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Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signatu
ure
I declare this is my own work.
A-level
CHEMISTRY
Paper 2 Organic and Physical Chemistry
7405/2
Monday 19 June 2023 Afternoon Time allowed: 2 hours
Materials
For Examiner’s Use
For this paper you must have:
the Periodic Table/Data Booklet, provided as an insert (enclosed) 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. 5
Answer all questions.
6
You must answer the questions in the spaces provided. Do not write 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). 9
All working must be shown.
Do all rough work in this book. Cross through any work you do not want to TOTAL
be marked.
Information
The marks for questions are shown in brackets.
The maximum mark for this paper is 105.
final
,final
, 2
Do not write
outside the
Answer all questions in the spaces provided. box
0 1 This question is about rates of reaction.
Figure 1 shows apparatus used to measure the rate of reaction when an acid reacts
with an excess of solid sodium hydrogencarbonate, NaHCO3
When different monoprotic organic acids are used, the rates at which gas escapes
can be used to compare the strengths of the acids.
A timer is started when the NaHCO3 is added to the acid and
the mass of CO2 gas lost is recorded at regular intervals.
(It is assumed that any change in mass is due to the loss of CO2)
Figure 1
0 1 . 1 Suggest a reason why using a conical flask instead of a beaker would give more
accurate results in this experiment.
[1 mark]
I
, 3
Do not write
outside the
Figure 2 shows the results of this experiment when 25.0 cm3 of a box
2.23 mol dm–3 solution of ethanoic acid reacts with an excess of NaHCO3
Figure 2
0 1 . 2 Use Figure 2 to calculate the rate of reaction at 2 minutes.
Deduce the units of your calculated rate.
[3 marks]
Rate Units
0 1 . 3 Chloroethanoic acid is a stronger acid than ethanoic acid.
Sketch, on Figure 2, the curve you would expect when 25.0 cm3 of a 2.23 mol dm–3
solution of chloroethanoic acid reacts with an excess of NaHCO3
Suggest why chloroethanoic acid is a stronger acid than ethanoic acid.
[3 marks]
7
Turn over ►
I
Please write clearly in block capitals.
Centre number Candidate number
Surname
Forename(s)
Candidate signatu
ure
I declare this is my own work.
A-level
CHEMISTRY
Paper 2 Organic and Physical Chemistry
7405/2
Monday 19 June 2023 Afternoon Time allowed: 2 hours
Materials
For Examiner’s Use
For this paper you must have:
the Periodic Table/Data Booklet, provided as an insert (enclosed) 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. 5
Answer all questions.
6
You must answer the questions in the spaces provided. Do not write 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). 9
All working must be shown.
Do all rough work in this book. Cross through any work you do not want to TOTAL
be marked.
Information
The marks for questions are shown in brackets.
The maximum mark for this paper is 105.
final
,final
, 2
Do not write
outside the
Answer all questions in the spaces provided. box
0 1 This question is about rates of reaction.
Figure 1 shows apparatus used to measure the rate of reaction when an acid reacts
with an excess of solid sodium hydrogencarbonate, NaHCO3
When different monoprotic organic acids are used, the rates at which gas escapes
can be used to compare the strengths of the acids.
A timer is started when the NaHCO3 is added to the acid and
the mass of CO2 gas lost is recorded at regular intervals.
(It is assumed that any change in mass is due to the loss of CO2)
Figure 1
0 1 . 1 Suggest a reason why using a conical flask instead of a beaker would give more
accurate results in this experiment.
[1 mark]
I
, 3
Do not write
outside the
Figure 2 shows the results of this experiment when 25.0 cm3 of a box
2.23 mol dm–3 solution of ethanoic acid reacts with an excess of NaHCO3
Figure 2
0 1 . 2 Use Figure 2 to calculate the rate of reaction at 2 minutes.
Deduce the units of your calculated rate.
[3 marks]
Rate Units
0 1 . 3 Chloroethanoic acid is a stronger acid than ethanoic acid.
Sketch, on Figure 2, the curve you would expect when 25.0 cm3 of a 2.23 mol dm–3
solution of chloroethanoic acid reacts with an excess of NaHCO3
Suggest why chloroethanoic acid is a stronger acid than ethanoic acid.
[3 marks]
7
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I
