Please write clearly in block capitals.
Centre number Candidate number INTERNATIONAL AS
Surname CHEMISTRY (9620)
Forename(s)
Candidate signature
CH01
I declare this is my own work.
Unit 1: Inorganic 1 and Physical 1
INTERNATIONAL AS Mark scheme
CHEMISTRY (9620) January 2026
Version: 1.0 Final
Unit 1: Inorganic 1 and Physical 1
Tuesday 13 January 2026 07:00 UK Time Time allowed: 1 hour 30 minutes
Materials
For this paper you must have: For Examiner’s Use
• the Periodic Table/Data Sheet, provided as an insert Question Mark
• a ruler with millimetre measurements
1
• a scientific calculator, which you are expected to use where appropriate.
2
Instructions 3
• Use black ink or black ball-point pen. 4
• Fill in the boxes at the top of this page.
• Answer all questions. 5
• You must answer the questions in the spaces provided. Do not write 6
outside the box around each page or on blank pages. 7
• If you need extra space for your answer(s), use the lined pages at the end of
8
this book. Write the question number against your answer(s).
• All working must be shown. TOTAL
• Do all rough work in this book. Cross through any work you do not want
to be marked.
Information
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 70.
*JaN26CH0101*
IB/G/Jan26/G4005/V5 CH01
, 2
MARK SCHEME – INTERNATIONAL AS CHEMISTRY – CH01 – JANUARY 2026
Do not write
outside the
Answer all questions in the spaces provided. box
Mark schemes are prepared by the Lead Assessment Writer and considered, together with the relevant
questions, by a panel of subject teachers. This mark scheme includes any amendments made at the
0 1 This question is about shapes of molecules and bonding in some boron compounds. standardisation events which all associates participate in and is the scheme which was used by them in
this examination. The standardisation process ensures that the mark scheme covers the students’
0 1 . 1 Explain why BH3 has a bond angle of 120° responses to questions and that every associate understands and applies it in the same correct way.
[2 marks] As preparation for standardisation each associate analyses a number of students’ scripts. Alternative
answers not already covered by the mark scheme are discussed and legislated for. If, after the
standardisation process, associates encounter unusual answers which have not been raised they are
required to refer these to the Lead Examiner.
It must be stressed that a mark scheme is a working document, in many cases further developed and
expanded on the basis of students’ reactions to a particular paper. Assumptions about future mark
schemes on the basis of one year’s document should be avoided; whilst the guiding principles of
assessment remain constant, details will change, depending on the content of a particular examination
paper.
– –
0 1 . 2 A BH4 ion is formed when a BH3 molecule reacts with a hydride ion (H ).
Further copies of this mark scheme are available from
State the type of bond formed in this reaction.
Explain how it is formed.
[2 marks]
Type of bond
Explanation
–
0 1 . 3 Which is correct about the bond angles in BH3 and BH4 ?
Tick () one box.
[1 mark]
–
The bond angle in BH3 is smaller than the bond angle in BH4
–
The bond angle in BH3 is the same as the bond angle in BH4
–
The bond angle in BH3 is larger than the bond angle in BH4 5
information
OxfordAQA retains the on all its publications. However, registered schools/colleges for OxfordAQA are permitted to copy material from this
booklet for their own int , with the following important exception: OxfordAQA cannot give permission to schools/colleges to photocopy any
material that is acknowledged to a third party even for internal use within the centre.
OxfordAQA International Examinations and its licensors. All rights reserved.
*02*
2
IB/G/Jan26/CH01
, 3
MARK SCHEME – INTERNATIONAL AS CHEMISTRY – CH01 – JANUARY 2026
Do not write
outside the
0 2 This question is about titration experiments between phosphoric acid (H3PO4) box
and sodium hydroxide. AS Chemistry
Mark Scheme Instructions for Examiners
0 2 . 1 A student does an experiment to determine the percentage purity of some
impure phosphoric acid. 1. General
The mark scheme for each question shows:
Method
3
• the marks available for each part of the question
1.56 g of the impure phosphoric acid are weighed directly into a 500 cm
volumetric flask. • the total marks available for the question
3
De-ionised water is then added to the volumetric flask to make exactly 500 cm
of solution. • the typical answer or answers which are expected
3 –3
25.0 cm portions of the diluted acid are titrated with 0.100 mol dm • extra information to help the examiner make his or her judgement and help to delineate what is acceptable or not worthy of credit or,
sodium hydroxide solution. in discursive answers, to give an overview of the area in which a mark or marks may be awarded.
The mean titre is 22.45 cm
3 The extra information in the ‘Comments’ column is aligned to the appropriate answer in the left-hand part of the mark scheme and
should only be applied to that item in the mark scheme.
The equation for the reaction is You should mark according to the contents of the mark scheme. If you are in any doubt about applying the mark scheme to a particular
response, consult your Team Leader.
H3PO4 + 3 NaOH → Na3PO4 + 3 H2O
At the beginning of a part of a question a reminder may be given, for example: where consequential marking needs to be considered in a
calculation; or the answer may be on the diagram or at a different place on the script.
Calculate the purity of the phosphoric acid as a percentage by mass.
[5 marks] In general the right-hand side of the mark scheme is there to provide those extra details which might confuse the main part of the mark
scheme yet may be helpful in ensuring that marking is straightforward and consistent.
The use of M1, M2, M3 etc in the right-hand column refers to the marking points in the order in which they appear in the mark scheme.
So, M1 refers to the first marking point, M2 the second marking point etc.
2. Emboldening
2.1 In a list of acceptable answers where more than one mark is available ‘any two from’ is used, with the number of marks
emboldened. Each of the following bullet points is a potential mark.
2.2 A bold and is used to indicate that both parts of the answer are required to award the mark.
2.3 Alternative answers acceptable for a mark are indicated by the use of or. Different terms in the mark scheme are shown by a / ;
eg allow smooth / free movement.
3
Purity by mass %
Question 2 continues on the next page
Turn over ►
*03*
IB/G/Jan26/CH01
Centre number Candidate number INTERNATIONAL AS
Surname CHEMISTRY (9620)
Forename(s)
Candidate signature
CH01
I declare this is my own work.
Unit 1: Inorganic 1 and Physical 1
INTERNATIONAL AS Mark scheme
CHEMISTRY (9620) January 2026
Version: 1.0 Final
Unit 1: Inorganic 1 and Physical 1
Tuesday 13 January 2026 07:00 UK Time Time allowed: 1 hour 30 minutes
Materials
For this paper you must have: For Examiner’s Use
• the Periodic Table/Data Sheet, provided as an insert Question Mark
• a ruler with millimetre measurements
1
• a scientific calculator, which you are expected to use where appropriate.
2
Instructions 3
• Use black ink or black ball-point pen. 4
• Fill in the boxes at the top of this page.
• Answer all questions. 5
• You must answer the questions in the spaces provided. Do not write 6
outside the box around each page or on blank pages. 7
• If you need extra space for your answer(s), use the lined pages at the end of
8
this book. Write the question number against your answer(s).
• All working must be shown. TOTAL
• Do all rough work in this book. Cross through any work you do not want
to be marked.
Information
• The marks for questions are shown in brackets.
• The maximum mark for this paper is 70.
*JaN26CH0101*
IB/G/Jan26/G4005/V5 CH01
, 2
MARK SCHEME – INTERNATIONAL AS CHEMISTRY – CH01 – JANUARY 2026
Do not write
outside the
Answer all questions in the spaces provided. box
Mark schemes are prepared by the Lead Assessment Writer and considered, together with the relevant
questions, by a panel of subject teachers. This mark scheme includes any amendments made at the
0 1 This question is about shapes of molecules and bonding in some boron compounds. standardisation events which all associates participate in and is the scheme which was used by them in
this examination. The standardisation process ensures that the mark scheme covers the students’
0 1 . 1 Explain why BH3 has a bond angle of 120° responses to questions and that every associate understands and applies it in the same correct way.
[2 marks] As preparation for standardisation each associate analyses a number of students’ scripts. Alternative
answers not already covered by the mark scheme are discussed and legislated for. If, after the
standardisation process, associates encounter unusual answers which have not been raised they are
required to refer these to the Lead Examiner.
It must be stressed that a mark scheme is a working document, in many cases further developed and
expanded on the basis of students’ reactions to a particular paper. Assumptions about future mark
schemes on the basis of one year’s document should be avoided; whilst the guiding principles of
assessment remain constant, details will change, depending on the content of a particular examination
paper.
– –
0 1 . 2 A BH4 ion is formed when a BH3 molecule reacts with a hydride ion (H ).
Further copies of this mark scheme are available from
State the type of bond formed in this reaction.
Explain how it is formed.
[2 marks]
Type of bond
Explanation
–
0 1 . 3 Which is correct about the bond angles in BH3 and BH4 ?
Tick () one box.
[1 mark]
–
The bond angle in BH3 is smaller than the bond angle in BH4
–
The bond angle in BH3 is the same as the bond angle in BH4
–
The bond angle in BH3 is larger than the bond angle in BH4 5
information
OxfordAQA retains the on all its publications. However, registered schools/colleges for OxfordAQA are permitted to copy material from this
booklet for their own int , with the following important exception: OxfordAQA cannot give permission to schools/colleges to photocopy any
material that is acknowledged to a third party even for internal use within the centre.
OxfordAQA International Examinations and its licensors. All rights reserved.
*02*
2
IB/G/Jan26/CH01
, 3
MARK SCHEME – INTERNATIONAL AS CHEMISTRY – CH01 – JANUARY 2026
Do not write
outside the
0 2 This question is about titration experiments between phosphoric acid (H3PO4) box
and sodium hydroxide. AS Chemistry
Mark Scheme Instructions for Examiners
0 2 . 1 A student does an experiment to determine the percentage purity of some
impure phosphoric acid. 1. General
The mark scheme for each question shows:
Method
3
• the marks available for each part of the question
1.56 g of the impure phosphoric acid are weighed directly into a 500 cm
volumetric flask. • the total marks available for the question
3
De-ionised water is then added to the volumetric flask to make exactly 500 cm
of solution. • the typical answer or answers which are expected
3 –3
25.0 cm portions of the diluted acid are titrated with 0.100 mol dm • extra information to help the examiner make his or her judgement and help to delineate what is acceptable or not worthy of credit or,
sodium hydroxide solution. in discursive answers, to give an overview of the area in which a mark or marks may be awarded.
The mean titre is 22.45 cm
3 The extra information in the ‘Comments’ column is aligned to the appropriate answer in the left-hand part of the mark scheme and
should only be applied to that item in the mark scheme.
The equation for the reaction is You should mark according to the contents of the mark scheme. If you are in any doubt about applying the mark scheme to a particular
response, consult your Team Leader.
H3PO4 + 3 NaOH → Na3PO4 + 3 H2O
At the beginning of a part of a question a reminder may be given, for example: where consequential marking needs to be considered in a
calculation; or the answer may be on the diagram or at a different place on the script.
Calculate the purity of the phosphoric acid as a percentage by mass.
[5 marks] In general the right-hand side of the mark scheme is there to provide those extra details which might confuse the main part of the mark
scheme yet may be helpful in ensuring that marking is straightforward and consistent.
The use of M1, M2, M3 etc in the right-hand column refers to the marking points in the order in which they appear in the mark scheme.
So, M1 refers to the first marking point, M2 the second marking point etc.
2. Emboldening
2.1 In a list of acceptable answers where more than one mark is available ‘any two from’ is used, with the number of marks
emboldened. Each of the following bullet points is a potential mark.
2.2 A bold and is used to indicate that both parts of the answer are required to award the mark.
2.3 Alternative answers acceptable for a mark are indicated by the use of or. Different terms in the mark scheme are shown by a / ;
eg allow smooth / free movement.
3
Purity by mass %
Question 2 continues on the next page
Turn over ►
*03*
IB/G/Jan26/CH01
