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COMBINED SCIENCE B

OCR 2024
GCSE Combined Science B Twenty First Century Science
J260/06: Chemistry (Higher Tier)

with Marking Scheme Merged
...
Do not write in the barcodes
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You can use an HB pencil, but only for graphs and diagrams
...
If you need extra space use the
lined pages at the end of this booklet
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• Answer all the questions
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Marks might
be given for using a correct method, even if your answer is wrong
...

• The marks for each question are shown in brackets [ ]
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• This document has 24 pages
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2
1
(a) Table 1
...

Table 1
...
54 × 10

Fullerene molecule

–9
1
...
88 × 10

Platinum nanoparticle

–8
1
...
and
...

Smallest
...


...

[2]
(b) Nanoparticles make effective catalysts because they have a high surface area to volume ratio
...
2 shows the surface area to volume ratio of some different sized particles
...
2
Nanoparticle
Size of Particle (nm)

Particle of
Fine Powder

Particle of
Coarse Powder

60

600

6000

0
...
01

0
...


...


...
[2]
© OCR 2024

3
(c) The nanoparticle shown is a cube
...
h

l

w

NOT TO SCALE
Calculate the surface area of the nanoparticle
...
nm
[3]

© OCR 2024

Turn over

4
2

A student is investigating the reaction between calcium hydroxide and hydrochloric acid
...

3
1 g masses of solid calcium hydroxide are added one by one to 50 cm of dilute hydrochloric
acid in a plastic cup
...

1
...

2
...

[2]
(b) The table shows the student’s results:
Mass of calcium hydroxide (g)

Temperature of hydrochloric acid (°C)

0

22
...
5

2

37
...
5

4

52
...
5

Plot the results from the table on the graph
...


(c) Draw a line of best fit
...

y = mx

y = mx

2

y = mx + c

y = mx – c

[1]

(e) Calculate the change in temperature if 3
...

Use the graph
...
°C [2]
(f)

Calculate the change in thermal energy when 3
...


3

Use the formula:
Change in thermal energy (J) = 4
...
02 g

Change in thermal energy =
...
The rest of the space
contains electrons
...

Particle

Relative Mass

Relative Charge


...



...



...


Proton
Neutron
Electron
[3]
(b) A student builds a model of an atom
...
7 cm to represent the nucleus in the model
...
Calculate the diameter of the model of the atom
...


Diameter of model =
...

Complete the table to show the number of each particle present in a phosphorus atom and a
sodium ion
...

+

Phosphorus atom, P

Sodium ion, Na


...



...



...


Number of Protons
Number of Neutrons
Number of Electrons
[3]
© OCR 2024

7
(d) The properties of elements depend on the electron arrangements of their atoms
...
8
...

The electron arrangement of fluorine is 2
...

Explain why magnesium is a metal and fluorine is a non-metal
...


...


...

Electrons from outer shell of metal atoms
–

–

–

–

–

–

+ – + –+ –+ – + –
+ – +
+ – +
–
–

+
–

–

+–

–

–

+

+

+

–

+

–

–

+– +–

+

–
–

–

+

–

––

–

–

–

–

– –

+

+

+

+

+

Metal ions
(a) Explain why metals are good electrical conductors, malleable, and have high melting points
...


...


...


...

In one experiment, they add a piece of magnesium to a blue aqueous solution of copper ions
...

Mg(s) + Cu

2+
(aq)

2+
Cu(s) + Mg (aq)

Explain how this reaction shows that magnesium is more reactive than copper
...


...


...


...

Most reactive


...


...

[2]

© OCR 2024

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10
5

The particle models for the different states of matter are shown
...

1
...

2
...

[2]
(b) The table gives some information about the movement and arrangement of particles for the
different states of matter
...

Movement of Particles

Arrangement of Particles
1 Regular

Solid


...

2
...

2
...


...


...
[2]

(d) Sulfur dioxide has a melting point of –73 °C and a boiling point of –10
°C
...
[1]

© OCR 2024

Turn over

12
6

A student wants to find the concentration of a sodium hydroxide solution
...
010 mol / dm dilute hydrochloric acid
...

Include an explanation of how this method gives high quality data
...


...


...


...


...


...


...

Titration
3
Volume of Acid Added (cm )

(i)

1

2

3

4

5

27
...
4

25
...
2

25
...


...
Give your answer to 1 decimal place
...
cm [3]

(iii) The student’s teacher states that the volume of the hydrochloric acid needed to react with
3
the sodium hydroxide should be 25
...

Explain what the student’s results show about the accuracy and precision of their experiment
...


...


...

N2(g) + 3H2(g)

(a)
(i) Define this symbol

2NH3(g)


...
[1]

(ii) Explain why reactions like this never give a 100% yield
...


...

The graph shows the effect of temperature and pressure on the yield of ammonia
...
Use words from the list
...


Increase


...



...

Temperature
...


...

Pressure
...


...

[4]
(c) Ammonium sulfate, (NH4)2SO4, is used by farmers as a fertiliser
...

Write a balanced symbol equation for the reaction
...


...


(a) Table 8
...

Table 8
...



...


[2]

(ii) Complete the word equation for the reaction between hydrochloric acid and sodium
hydroxide
...

[1]

+
(b) Table 8
...


Table 8
...
1

(i)

+
Concentration of H (aq)
3
(mol / dm )

1 × 10

0
...
001

1 × 10

–1
–2
–3

pH
1
2
3

+
Describe the relationship between H concentration and pH shown in Table 8
...



...


...
[2]
3
(ii) What is the pH of 0
...
[1]

© OCR 2024

17
(c) A student does an experiment to find the pH of different concentrations of dilute ethanoic
acid, CH3COOH
...

(i)

Describe how the student finds the pH using this test
...


...
3
...
3
Concentration of CH3COOH (aq)
3
(mol / dm )

pH

0
...
01

3

0
...


...
[1]

© OCR 2024

Turn over

18
9

Electrolysis is the decomposition of ionic compounds using electricity
...

Carbon anodes

Molten
aluminium
oxide

+
–

Carbon lining
as cathode
Molten
aluminium
(i)

Explain why the electrolysis must use molten aluminium oxide, and not solid aluminium oxide
...
[1]

(ii) The half equations show the reactions at the electrodes
...

Oxidised
...

Explanation
...

[3]
(iii) This is the balanced symbol equation for the decomposition of aluminium oxide by electrolysis:
2Al 2O3

4Al + 3O2

Calculate the mass of aluminium that will be produced when 100 g of aluminium oxide is used
...

Relative atomic masses: Al = 27
...
0
...
g [4]
© OCR 2024

19
(b) When aqueous sodium sulfate is electrolysed the products are hydrogen gas and oxygen gas
...

Include labels
...
State where the H ions and OH ions come from
...
[1]

(iii) Explain why hydrogen is formed instead of sodium
...


...


Electrode

Product

Half Equation

Anode (+)
Cathode (–)
[3]
END OF QUESTION PAPER
© OCR 2024

20
EXTRA ANSWER SPACE
If you need extra space use these lined pages
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© OCR 2024

22

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OCR qualifications include
AS/A Levels, Diplomas, GCSEs, Cambridge Nationals, Cambridge Technicals, Functional Skills,
Key Skills, Entry Level qualifications, NVQs and vocational qualifications in areas such as IT,
business, languages, teaching/training, administration and secretarial skills
...
OCR is a not-for-profit organisation; any surplus made
is invested back into the establishment to help towards the development of qualifications and
support, which keep pace with the changing needs of today’s society
...
It shows the basis on which marks were awarded by examiners
...

All examiners are instructed that alternative correct answers and unexpected approaches
in candidates’ scripts must be given marks that fairly reflect the relevant knowledge and
skills demonstrated
...

© OCR 2024

Oxford Cambridge and RSA Examinations

J260/06

Mark scheme

June 2024

MARKING INSTRUCTIONS
PREPARATION FOR MARKING
RM ASSESSOR
1
...


2
...
These are available in RM Assessor
...


Log-in to RM Assessor and mark the required number of practice responses (“scripts”) and the required number of
standardisation responses
...


Mark strictly to the mark scheme
...


Marks awarded must relate directly to the marking criteria
...


The schedule of dates is very important
...
If you experience problems, you must contact your Team Leader (Supervisor) without delay
...


If you are in any doubt about applying the mark scheme, consult your Team Leader by telephone, email or via the RM Assessor
messaging system
...


Mark scheme

June 2024

Work crossed out:
a
...


if a candidate crosses out an answer to a whole question and makes no second attempt, and if the inclusion of the answer does not
cause a rubric infringement, the assessor should attempt to mark the crossed out answer and award marks appropriately
...


Always check the pages (and additional objects if present) at the end of the response in case any answers have been continued there
...


7
...
Award NR (No Response)
-if there is nothing written at all in the answer space
-OR if there is a comment which does not in any way relate to the question (e
...
‘can’t do’, ‘don’t know’)
-OR if there is a mark (e
...
a dash, a question mark) which isn’t an attempt at the question
...


8
...
Please refer to
these comments when checking your practice responses
...

If you have any questions or comments for your Team Leader, use the phone, the RM Assessor messaging system, or email
...


Assistant Examiners will send a brief report on the performance of candidates to their Team Leader (Supervisor) via email by the end of the
marking period
...
Constructive
criticism of the question paper/mark scheme is also appreciated
...


Mark scheme

June 2024

For answers marked by levels of response:
Read through the whole answer from start to finish, using the Level descriptors to help you decide whether it is a strong or weak answer
...
Using a ‘best-fit’ approach based on the skills and science content evidenced within the
answer, first decide which set of level descriptors, Level 1, Level 2 or Level 3, best describes the overall quality of the answer
...

The lower mark should be awarded where the level descriptor has been evidenced but aspects of the communication statement (in
italics) are missing
...

The communication statement determines the mark within a

level
...


Mark scheme

Annotations available in RM Assessor

Annotation

Meaning
Correct response
Incorrect response
Omission mark
Benefit of doubt given
Contradiction
Rounding error
Error in number of significant figures
Error carried forward
Level 1
Level 2
Level 3
Benefit of doubt not given
Noted but no credit given
Ignore

5

June

J260/06
2024
12
...

Annotation

Meaning

/

alternative and acceptable answers for the same marking point



Separates marking points

DO NOT ALLOW

Answers which are not worthy of credit

IGNORE

Statements which are irrelevant

ALLOW

Answers that can be accepted

()

Words which are not essential to gain credit

__

Underlined words must be present in answer to score a mark

ECF

Error carried forward

AW

Alternative wording

ORA

Or reverse argument

6

June

J260/06
13
...
This material includes:
•

the specification, especially the assessment objectives

•

the question paper

•

the mark scheme
...

You should ensure also that you are familiar with the administrative procedures related to the marking process
...
If you are examining for the first time, please read carefully Appendix 5 Introduction to Script Marking:
Notes for New Examiners
...
Your first point of contact is your Team Leader
...


AO1
...


AO1
...

Apply knowledge and understanding of scientific ideas and scientific enquiry, techniques and procedures
...
1

Apply knowledge and understanding of scientific ideas
...
2

Apply knowledge and understanding of scientific enquiry, techniques and procedures
...
1

Analyse information and ideas to interpret and evaluate, make judgements and draw conclusions and develop and improve
experimental procedures
...


AO3
...


AO3
...


AO3
...


AO3
...


AO3
...


AO3
...


AO3
...


AO3
...


8

J260/06

Mark scheme

1

AO
element
2
...
54 x 10-10
Silver (atom) / 2
...
10 x 10-9
Platinum (nanoparticle) / 1
...
2

As size/particle gets bigger, (surface area to volume)

2

3
...
54 x
silver (atom) / 2
...
ORA

✓

OR

ALLOW size increases 10 times ratio
decreases to/by a tenth/words to the effect
of going up and down by factor of 10

Size increase ten times, (surface area to volume)
ratio decreases ten ti

Correct species
✓
Balancing

+

ALLOW delocalised
...


Malleable – Ions can slide over each other

ions and electrons

Guidance

+

2Ag

Magnesium/Mg
Iron /Fe
Copper / Cu
Silver /Ag
✓✓

13

ALLOW bonds between ions and electrons
...

IGNORE magnesium displaces copper
DO NOT ALLOW balancing of incorrect
species
...
1

4

1
...
1

1 mark if both points made but no reference to
particles etc

OR

(d)

DO NOT ALLOW Fairly/quite close together

Random 
Far apart 

Gas

5 correct = 4 marks
4 correct = 3 marks
2 or 3 correct = 2 marks
1 correct = 1 mark

ALLOW heat for energy
...
2a

J260/06

6

Mark scheme

Question

Answer

Marks

(a)*

Please refer to the marking instructions on page 4 of
this mark scheme for guidance on how to mark this
question
...

There is a well-developed line of reasoning which is
clear and logically structured
...

Level 2 (3–4 marks)
Detailed description of titration method
...

There is a line of reasoning presented with some
structure
...

Level 1 (1–2 marks)
Basic description of titration method
...
The information is in the most part
relevant
...


15

6

June 2024
AO
element
1
...
2 Demonstrates knowledge and
understanding of the procedure for a
titration to give high quality data
(accuracy, precision, repeatability,
reproducibility)
• measure the sodium hydroxide/acid
• into container
• add indicator
• Add acid/sodium hydroxide bit by bit
• Until colour change
• Note volume of acid
• Use of conical flask/pipette/burette
• put on white tile
• note initial/ volume on burette
• swirl flask when adding the
acid/sodium hydroxide
• note volume on when colour changes
• do a rough one first
• repeat until results close together
• add acid drop by drop near end point
• rinse pipette/burette with solution
Quality data explanation:
• pipette gives exact volume each time
• burette small graduations/controllable
tap
• white tile helps to see colour change
• swirling so acid all mixed in
• rough one helps to know roughly
where end point is
• drop by drop so don’t go past end
point
• repeated results test consistency /
precision

J260/06

Mark scheme

Question
(b)

Answer
(i)

To get a rough idea of when colour change
happens/to see when need to add slowly

(ii)

Marks
1





First check the answer on answer line

June 2024
AO
element
1
...
7(cm3)

If answer = 25
...
4 + 25
...
2 + 25
...
1

Guidance



2
...
1 ÷ 4 =) 25
...
3 (cm3) (1dp)

(iii)

2
Accuracy – not good/good because experimental
result (25
...
8cm3)

1
...
1b

(25
...
3 + 25
...
2 + 27
...
3
(128
...
66
= 25
...
7cm3) is close to true
value (25
...




(Increase in pressure) increases the yield
...
1

1

1
...
1a x 2

Marks

(i)







Particles have more KE/move faster
...
1

More (chance of) effective collisions/more (chance of)
successful collisions/more particles have enough
energy to react/more particles have activation energy
...
g
...




Particle move closer together
...


(c)

Guidance

1
...
2
1
...

Balancing and state symbols dependent on
correct formulae
...
1

1

1
...
2

IGNORE references to more or less acidic
...
2
1
...
2

Marks








(ii)

Water

(i)

Increase in H+ concentration gives decrease in pH

ORA

June 2024
Guidance

(Increase in H+ concentration) by 10 (gives decrease

(c)

(ii)
(i)

in pH) by 1

4





Compare colour of Universal indicator with colour
chart /pH chart

(ii)



Use a pH meter



18

IGNORE comparisons of colour with
acid/alkaline /neutral
ALLOW comparisons of colour with pH e
...
1

3

2
...
9 (g) award 4 marks

= 52
...
9 (g) (3sf)



DO NOT ALLOW oxygen / aluminium

4



(54 ÷ 102) x 100 / (100 ÷ 102) x 2 x 27

IGNORE liquid ions can move/are freely
moving
IGNORE unqualified/particles
DO NOT ALLOW atoms/electrons

IGNORE references to incorrect particles
ALLOW particle named as oxidised loses
electrons AND particle named as reduced
gains electrons



(relative formula mass of Al2O3 =) 102

Guidance

2
...
g
...
g
...




1
...
2

ALLOW ‘bung’ labelled as electrolyte/sodium
sulfate solution / ions drawn
...
e
...
2
2
...
2

ALLOW ‘it’ with no names instead of hydrogen



ORA



(iv) Anode – oxygen AND cathode – hydrogen
2H+ + 2e- →
H2 
4OH-

→ O2

+ 2H2O + 4e

ALLOW marking points 2 and 3 if shown at
incorrect electrode



20



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