Question

How long will it take to plate 1.25 grams of Copper metal from a solution of CuSO₄, if a current of 2.0 A is used? Assume 100% efficiency.

Answer 1

Convert the mass of Cu produced into moles using the molar mass of Cu: 1.25 /63.54 = 0.019672 Moles

half-reaction for the production of Zn at the cathode.

Cu²⁺(aq) + 2 e^- Cu(s)

Calculate the moles of e^- required to produce the moles of Cu using the stoichiometry of the balanced half-reaction.   According to the equation 2 moles of electrons will produce one mole of Copper.

                                               = 0.019672 Moles x 2 = 0.039345

Convert the moles of electrons into coulombs of charge using Faraday's constant.

                                                = 0.039345 x 96485 C = 3796 C

Calculate the time using the current and the coulombs of charge.

                                                    2 Amps x t = 3796 C

                                                                  t = 3796 /2 = 1898 Seconds or 31.64 Min

1898 Seconds or 31.64 Min will take to plate 1.25 grams of Copper metal from a solution of CuSO₄.