When electricity (the flow of electrons) is passed through a solution, it causes

Question

When electricity (the flow of electrons) is passed through a solution, it causes an oxidation-reduction (redox) reaction to occur. If the solution contains a metal cation such as Ag+, the flow of electrons will reduce the silver ion, causing solid silver to plate onto the electrode. The amount of metal plated depends on the number of electrons passed.

The total charge of a mole of electrons is 96,500 coulombs (C) and

1ampere(A)=1coulomb/second(C/s)

A.... What mass of Cu(s) is electroplated by running 24.0A of current through a Cu2+(aq) solution for 4.00 h?

B.. How many minutes will it take to electroplate 57.1g of gold by running 5.00 A of current through a solution of Au+(aq)?

Explanation / Answer

a) total charge passed in 4 hours = 4*60*60*24 C = 345600 C = 345600/96500 F = 3.5813 F

copper needs two electrons...moles of copper deposited = 3.5813/2 = 1.79067

mass of copper = 1.79067*63.5 = 113.7 g

b) moles of gold deposited = 57.1/197 = 0.2898

gold needs one electron....so moles of electrons required = 0.2898

charge = 0.2898*96500 = 27970.30 C

time in minutes = 27970.3/(5*60) = 93.23 minutes

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