Please help and show work. Electroplating is a way to coat a complex metal objec
ID: 529822 • Letter: P
Question
Please help and show work.
Electroplating is a way to coat a complex metal object with a very thin (and hence inexpensive) layer of a precious metal, such as silver or gold. In essence the metal object is made the cathode of an electrolytic cell in which the precious metal cations are dissolved in aqueous solution. Suppose a current of 0.270 A is passed through an electroplating cell with an aqueous solution of Ag_2 SO_4 in the cathode compartment for 72.0 seconds. Calculate the mass of pure silver deposited on a metal object made into the cathode of the cell. Round your answer to 3 significant digits. Also, be sure your answer contains a unit symbol.Explanation / Answer
In a galvanic cell, anode is considered negative while cathode is positive. The electrons flow from anode to cathode as oxidation takes place at anode while reduction takes place as cathode. At cathode, the Ag+ ion which has +1 oxidation state is reduced to elemental silver which has 0 oxidation state.
The half reactions can be given as:
Ag+(aq) + e- -----> Ag(s) ……… Reduction
Mathematically, Faraday’s laws for electrolysis are summarised as:
m = QM / zF
Where,
m = the mass of the substance liberated at an electrode (g)
Q = the total electric charge that was passed through the substance = Current (in A) • total time (t)
Q = 0.270 A •72 s = 19.44 A•s = 19.44 C
F = Faraday’s constant = 96485 C mol1
M = the molar mass of the substance = 107.87 g mol-1 (for Ag)
z = the electrons transferred per ion = 1 (from the above half equation)
m = 19.44 C• 107.87 g mol-1 / 1• 96485 C mol1
m = 0.0217 g