Chemistry · Electrochemistry · Electroplating

Electroplating zinc with copper

A clean zinc plate (cathode) and a copper plate (anode) are dipped in copper(II) sulfate solution and connected to a battery. When current flows, the zinc plate gains a copper coating while the copper plate dissolves. Constant current and time → predictable mass of copper deposited.

t = 0 s · I = 0.50 A

Charge passed

0 C

Moles of e⁻

0.00 × 10⁻³

Mass of Cu deposited

0.000 g

Half-equations

at the cathode (zinc plate)
Cu²⁺(aq) + 2e⁻ → Cu(s)
Copper deposits as a layer on the zinc.
at the anode (copper plate)
Cu(s) → Cu²⁺(aq) + 2e⁻
Copper dissolves to replenish [Cu²⁺] in solution.

Exam-style questions

1. Which electrode must the OBJECT TO BE PLATED be connected to?

2. Why is the OTHER electrode made of PURE COPPER?

3. Half-equation at the CATHODE (zinc plate):

4. Using F = 96500 C mol⁻¹ and Ar(Cu) = 63.5, what mass of Cu would 0.50 A for 1200 s deposit?