What type of power source, AC or DC, is used to drive the reaction in this cell? When an electric current passes through the CuCl 2 (aq), the mass of electrode P increases. Is electrode P the CATHODE or the ANODE? Write down the relevant half-reaction to support the answer. The impure copper contains zinc impurities which are oxidised to zinc ions. Refer to the relative strengths of oxidising agents to explain why zinc ions will not influence the quality of the pure copper produced in this cell. Electrodes P and Q are now replaced by carbon electrodes. What will be observed at electrode Q? How will the concentration of the electrolyte change as the reaction proceeds? Choose from INCREASES, DECREASES or REMAINS THE SAME.

NSC Physical Sciences Electrochemistry: What type of power source, AC or

What type of power source, AC or DC, is used to drive the reaction in this cell? When an electric current passes through the CuCl2(aq), the mass of electrode P increases - NSC Physical Sciences - Question 9 - 2017 - Paper 2

Question 9

What type of power source, AC or DC, is used to drive the reaction in this cell? When an electric current passes through the CuCl2(aq), the mass of elect... show full transcript

Worked Solution & Example Answer:What type of power source, AC or DC, is used to drive the reaction in this cell? When an electric current passes through the CuCl2(aq), the mass of electrode P increases - NSC Physical Sciences - Question 9 - 2017 - Paper 2

Step 1

What type of power source, AC or DC, is used to drive the reaction in this cell?

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Answer

The type of power source used to drive the reaction in this electrochemical cell is DC (Direct Current).

Step 2

When an electric current passes through the CuCl2(aq), the mass of electrode P increases. Is electrode P the CATHODE or the ANODE? Write down the relevant half-reaction to support the answer.

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Answer

Electrode P is the CATHODE. The relevant half-reaction that supports this is:

ightarrow Cu$$ This indicates that copper ions in the solution are being reduced to solid copper at the cathode.

Step 3

Refer to the relative strengths of oxidising agents to explain why zinc ions will not influence the quality of the pure copper produced in this cell.

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Answer

The reason zinc ions will not influence the quality of the pure copper is that $Cu^{2+}$ is a stronger oxidising agent than $Zn^{2+}$ . Therefore, $Zn^{2+}$ ions will not be reduced to zinc, ensuring that only copper is deposited.

Step 4

What will be observed at electrode Q?

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Answer

At electrode Q, chlorine gas/bubbles will be formed.

Step 5

How will the concentration of the electrolyte change as the reaction proceeds? Choose from INCREASES, DECREASES or REMAINS THE SAME.

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Answer

The concentration of the electrolyte will DECREASE as the reaction proceeds.

What type of power source, AC or DC, is used to drive the reaction in this cell? When an electric current passes through the CuCl<sub>2</sub>(aq), the mass of electrode P increases - NSC Physical Sciences - Question 9 - 2017 - Paper 2

Worked Solution & Example Answer:What type of power source, AC or DC, is used to drive the reaction in this cell? When an electric current passes through the CuCl<sub>2</sub>(aq), the mass of electrode P increases - NSC Physical Sciences - Question 9 - 2017 - Paper 2

What type of power source, AC or DC, is used to drive the reaction in this cell?

When an electric current passes through the CuCl<sub>2</sub>(aq), the mass of electrode P increases. Is electrode P the CATHODE or the ANODE? Write down the relevant half-reaction to support the answer.

Refer to the relative strengths of oxidising agents to explain why zinc ions will not influence the quality of the pure copper produced in this cell.

What will be observed at electrode Q?

How will the concentration of the electrolyte change as the reaction proceeds? Choose from INCREASES, DECREASES or REMAINS THE SAME.

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