Learners set up a galvanic cell and measure its emf under standard conditions - NSC Physical Sciences - Question 8 - 2017 - Paper 2
Question 8
Learners set up a galvanic cell and measure its emf under standard conditions.
8.1.1 Write down the name of component Y.
8.1.2 Is A at the ANODE or the CATHODE?
8... show full transcript
Worked Solution & Example Answer:Learners set up a galvanic cell and measure its emf under standard conditions - NSC Physical Sciences - Question 8 - 2017 - Paper 2
Step 1
8.1.1 Write down the name of component Y.
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Answer
The name of component Y is a Voltmeter or Multimeter.
Step 2
8.1.2 Is A at the ANODE or the CATHODE?
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Answer
A is at the ANODE.
Step 3
8.1.3 Write down the overall (net) cell reaction that takes place in this cell when it is working.
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The overall (net) cell reaction is:
ightarrow ext{3Ag}(s) + ext{At}^3+(aq)$$
Step 4
8.1.4 Calculate the initial emf of this cell.
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To calculate the initial emf (E_cell), we use the formula:
Ecell=Ereduction−Eoxidation
For this cell:
Ecell=0.80extV−1.66extV=2.46extV
Step 5
8.2.1 Write down the NAME of a suitable electrode for half-cell Q.
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The suitable electrode for half-cell Q is Platinum (Pt).
Step 6
8.2.2 State the standard conditions under which the half-cells should operate to ensure a fair comparison.
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The standard conditions are:
Concentration: 1 mol·dm⁻³
Temperature: 25 °C/298 K
Pressure: 101.3 kPa/1.01 × 10⁶ Pa/1 atm
Step 7
8.2.3 Write down the NAME or FORMULA of the strongest reducing agent in the half-cells above.
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The strongest reducing agent in the half-cells is Zinc (Zn) or its formula, Zn.
Step 8
8.2.4 Which combination of half-cells would produce the highest emf?
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The combination of half-cells that would produce the highest emf is PQ.
