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ocr A Level Chemistry B (Salters) (H433-03) Question Paper June2024
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ocr A Level Chemistry B (Salters) (H433-03) Question Paper June2024
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ocrFriday 21 June 2024 – Morning
A Level Chemistry B (Salters)
H433/03 Practical skills in chemistry
Time allowed: 1 hour 30 minutes
You must have:
the Practical Insert (inside this document)
the Data Sheet for Chemistry B
You can use:
a scientific or graphical calculator
an HB pencil
Please write clearly in black ink. Do not write in the barcodes.
Centre number Candidate number
First name(s)
INSTRUCTIONS
Last name
• Use black ink. You can use an HB pencil, but only for graphs and diagrams.
• Write your answer to each question in the space provided. If you need extra space use
the lined pages at the end of this booklet. The question numbers must be clearly shown.
• Answer all the questions.
• Use the Insert to answer Question 4.
• Where appropriate, your answer should be supported with working. Marks might be
given for using a correct method, even if your answer is wrong.
INFORMATION
• The total mark for this paper is 60.
• The marks for each question are shown in brackets [ ].
• Quality of extended response will be assessed in questions marked with an asterisk (*).
• This document has 20 pages.
ADVICE
• Read each question carefully before you start your answer.
Turn over
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, 2
1 This question is about electrochemical cells.
Table 1.1 shows some standard electrode potentials.
Table 1.1
Half-reaction Eo/V
Zn2+(aq) + 2e– Zn(s) –0.76
Fe2+(aq) + 2e– Fe(s) –0.44
Pb2+(aq) + 2e– Pb(s) –0.13
Cu2+(aq) + 2e– Cu(s) +0.34
Ag2O(s) + H2O(l) + 2e– 2Ag(s) + 2OH–(aq) +0.34
Fe3+(aq) + e– Fe2+(aq) +0.77
Ag+(aq) + e– Ag(s) +0.80
Cl2(aq) + 2e– 2Cl –(aq) +1.36
(a) The values in Table 1.1 are described as standard electrode potentials.
(i) Name the electrode against which these values are measured.
................................................................................................................................................... [1]
(ii) What are the standard conditions at which these standard electrode potentials are measured?
..........................................................................................................................................................
................................................................................................................................................... [2]
(b)
(i) Some students set up the cell below. The cell consists of a copper/copper ion half-cell and
a lead/lead ion half-cell. The left-hand electrode is negative.
– +
V
................................
salt bridge ................................
................................ ................................
Identify the metals and ions by labelling the diagram with element symbols and ion formulae.
Include state symbols. [2]
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, 3
(ii) Suggest how the students make the salt bridge.
..........................................................................................................................................................
................................................................................................................................................... [1]
(iii) Use Table 1.1 to calculate E o
for the cell.
E o
cell =.......................................................V [1]
(c) ‘Button batteries’ are small cells used where there is not much space, for example, in a watch
or mobile phone.
The make-up of a silver oxide (Ag2O) button battery is shown below.
insulating seal
negative electrode top cup
(–)
zinc powder in an alkaline
electrolyte encased in a
conducting steel top cup
positive electrode (+)
consisting of a silver oxide (Ag2O)
paste in a conducting steel bottom cup porous separator bottom cup
(i) Use Table 1.1 to write ion-electron half equations for the reactions happening at the negative
and positive electrodes.
Then write the equation for the overall cell reaction.
Half-equation for the negative electrode:
Half-equation for the positive electrode:
Equation for the overall cell reaction:
[3]
(ii) Suggest the purpose of the porous separator shown in the diagram.
..........................................................................................................................................................
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