Question

What mass of Cu(s) is electroplated by running 19.5 A of current through a Cu2 (aq) solution for 4.00 h

Answer 1

Answer:

92.46 g

Explanation:

The reaction is

$Cu^{2+}+2e^-\rightarrow Cu$

I = Current = 19.5 A

t = 4 hours = $4\times 60\times 60=14400\ \text{s}$

F = Faraday constant = 96485.33 C/mol

Molar mass of copper = 63.546 g/mol

Charge is given by

$Q=It\\\Rightarrow Q=19.5\times 14400\\\Rightarrow Q=280800\ \text{C}$

Moles of electrons is given by

$\dfrac{Q}{F}=\dfrac{280800}{96485.33}\\ =2.91\ \text{mol}$

Moles of copper is

$\dfrac{1}{2}\times \dfrac{Q}{F}=\dfrac{1}{2}\times 2.91\\ =1.455\ \text{mol}$

Mass of copper would be

$\text{Moles}\times \text{Molar mass of copper}=1.455\times 63.546\\ =92.46\ \text{g}$

The mass of copper electroplated is 92.46 g.