2
1
Priya investigates the effect of nitrate ions and magnesium ions on the growth of barley
seedlings.
Priya does three experiments.
In each experiment she puts one barley seedling and 3 cm3 of a mineral solution into a test-tube.
barley
seedling
barley
seedling
barley
seedling
mineral solution
containing nitrate
ions and
magnesium ions
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
in g
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.
mineral solution containing nitrate ions and magnesium ions have the greatest mass
magnesium need to make chlorophyll
nitrate need to make protein
the mass of the mineral solution containing nitrate ions and no magnesium ions is greater than the mass of
mineral solution containing magnesium ions and no nitrate ions
[4]
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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
gas
water
dilute hydrochloric acid
calcium carbonate
(a) (i) Identify the independent variable in this investigation.
concentration of the acid
[1]
(ii) Describe how Blessy measures the dependent variable in this investigation.
dependent variable volume of gas
how it is measured
the water level in the measuring cylinder
[1]
(iii) Identify two variables that Blessy must control.
1
same temperature
2
same volume of acid
[1]
(b) Identify one safety risk in the investigation and describe how to control the risk.
safety risk
the acid is very dangerous
how to control the risk
wear safety glasses
[2]
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4
3
The diagram shows the range of frequencies of sound waves that different animals hear.
1000 000
100 000
10 000
frequency
in Hz
1000
100
10
1
goldfish
raccoon
mouse
bat
animal
(a) Write down the lowest frequency of sound a racoon hears.
100
Hz
[1]
(b) Estimate the range of frequencies a mouse hears.
Hz
90000
[1]
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(c) Look at the graph showing the waveforms of two sound waves.
Waveform A and waveform B have different frequencies and different amplitudes.
waveform B
displacement
in cm
waveform A
4
2
0
time
–2
–4
(i) Describe how increasing the frequency of a sound wave changes the sound we hear.
[1]
increases the pitch
(ii) Describe how increasing the amplitude of a sound wave changes the sound we hear.
increases the loudness
[1]
(d) (i) Calculate how many times bigger the amplitude of waveform B is than waveform A.
4
[1]
(ii) Calculate how many times bigger the frequency of waveform A is than waveform B.
2
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[1]
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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.
120 000
100 000
80 000
number
of cheetahs
60 000
40 000
20 000
0
1900
1940
1980
2020
2060
3000
year
(i) Describe the change in the number of cheetahs between 1900 and 2020.
decreases
[1]
(ii) Draw an extension to the line of best fit to the x-axis.
Estimate the year when the cheetah becomes extinct.
year
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2060
[2]
7
(iii) The change in the number of cheetahs may be due to natural selection.
Describe the theory of natural selection.
[2]
(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
there are more female to produce offspring
.
The population of sea turtles might decrease because
there are less male to mate with female
.
[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 decrease
reason 1
the nesting site will flood
reason 2
the baby turtles will down because it doesn't have enough oxygen to breath
[2]
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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
in g
volume
in cm3
density
in g / cm3
A
395
50
7.9
B
0.22
100
C
452
40
D
328
45
E
340
38
0.0022
11
7.3
8.9
(a) Calculate the density of substance E.
Give your answer to two significant figures.
density of substance E =
8.9
g / cm3 [3]
(b) Which substance in the table is a gas?
Explain your answer.
substance B
explanation
The demsity of gas will lower than the dinsity of water
[2]
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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.
the particles received enrgy from the skin
heat energy transfer from the skin
[3]
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
organism to another organism
decomposition
the breakdown of dead and
decaying waste material
feeding
the burning of fossil fuels
photosynthesis
the release of energy from the
breakdown of glucose
respiration
the formation of glucose and
oxygen by green plants
[4]
(b) Name the process in the carbon cycle that decreases the amount of carbon in the
atmosphere.
[1]
photosynthesis
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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.
tectonic plates
[1]
(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.
crust
mantle
[1]
(ii) Look at the diagram showing the formation of a mid-ocean ridge.
Draw arrows on the diagram to show the pathway of the convection currents which
cause the formation of the mid-ocean ridge.
mid-ocean ridge
crust
mantle
[1]
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(c) Look at the map showing the position of active volcanoes and the boundaries of floating rock
in the Earth’s crust.
North
America
Asia
Europe
Asia
Atlantic
Ocean
Africa
Pacific
Ocean
Indian
Ocean
South
America
Indian
Ocean Australia
Atlantic
Ocean
South
Africa
Antarctica
key
active volcano
boundary of floating rocks
(i) Why are active volcanoes used as evidence for the location of the boundaries of the
floating rocks?
[1]
(ii) Suggest why there are no active volcanoes near South Africa.
it doesn't have boundaries near South Africa
[1]
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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?
copper nitrate
[1]
(b) The mass is conserved during this reaction.
What is the meaning of the words mass is conserved?
[1]
(c) Water molecules are made in this reaction.
Name and describe the type of bond present in a water molecule.
name
covalent bond
description
Shared electron
[2]
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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]
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