Question

A zinc electrode was kept in a 0.1 M ZnSO4(aq) solution, and a copper electrode was kept in a 0.1 M CuSO4(aq) solution. When 1500 C of electricity was passed through the cell, how many grams of copper were deposited on the cathode? (Assume 100 % efficiency and the Faraday constant is 96500 C/mol)

Answer 1

To determine the amount of copper deposited on the cathode, we first need to find the number of moles of electrons transferred during the process. We can do this using the Faraday constant  96500 C/mol .Number of moles of electrons = Charge  C  / Faraday constant  C/mol Number of moles of electrons = 1500 C / 96500 C/mol = 0.01554 molIn the redox reaction, copper ions  Cu  gain two electrons to form copper metal  Cu :Cu + 2e  CuSince 2 moles of electrons are required to deposit 1 mole of copper, we can now find the number of moles of copper deposited:Number of moles of copper = Number of moles of electrons / 2Number of moles of copper = 0.01554 mol / 2 = 0.00777 molNow, we can calculate the mass of copper deposited using the molar mass of copper  63.55 g/mol :Mass of copper = Number of moles of copper  Molar mass of copperMass of copper = 0.00777 mol  63.55 g/mol = 0.493 gTherefore, 0.493 grams of copper were deposited on the cathode.