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CHEMISTRY B

OCR 2024
GCSE Chemistry B (Twenty First Century Science)
J258/03 Breadth in Chemistry (Higher Tier)
With Marking Scheme Merged

Oxford Cambridge and RSA

Friday 17 May 2024 – Morning
GCSE (9−1) Chemistry B (Twenty First Century Science)
J258/03 Breadth in Chemistry (Higher Tier)
Time allowed: 1 hour 45 minutes
You must have:
• a ruler (cm/mm)
• the Data Sheet for GCSE (9–1) Chemistry B

H

(inside this document)
You can use:
• an HB pencil
• a scientific or graphical calculator

*

J

2

5

8

0

3

*

Please write clearly in black ink
...

Centre number

Candidate number

First name(s)
Last name
INSTRUCTIONS
• Use black ink
...

• Write your answer to each question in the space provided
...
The question numbers must be clearly shown
...

• Where appropriate, your answer should be supported with working
...

INFORMATION
• The total mark for this paper is 90
...

• This document has 24 pages
...


2
1

Fertilisers are used to increase the growth of plants
...


(a) Nitrogen is one essential plant nutrient element
...

1
...

[2]
(b)
(i) State one disadvantage of the over-use of synthetic fertilisers
...


...


...
[1]

© OCR 2024

3
(c) An example of a synthetic fertiliser is ammonium nitrate, NH4NO3
...
NH4OH(aq) + HNO3(aq)

NH4NO3(aq) + H2O(l)

The relative formula masses for the reactants and products are shown in the table
...
0

HNO3

NH4NO3

63
...
0

H2O
18
...

Use the equation:
atom economy = mass

of atoms in desired product ×

100% total mass of atoms in reactants

Give your answer to 1 decimal place
...
% [4]

© OCR 2024

Turn over

4
2

Sodium chloride is an ionic compound
...
2
...

Fig
...
1
_
+_
+
_
_
+ _
+ _
_
+
+_
_
+
_
+
_

+_ +

Model A
(i)

+ _
+ _+
+
_
_ +
+

_+

_

_+

Model B

Model C

Describe the attraction between ions in sodium chloride
...


...


...
2
...

Model A does not show the relative sizes of the ions
...

None of the models show that sodium chloride is a compound
containing two elements
...

[2]

© OCR 2024

5
(iii) Fig
...
2 shows the dot and cross diagram for sodium chloride
...
2
...

Fig
...
2
+
Na

Cl

Na

Cl

Sodium atom

Chlorine atom

Sodium ion

Chloride ion
[2]

(b) How does the arrangement of electrons in atoms of sodium and chlorine relate to their group and
period in the Periodic Table?

...


...
[2]
(c) An atom of sodium has an atomic number of 11 and a mass number of 23
...


Number of protons =
...

Number of electrons =
...

The diagram shows a chromatogram for the two dyes
...


...
[1]

(b) Calculate the Rf value of dye B
...


Rf value =
...

What must be sprayed onto the chromatogram so any colourless substances can be seen?

...

A student tests three solutions, A, B, and C, to find out whether they contain halide
ions
...

The table below shows their results
...


...


...


...

You need to:
•
•

add the name and the formula for the product
add the missing state symbols
...
) + Br (
...


...

Explain why dilute hydrochloric acid is not a suitable acid to use to acidify the silver nitrate
solution
...


...


(a) Copper can be extracted from an aqueous solution of copper sulphate using electrolysis
with inert electrodes
...

Cathode
Ions attracted

2+

Cu

,H

Anode

+

SO

2–

, OH

–

4

Products formed
Half equation
(i)

Copper
2+
–
Cu (aq) + 2e

Oxygen and water
Cu(s)

–
Write the balanced half equation for the formation of oxygen gas and water from OH ions at
the anode
...
[2]

(ii) Why is the formation of copper from copper ions a reduction reaction?

...
[1]

(iii) Explain why copper and not hydrogen is formed at the cathode
...


...


...


...
[1]

© OCR 2024

9
(b) Aluminium is extracted from aluminium oxide by electrolysis
...

(i)

Complete the balanced symbol equation for the electrolysis of aluminium oxide
...
Al 2O3


...
O2
[2]

(ii) Which two statements explain why the industrial electrolysis of aluminium oxide is very
expensive?
Tick (✓) two boxes
...

Electrolysis uses a large amount of energy
...

The demand for aluminium is very high
...

[2]
(iii) Describe a test to identify oxygen
...


...


...

The diagram shows how the student measures the mass before and during the reaction
...
00g

–7
...


...

Explain why
...


...


...
0 g of HCl
...


Relative atomic masses (Ar): H = 1
...
5
mass of substance
relative formula mass

Number of moles =
...
0 × 10 atoms in one mole of

atoms
...

24
1
...
4 × 10

24
4
...

2H2O2(aq)

2H2O(l) + O2(g)

(a) Manganese dioxide is a catalyst for this reaction
...

It decreases the frequency of particle collisions
...

It lowers the temperature of the reaction
...

[1]
(b) Explain why increasing the concentration of the aqueous hydrogen peroxide also speeds up the
reaction
...


...


...
[2]

© OCR 2024

13
(c) In one experiment, 0
...

Calculate the volume of 0
...

Use the formula: number of moles of gas =

volume of gas (dm3)
24 (dm3)

3
Give your answer in cm
...
cm [3]

© OCR 2024

Turn over

14
8

Fossil fuels are used as energy sources
...

(i)

Name this alkane
...
[1]

(ii) Combustion of natural gas increases the temperature of the surroundings
...


...

Name one pollutant caused by the incomplete combustion of natural gas
...

The balanced symbol equation for the reaction in the hydrogen fuel cell is:
2H2 + O2

2H2O

The table shows the bond energies involved in the reaction
...


Energy needed to break bonds in the reactants =
...
kJ

Overall energy change =
...

The table shows information about hydrogen and diesel
...
09

crude oil

–80 to 0

200 to 350

0
...

Name the products formed during complete combustion of diesel
...


...


...


...
[2]

(iii) Explain why the density of hydrogen and diesel are very different
...


...


...
[2]

© OCR 2024

Turn over

16
9

The table shows some information about the homologous series of alcohols
...

Name

Formula

Displayed formula
H

CH3OH

H


...


Propanol

Butanol

C3H7OH

C4H9OH

H

H

H

C

C

C

H
H H

H
H

H
H

C

C

C

C

H

H

H

H

H

H

O

H

O

H

[2]
(b) Alcohols oxidise to form carboxylic acids
...


...
Show all the bonds
...

The balanced symbol equation for the reaction is:
2Ag2O

4Ag + O2

(a) Calculate the theoretical yield of silver made when 250 g of silver oxide completely decomposes
...


Theoretical yield =
...

Some black silver oxide powder remains visible after the experiment
...

1
...

2
...

[2]

© OCR 2024

Turn over

18
11 A student does some experiments with dilute and concentrated acids
...
11
...


Fig
...
1

+
(a) Complete Fig
...
2 to show the H ions in a dilute solution of acid
...
11
...

Explain why they are incorrect
...


...

They record the pH of each acid and the time taken for each reaction to finish (the reaction time)
...

Acid

pH

Reaction time (s)

A

1

10

B

3

200

C

5

1000

Which acid is the weakest acid?
Explain your answer
...


...


...


...
[3]

(c)
(i) Describe how to use Universal indicator to measure the pH of a solution
...


...
1 mol /
3
dm
...

–1
3
1 × 10 mol / dm

–2
3
1 × 10 mol / dm

–3
3
1 × 10 mol / dm

1 × 10

–4

3

mol / dm

[1]

© OCR 2024

Turn over

20
12 Group 7(17) of the Periodic Table contains non-metals called halogens
...

Complete the table
...



...


The balanced symbol equation for the reaction is:
Cl 2(aq) + 2NaI(aq)
(i)

2NaCl (aq) + I2(aq)

Explain what the student observes when the reaction takes place
...


...


...

Use the symbol equation to help you
...
[1]

END OF QUESTION PAPER
© OCR 2024

21
EXTRA ANSWER SPACE
If you need extra space use these lined pages
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© OCR 2024

23

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...

The second line reads:
Name of the type of reaction that increases the temperature of the surroundings
...

The line should now read:
Name the type of reaction that increases the temperature of the surroundings
...
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

J258/03

Mark Scheme

June 2024

MARKING INSTRUCTIONS
PREPARATION FOR MARKING
RM ASSESSOR
1
...

2
...
These are available in RM A ssessor
...

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
...
Con structive 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 2024

J258/03

Mark Scheme

June 2024

12
...


Annotation
/
✓

DO NOT ALLOW

Meaning
alternative and acceptable answers for the same marking point
Separates marking points
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

J258/03
13
...
This mate rial 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
...


AO2

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

J258/03

Mark Scheme

Phosphorus / P✓
Potassium / K ✓

2

AO
element
1
...
1

IGNORE bioaccumulation
IGNORE more weeds unqualified
IGNORE death of plants/animals/less
biodiversity/poor soil fertility

(ii)

There are not enough natural fertilisers / synthetic
fertilisers can be manufactured in large quantities / need
to grow more food/crops / lead to faster growth / more
yield ✓

1

3
...
g
...
g
...
6(%) award 4 marks

June 2024

4

(mass of atoms in desired product) = 80
...
6 is max 3

3 x 2
...
0 + 63
...
0 ✓

ALLOW 80 if shown as numerator in calculation
(even if added to another number)
ALLOW MP2 anywhere (even if shown as
numerator)
ALLOW 35+63 (only) seen anywhere in calculation
DO NOT ALLOW other numbers added to 35 + 63

atom economy =
80
...
0 x 100 OR = 81
...
6326…
...
6 (%) ✓

MP4 ALLOW incorrect answer, with working to 1dp
1
...
1

between oppositely charged ions / between positive ions
and negative ions ✓
sodium ions are positively charged and chloride ions are
negatively charged ✓
(ii)
(iii)

Guidance
IGNORE attractive forces / static forces
ALLOW electrostatic attraction
MAX 1 if single bonds /covalent bonds / imfs /
delocalised electrons / protons and electrons are
stated
ALLOW cation = positive ion and anion = negative
ion throughout
IGNORE ‘chlorine’ ions
IGNORE between sodium ions and chloride ions
ALLOW 2 marks for ‘attractive forces between
positive sodium ions and negative chloride ions’

Model C does not show the 3-D arrangement of ions ✓
Only one model shows that chlorine is an anion ✓
electron arrangement of 2
...
8 drawn ✓

2

3
...
2

ALLOW different symbols for electrons / all the
same electron symbol

2

2
...

DO NOT ALLOW sodium has two shells and is in
period 2

Number of electrons in outer shell is the same as the
group number / sodium is in group 1 and has 1 electron
in the outer shell / chlorine is in Group 7 and has 7
electrons in the outer shell ✓

IGNORE references to losing/gaining electrons
DO NOT ALLOW if statement for chlorine or
sodium is incorrect

-1/1-/-✓
(b)

(c)

Protons = 11 ✓
Neutrons = 12 ✓
Electrons = 11 ✓

2

11

2
...
2

(b)

FIRST CHECK THE ANSWER ON THE ANSWER LINE
If answer = 0
...
2
ALLOW 3
...
1
ALLOW answers in mm e
...
35mm

3
...
0) ✓

ALLOW 6
...
1 (cm)
ALLOW ECF on incorrect measurements for MP3
and MP4

Rf= spot distance / solvent distance OR 3
...
0 (=
0
...
58(3) ✓

(c)

IGNORE to separate the spots/dyes / so that the
dyes/spots move / otherwise spots/dyes don’t move

Locating agent ✓

1

12

1
...
g
...
2b

3

1
...
1

aq and aq ✓

DO NOT ALLOW numbers added such that
equation does not balance
IGNORE Ag+Br-

2
...
1

Guidance
DO NOT ALLOW contains chlorine ions / iodine
ions
ALLOW no chloride and no bromide and no iodide
ions present

IGNORE it will react with silver nitrate
DO NOT ALLOW contains chlorine

J258/03

Mark Scheme

Question
5

(a)

Answer
(i)

4OH→ O

Marks

+ 2H O + 4e

-

2

2

June 2024

AO
element
2
...
g
...


(iii)

(iv)



ALLOW 4OH - 4e → O

copper ions gain electrons / (reduction is) gain of
electrons/ 
Copper less reactive than hydrogen/lower in reactivity
series than hydrogen 
Copper ions gain electrons more easily (than hydrogen
ions) / copper ions reduced more easily 
Any one from

1

1
...
1

1

1
...


IGNORE names of gases
ALLOW brown / red-brown / orange / black solid
ALLOW pink solid alone but DO NOT ALLOW pink
solid on anode
IGNORE cathode increases in size/layer forms

Pink solid (on cathode/electrode) 

(Blue) colour of solution fades/goes colourless
2Al2O3 → 4Al ✓ + 3O2✓

2

ALLOW ‘- (4)e’ on the LHS
2

(ii)

2



A high temperature is needed for the process
...
✓
Glowing splint ✓
Flame will re-ignite if oxygen is present ✓

2

2
...
1

2

1
...
1

(ii)

carbon dioxide is made / a gas is made ✓

2

1
...
g
...
1369 award 3 marks

3

2
...
5 + 1) OR 36
...
5 + 1) OR 36
...
0/36
...
14 / 0
...
1369863…)
ALLOW answer to more than 2 sig figs if answer
rounds to 0
...
8 x 1024 ✓

1

15

1
...
1

(b)

Particles closer together / more particles per unit volume
✓

2

1
...
4 x 10x

3

Note: 2
...
of moles x 24 ✓

2 x 2
...
1 x 24 OR = 2
...
1 x 24 as evidence of MP1 and MP2
MP2 ALLOW substitution into unrearranged formula
i
...
0
...
4 (MP1 and MP2)

1
...
1
1
...
1

Guidance

DO NOT ALLOW carbon dioxide
IGNORE methane / unburnt hydrocarbons / soot

(b)

FIRST CHECK THE ANSWER ON THE ANSWER LINE
If answer = -490(kJ) award 3 marks
(2 x 434 kJ) + 498 kJ = 1366 kJ ✓

3

2
...
2

MP3 ALLOW ECF on (MP1 - MP2)
IGNORE 490, answer must show negative sign
If ECF value is positive, answer does not need
positive sign
...
1b

2

Names take precedence
ALLOW MP1 for producing hydrogen or diesel uses
energy / uses energy from fossil fuels
ALLOW (combustion of) hydrogen does not cause
global warming/climate change/produce
greenhouse gases / NOx/SO

/CO/C

2

particulates/cause acid rain ORA
ALLOW ‘carbon dioxide causes global
warming/climate change/is a greenhouse gas’ alone
(link to diesel is in ci)
IGNORE diesel produces carbon dioxide alone
IGNORE references to fuel cells

17

J258/03

Mark Scheme

(iii)

Diesel is a liquid and hydrogen is a gas ✓

2

June 2024

3
...
1

✓

(b)

(i)

Guidance

ALLOW -OH
DO NOT ALLOW -HO

Propanoic (acid) ✓

(ii)

1

1
...
2
DO NOT ALLOW -OH

✓

18

J258/03

Mark Scheme

Question
10

(a)

Answer

Marks

FIRST CHECK THE ANSWER ON ANSWER LINE

June 2024

AO
element

4

Guidance
ALLOW answers based on A Ag = 107
...
2

ALLOW (2 x 108) +16
ALLOW RFM Ag O = 231
...
7586…
...
2
Note (2x108) =216 and (4x108) =432

✓

✓

OR ALTERNATIVE ROUTE
MP1 Ag2O RFM = 232 or 2xRFM = 464

✓

1
...
2

ALLOW (2 x 108) +16
ALLOW RFM Ag O = 231
...
931)
MP3 shows MP2 x 250 (= 232
...
)

✓
2 x 2
...
2
3
...
1

Guidance
Judge number by eye
ALLOW particles similar size or smaller
IGNORE shading/no shading
Particles must be single, randomly arranged

(b)

(i)

Strength of acid depends on degree of ionisation/strong
acids fully ionise/are more fully ionised ORA ✓

1

1
...
2b
IGNORE ‘it is pH5’ unqualified

Highest pH/ slowest reaction/longest time to react / pH
closest to 7/neutral✓

IGNORE fewer/less hydrogen ions

so lower concentration of hydrogen ions✓
(c)

ALLOW ‘how well ionised/ better ionised’ etc for
degree of ionisation
ALLOW dissociated for ionised
IGNORE ‘ionised’ alone unqualified
IGNORE references to pH
IGNORE references to hydrogen ion concentration
alone

(i)

(Add a few drops and) colour judged against a chart/pH
scale ✓

1

1
...
0 x 10-3 moldm-3✓

1

1
...
1

Brown solution formed ✓

3

1
...
1

IGNORE state symbols



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