MEMORANDUM
GRADE 11
PHYSICAL SCIENCES: CHEMISTRY
Paper 2
MARKS: 150
TIME: 3 hours
Learning Outcomes and Assessment Standards
LO1
LO2
LO3
AS 11.1.1:
Plan and conduct a
scientific investigation to
collect data systematically
with regard to accuracy,
reliability and the need to
control variables.
AS 11.2.1:
Define and discuss basic
prescribed scientific
knowledge.
AS 11.3.1:
Research, discuss,
compare and evaluate
scientific and indigenous
knowledge claims by
indicating the correlation
among them, and explain
the acceptance of different
claims.
AS 11.1.2:
Seek patterns and trends,
represent them in different
forms to draw conclusions,
and formulate simple
generalisations.
AS 11.2.2:
Express and explain
prescribed scientific
theories, models and laws
by indicating the
relationship between
different facts and
concepts in own words.
AS 11.3.2:
Identify ethical and moral
issues related to the
development of science
and technology and
evaluate the impact (pros
and cons) of the
relationship from a
personal viewpoint.
AS 11.1.3:
Apply known problemsolving strategies to solve
multi-step problems.
AS 11.2.3:
Apply scientific knowledge
in everyday life contexts.
MEMORANDUM: Maskew Miller Longman, Focus on Physical Sciences Grade 11 – Chemistry: Paper 2
Page 2 of 10
Section A
Question 1: One-word items
1.1
Lewis acid ✓
[11.2.1]
(1)
1.2
real gases✓
[11.2.1]
(1)
1.3
polymerisation✓
[11.2.1]
(1)
1.4
empirical formula✓
[11.2.1]
(1)
1.5
stratosphere✓
[11.2.1]
(1)
[5]
Question 2: False items
2.1
If the bonds in a molecule are polar, the molecule could be either polar or
non-polar.✓✓
[11.2.3]
(2)
2.2
The volume of all gases at standard temperature and pressure
is 22,4 dm3.✓✓
[11.2.3]
(2)
2.3
A chemical bond is the net electrostatic force that two atoms sharing
electrons exert on each other.✓✓
[11.2.3]
(2)
2.4
Hydrogenation of vegetable oils leads to the formation of margarine.✓✓
[11.2.3]
(2)
2.5
The auroras are found in the ionosphere.✓✓
[11.2.3]
(2)
[10]
Question 3: Multiple choice
3.1
C✓✓
[11.2.2]
(2)
3.2
D✓✓
[11.2.2]
(2)
3.3
B✓✓
[11.2.1]
(2)
3.4
B✓✓
[11.2.2]
(2)
3.5
C✓✓
[11.2.3]
(2)
[10]
Total Section A: 25
MEMORANDUM: Maskew Miller Longman, Focus on Physical Sciences Grade 11 – Chemistry: Paper 2
Page 3 of 10
Section B
Question 4
4.1
What is the relationship between volume and temperature of a given
mass of gas that is kept at constant pressure?✓✓
[11.1.1]
(2)
4.2
The volume of a gas is directly proportional to the absolute temperature
when is kept at constant pressure.✓✓
[11.1.1]
(2)
4.3
Graph of volume versus temperature
Criteria for the graph
1
Suitable heading
✓
Axes correctly labelled with units
✓
Correct scale on both axes
✓
Points correctly plotted
✓
Straight line graph drawn through points
✓
0
Total out of 5
[11.1.2]
(5)
4.4
[11.1.1]
(1)
pressure✓
MEMORANDUM: Maskew Miller Longman, Focus on Physical Sciences Grade 11 – Chemistry: Paper 2
Page 4 of 10
∞y ∞y
4.5 Gradients are equal ↓ ___
​ ∞x ​ = ___
​  x ​✓
∞
24,6/x = /100✓
x = 273,33
Temperature = – 273,33 °C✓
Absolute zero temperature✓
[11.1.3]
(4)
[11.1.3]
(6)
[20]
5.1.2
[11.2.2]
(2)
[11.2.2]
(2)
[11.2.2]
(3)
9 × 1023 V
4.6Gradient = _______
​
​= ​ __ ​✓
T
373
pV = nRT
nRT
pV = ____
​   ​✓
V
0,3 × 8,31 × 373
= ​ _____________
​
✓✓
9 ×1023
= 103,3 kPa✓
Question 5
5.1.1
5.2.1 +6✓
5.2.2 +6✓
5.2.3 +2✓
MEMORANDUM: Maskew Miller Longman, Focus on Physical Sciences Grade 11 – Chemistry: Paper 2
Page 5 of 10
5.3
6,67
n(H) = ____
​   ​= 6,67 mol✓
1
40
n(C) = ___
​   ​= 3,33 mol✓
12
53,33
n(O) = _____
​
​= 3,33 mol✓
16
H : C : O
6,67 :3,33 :3,33✓
> 2 : 1 : 1✓
> H2 C1O1
Mr(H2CO) = 30
Mr(x) = 180 = 6 × 30✓
Molecular formula = H12C6O6✓
5.4.1 Mr[(COOH)2∙10H2O] = 2(45)+10(18)✓
= 270✓
24
% C = ____
​   ​× 100✓✓ = 8,89 %✓
270
180
5.4.2 % H2O = ____
​   ​× 100✓ = 66,67 %✓
270
Mass of water = 66,67 % of 20 g✓
= 13,33 g✓
[11.1.3]
(7)
[11.1.3]
(5)
[11.1.3]
(4)
[23]
Question 6
6.1
Concentration is the number of moles of the substance per unit volume of
the solution.✓✓
[11.2.1]
6.2 c1V1 = c2V2✓
6 × V1✓ = 0,1 × 500✓✓
V1 = 8,33 cm3 ✓
Apparatus:
• burette
• Erlenmeyer flask
• pipette
• burette stand (4 × 0,5)✓
(2)
[11.1.3]
(5)
[11.1.2]
(2)
MEMORANDUM: Maskew Miller Longman, Focus on Physical Sciences Grade 11 – Chemistry: Paper 2
Page 6 of 10
6.3.2 Method:
• Fill burette with HCℓ solution.✓
• Pipette 25 cm3 of Na2CO3 into all three Erlenmeyer flasks.✓
• Add 3 drops of methyl orange indicator to each flask.✓
• Carefully add HCℓ solution from the burette to the carbonate
• solution until the colour of the indicator just changes.
• Note the volume of the acid added.✓
• Repeat the experiment with the other two flasks.✓
[11.1.2]
(5)
6.4
2HCℓ + Na2CO3 → 2NaCℓ + CO2 + H2O ✓✓ balance✓
[11.2.2]
(3)
6.5
It ionises almost completely in water.✓✓
[11.2.1]
(2)
[11.1.3]
(6)
[25]
7.1.1 2H2(g) + O2(g) → 2H2O✓
[11.2.2]
(1)
7.1.2 From balanced equation:
Volume of H2 that reacts with 20 cm3 O2 = 40 cm3✓✓
Volume of H2O formed = 40 cm3✓
Volume of H unreacted = 10 cm3✓
Volume of gases remaining = 50 cm3✓
[11.1.3]
(5)
7.1.3 oxygen✓
[11.1.2]
(1)
From the balanced equation 0,1 mol Zn will produce 0,1 mol ZnSO4.✓
[11.1.3]
(4)
6.6
Average volume of HCℓ = 40,66 cm3✓
Average volume of Na2CO3 = 25,0 cm3
Let HCℓ = a
and Na2CO3 = b
caVa __
na
____
​
​ = ​ n  ​
cbVb
b
↓ caVa × nb = cbVb × na✓
0,1 × 40,66 × 1✓✓ = cb × 25 × 2✓
cb = 0,08 mol∙dm3✓
Question 7
7.2.1 Zn(s) + 2H2SO4(aq) → ZnH2SO4(aq) + H2(g)✓
n(Zn) = 6,45/65 mol
= 0,1 mol✓✓
MEMORANDUM: Maskew Miller Longman, Focus on Physical Sciences Grade 11 – Chemistry: Paper 2
Page 7 of 10
7.2.2 1 mol Zn produces 22,4 dm3 hydrogen✓
↓ 0,1 mol Zn will produce 2,24 dm3 hydrogen✓✓
[11.1.3]
(3)
7.2.3 1 mol H2 → 6,02 × 1023 molecules H2✓
↓ 0,1 mol H2 will have 0,1 × 6,02 × 1023 molecules H2✓
= 6,02 × 1022 molecules H2✓
[11.1.3]
(3)
[17]
8.1
A redox reaction is one in which there is transfer of electrons.✓✓ [11.2.1]
(2)
8.2
Exothermic✓
Energy is released or ∆H < 0✓
(2)
Question 8
[11.2.2]
8.3
Criteria for graph
Checklist
Correct shape – products show lower energy than reactants
✓
Heat of reaction indicated correctly
✓
Activation energy indicated correctly
✓
Energy of products indicated correctly
✓
Energy of reactants indicated correctly
✓
Activated complex indicated correctly
✓
8.4
Marks
CO is the reducing agent.✓
Carbon undergoes an increase in oxidation number.✓✓
[11.1.3]
(6)
[11.2.2]
(3)
[13]
MEMORANDUM: Maskew Miller Longman, Focus on Physical Sciences Grade 11 – Chemistry: Paper 2
Page 8 of 10
Question 9
9.1
hydrocarbons – compounds containing carbon and hydrogen only✓
saturated – all bonds between carbon atoms are single bonds✓
unsaturated – there are double and triple bonds between carbon atoms✓
[11.2.1]
9.2.1 unsaturated hydrocarbon✓
(3)
[11.2.2] (1)
9.2.2 The double bond between carbon atoms break and a hydrogen is
attached to each carbon atom.✓✓
[11.2.2]
(2)
9.3
[11.2. 3]
(5)
[11.2.3]
(4)
[15]
9.4.1 substitution✓
9.4.2 dehydrohalogenation/elimination✓
9.4.3 hydration/addition✓
9.4.4 dehydration/elimination✓
MEMORANDUM: Maskew Miller Longman, Focus on Physical Sciences Grade 11 – Chemistry: Paper 2
Page 9 of 10
Question 10
10.1 oil – refined into petrol and other useful chemicals✓✓
coal – needed for power stations for generation of electricity✓
[11.2.1]
(3)
10.2 carbon dioxide, methane, oxides of nitrogen✓✓
These gases form a layer above Earth and trap heat resulting in an
increase in the temperature on Earth.✓✓
[11.3.2]
(4)
10.3 These gases can scatter harmful radiation and prevent them from
entering Earth’s atmosphere.✓
[11.3.2]
(1)
10.4 Coal burning releases SO2 into the atmosphere which dissolves in water
to produce acid rain.✓✓
[11.3.2]
(2)
10.5 troposphere✓
[11.2.2]
(1)
10.6 catalytic converters✓
[11.2.2]
(1)
[12]
Total Section B: 125
Grand total: 150
MEMORANDUM: Maskew Miller Longman, Focus on Physical Sciences Grade 11 – Chemistry: Paper 2
Page 10 of 10