Learners performed an experiment to determine the electrode potential of an electrochemical cell under standard conditions - NSC Technical Sciences - Question 6 - 2023 - Paper 2
Question 6
Learners performed an experiment to determine the electrode potential of an electrochemical cell under standard conditions. They assembled the apparatus, as shown in... show full transcript
Worked Solution & Example Answer:Learners performed an experiment to determine the electrode potential of an electrochemical cell under standard conditions - NSC Technical Sciences - Question 6 - 2023 - Paper 2
Step 1
State the energy conversion taking place in this cell.
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Answer
The energy conversion taking place in this cell is from chemical energy to electrical energy. This transformation occurs due to the electrochemical reactions happening at the electrodes.
Step 2
Write down a balanced net ionic reaction of the cell.
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Answer
The balanced net ionic reaction for the cell is:
Mg(s)+Zn2+(aq)→Mg2+(aq)+Zn(s)
Step 3
In which direction will the SO4^2- ions migrate through the salt bridge? Write down only FROM Zn TO Mg or FROM Mg TO Zn.
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The SO4^2- ions will migrate from Zn to Mg.
Step 4
Is the cell reaction spontaneous or non-spontaneous?
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The cell reaction is spontaneous, as it has a positive cell potential.
Step 5
Calculate the emf of the cell.
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The electromotive force (emf) of the cell can be calculated using the standard reduction potentials:
Ecell=Ecathode−Eanode
Given:
Ecathode=−2.36V (for Mg)
Eanode=−0.76V (for Zn)
Calculating gives:
Ecell=−0.76−(−2.36)=1.60V
Step 6
Write down the NAME of component A.
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The name of component A is the salt bridge.
Step 7
Will the light bulb glow? Write down YES or NO.
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No, the light bulb will not glow.
Step 8
Explain the answer to QUESTION 6.2.2.
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The light bulb will not glow because component A, the salt bridge, is responsible for maintaining the flow of ions between the two half-cells. Its removal interrupts the circuit, preventing current flow and thus the bulb will not light up.
