3.What mass of copper could be deposited from a copper(II) Sulphate solution using a current of 5.0 A over 100 seconds? ( F =96,500C, Charge of Cu in CuSO4 = +2)

Mass of copper : 0.165 g

Given

5.0 A over 100 seconds

Required

Mass of copper

Solution

Faraday's law:

The mass of the substance formed at each electrode is proportional to the electric current flowing in the electrolysis

e = Ar / valence = eqivalent weight

i = current

t = time

W = weight

CuSO₄ ----> Cu²⁺ + SO₄²⁻

Cu ----> Cu²⁺ + 2e

e = Ar/2

= 63,5/2 = 31,75

the answer is true.

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3