Question

A current of 5.94A is passed through a Cu(NO₃)₂ solution. How long (in hours)would this current have to be applied to plate out 6.30g of copper?  

Answer 1

the electrolysis expression is:

Cu2+ + 2e- ------> Cu

1 mol of Cu requires 2 mol of electron

1 mol of electron = 96485 C

So,1 mol of Cu requires 192970 C

let us calculate mol of element deposited:

we have below equation to be used:

number of mol, n = mass/molar mass

= 6.3/63.55

= 0.09913 mol

total charge = mol of element deposited * charge required for 1 mol

= 0.09913*192970

= 19130 C

we have below equation to be used:

time = Q/i

= 19130/5.94

= 3220.5 seconds

= 3220.5/60 min

= 53.7 min

= 53.7/60 hr

= 0.895

Answer: 0.895 hr