We want to determine the purity of copper in the wires used for electrical cables. This can be done using an electrolysis device with platinum electrodes and the following procedure: Weigh the electrodes and a piece of copper wire from a wire and record their mass. Dissolve the copper metal (Cu) with a solution of relatively dilute HNO3 (aq). Add hydrazine (N2H4) to the solution to give the solution a reducing agent better than H2O. Place the solution in the electrolysis apparatus, immerse the electrodes in it and start transmitting electricity. Copper metal (Cu) begins to deposit on one of the two electrodes. At the same time, we observe that gas bubbles are released from the solution. When the reaction is complete, stop the passage of electricity, disconnect the electrode, to which Cu has been deposited, and after drying, weigh it. From the difference in mass of the electrode and the known amount of Cu that we had dissolved, we calculate the purity of Cu. (a) How can we remove Cu from the electrode to which it has been deposited? (b) If we have dissolved 0.5893 g of cable and the electrode weighs 35.6745 g before electrolysis and 36.2362 g after electrolysis, calculate the purity of Cu in the cable. Consider electrolysis to be quantitative.
We want to determine the purity of copper in the wires used for electrical cables. This can be done using an
Weigh the electrodes and a piece of copper wire from a wire and record their mass.
Dissolve the copper metal (Cu) with a solution of relatively dilute HNO3 (aq).
Add hydrazine (N2H4) to the solution to give the solution a reducing agent better than H2O.
Place the solution in the electrolysis apparatus, immerse the electrodes in it and start transmitting electricity.
Copper metal (Cu) begins to deposit on one of the two electrodes. At the same time, we observe that gas bubbles are released from the solution.
When the reaction is complete, stop the passage of electricity, disconnect the electrode, to which Cu has been deposited, and after drying, weigh it.
From the difference in mass of the electrode and the known amount of Cu that we had dissolved, we calculate the purity of Cu.
(a) How can we remove Cu from the electrode to which it has been deposited?
(b) If we have dissolved 0.5893 g of cable and the electrode weighs 35.6745 g before electrolysis and 36.2362 g after electrolysis, calculate the purity of Cu in the cable.
Consider electrolysis to be quantitative.
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