𝐻2) 

𝑛
𝑐 = 𝐻𝐶𝑙   Substitute/Substitusie
𝑉 𝑛
0,25 in 𝑐 = 𝐻𝐶𝑙
𝑉
2,86𝑥10−3  Final answer/Finale antwoord:
0,25 = 𝑉 0,011 dm3/11 cm3 
2,86𝑥10−3 
V=
0,25
= 0,011 dm3 

If learner used Mg:

𝑚
𝑛=
𝑀
11
= 
24
= 0,458 mol
n(Mg) = 2 𝑛(HCℓ ) =0,917 mol

𝑛𝐻𝐶𝑙
𝑐= 
𝑉

0,917
0,25 =
𝑉

V = 3,67 dm3 

(4)
[20]

QUESTION/VRAAG 6

6.1 6.1.1 Concentration of N2 increases/Konsentrasie van N2 verhoog  (1)

6.1.2 Pressure increased/Druk verhoog  (1)

6.1.3 Temperature increased/Temperatuur verhoog  (1)

6.2 When equilibrium in a closed system is disturbed, the system will reinstate a new
equilibrium by favouring the reaction that will oppose the disturbance.  (2 or 0)

Wanneer die ewewig in ʼn geslote sisteem versteur word, stel die sisteem ʼn nuwe
ewewig in deur die reaksie wat die versteuring teenwerk, te bevoordeel (2 of
0) (2)

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6.3 6.3.1 Decreases / Verminder  (1)

6.3.2  The pressure will decrease. 

 The system will favour the reaction that increases the number of
gas molecules or number of particles. 
 Hence, the reverse reaction will be favoured. 

 Die druk sal verminder. 

 Die sisteem bevoordeel die reaksie wat die hoeveelheid gas
molekule sal vermeerder. 
 Gevolglik, sal die terugwaartse reaksie bevoordeel word.  (3)

6.4 CALCULATION USING NUMBER OF MOLES/BEREKENING MET DIE AANTAL

MOL

Mark allocation/Puntetoekening:

𝑚
a. Use of/gebruik van n = 
𝑀
b. n(NH3) at equilibrium/by ewewig = 1,2 mol 
c. Using/Gebruik ratio/verhouding n(N2): n(H2) : n(NH3) = 1:3:2 
d. n(N2) at equilibrium (initial – change)/n(N2) by ewewig (aanvanklik – verander)
e. n(H2) at equilibrium (initial – change)/n(H2) by ewewig (aanvanklik – verander)
f. Divide by volume/deel deur volume
g. Kc expression/uitdrukking 
h. Substitution into Kc expression/Vervang in Kc uitdrukking 
i. Final answer/Finale antwoord: 0,25 

𝑚
n(NH3) =
𝑀
20,4
= a
17

= 1,2mol b
OR/OF
give two marks in table for 1,2 mol/gee twee punte in tabel vir 1,2 mol

N2 H2 NH3
Molar ratio/Molêre verhouding 1 3 2
Initial moles/Aanvanklike mol 5 5 0
Change in moles/Verandering in mol 0,6 1,8 1,2 Ratio/Verhouding c
Equilibrium moles/Ewewig mol 4,4 d 3,2 e 1,2
Concentration at equilibrium/ 0,88 0,64 0,24 Divide by/
Konsentrasie by ewewig Deel deur 5 f
[𝑵𝑯𝟑 ]𝟐
Kc =  g carry over
[ 𝑵𝟐 ][𝑯𝟐 ]𝟑
= (0,24)2
(0,88)(0,64)3  h
= 0,25 i
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CALCULATIONS USING NUMBER OF CONCENTRATIONS/ BEREKENINGE

MET BEHULP VAN KONSENTRASIES

Mark allocation/Puntetoekening:
𝑚
a. Use of/gebruik van c = 
𝑀𝑉
b. (NH3) at equilibrium/by ewewig = 0,24 mol·dm-3 
c. Using concentration ratio/Gebruik konsentrasieverhouding
[N2]: [H2] : [NH3] = 1:3:2 
d. Divide by volume/Verdeel volgens volume
e. Equilibrium concentration of N2 (initial – change)/Ewewingskonsentrasie van N2
(aanvanklik – verander)/
f. Equilibrium concentration of H2 (initial – change)/Ewewingskonsentrasie van H2
(aanvanklik – verander)/ 
g. Kc expression/uitdrukking 
h. Substitution into Kc expression/Substitusie in Kc uitdrukking 
i. Final answer/Finale antwoord: 0,25 

N2 H2 NH3
Molar ratio/Molêre verhouding 1 3 2
Initial concentration/ 1 1 0
Aanvanklike konsentrasie
Change in concentration/ 0,6 1,8 1,2  Divide by/
Verandering in konsentrasie Verdeel deur 5 d
Equilibrium concentration/ 0,12 0,36 0,24 
Ewewigskonsentrasie b
Concentration at equilibrium/ 0,88 0,64 0,24  Ratio/
Konsentrasie by ewewig e f a Verhouding c
[𝑵𝑯𝟑 ]𝟐 𝐦
Kc =  g c =
[ 𝑵𝟐 ][𝑯𝟐 ]𝟑 𝐌𝐕

= (0,24)2 = 20,4
(0,88)(0,64)3  h 17 x 5
= 0,25 i = 0,24
(9)
6.5 Decrease/Verlaag  (2)
[20]
QUESTION/VRAAG 7

7.1 An acid is a substance that produces hydrogen ions (H+)/hydronium ions

(H3O+) when it dissolves in water.  (2 or 0)
ʼn Suur is ʼn stof wat waterstofione (H+)/hidroniumione(H3O+) produseer
wanneer dit in water oplos  (2 or 0). (2)

7.2 7.2.1 X  (1)

7.2.2 NH4+ + H2O  ⇌ H3O+ + NH3  (Balancing / Balansering) (3)

7.2.3 Acidic/Suur
Hydronium ions (H3O+) are formed in the solution./Hidroniumione
(H3O+) word gevorm in die oplossing  (2)

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𝒎
7.3 7.3.1 c= 
𝑴𝑽
𝟒
=
(𝟒𝟎)(𝟎,𝟓)


= 0,2 mol.dm-3

OR/OF
𝒎 𝟒
n(NH3) = = =0,1 mol
𝑴 𝟒𝟎

n 

= 0,2 mol•dm-3
(3)

7.3.2 OPTION/OPSIE 1 OPTION/OPSIE 2

ca Va= na cb Vb = nb
cb Vb nb
(0,2)(0,0125) = nb
ca (25) = 1
(0,2) (12,5) 2 nb = 0,0025 mol

ca = 0,05 mol•dm-3 na =1/2(0,0025)

[H3O+] = 2 (0,05) ca = na
Va
pH = -log [H3O+]
ca= 0,00125
pH= -log (0,1) 0,025

pH = 1 ca= 0,05 mol.dm-3

[H3O+] = 2 (0,05)

pH = -log [H3O+]

pH= -log (0,1)

pH = 1 (7)
[18]

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QUESTION/VRAAG 8

8.1 Temperature/Temperatuur: 298 K (25 °C) 

Concentration of electrolyte / Konsentrasie van die elektroliet: 1 mol·dm-3  (2)

8.2 B  (1)

8.3 Ba(s) → Ba2+(aq) + 2e- double arrow – penalise by one mark. (2)

8.4 Ba(s) | Ba2+(aq) (1mol.dm-3)|| Cu2+(aq) (1mol.dm-3)|Cu (s) 

(The concentration and phases can be omitted. / Die konsentrasie en fases kan
weggelaat word.)

Ba | Ba2+ || Cu2+ | Cu  (3)

8.5 Eθcell = Eθ cathode/katode – Eθ anode/anode  (no abbreviations in formula allowed)

= 0,34– (-2,90)
= 3,24 V  (4)

8.6 8.6.1 Do not mark (0)

8.6.2 Decreases / Verlaag  (2)

[14]

QUESTION 9

9.1 Electrical energy  to Chemical energy 

Elektriese energie  na Chemiese energie  (2)

9.2 A layer of copper will be deposited on the electrode/ mass increase 

’n Lagie koper sal op die elektrode neerslaan/die massa vermeerder  (1)

9.3 Not possible for this cell – allocate 2 marks to all learners   (2)

9.4 The blue colour will go lighter or go clear. OR the blue colour will remain
unchanged. 

Die blou kleur sal ligter word of kleurloos wees. OF die blou kleur sal
onveranderd bly.  (1)
[6]

TOTAL/TOTAAL: 150

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