Pearson Edexcel as level chemistry (8CH0/02 )
question paper 2 june 2024 Merged with mark
scheme
, Answer ALL questions.
Some questions must be answered with a cross in a box . If you change your mind about an
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answer, put a line through the box and then mark your new answer with a cross .
1 The relative molecular mass of a solid dicarboxylic acid, HOOC(CH2)nCOOH, can be
found using a titration. The acid, which can be represented as H2A, was dissolved in
deionised water and the solution made up to 250 cm3.
(a) Which piece of apparatus should be used for making a solution with a volume of
exactly 250 cm3 ?
(1)
A burette
B measuring cylinder
C pipette
D volumetric flask
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(b) A solution of 0.100 mol dm–3 sodium hydroxide solution was added to a burette.
A rough titration was carried out on a 25.0 cm3 portion of the acid solution.
(i) The diagram shows the burette before the rough titration.
What is the initial burette reading for this titration?
(1)
2.0
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3.0
A 2.40 cm3
B 2.45 cm3
C 3.55 cm3
D 3.60 cm3
2
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, (ii) The final burette reading for the rough titration was 26.50 cm3.
Calculate the volume of sodium hydroxide solution added in the
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rough titration, using your answer to (b)(i).
(1)
(iii) Describe how you would use the rough titration value when carrying out the
accurate titrations.
(1)
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3
■■■■ Turn over
, (c) 25.0 cm3 portions of the acid solution were titrated with
0.100 mol dm–3 sodium hydroxide solution.
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The equation for the reaction is shown.
H2A(aq) + 2NaOH(aq) → Na2A(aq) + 2H2O(l)
The acid solution was pipetted into a conical flask and titrated.
The accurate titrations were carried out three times.
The following results were recorded for the accurate titrations.
Titration number 1 2 3
Burette reading (final) / cm3 47.80 24.35 47.60
Burette reading (initial) / cm3 24.50 1.00 24.35
Volume of NaOH used / cm3 23.30 23.35 23.25
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(i) Calculate the mean titre for these accurate titrations.
(1)
(ii) Calculate the number of moles of sodium hydroxide in the mean titre.
(1)
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4
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question paper 2 june 2024 Merged with mark
scheme
, Answer ALL questions.
Some questions must be answered with a cross in a box . If you change your mind about an
DO NOT WRITE IN THIS AREA
answer, put a line through the box and then mark your new answer with a cross .
1 The relative molecular mass of a solid dicarboxylic acid, HOOC(CH2)nCOOH, can be
found using a titration. The acid, which can be represented as H2A, was dissolved in
deionised water and the solution made up to 250 cm3.
(a) Which piece of apparatus should be used for making a solution with a volume of
exactly 250 cm3 ?
(1)
A burette
B measuring cylinder
C pipette
D volumetric flask
DO NOT WRITE IN THIS AREA
(b) A solution of 0.100 mol dm–3 sodium hydroxide solution was added to a burette.
A rough titration was carried out on a 25.0 cm3 portion of the acid solution.
(i) The diagram shows the burette before the rough titration.
What is the initial burette reading for this titration?
(1)
2.0
DO NOT WRITE IN THIS AREA
3.0
A 2.40 cm3
B 2.45 cm3
C 3.55 cm3
D 3.60 cm3
2
■■■■
, (ii) The final burette reading for the rough titration was 26.50 cm3.
Calculate the volume of sodium hydroxide solution added in the
DO NOT WRITE IN THIS AREA
rough titration, using your answer to (b)(i).
(1)
(iii) Describe how you would use the rough titration value when carrying out the
accurate titrations.
(1)
. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. .. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. .. ... .. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. .. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. . . . ......................
. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. .. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. .. ... .. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. .. .. .. ... .. .. ... .. ... .. . . ... .. .. ... .. .. ... .. ... .. .. . ......................
. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. .. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. .. ... .. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. .. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. . . . ......................
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. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. .. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. .. ... .. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. .. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. . . . ......................
. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. .. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. .. ... .. .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. ... .. .. ... .. .. ... .. .. ... .. .. .. .. ... .. .. ... .. ... .. . . ... .. .. ... .. .. ... .. ... .. .. . ......................
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3
■■■■ Turn over
, (c) 25.0 cm3 portions of the acid solution were titrated with
0.100 mol dm–3 sodium hydroxide solution.
DO NOT WRITE IN THIS AREA
The equation for the reaction is shown.
H2A(aq) + 2NaOH(aq) → Na2A(aq) + 2H2O(l)
The acid solution was pipetted into a conical flask and titrated.
The accurate titrations were carried out three times.
The following results were recorded for the accurate titrations.
Titration number 1 2 3
Burette reading (final) / cm3 47.80 24.35 47.60
Burette reading (initial) / cm3 24.50 1.00 24.35
Volume of NaOH used / cm3 23.30 23.35 23.25
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(i) Calculate the mean titre for these accurate titrations.
(1)
(ii) Calculate the number of moles of sodium hydroxide in the mean titre.
(1)
DO NOT WRITE IN THIS AREA
4
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