Cambridge Assessment
International Education
Science
Stage 9
Paper 2
2023
45 minutes
No additional materials are needed.
INSTRUCTIONS
« Answer all questions.
« Write your answer to each question in the space provided.
« You should show all your working on the question paper.
INFORMATION
« The total mark for this paper is 50.
« The number of marks for each question or part question is shown in brackets [ ].
3146_02/6RP
©UCLES 2023
2
1
Priya investigates
seedlings.
the
effect
of nitrate
ions
and
magnesium
ions
on
the
growth
of barley
Priya does three experiments.
In each experiment she puts one barley seedling and 3cm’ of a mineral solution into a test-tube.
barley
seedling
barley
seedling
mineral solution
containing nitrate
ions and
magnesium ions
barley
seedling
mineral solution
containing
magnesium ions
and no nitrate ions
mineral solution
containing nitrate
ions and no
magnesium ions
After four weeks Priya dries the seedlings in an oven and measures their dry mass.
Here are her results.
dry mass of the
barley seedling
ing
experiment
mineral solution containing nitrate ions and magnesium ions
3.8
mineral solution containing magnesium ions and no nitrate ions
1.9
mineral solution containing nitrate ions and no magnesium ions
2.8
Describe and explain the effect of nitrate ions and the effect of magnesium ions on the growth of
barley seedlings.
Use information from the table in your answer.
© UCLES 2023
3146_02
3
2
Dilute hydrochloric acid reacts with calcium carbonate.
Blessy plans an investigation to find out the effect of concentration of acid on the rate of this
reaction.
The diagram shows the equipment she uses.
measuring
cylinder
delivery tube
conical
flask
dilute hydrochloric acid
calcium carbonate
(a)
(i)
Identify the independent variable in this investigation.
nul
(ii)
Describe how Blessy measures the dependent variable in this investigation.
dependent variable
how it is measured
1
(iii) Identify two variables that Blessy must control.
1
1
(b)
Identify one safety risk in the investigation and describe how to control the risk.
safety risk
how to control the risk
© UCLES 2023
3146_02
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4
3
The diagram shows the range of frequencies of sound waves that different animals hear.
1000 000
100000
10000
frequency
in Hz
1000
00—
.
-
10
goldfish
raccoon
mouse
bat
animal
(a)
Write down the lowest frequency of sound a racoon hears.
1
(b)
Estimate the range of frequencies a mouse hears.
1
© UCLES 2023
3146_02
5
(c)
Look at the graph showing the waveforms of two sound waves.
Waveform A and waveform B have different frequencies and different amplitudes.
displacement
incm
4
A
waveform B
waveform A
time
(i)
Describe how increasing the frequency of a sound wave changes the sound we hear.
1
(ii)
Describe how increasing the amplitude of a sound wave changes the sound we hear.
mul
(d)
(i)
Calculate how many times bigger the amplitude of waveform B is than waveform A.
Nyl
(ii)
© UCLES 2023
Calculate how many times bigger the frequency of waveform A is than waveform B.
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6
4
This question is about the population of cheetahs and sea turtles.
(a)
Look at the graph showing the change in the number of cheetahs since 1900.
120000
1~
100000 -
80000
number
of cheetahs
!
0000
‘
N
40000
20000
R
B
0
1900
1940
EEEN:
RN
1980
2020
2060
3000
year
(i)
Describe the change in the number of cheetahs between 1900 and 2020.
(i)
Draw an extension to the line of best fit to the x-axis.
Estimate the year when the cheetah becomes extinct.
year
© UCLES 2023
3146_02
2]
7
(iii) The change in the number of cheetahs may be due to natural selection.
Describe the theory of natural selection.
L2
(b)
Carbon dioxide levels in the atmosphere are linked to increased Earth surface temperature
and rising sea levels.
Sea turtles live in the ocean and come to shore to build nesting sites in the sand.
The sex of the sea turtle offspring is linked to the surface temperature of the sand.
At warmer temperatures more of the offspring are female than male.
(i)
The population of the sea turtles might change because of an increase in the surface
temperature of sand.
Complete the sentences.
The population of sea turtles might increase because
The population of sea turtles might decrease because
[2]
(ii)
Suggest how the rising sea level will affect the population of the sea turtles.
Write down two reasons for your answer.
effect on the population
reason 1
reason 2
[2]
© UCLES 2023
3146_02
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8
5
Chen measures the mass and volume of some substances.
He calculates the density of each substance.
The table shows his results.
substance
mass
N
ing
volume
N
3
incm
A
395
50
79
100
0.0022
B
(a)
0.22
c
452
40
1"
D
328
45
73
E
340
38
Calculate the density of substance E.
Give your answer to two significant figures.
density of substance
(b)
Which substance in the table is a gas?
Explain your answer.
substance
explanation
© UCLES 2023
density.
3
ing/cm
N
3146_02
E=
9
6
Perspiration is a watery liquid produced by the skin.
The water evaporates to cool the skin.
Explain the cooling effect of evaporation.
Use ideas about particles.
7
This question is about the carbon cycle.
(a)
Draw a straight line to match the process to its correct description.
process
description
combustion
carbohydrate moves from one
.
y
organism to another organism
the breakdown of dead and
decomposition
decaying waste material
feeding
the burning of fossil fuels
the release of energy from the
photosynthesis
breakdown of glucose
the formation of glucose and
oxygen by green plants
respiration
[4]
(b)
Name the process
atmosphere.
in the
carbon
cycle
that
decreases
the
amount
of carbon
in the
nyl
© UCLES 2023
3146_02
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10
8
The Earth’s crust is split into large pieces of rock.
These large pieces of rock float on top of the molten magma in the mantle.
(a)
Write down the name of these large pieces of floating rock.
(b)
Convection currents in the mantle cause these floating rocks to move.
(i)
Look at the diagram showing the formation of volcanoes.
Draw arrows on the diagram to show the pathway of the convection currents in the mantle.
1
(ii)
Look at the diagram showing the formation of a mid-ocean ridge.
Draw arrows on the diagram to show the pathway
cause the formation of the mid-ocean ridge.
of the convection
currents which
mid-ocean ridge
crust
mantle
1
© UCLES 2023
3146_02
"
(c) Look at the map showing the position of active volcanoes and the boundaries of floating rock
in the Earth’s crust.
Antarctica
key
A active volcano
— boundary of floating rocks
(i)
Why are active volcanoes used as evidence for the location of the boundaries of the
floating rocks?
nul
(i)
© UCLES 2023
Suggest why there are no active volcanoes near South Africa.
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12
9
Copper oxide reacts with dilute nitric acid to make a salt and water.
(a)
What is name of the salt made in this reaction?
nul
(b)
The mass is conserved during this reaction.
What is the meaning of the words mass is conserved?
(c)
Water molecules are made in this reaction.
Name and describe the type of bond present in a water molecule.
name
description
2]
© UCLES 2023
3146_02
13
10
Look at the diagram showing a model to help explain how an electrical circuit works.
pump
@
|
pipe
hot water
radiator
(a)
The radiator in the model represents a lamp in the circuit.
What is represented in the electrical circuit by the pump and the hot water?
pump
hot water
2]
(b)
Write down one strength and one limitation of this model of an electrical circuit.
strength
limitation
2]
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 Assessment
International Education Copyright Acknowledgements Booklet. This is produced annually and is available to download at
hitps:/flowersecondary.cambridgeinternational org/
Cambridge Assessment Interational Education is part of Cambridge Assessment Cambridge Assessment is the brand name of the University of Cambridge
Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge
© UCLES 2023
3146_02
[Turn over
£202 310N @
The Periodic Table of Elements
Group
2
3
Be
Na
Mg
|
K
|
z0orle
19
™
20
5
B
rame
reltive atormic mass
beron
il
B
Al
21
2
Sc
Ti
Rb
Sr
Y
Zr
Cs
Ba
fanthancis
Hf
Fr
Ra
potmsom | cobum | samdom | v
s | a0
i
4
7
3
3
[
2
%
v
Cr
Nb
Mo
Ta
lanthanoids
actinoids
m
89-103
actrolde
B
v
78
104
Rf
Db
2
2
7
Mn
Fe
Tc
Ru
w
Re
Os
Ir
Sg
Bh
Hs
Mt
| vwdon | ovomiom | rangmness | on
51
)
5
5
G
2
@
w“
wodum | soom | ywum | sonum | notum | moyosenm |
e | e
&
i
£
@
3
B
8771
2
7
7
|
6
7
8
2
6
7
C
N
Si
P
aaron | togen
12
14
18
[
O
16
S
9
reum
o
tuorne
19
7
roon
20
8
F
Cl
Ne
Ar
dominom | sicon | prownons | wute | comme | won
Ca
camn | buom
W | W
o
o
5
oo
sodum | magnesom
n
|
He
atomic symbol
iwn | ooy
A
i
2
4
H
Key
atomic numer
O
Li
3
1
Co
conat
5
3
Rh
2
Ni
2
El
F
31
Ge
As
Zn
Ag
Cd
Pt
Au
Hg
Tl
Pb
Ds
Rg
Cn
Nh
Fi1
Pd
copper
[
a7
0
]
s
an
™
o
In
towetum | rtnenum | modum | pwedun | sher | esamum | noun
o1
03
o0
08
T2
s
7
7
7
7
7
B
81
| tamwom | ungren | e
i
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e
105
106
o7
i
2
Cu
kel
5
©
Ga
=
| omm | vaum | st
%0
0z
o
108
109
o
oo
T
[
mocury | vaum
201
204
112
3
B
2
355
Se
Br
wu
3
©
3
Kr
| gmwn | wsne | sseim | oomne | kopen
i
7
7
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[
5
51
52
B
B
Sn
o0
Sb
Te
Bi
Po
Mc
Lv
I
B
wtmory | o
22
i
o
2
| lodne
il
3
2jond
T4
bean | poorim | asaine |
209
z
115
6
17
At
Ts
Xe
o
51
o
Rn
radon
118
Og
refostum | dubrum | sosbogum | bovim | hassm | matnarum | damstaiun | roongenm | copemeum | nosm | fodum | moscorum | Ivemorm | temnessne | oganosson
&
5
3
La
Ce
Pr
Nd
Ac
Th
Pa
U
o1
B3
B
&
3
&
&
3
&
Pm
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Np
Pu
Am
Ccm
Bk
cf
Es
Fm
Md
-
-
o
-
-
7
7
Yb
Lu
No
Lr
fhanin | carom [ aseccymom | restymm | prometsun | sematum | ovosom | osdolnin | toom | oysrosim | homum | ewem | tum | ywedim | eten
139
140
14t
164
180
182
187
189
183
165
167
169
178
5
8
%
o1
2
B
B
&3
o
o7
o
o
100
01
102
103
scinom | von | ooucinim | umion
2z
28
purum | outonom | amriom | cuiom | berkeiun | catorin | snsium | fermum
-
dom | noseium | awrancm
-
143
1