Question

Metal plating is done by passing current through a metal solution. For example, an item can become gold plated by attaching the item to a power source and submerging it into a Au3 solution. The item itself serves as the cathode, at which the Au3 ions are reduced to Au(s). A piece of solid gold is used as the a node and is also connected to the power source, thus completing the circuit.
Required:
What mass of gold is produced when 15.0A of current are passed through a gold solution for 15.0min ?

Answer 1

Answer:

9.18g

Explanation:

Step 1: Write the reduction half-reaction

Au³⁺(aq) + 3 e⁻ ⇒ Au(s)

Step 2: Calculate the mass of gold is produced when 15.0A of current are passed through a gold solution for 15.0min

We will use the following relationships:

• 1 min = 60 s

• 1 A = 1 C/s

• 1 mole of electrons has a charge of 96486 C (Faraday's constant).

• 1 mole of Au is produced when 3 moles of electrons circulate.

• The molar mass of Au is 196.97 g/mol.

The mass of gold produced is:

$15.0 min \times \frac{60s}{1 min} \times \frac{15.0C}{1s} \times \frac{1 mol e^{-} }{96486C} \times \frac{1molAu}{3 mol e^{-} } \times \frac{196.97gAu}{1molAu} = 9.18gAu$