- JANUARY EDITION -
This monthly document contains one exam-style question per science surrounding the required
practical activities that need to be carried out as part of the AQA/Edexcel specifications.
We have created these questions and mark schemes based on the content of the exam board’s
specification(s), sample assessment materials and other published material. Therefore, EzyEducation
Ltd. takes no responsibility for the relevance of this document to actual examinations set.
We
REQUIRED PRACTICALS
PRACTICE QUESTIONS
Required Practicals Practice Questions (January Edition)
1
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Disclaimer
The questions in this
document are in a similar style
to what you would typically
see in an exam paper. There
can be no guarantee of the
extent to which these
questions will reflect the
actual examination questions
students will sit.
The mark schemes have
been presented in a format
that allows students to mark
their own responses to the
questions in this document.
The mark schemes contain
more detail than would
normally be found in a mark
scheme. Any comments
reflect our opinions and not
those of the exam board.
We are providing
opportunities for students to
apply skills that will be
required to achieve a Grade
5 or above. Therefore, this
content is suitable for both
Foundation and Higher Tier
students.
Question 1 – Biology Required Practical In this question students are required to apply knowledge of a required practical activity and
the theory behind it to a new, and possibly unfamiliar situation.
Question 2 – Chemistry Required Practical In this question students are required to evaluate an experiment on the reaction between
calcium and water.
Question 3 – Physics Required Practical In this question students are required to evaluate and analyse the results of an experiment
to determine the density of steel.
Inside this Month’s Edition
Required Practicals Practice Questions (January Edition)
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(a) Complete the table to show what the student would observe if they are right about the
food sample.
[3 marks]
Question 1 A student wanted to confirm that a sample of food contains fat and protein, but no starch.
The student carried out the tests described in the table in Figure 1.
Test Result
Add Biuret solution and shake
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Add ethanol and shake, and then
add water and shake
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Add iodine
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Figure 1
Required Practicals Practice Questions (January Edition)
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(b) Some students are told by their teacher that starch is digested and broken down into
iiiiiiiiiiglucose when a piece of bread is chewed in the mouth.
The students decide to investigate how long it takes for this digestion to start.
Describe how the students might carry out their investigation.
Your description should include:
the steps to be followed
details of the measurements to be made
details of the variables to be controlled and the methods of doing so.
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[6 marks]
Required Practicals Practice Questions (January Edition)
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Question 2
The equation represents the chemical reaction between calcium and water.
𝐂𝐚(𝐬) + 𝟐𝐇𝟐𝐎(𝐥) → 𝐂𝐚(𝐎𝐇)𝟐(𝐚𝐪) + 𝐇𝟐(𝐠)
A student knows that this reaction is exothermic and wants to know how much energy is
released when 1.0 g calcium reacts with water.
In an experiment the student drops small pieces of calcium into 25 cm3 water and measures
the resulting temperature rise.
The table in Figure 1 shows the results of this experiment.
* the liquid is a dilute solution of calcium hydroxide
Figure 1
(a) Complete the table by calculating the temperature rise per gram for experiment 4 and the
mean temperature rise per gram.
[4 marks]
Experiment Mass of calcium
(g)
Temperature rise in
water* (℃)
Temperature rise in
water per gram of
calcium (℃/𝐠)
1 0.024 3 125
2 0.015 2 133
3 0.029 4 138
4 0.021 3
5 0.032 5 156
Mean
Required Practicals Practice Questions (January Edition)
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(b) The uncertainty in a set of results can be calculated using the equation
𝐮𝐧𝐜𝐞𝐫𝐭𝐚𝐢𝐧𝐭𝐲 =𝐫𝐚𝐧𝐠𝐞 𝐨𝐟 𝐫𝐞𝐬𝐮𝐥𝐭𝐬
𝟐
Use this equation to calculate the uncertainty in the mean value of the temperature rise
per gram of calcium.
𝐮𝐧𝐜𝐞𝐫𝐭𝐚𝐢𝐧𝐭𝐲 = ________________________________ ℃/𝐠 [2 marks]
(c) The temperature rise in the water is related to the energy absorbed by the water by the
following equation
𝐞𝐧𝐞𝐫𝐠𝐲 = 𝐦𝐚𝐬𝐬 𝐨𝐟 𝐰𝐚𝐭𝐞𝐫 × 𝐬𝐩𝐞𝐜𝐢𝐟𝐢𝐜 𝐡𝐞𝐚𝐭 𝐜𝐚𝐩𝐚𝐜𝐢𝐭𝐲 𝐨𝐟 𝐰𝐚𝐭𝐞𝐫 × 𝐭𝐞𝐦𝐩𝐞𝐫𝐚𝐭𝐮𝐫𝐞 𝐫𝐢𝐬𝐞
Given that the mass of 25 cm3 water is 25 g and the specific heat capacity of water
4.2J/(g℃), calculate the mean amount of energy released when 1.0 g reacts with water.
𝐞𝐧𝐞𝐫𝐠𝐲 = _____________________ 𝐉
[2 marks]
(d) Explain why the student does not simply react 1 g calcium with water in their experiment.
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[3 marks]
Required Practicals Practice Questions (January Edition)
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(e) Another student suggests that the value for the energy released per gram of calcium
would be more accurate if the first student had used a digital thermometer capable of
reading temperature to the nearest 0.1 ℃ and a balance capable of measuring mass to the
nearest 0.0001 g.
Explain the impact these changes would have on the accuracy of the first student’s result.
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[6 marks]
Required Practicals Practice Questions (January Edition)
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Question 3
A student wanted to find the density of the steel used to make ball-bearings.
The student used the water displacement method to find the volumes of different numbers of
ball-bearings, as shown in Figure 1.
Figure 1
(a) Describe how the student can find the total volume of the ball-bearings using this method.
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[1 mark]
measuring
cylinder
Required Practicals Practice Questions (January Edition)
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(b) The graph in Figure 2 shows the total volumes of different numbers of ball bearings.
Figure 2
(i) Draw the line of best fit on the graph.
[1 mark]
(ii) The manufacturer of the ball bearing claims that they are identical to each other.
Use the graph to explain if this claim is true.
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Required Practicals Practice Questions (January Edition)
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[5 marks]
Figure 3
Use information in Figure 3 and Figure 2 to calculate the density of the steel used to make the
ball bearings.
density = ______________________ g/cm3
[4 marks]
Required Practicals Practice Questions (January Edition)
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Mark Scheme – Q1
Answers Extra Guidance Mark AO/Spec. Ref
a The Biuret solution changes
colour (from blue) to violet 1
AO1
AQA: 4.2.2.1 and RP4
Edexcel: 1.13B
a
A white emulsion forms on the
surface of the ethanol / water
mixture
1
a
The iodine does not change
colour / remains (reddy)
brown
1
b
Cut a number of pieces of
bread (of exactly the same
size)
Allow a specific number – five or
six, for example 1
AO2/3
AQA: 4.2.2.1 and RP4
Edexcel: 1.12, 1.13B
WS2.2
b
One student to chew one
piece of bread for 5 seconds
and then spit the chewed
bread into a beaker / petri
dish / test tube / boiling tube
Allow any sensible time up to 10
seconds. 1
b
Transfer some of the chewed
bread to a test tube or boiling
tube and add 2 cm3
Benedict’s solution and heat
gently
Allow any volume of Benedict’s
solution up to 10 cm3 or mention
of a fixed volume.
1
b
If digestion has started the
Benedict’s solution will
change colour (from blue to
orange, red or green)
Ignore the use of iodine to test
for the presence of starch
(starch will probably be present
even after digestion has started)
1
b
Repeat the experiment with
the other pieces of bread,
chewing them for different
times until glucose is
detected.
1
b
Two control variables and
how they are controlled (if
not obvious)
Any two from:
•pieces of bread must be cut to
the same size
•pieces of bread must be of the
same type / from the same loaf
1
Required Practicals Practice Questions (January Edition)
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•bread must be chewed at the
same rate (move the jaw every
two seconds, for example)
•conditions in the mouth should
be the same for each piece of
bread (wash mouth with a glass
of water between pieces of
bread, for example)
•Same student carries out the
experiment each time
Total marks 9
EzyScience Additional Feedback:
(a) The food tests and expected positive results must be learned.
(b) This is the application of a standard food test to a (probably) unfamiliar scenario. The use of bullet
points is strongly recommended here – what is being looked for is a set of simple steps in a sensible
order that are clear enough to be followed by someone else. An examiner would look for the points
identified above, regardless of how the answer is written. However, it should be realised that credit is
more likely to be given if the points are made clearly.
Mark Scheme – Q2
Answers Extra guidance Mark AO/ Spec. Ref
a 3 ÷ 0.021 1
AO1/2/3
AQA: 5.5.1.1 and RP4
Edexcel: 7.10
WS3.3
a 143 or 140 (C/g)
Accept 142.9, but NOT answers
to any more significant figures
143 or 142.9 on its own scores
both marks, but a correct value
given to more than 4 significant
figures on its own scores only
one mark)
1
a (125 + 133 + 138 + 143 + 156)/5 Allow
(133 + 138 + 143 + 156)/4 =
142.5 or 143 or 140
OR
(125 +133 + 138 + 143)/4 =
134.75 or 134.8 or 135 or 130
for two marks
1
a 139 1
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b (156 – 125) ÷ 2 1
AO3
WS3.4
b 16 (C/g)
Accept 15.5
Accept any answer consistent
with an incorrect answer to
part (a)
Correct answer on its own
scores two marks
1
c E = 25 x 4.2 x 139
Allow any correct version of this
equation with values
substituted in correctly
1
AO3
AQA: 5.5.1.1 and RP4
c 14,595 (J)
Allow the correct answer
rounded correctly to 4, 3 or 2
significant figures
Accept any answer consistent
with an incorrect answer to
part (a)
1
d The boiling point of water is 100
C 1
AO3
WS2.2, 2.3 d The water would boil into a gas 1
d
The temperature rise
(corresponding to the energy
supplied) could not be measured
1
e
An improvement in resolution of
0.1 C is (more) significant
compared to an actual
temperature change of 2, 3, 4 or
5 C Allow references to
improvements in resolution of
() 0.5 C and () 0.0005 g
1
AO3
WS 3.7
e
An improvement in resolution of
0.0001 g is less significant
compared to an actual mass of
about 0.025 g
1
e There are other sources of
uncertainty in this experiment 1
e At least one other source of
uncertainty identified
P Possible sources of uncertainty:
Measuring the volume of the
water
Heat losses to the
surroundings / equipment
1
Required Practicals Practice Questions (January Edition)
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Accept suggested methods to
reduce these uncertainties,
such as using a pipette to
measure out the water or
insulating the water container
e
The uncertainty calculated in
part (b) is much more significant
than the uncertainty in the mass
1
e A clear statement linking all these
ideas together
e.g. – The improvement in
resolution for the temperature
rise is more significant than the
improvement in resolution for
the mass. There are other
sources of uncertainty, such as
measuring the volume of water
and the transfer of heat to the
surroundings. The uncertainty in
the value of energy per g of
calcium (16) is more significant
than the uncertainty in the
mass.
1
Total marks 17
EzyScience Additional Feedback:
(a) Although the calculations here are fairly straightforward it is always worth showing the working out to
minimise the loss of marks in the event of a slip, such as putting a decimal point in the wrong place. Note
that the number of significant figures allowed in the final answer is restricted, even though this is not
mentioned in the question itself. This would probably not happen in an exam, but nonetheless writing
answers to a sensible number of significant figures (usually 2, 3 or 4) is a habit worth developing.
(b) This is simply the application of an equation provided to you in the question, but once again it is worth
showing your working out.
(c) This is simply the application of an equation provided to you in the question, but once again it is worth
showing your working out. Because the answer here is in the form of a naturally truncated decimal up to
five significant figures is allowed, but once again, rounding to a sensible number of significant figures is
encouraged.
(d) This question requires a ‘common sense’ approach to recognise that a temperature rise of more than
100 C in the water is meaningless in practice and to describe what the consequences of using 1 g
calcium would be.
(e) This question is likely to be very challenging and is related to the Working Scientifically section of the
specification rather than the chemistry content. Although using measuring instruments, such as
thermometers and balances, with better resolution might improve the accuracy of particular
measurements, they might not make a significant impact to the overall accuracy of the quantity being
determined, in this case the energy released per gram of calcium, especially when there are other
sources of uncertainty. When faced with a question like this a good approach is to use bullet points to list
the factors that need to be considered. Ideally, these will then be connected in a clear statement, but
even if this last step is not taken, most of the marks can still be scored.
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Mark Scheme – Q3
Answers Extra guidance Mark AO/ Spec. Ref
a
Subtract first volume of water (without
ball-bearings) from the second volume
of water (with the ball-bearings)
Allow answers in the form
V2 – V1 if the meanings of the
symbols are made clear, possibly
by labelling the diagram.
1 AO2/3
WS 2.2
bi
Single straight line passing through
(0,0) with plotted points scattered
around the line evenly
1 AO3
WS 3.5
bii The plotted points are scattered
around the (straight) line of best fit
Allow the idea of the line of best
fit not passing through all the
plotted points
1
AO3
WS 3.3
bii Each set of 50 ball bearings has a
(slightly) different volume 1
bii There must be some variation in
volume / diameter 1
bii (However,) scatter is small. Allow the idea of the points all
being close to the line of best fit 1
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bii (So) variation in volume / diameter is
small 1
biii density = mass ÷ volume
Allow D = m/V or = m/V without
explanation – if other symbols are
used they must be defined for this
mark
1
AO1/3
AQA: 4.3.1.1 and
RP5
Edexcel: 14.2, 14.3
WS 3.3
biii Mass (of 120 ball bearings)
(= 70.3 – 1.2) = 69.1 (g) 1
biii Volume (of 120 ball bearings)
= 7.6 (cm3)
Allow a value consistent with
whichever line of best fit is drawn
1
Required Practicals Practice Questions (January Edition)
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biii Density (= 69.1 ÷ 7.6) = 9.1 (g/cm3)
Allow answers up to 4 significant
figures (9.092) – rounding must be
correct
A correct answer consistent with
the line of best fit on its own
scores all four marks
1
Total marks 11
EzyScience Feedback:
(a) For one mark only a simple
(b) (i) Care needs to be taken when drawing lines of best fit through plotted points. There is clearly a linear
trend here, so a straight line is required; in this case the line should pass through (0,0) and the plotted
points should be scattered as evenly as possible around the line. This is an important skill, but in exams
these marks are often not scored.
(ii) – To answer this question, you need to realise that the scatter of the plotted points about the line of
best fit is significant and has a cause.
(iii) – It is tempting in questions like this simply to put the numbers into a calculator, but a simple slip,
such as a rounding error, might then result in no marks being scored. For this reason, it is always worth
showing your working-out.