Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

CHEMISTRY A

OCR 2024
GCSE Chemistry A (Gateway Science)
J248/04 (Higher Tier)
With Marking Scheme Merged

Oxford Cambridge and RSA

Tuesday 11 June 2024 – Morning
GCSE (9–1) Chemistry A (Gateway Science)
J248/04 (Higher 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)

H

You can use:
• a scientific or graphical calculator
• an HB pencil
4 *

*

J

2

4

8

2
Section A
You should spend a maximum of 30 minutes on this section
...


1

Which substance is an unsaturated hydrocarbon?
A CH4 B
C2H6 C
C3H6 D
C3H8
Your answer

2

[1]

What happens when liquid bromine, Br2,
boils? A Covalent bonds break
B Electrostatic forces break C
Intermolecular forces break D
Ionic bonds break

Your answer
3

[1]

What is a life-cycle assessment?
A Analysis of the cost of making, using, and disposing of a product
...

C Analysis of the potential environmental impact of manufacturing a product
...


Your answer

© OCR 2024

[1]

3
4

Which of these is one of the four nucleotides in the polymer
DNA? A Cytosine
B Deoxyribose C
Fructose
D Phosphate

Your answer
5

[1]

Polyesters are condensation polymers
...

Nitrogen monoxide is made
...

B It is dependent on weather conditions
...

D It produces carbon dioxide gas when the plants are burnt
...
5 cm / s

B

3
2
...
0 cm / s

D

3
50
...

Which small molecule is made as well as nylon?
A HCl
B H2 C
H2O D
NH3
Your answer

© OCR 2024

[1]

Turn over

6
12 The reaction between hydrogen, H2, and iodine, I2, is reversible
...


What will increase the yield of hydrogen iodide,
HI? A Adding a catalyst
B Adding less hydrogen
C Decreasing the temperature D
Increasing the pressure

Your answer

[1]

13 Which statement about activation energy is correct?
A Activation energy is increased by the addition of a catalyst
...

C Activation energy is the minimum amount of energy for a reaction to occur
...


Your answer

[1]

14 What is the volume of 0
...
4 dm
B 16
...
0 dm
D 46
...
0 H = 1
...


(i)

Element

3
Density (g / cm )

Lithium

0
...
97

98

883

Potassium

0
...
53

39

688

Melting Point (°C)

Boiling Point (°C)

State one trend in the properties of the Group 1 elements shown in the table
...


...

Predict the melting point of caesium using the information in the table
...
°C [1]

(b) The Group 1 elements all react with Group 7 elements to form ionic compounds
...


...
[1]

(ii) The Group 1 elements become more reactive down the
group
...


...


...


...
Write the balanced symbol equation for this reaction
...
[2]
© OCR 2024

9
(c) Group 7 ions can be identified using silver nitrate solution
...

The diagram shows the student’s experiment
...

Explain why
...


...
[2]

© OCR 2024

Turn over

10
17 Ammonia is made in the Haber process
...

N2 + 3H2

2NH3

(a) The reversible reaction is carried out in a closed system
...


...


...

Only ammonia, NH3, is being made
...

The forward and backward reactions are happening at the same rate
...

The reaction has finished
...

The reaction can be reversed by altering the pressure
...


...
They actually make 620 tonnes of ammonia
...


Percentage yield of ammonia =
...
Use the balanced symbol equation
...
[1]

© OCR 2024

Turn over

12
18 A student sets up three test tubes to investigate the rusting of iron as shown in Fig
...
1
...
18
...

They measure the mass of each nail again after a week
...

Test tube

Mass of nail at start (g)

Mass of nail after a week (g)

1

4
...


2

4
...


3

4
...
51

Complete the table to estimate the mass of the nails in test tubes 1 and 2 after a week
...
18
...

Fig
...
2
Test tube 4

Test tube 5

Painted
iron nail

Iron nail
coated with zinc

Scratch

Scratch

Water

Water

The iron nail in test tube 4 rusted
...

Explain why
...



...



...

[3]
© OCR 2024

13
(c) Copper is extracted by heating copper oxide with carbon
...


...


...

2CuO + C

2Cu + CO2

Give your answer to 2 significant figures
...
5
Relative molecular mass (Mr): CuO = 79
...
tonnes [3]

© OCR 2024

Turn over

14
(iii) Copper is used in electrical wires
...

100
90
80

Relative
electrical
conductivity

70
60
50

40

0
...
2

0
...
6
0
...
0

Copper extracted from copper oxide is about 99% pure
...

Use data from the graph in your answer
...


...
[2]

© OCR 2024

15
BLANK PAGE

PLEASE DO NOT WRITE ON THIS PAGE

© OCR 2024

Turn over

16
19 The first member of the alkane homologous series is methane, CH4
...


...


...

Carbon monoxide and water are made in incomplete combustion
...


...

LPG
Petrol
Paraffin

Fuel oil
Crude oil
Bitumen
The LPG fraction contains propane and butane
...

Use ideas about intermolecular forces
...


...


...


...
[1]

© OCR 2024

17
(f)

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

(a) Describe how the amounts of these gases changed over time to develop an oxygen-rich
atmosphere
...


...


...


...

100
Nitrogen
80
Percentage
of gas (%)

Carbon dioxide

60
40
20
0
4500

(i)

Oxygen
4000

3500

3000 2500 2000
Millions of years ago

1500 1000

500

Describe the relationship between the percentage of carbon dioxide and the percentage
of nitrogen in the atmosphere
...


...

Answer =
...

This graph shows
•
•

how the amount of sulfur dioxide changed from 1995 to 2017
how the pH of rainwater changed from 1995 to 2017
...
0
6
...
0

sulfur dioxide

5
...
0

1995

2000

2010

4
...

Use the graph
...


...


...

Suggest why
...


...

They do a titration experiment
...


Burette
Sodium hydroxide
solution

3
25 cm of dilute hydrochloric acid

(a) Describe how the student uses the apparatus to do the titration
...


...


...


...


...


...
[5]

© OCR 2024

21
(b) The student repeats the titration four times
...

(i)

What is meant by concordant results?

...
12 mol / dm dilute hydrochloric acid in the conical flask
3
adds 0
...


The equation for the reaction is shown
...


3
Average volume of sodium hydroxide =
...
The diagram shows their experiment
...

(a)
(i) Suggest another piece of equipment that could be used to measure the volume of carbon dioxide
gas
...
[1]
(ii) Explain how the student could tell that the dilute hydrochloric acid is the limiting reactant in
this reaction
...


...

80
70
60
50
Volume of
carbon dioxide

gas

40

3
(cm )

30
20
10

0 0

30

60

90

120

150

180

210

240 270

Time (s)
Use the graph and a tangent line to calculate the rate of the reaction at 60 seconds
...
cm / s [3]

(c) The rate of the reaction can be changed by adding a catalyst
...
[1]

(ii) How does the mass of the catalyst change during the experiment?

...

The student does two experiments
...

The table shows their results
...
0044

0
...

Use the reacting particle model
...


...


...


...


...


...


...
[6]

END OF QUESTION PAPER

© OCR 2024

25
EXTRA ANSWER SPACE
If you need extra space use these lined pages
...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...

© OCR 2024

27

...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...
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

J248/04

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 requir ed, 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 m ost
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 (deve loped) 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, th e 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

J248/04

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

J248/04
12
...
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
...

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

J248/04

Mark Scheme

June 2024

For answers to Section A if an answer box is blank ALLOW correct indication of answer e
...
circled or underlined
...
1

1

2
...
1

1

1
...
1

1

2
...
1

1

2
...
1

✓
✓
✓
✓
✓
✓
✓
✓
✓

9

A

10

A✓

1

1
...
1

12

C✓

1

1
...
1

14

A

1

2
...
1

✓
✓

Guidance

J248/04

Mark Scheme

Question
16 (a) (i)

(b)

(ii)
(i)

AO
Marks element
1
3
...
2a
1
...
1

(Down the group) outer shell electron is further from the
nucleus

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

✓

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)

Less attraction between nucleus and outer shell electron

DO NOT ALLOW references to intermolecular

/ more shielding

forces
ALLOW electrons in plural
IGNORE outer electron is lost more quickly
ALLOW any correct multiple, including fractions
ALLOW = for →
DO NOT ALLOW and / & instead of ‘+’

✓

Outer electron is lost more easily

✓

(iii) 2Na + Br2 → 2NaBr
Formulae

2

✓

Balancing

✓

2 x 2
...
g
...
2

Answer
Any two from:
They used hydrochloric acid

✓

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)

Guidance

✓

(Hydrochloric acid) contains chloride ions

chloride ions)

June 2024

✓

12

J248/04

Mark Scheme

Question
17 (a) (i)

(ii)

Answer
⇌ sign (in equation)

✓

Idea of no loss or gain of reactants and products

June 2024

Marks

AO
element

1

1
...
g
...
1

ALLOW ‘substance(s)’ for reactants / products
ALLOW idea that that nothing can get in or out /
a description of a closed system, e
...
, a flask with
a bung in
IGNORE just no gas can escape

2

2 x 1
...
1ALLOW increase or decrease
ALLOW add more products / ammonia
IGNORE concentration

J248/04

Question
(c)

Mark Scheme

= 77
...
1

Answer
First check the answer on the answer line
If answer = 77
...
1

ALLOW no waste product(s) or byproducts are
made / all the products are useful
IGNORE no atoms lost / idea that everything is
used / nothing is wasted / idea that mass of
reactants equals mass of product(s)

14

J248/04

Mark Scheme

Question

Answer
Test tube 1 – a mass value > 4
...
2a

3

2 x 3
...
46(g)
Test tube 4
Idea that the scratch in the paint exposed the iron to

(b)

air/oxygen and/or water (so it rusted)

(i)

and/or water

Test tube 5
Idea that (even when the zinc coating is scratched) the

ALLOW idea of sacrificial protection

zinc will corrode first

DO NOT ALLOW zinc will rust (first)

✓

because zinc is more reactive (than iron) /
(c)

ALLOW the iron reacted with the air/oxygen

✓

zinc loses electrons more easily (than iron)
Copper oxide / CuO loses oxygen or
copper oxide / CuO is reduced

1 x 1
...
2

DO NOT ALLOW copper loses oxygen
BUT ALLOW copper gains electrons /
copper (cat)ions are reduced (to form copper
atoms)
ALLOW carbon loses electrons

✓

15

J248/04

Mark Scheme

Question
(ii)

Answer
First check the answer on the answer line
If answer = 12 (tonnes) award 3 marks
If answer = 12,000,000 g award 3 marks

June 2024

Marks
3

AO
element

Guidance

✓

Mass of CuO = 15 x 63
...
5
159
= 11
...
2

✓

ALLOW ECF marks for e
...
, 15 x 79
...
78
63
...
2

2

✓

2 x 3
...
g
...
g
...
1
2 x 2
...
g
...
1

4

4 x 1
...
1

J248/04

Question

Mark Scheme

Answer

Marks
4

19 (f)

✓✓✓✓

18

June 2024

AO
element
4 x 2
...
1

✓

Guidance
ALLOW MAX 2 marks if processes not in the
correct order

✓

(Water vapour condensed) to form oceans
Plants or algae evolved and used photosynthesis to take
in carbon dioxide and make oxygen
(b)

(i)

✓

As the percentage of carbon dioxide decreases, the
percentage of nitrogen increases / ORA

(c)

(ii)
(i)

✓

Answer in range 1700 – 1600 (millions of years)

3
...
1a
3 x 3
...
g
...
1a
ALLOW a named form of renewable energy e
...
,
solar panels, wind turbines, tidal turbines

✓

ALLOW idea that the amount of sulfur dioxide (in
the atmosphere) has decreased

19

J248/04

Mark Scheme

Question
21 (a)

AO
Marks element
5
5 x 1
...
g
...
1(0) (cm3) of each other

✓

1

20

1
...
2(0) (cm3) of each other
IGNORE results which are similar

J248/04

Question
21 (b) (ii)

Mark Scheme
AO
Marks element
4
4 x 2
...
5 (cm3) award 4 marks
moles of acid = 0
...
0 / 0
...
025 /
1000
0
...
0 x10-3

✓

idea that moles of alkali = moles acid / 1:1 ratio
or
moles of alkali =0
...
0 x10-3

✓

ALLOW ECF from moles of acid

volume of alkali = 0
...
0075 dm3
0
...
5 cm3

✓
ALLOW ECF from moles of alkali
i
...
volume = moles
0
...
2

Answer

(Gas) syringe / (upturned) burette

✓

Idea that marble chips are left over at the end of the
reaction / marble chips are in excess
Tangent drawn at 60 seconds

(b)

Rate = y-step = 71 - 20

June 2024

1

✓

2
...
2
ALLOW ECF for y-step and x-step from incorrect
tangent / attempted tangent

= 0
...
43 / 0
...
4 – 0
...
2

1

1
...

Level 3 (5–6 marks)
Analyses the results to conclude that experiment 2 has the
faster rate of reaction and suggests how the experiment
could be improved
...

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

Level 2 (3–4 marks)
Analyses the results to conclude that experiment 2 has the
faster rate of reaction OR suggests how the experiment could
be improved
AND
Applies knowledge and understanding to clearly explain the
difference in the rate of reaction
...
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 AO3
...
2b • The data shows that experiment 2 has a faster rate
...
3b

AO2
...

• Smaller pieces have a larger surface area so there is
a higher collision frequency, and the reaction is faster
...

• Higher temperature means that the particles move
faster / have more energy
...

AO3

---