Required Practicals Practice Questions (January Edition) · REQUIRED PRACTICALS PRACTICE QUESTIONS. Required Practicals Practice Questions (January Edition) ... Question 3 – Physics

- 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

Email: [email protected] I Telephone: 01329 285415 I Copyright (2020) of EzyEducation Ltd

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

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2


(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



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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]



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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



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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]



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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]



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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.

.…………………………………………………………………………………………………………………………

………………………………………………………………………………………………………………………….

[1 mark]

measuring

cylinder



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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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[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]



10


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


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



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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


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



12


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


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



13


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.



14


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



15


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



16


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.


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Required Practicals Practice Questions (January Edition) · REQUIRED PRACTICALS PRACTICE QUESTIONS. Required Practicals Practice Questions (January Edition) ... Question 3 – Physics