Question

Calculate the current that must pass through copper salt electrolyte which will deposit 3g of copper in 5mins

Answer 1

The half equation to use is;

Cu²+ + 2e^- $\to$ Cu_(s)

Atomic mass of Cu is 63.54g

It takes 2 mol of electrons to deposit 1 mol of solid Cu from 1 mol of Cu²⁺ ions.

Thus moles of Cu deposited;

$$=\frac{3g}{63.54g} = 0.0472$$

Moles of electrons $=$ 2 $\times$ 0.472

$=$ 0.0944 mol

Quantity of charge (Q) required $=$ moles x faraday

$=$ 0.0944 mol $\times$ 96485C

$=$ 9108.184C

But we know that ;

Quantity of Charge (Q) $=$ Current (I) in amps $\times$ time (t) in seconds

Q $=$ I $\times$ t

$\therefore$ I $=$ Q$/$ t

$=$ $\dfrac{9108.184C}{5×60s}$

$=$ $30.36Amp$

Note: Do not round off the values until the final answer. Use the values in the calculator