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

---

COMBINED SCIENCE A

OCR 2024
GCSE Combined Science A
(Gateway Science)
J250/09 Chemistry (Higher Tier)
With Marking Scheme Merged

Oxford Cambridge and RSA

Friday 17 May 2024 – Morning
GCSE (9–1) Combined Science
A (Gateway Science)
J250/09 Chemistry (Higher Tier)
Time allowed: 1 hour 10 minutes

H

You must have:
• a ruler (cm/mm)
• the Data Sheet for GCSE (9–1) Combined Science
A (Chemistry) (inside this document)
You can use:
• a scientific or graphical calculator
• an HB pencil
*

J

2

5

0

0

9

*

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 60
...

• 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
...


Which row describes this change?
Type of change

Explanation

A

chemical

The particles break up and then join together in a different way
...


C

physical

The particles break up and then join together in a different way
...


Your answer

2

[1]

Which element in the table is a non-metal?
Appearance at
room temperature

Melting point (°C)

Electrical conductivity

A

silver liquid

–39

high

B

orange-red solid

1083

high

C

yellow solid

113

low

D

silvery-white

3422

high

Your answer

© OCR 2024

[1]

3
3

The graph shows how the temperature of two samples of a substance, Y and Z, changes as
they melt from solids to liquids
...
What is the formula of the compound formed when boron reacts with chlorine?
A BCl
B BCl3 C
B3Cl D
B3Cl7
Your answer

© OCR 2024

[1]

5
7

The equation shows the reaction of zinc carbonate when it is heated
...
0 g of zinc carbonate is heated in a test tube for 10 minutes
...
6 g
...
6 g of carbon dioxide is produced
...
6 g of zinc oxide is produced
...
4 g of carbon dioxide is produced
...
6 g of zinc oxide is produced
...

B The mole is the unit for the amount of a substance
...
D
One mole contains 1
...


Your answer
9

[1]

Magnesium reacts very slowly with oxygen at room temperature
...

Which statement is correct?
A The activation energy for the reaction is high
...

C Magnesium is an unreactive metal
...


Your answer

© OCR 2024

[1]

Turn over

6
10 What is the empirical formula of this compound?
Key:
= Carbon
= Hydrogen
= Oxygen
A

CHO

B

CH3O

C

C2H6O2

D

HOCH2CH2OH

Your answer

© OCR 2024

[1]

7
BLANK PAGE

PLEASE DO NOT WRITE ON THIS PAGE

© OCR 2024

Turn over

8
Section B

11 Lithium reacts with oxygen to form lithium oxide
...
9

8
O
16
...

Use the Periodic Table on the Data Sheet
...


...

Complete the balanced symbol equation for the reaction
...
Li + O2


...


...
Describe how an atom of lithium forms a lithium ion
...


...
Explain why they are correct
...


...
[1]

© OCR 2024

9

(f)

Lithium can exist as two isotopes
...


...


...
One alloy contains 2%
lithium
...

Lithium atoms

Aluminium atoms

(i)

Calculate the percentage of lithium atoms in the alloy drawn by the student
...
% [2]
(ii) Suggest a reason why the student’s diagram is incorrect
...


...
It contains potassium ions, K , and bromide ions, Br
...

(a) Describe what happens when solid potassium bromide is heated up until it melts into a liquid
...


...


...


...
[3]
(b) Explain why potassium bromide must be molten for electrolysis to happen
...


...

Product
...

[2]
(d) The electrolysis is repeated with a solution of potassium bromide
...

Explain why the student is incorrect
...

Reason
...

[2]

© OCR 2024

11
13* A student has samples of three solids labelled A, B and C
...

They know the following information
...

Describe any observations that the student would see in these experiments and how they
help show the labels are correct
...


...


...


...


...


...


...

–
OH

+
H

–

H

Cl

H+
Cl

–

Cl

–

–
OH

+

–

2+
Ca

+
OH

→

+

–

Cl
2+
Ca

–

Cl

–

Cl –

2+

Ca

+
H
P

–
OH

2+
Ca
–
Cl

Q

R

(a) Write the formula of the molecules in the box for R to show a balanced reaction
...

Name
...

[2]
(c) Name the type of reaction which happens between solutions P and Q
...
[1]
(d) Which of the solutions in the diagram shows a strong acid?
Tick (3) one box
...

1
...

2
...

[3]

© OCR 2024

13
3
(e) A student dissolves 2 g of a strong acid in 250 cm of water
...


3
Concentration of the solution =
...

2CuO + C

2Cu + CO2

When 2
...
00 g of carbon, copper oxide is the limiting reactant
...


...
[1]
(b) Calculate the number of moles in 2
...
00 g of
carbon
...

Relative atomic mass (Ar):

C = 12
...
0

Cu = 63
...
00 g of copper oxide =
...
00 g of carbon =
...


...


...
045
...
045 moles of copper oxide
...

Relative atomic mass (Ar): Cu = 63
...
g [3]

© OCR 2024

Turn over

16
16 The diagram shows the model of the atom developed by Rutherford
...

They fired positively charged alpha particles at very thin gold foil
...

Observation 1
...

Observation 2
...

Conclusion
...

[3]
(b) Describe how Bohr improved Rutherford’s model of the atom
...


...



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


...


...


...


...


...


...


...


...


...


...


...


...

© OCR 2024

18

...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...

© OCR 2024

20

...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...


...



...


...


...


Higher
GCSE
Combined Science Chemistry A Gateway Science
J250/09: Paper 9 (Higher Tier)
General Certificate of Secondary Education

Mark Scheme for June 2024

Oxford Cambridge and RSA Examinations

OCR (Oxford Cambridge and RSA) is a leading UK awarding body, providing a wide range of
qualifications to meet the needs of candidates of all ages and abilities
...


It is also responsible for developing new specifications to meet national requirements and
the needs of students and teachers
...

This mark scheme is published as an aid to teachers and students, to indicate the requirements
of the examination
...
It does not
indicate the details of the discussions which took place at an examiners’ meeting before
marking commenced
...

Mark schemes should be read in conjunction with the published question papers and the
report on the examination
...


Make sure that you have accessed and completed the relevant training packages for on-screen marking: RM Assessor Online Training; OCR
Essential Guide to Marking
...


Make sure that you have read and understood the mark scheme and the question paper for this unit
...


3
...


MARKING
1
...


2
...


3
...
It is essential that you meet the RM Assessor 50% and 100% (traditional 50% Batch 1 and
100% Batch 2) deadlines
...


4
...


2

J250/09
5
...
Where no
alternative response has been provided, examiners may give candidates the benefit of the doubt and mark the crossed out response where
legible
...
Enter a mark for each question answered into RM
assessor, which will select the highest mark from those awarded
...
)
Multiple Choice Question Responses
When a multiple choice question has only a single, correct response and a candidate provides two responses (even if one of these responses
is correct), then no mark should be awarded (as it is not possible to determine which was the first response selected by the candidate)
...

Contradictory Responses
When a candidate provides contradictory responses, then no mark should be awarded, even if one of the answers is correct
...

The response space should be marked from left to right on each line and then line by line until the required number of responses have been
considered
...
Examiners will have to apply judgement as to whether a ‘second response’
on a line is a development of the ‘first response’, rather than a separate, discrete response
...
)

3

J250/09

Mark Scheme

June 2024

Short Answer Questions (requiring a more developed response, worth two or more marks)
If the candidates are required to provide a description of, say, three items or factors and four items or factors are provided, then mark on a
similar basis – that is downwards (as it is unlikely in this situation that a candidate will provide more than one response in each section of the
response space
...
Examiners will need to apply professional judgement as to
whether the second (or a subsequent) response is a ‘new start’ or simply a poorly expressed continuation of the first response
...


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


7
...

Team Leaders must confirm the correct use of the NR button with their markers before live marking commences and should check this
when reviewing scripts
...


The RM Assessor comments box is used by your Team Leader to explain the marking of the practice responses
...
Do not use the comments box for any other reason
...


9
...
The report should contain notes on particular strengths displayed as well as common errors or weaknesses
...


4

J250/09
10
...
The
indicative scientific content in the Guidance column indicates the expected parameters for candidates’ answers, but be prepared to recognise and
credit unexpected approaches where they show relevance
...


Once the level is located, award the higher or lower mark:
The higher mark should be awarded where the level descriptor has been evidenced and all aspects of the communication statement
(in italics) have been met
...

In summary:
The skills and science content determines the level
...
Level of response question on this paper is 13
...


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

6

June 2024

J250/09

Mark Scheme

June 2024

Abbreviations, annotations and conventions used in the detailed Mark Scheme (to include abbreviations and subject-specific conventions)
...


Mark Scheme

June 2024

Subject-specific Marking Instructions

INTRODUCTION
Your first task as an Examiner is to become thoroughly familiar with the material on which the examination depends
...


You should ensure that you have copies of these materials
...
These are set out in the OCR
booklet Instructions for Examiners
...

Please ask for help or guidance whenever you need it
...


8

J250/09

Mark Scheme

June 2024

The breakdown of Assessment Objectives for GCSE (9-1) Combined Science A:
Assessment Objective
AO1

Demonstrate knowledge and understanding of scientific ideas and scientific techniques and procedures
...
1

Demonstrate knowledge and understanding of scientific ideas
...
2
AO2

Demonstrate knowledge and understanding of scientific techniques and procedures
...


AO2
...


AO2
...


AO3
AO3
...

Analyse information and ideas to interpret and evaluate
...
1a

Analyse information and ideas to interpret
...
1b

Analyse information and ideas to evaluate
...
2

Analyse information and ideas to make judgements and draw conclusions
...
2a

Analyse information and ideas to make judgements
...
2b

Analyse information and ideas to draw conclusions
...
3

Analyse information and ideas to develop and improve experimental procedures
...
3a

Analyse information and ideas to develop experimental procedures
...
3b

Analyse information and ideas to improve experimental procedures
...
g
...

Question

Answer

Marks

AO
element

1

A

1

1
...
1

3

C

1

2
...
2

5

D

1

1
...
2

7

A

1

1
...
1

9

A

1

2
...
1

Guidance

J250/09
Question
11 (a)

Mark Scheme
Answer

Marks

Idea that lithium is on the left (of the Periodic Table) /
metals are on the left and oxygen is on the right (of the
Periodic Table) / non-metals are on the right

1



June 2024
AO
Guidance
element
1
...
1

✓



(c)

2,1

(d)

It loses (electrons)



1

2
...
1

2

2 x 2
...
1b

2

2 x 1
...
g
...
57 / 28
...
2

1

3
...
571428



= 28
...
6 / 29 (%)

(ii)

June 2024



Idea that the diagram contains too many atoms of lithium
/ too few aluminium atoms



ECF from an incorrectly calculated percentage
relating to the diagram e
...
value is below 2%
lithium
INGORE any reference to percentage values

12

J250/09
Question
12 (a)

Mark Scheme
Answer

Marks

Any 3 from:

3

Ions in a solid vibrate in a fixed position



June 2024
AO
Guidance
element
3 x 1
...
2

DO NOT ALLOW delocalised electrons

2

2 x 1
...
1b

DO NOT ALLOW ions
ALLOW half equation given here if product is H2

J250/09

Mark Scheme

June 2024

AO
Guidance
element
NB
...
If only one experiment discussed, then also maximum level 2
...


4 x 2
...
3a

IGNORE repeats of the stem of the question
regarding solubility in water and reaction with acid
...
g
...
The information presented
is relevant and substantiated
...

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

Level 1 (1–2 marks)
Basic description of an experiment and a
linked observation or relevant conclusion
...
1 Apply knowledge and understanding
of scientific ideas e
...
,
Describes experiments and observations
• Add solid to water and determine solubility
• If the solid dissolves/disappears it is soluble
• If the solid does not dissolve/disappear it
is insoluble
• Add solid to dilute hydrochloric acid
and determine if a reaction has taken place
• Carbonates fizz when added to acid
• Sodium chloride does not fizz when added
to acid
AO3
...
g
...
The information is in the most part relevant
...


14

J250/09
Question
14 (a)

Mark Scheme
Answer

Marks

Formula: H2O drawn or written



Balancing: 4 H2O drawn or written

(b)

2





AO
Guidance
element
2 x 2
...
2
2
...
2b

3

2 x 3
...
250 (dm3)

3



ALLOW ECF for incorrect or missing conversions
e
...
8 x 10 -3 / 0
...
8 for 2 marks

2 ÷ 0
...
1


15

J250/09

Mark Scheme
Or



2 ÷ 250 = 0
...
008 x 1000

16

June 2024

J250/09
Question
15 (a)

Mark Scheme
Answer

Marks

Idea that the amount of product is determined by the
amount of the limiting reactant / AW

(b)

1

June 2024
AO
Guidance
element
1
...
g
...
00 ÷ 79
...
025172

3 x 2
...
00 ÷ 12
...
083333

Both answers must be quoted to 3 decimal
places 0
...
083
(c)



Idea that the moles of copper oxide are less than the



moles of carbon / ORA
(d)

1



First check the answer on the answer line
If answer = 2
...
045 x 63
...
1b

3



2 x 2
...
8575 
1
...
9 (g) to 2 significant figures 

17

ALLOW ECF common examples include moles of
Cu multiplied by 2 (5
...
6g)
ALLOW ECF for sig fig mark from a valid
calculation

J250/09

Question
16 (a)

Mark Scheme

Answer

Marks

Any 2 observations from:
Observations

3

Idea that most particles went (straight) through

June 2024
AO
Guidance
element
3 x 1
...
1

(c)

1 x 10-10 – 9 x 10-10 (m)

1

1

---