Notesale: Turn your study into money

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CHEMISTRY A

OCR 2024
GCSE Chemistry A (Gateway Science)
J248/02 (Foundation Tier)
With Marking Scheme Merged

Oxford Cambridge and RSA

Tuesday 11 June 2024 – Morning
GCSE (9–1) Chemistry A (Gateway Science)
J248/02 (Foundation Tier)
Time allowed: 1 hour 45 minutes
You must have:
• a ruler (cm/mm)
• the Data Sheet for GCSE (9–1) Chemistry
A (inside this document)

F

You can use:
• a scientific or graphical calculator
• an HB pencil

*

J

2

4

8

0

2

*

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
...

• Quality of extended response will be assessed in questions marked with an asterisk (*)
...

ADVICE
• Read each question carefully before you start your answer
...

Write your answer to each question in the box provided
...
What is the colour of the precipitate made?
A Blue B
Green
C Orange-brown D
White

Your answer
3

[1]

Which change would decrease the rate of a chemical reaction?
A Adding a catalyst
B Increasing the concentration of the solution C
Increasing the size of the solid pieces
D Increasing the temperature

Your answer

© OCR 2024

[1]

3
4

What is the major source of oxides of nitrogen in the
atmosphere? A Combustion of impurities in coal
B High temperature reactions in car engines C
Incomplete combustion of fossil fuels
D Industrial processes such as metal extraction

Your answer
5

[1]

How many different monomers (nucleotides) is DNA made
from? A 2
B3C
4D5

Your answer
6

[1]

What is the functional group in an alcohol molecule?
A –C–H
B –C=C–
C –COOH D
–O–H

Your answer
7

[1]

What is the balanced equation for the reaction of sodium with oxygen?
A Na + O

NaO

B Na + O2

NaO2 C

4Na + O2

2Na2O D

Na2 + 2O

2NaO

Your answer
© OCR 2024

[1]
Turn over

4
8

Which row describes the three halogens at room temperature?
Chlorine

Bromine

Iodine

A

green gas

orange-brown gas

grey solid

B

green gas

orange-brown liquid

grey solid

C

green gas

orange-brown liquid

purple gas

D

green liquid

orange-brown liquid

grey solid

Your answer
9

[1]

The table shows the results of the reactions between four metals and their metal oxides
...

What is the best method for determining the rate of reaction?

A Measure the loss in mass using a balance
...

C Use a pH meter
...


Your answer

[1]

11 Which polymer would be best for making a washing up bowl?
Maximum useable
temperature (°C)

Strength

A

38

high

B

85

low

C

110

high

D

160

low

Polymer

Your answer

[1]

3
3
12 4
...
12 dm of water vapour
...
3%
B 2
...
0% D
97
...
Carbon dioxide is a waste product
...
3

CO2 = 44
...
8%

B

52
...
6%

D

109
...

(a) The first member of the alkane homologous series is methane, CH4
...


...


CH4 + 2 ………
...

State why carbon monoxide is a problem
...
[1]

(d) Methane is obtained from the fractional distillation of crude oil
...

Crude oil is separated by fractional distillation because the molecules have
different
...
intermolecular forces
...
to break
...

There is a high demand for short chain molecules
...

combustion

cracking

oxidation

polymerisation

[1]

© OCR 2024

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8
(f)

Draw lines to connect each description with its correct structural formula
...
17
...

Fig
...
1
Test tube 1

Test tube 2

Test tube 3

Rubber
bung
Oil
Iron nail

Iron nail

Iron nail

Water

Dry air

Water

The student measures the mass of each nail at the start and the end of the experiment
...

(a) Explain why the iron nail in test tube 1 is the only nail that rusts
...


...


...
17
...

Fig
...
2

Painted
iron nail
Water
The mass of this iron nail was unchanged after a week
...


...


...
1 shows some properties of three different materials
...
1

Melting point (°C)
Strength (MPa)

Ceramic

Metal

Polymer

2200

1083

204

416

69

27

18

388

Relative thermal
conductivity
(i)

0
...


Which material would you choose to make the base of a pan?
Explain your choice using the information in Table 17
...

Material
...


...

[3]
(ii) Estimate how many times higher the melting point of the ceramic is compared to the
polymer
...


Answer =
...
2 shows some information about recycling containers made from different materials
...
2
Time powering a TV from the
energy saved by recycling
(hours)

CO2 saved by recycling
each year (kg)

Aluminium cans

4

294

Glass bottles

3

9

Plastic bottles

6

23

A student thinks that recycling aluminium cans is the most beneficial to the environment
...

Use information from Table 17
...


...


...
[2]

© OCR 2024

Turn over

12
18
(a) The sentences describe one possible theory for how the Earth’s atmosphere
evolved
...

B Carbon cycle now keeps the composition of the atmosphere almost constant
...

D Water vapour condensed to form oceans
...
F
Volcanoes released water vapour and carbon dioxide
...

Two have been done for you
...

Gas

Percentage in Earth’s
atmosphere (%)


...

Carbon dioxide / noble gases / water vapour

78
21
1
[2]

(c) Clean water is essential for life
...


...


...


...


...

The graph shows how the amount of sulfur dioxide changed from 1995 to 2015
...

Key:
Amount of sulfur dioxide
pH of rainwater
7
...
5
Increasing
amount of

6
...
5

pH of rainwater

5
...
5
2015

Year
Acid rain is an environmental problem
...

Complete the table by correctly identifying which word finishes each sentence
...

Decreases

Increases

Stays the
same

When the amount of sulfur dioxide increases
the pH of rainwater
...

When the rainwater is more acidic the
amount of acid rain
...


...
[1]
© OCR 2024

Turn over

14
19 A student investigates the neutralisation reaction between sodium hydroxide solution and
dilute hydrochloric acid
...

The diagram shows the apparatus they use
...
[1]

(b) The student places the conical flask on a white tile
...


...
[1]

(c) The student adds the alkali to the acid drop by drop near the endpoint of the titration
...


...
[1]

© OCR 2024

15
(d) The neutralisation reaction between sodium hydroxide solution, NaOH, and dilute hydrochloric
acid, HCl, makes a salt and water
...


...

H2SO4 + 2KOH

K2SO4 + 2H2O

Calculate the mass of potassium sulfate, K2SO4, that could be made from 6
...

Give your answer to 3 significant figures
...
0 K = 39
...
0 S = 32
...
g [4]

© OCR 2024

Turn over

16
20 A student investigates the reaction between marble chips and dilute hydrochloric
acid
...

Measuring cylinder
Bubbles of carbon dioxide

Dilute hydrochloric acid
Water
Marble chips
The student measures the volume of carbon dioxide gas collected in the measuring cylinder
every 30 seconds
...

Balance
Beaker
Gas syringe
Pipette
[1]
(b) The table shows the student’s results
...


[3]

(ii) Draw a curve of best fit
...

Time =
...

Explain why the reaction stops
...


...

The student does two experiments
...

The table shows their results
...

Use the student’s results and the reacting particle model
...


...


...


...


...


...


...
[6]

© OCR 2024

19
BLANK PAGE

PLEASE DO NOT WRITE ON THIS PAGE

© OCR 2024

Turn over

20
21
(a) The table shows some properties of four Group 1 elements
...
53

180

1342

Sodium

0
...
86

63

759

Rubidium

1
...


...
[1]

(ii) Caesium is below rubidium in Group 1
...

Melting point of caesium =
...

(i)

Explain why the Group 1 elements all react in the same way
...


...
Explain why
...


...


...
[3]

(iii) Sodium reacts with bromine, Br2, to make sodium bromide,
NaBr
...


...

A student tests a compound for chloride ions
...


Solution of compound
dissolved in dilute
hydrochloric acid

Add silver
nitrate solution

White precipitate
formed

The student’s experiment does not work to identify chloride ions
...


...


...
This is the balanced symbol equation for this process
...

(i)

State how you can tell that this reaction is reversible
...
[1]

(ii) What is a closed system?

...
[1]

(iii) If dynamic equilibrium is reached, which of these statements are correct?
Tick (✓) two boxes
...

The amounts of reactants and products are constant
...

The forward reaction is faster than the backward reaction
...

[2]

(b) The reaction in the Haber process can be reversed by altering the reaction conditions
...

Suggest one other change that could be made to the reaction conditions
...
[1]

© OCR 2024

23
(c) A factory predicts they will make 800 tonnes of
ammonia
...

Calculate the percentage yield of ammonia
...
% [2]
(d) State why the reaction in the Haber process has an atom economy of
100%
...


...
You must write the question numbers clearly
in the margin
...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


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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

J248/02

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

Crossed Out Responses
Where a candidate has crossed out a response and provided a clear alternative then the crossed out response is not marked
...

Rubric Error Responses – Optional Questions
Where candidates have a choice of question across a whole paper or a whole section and have provided more answers than required, then
all responses are marked and the highest mark allowable within the rubric is given
...
(The underlying assumption is that the candidate has penalised themselves
by attempting more questions than necessary in the time allowed
...

When a question requires candidates to select more than one option/multiple options, then local marking arrangements need to ensure
consistency of approach
...

Short Answer Questions (requiring only a list by way of a response, usually worth only one mark per response)
Where candidates are required to provide a set number of short answer responses then only the set number of responses should be marked
...
The remaining responses should not then be marked
...
(The underlying assumption is that the candidate
is attempting to hedge their bets and therefore getting undue benefit rather than engaging with the question and giving the most
relevant/correct responses
...
)
Longer Answer Questions (requiring a developed response)
Where candidates have provided two (or more) responses to a medium or high tariff question which only required a single (developed) response
and not crossed out the first response, then only the first response should be marked
...

6
...
If
the candidate has continued an answer there then add the annotation ‘SEEN’ to confirm that the work has been seen
...


Award No Response (NR) if:
•

there is nothing written in the answer space

Award Zero ‘0’ if:
• anything is written in the answer space and is not worthy of credit (this includes text and symbols)
...

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
...


5

J248/02

11
...

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

7

J248/02
12
...
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
...


9

J248/02

Mark Scheme

June 2024

For answers to Section A if an answer box is blank ALLOW correct indication of answer e
...
circled or underlined
...
2

1

1
...
2

1

1
...
1

1

1
...
1

1

1
...
2

1

2
...
1

12

B✓

1

2
...
1

14

C

1

2
...
1

15

C

✓

✓
✓
✓

Guidance

J248/02

Mark Scheme

Question
16 (a)
(b)

(c)

Answer
Ethane

Marks

AO
element

1
2

1
...
1

1

1
...
g
...
1

Guidance

✓
ALLOW size / mass / intermolecular force

✓
ALLOW more/higher/ larger/ strong or AW
IGNORE many/ lots of

✓

Cracking

ALLOW heat
IGNORE force

✓
1

12

1
...
1 Mark each left-hand box
Each box may only have one line

J248/02

Mark Scheme

Question
17 (a)

Answer

2

AO
element
2 x 3
...
2b

Marks

Any two from:

June 2024
Guidance

Idea that tube 1 contains water / there was no water in
test tube 2 / water is needed for rusting

✓

Idea that tube 1 contains air / there was no air in test
tube 3 / air is needed for rusting
(b)

The nail does not rust

✓

✓

(Idea that paint acts as a) barrier to air and/or water

(c)

(i)

Material – Metal

(d)

IGNORE ‘it conducts heat’ / it conducts heat well’
ALLOW it conducts most heat

✓

DO NOT ALLOW it has the highest mpt
IGNORE arguments about strength / bpt of pan
material

✓

Recycling aluminium saves the most CO2 per year

IGNORE paint is a barrier / protects nail
...
2a

✓

Idea that metal has a suitable / high melting point

(2000 ÷ 200 =) 10

2
...
1a
2 x 3
...
8, 11
IGNORE ‘saves 294kg CO2 a year’ / most
beneficial to environment

ALLOW releases least CO2 into the
environment
Idea that recycling aluminium saves a reasonable

ALLOW saves 4 hours energy without comparator

amount of energy

IGNORE Al powers TVs

✓

14

J248/02

Mark Scheme

Question

Answer

18 (a)

Nitrogen

(b)

Oxygen
(c)

2

2 x 1
...
1

DO NOT ALLOW portable (water)

1

1
...
2

IGNORE kills germs / cleans water
Attacking/neutralising bacteria = BOD
IGNORE gets rid of bacteria
Bleaches universal indicator = 1 for the bleach
mark

3

3 x 3
...
1

Guidance
All 4 correct = 3 marks
2 correct = 2 marks
1 correct = 1 mark

✓
✓
✓

(i)

Potable (water)

(ii)

Kills bacteria / kills microorganisms

(iii)

Damp (blue) litmus paper

✓

✓

(Turns red then) is bleached
(d)

3

AO
element
3 x 1
...
2
1
...
2

✓

Idea of making it easier to see precisely when the
✓

Idea of (more) accurate/precise end point /

June 2024
Guidance
ALLOW range of spelling
Must have idea of colour and idea of change
ALLOW to know when it turns clear
IGNORE idea of improving measuring volumes of
solution
ALLOW to make it more accurate
ALLOW to see at what point the colour changed
IGNORE So they can calculate how many drops
added to make it change

Idea of speed of change /
Easier to stop excess alkali being added (when the
indicator changes colour)
(d)

HCl + NaOH → NaCl + H2O
Correct formula for NaCl

2

2 x 2
...
6 (g) award 4 marks

4

✓

Mr of H2SO4 = 98
...
3
Substitution into Mass of K2SO4 = 6
...
3 ✓
98
...
62

3 x 2
...
6 (g)

✓

1 x 1
...
2

3

3 x 2
...
2

IGNORE downturn after 270 sec, not before
ALLOW line to miss an occasional point by a
square or so
...

DO NOT ALLOW a bit of double line
DO NOT ALLOW straight line dot-to-dot except
first interval

1
1

2
...
2

ALLOW ECF
ALLOW the reactants are used up, not ‘may be’
IGNORE ‘Too many marble chips for the acid to
dissolve’/ ‘The acid stops giving off CO2’ / ‘The
marble is used up’

✓

Idea that all the (dilute hydrochloric) acid was used up /
(dilute hydrochloric) acid was the limiting reactant

Guidance

✓

17

J248/02
Question
20 (c)*

Mark Scheme
Answer

Marks
6

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

AND
Applies knowledge and understanding to give a detailed
explanation why experiment 2 is faster
...
The information presented is relevant and
substantiated
...

AND
Suggests how the experiment could be improved OR applies
knowledge and understanding to attempt to explain why
experiment 2 is faster
...
The
information presented is relevant and supported by some
evidence
...

There is an attempt at a logical structure with a line of reasoning
...

0 marks
No response or no response worthy of credit
...
2
2 x 3
...
3b

Guidance
AO3
...

• The data shows that experiment 2 has a faster rate
because the reaction time is shorter
...
2 Applies knowledge & understanding to explain
results
• Experiment 2 is faster because the magnesium is in
smaller pieces (than experiment 1)
...

• Experiment 2 is faster because the temperature of the
acid is higher (than experiment 1)
...

• There is a higher frequency of (successful) collisions,
and the reaction is faster
...
3b Analyses information to improve
experimental procedures
• The experiment could be improved by only changing
one variable (size of magnesium / temperature of
acid) at a time
• But the data shows that experiment 2 is faster than
experiment 1
...
1a

1
1

3
...
1

Marks

Melting point decreases (down the group) /

June 2024

✓

✓

(b)

(ii)
(i)

Answer in range 35 – 10 (°C)
(Group 1 elements) all have 1 electron in the outer or
valence shell /

Guidance
ALLOW ORA
Assume unqualified answers refer to down the
group
IGNORE references to density

ALLOW (Group 1 elements) all have the same
number of electrons in the outer or valence shell

Idea that (Group 1 elements) all want to lose 1 electron

ALLOW idea that (Group 1 elements) all want to

to get a full or complete (outer) shell

lose 1 electron to become stable
Reference to outer shell electron must be
made at least once to award 3 marks
Mark independently
ALLOW valence electron for outer shell electron
ALLOW (Down the group) the atomic radius is
larger / more (electron) shells (down the group)

✓

(ii)

3

3 x 1
...
1

IGNORE state symbols
Balancing mark is dependent on the correct
formulae but
ALLOW 1 mark for a balanced equation with a
minor error in subscripts / formulae
e
...
2NA + Br2 → 2NaBr

19

J248/02

Mark Scheme

Question
(c)

Answer

Marks

Any two from:

2

They used hydrochloric acid

✓

Guidance

IGNORE chlorine ions
ALLOW (hydrochloric acid) contains chlorine

Idea that experiment will give a positive result (for

✓

Nitric acid should have been used (instead of
hydrochloric acid)

AO
element
2 x 2
...
1

ALLOW a description of the ⇌, e
...
, the double
arrow / the arrow pointing both ways / equilibrium
symbol
IGNORE just ‘the reversible symbol’ / the symbol
in the middle
BUT ALLOW ‘the reversible arrow’

1

1
...
g
...
1

1

2
...
5 or 78 (%) award 2 marks
Percentage yield = 620 x 100
800

✓
ALLOW ECF
ALLOW % yield = (am pm) x 100
for 1 mark if no other mark awarded

Idea that there is only one product /
only ammonia is made

2 x 2
...
5 or 78 (%)

(d)

2

June 2024

1

✓

2

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