What mass of gold is produced when 19.5 A of current are passed through a gold solution for 35.0 min ?

[匿名]

2020-11-30 2:46 pm

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 anode and is also connected to the power source, thus completing the circuit.

What mass of gold is produced when 19.5 A of current are passed through a gold solution for 35.0 min ?

Please include units.

回答 (1)

Uncle Michael

2020-12-01 9:02 am

✔ 最佳答案

Au³⁺(aq) + 3e⁻ → Au(s)
Mole ratio e⁻ : Au = 3 : 1

Amount of electricity = (19.5 C/s) × (35.0 × 60 s) = 40950 C

1 mole of e⁻ carries 96485 C of electricity.
No. of moles of e⁻ = (40950 C) /(96485 C/mol) = 0.4244 mol

Au³⁺(aq) + 3e⁻ → Au(s)
Mole ratio e⁻ : Au = 3 : 1
No. of moles of Au produced = (0.4244 mol) × (1/3) = 0.1415 mol

Molar mass of Au = 197.0 g/mol
Mass of Au produced = (0.1415 mol) × (197.0 g/mol) = 27.9 g

====
OR:
(19.5 C/s) × (35.0 × 60 s) × (1 mol e⁻ / 96485 C) × (1 mol Au / 3 mol e⁻) × (197.0 g Au / 1 mol Au)
= 27.9 g Au

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