Question

When electroplating copper on iron key, does displacement reaction ever occur? Explain your answer.

Answer 1

Answer:

Copper roofing is a prominent part of campus architecture. While durable, copper roofing is

very expensive. College architects have attempted to find cost effective alternative roofing

materials. Aluminum or especially polymer coated steel roofing is significantly cheaper than

copper. The characteristic color of aged copper is light green. The light green “patina” on

oxidized copper is primarily a mixture of copper sulfates and oxides. Aluminum and steel

roofing is commercially available with a painted green patina. However, previous college

presidents have rejected the cheaper materials because the painted coatings do not resemble the

aged patina on existing roofs. To make matters worse, newly installed copper roofing rapidly

oxidizes to a dull dark brown, which also does not match the patina of aged copper. The dark

brown patina on recently installed copper is primarily mixed copper sulfide and oxides. The

color of copper oxides depends on the details of the crystal structure of the oxide, which is

determined by the history of exposure of the metal to the atmosphere.

The chemistry department has been asked for advice concerning treatments that produce a light

green patina on copper or other roofing metals, particularly steel. The current college policy is to

replace existing copper roofs with new copper and simply wait the dozen or so years that is

required to produce the characteristic light green patina. In this lab exercise we consider the

possibility of using a cheaper metal that has been electroplated with a thin layer of metallic

copper that is subsequently treated to produce a light green patina. Electroplating is an energy

intensive process. The scientific goal of this experiment is to determine the efficiency of copper

electroplating on nickel coated steel or brass. The esthetic goal is to determine the suitability of

several different commonly used coloring processes. These processes produce a thin layer of

mixed copper salts that precipitate on the surface of the copper metal from aqueous solution.

Electrochemistry: Oxidation/reduction reactions are often studied by running the reactions as

electrochemical cells. For example the reaction, Zn(s) + Cu2+ (aq) → Zn2+ (aq) + Cu (s), can be

separated into two half-reactions that form the basis of the electrodes in an electrochemical cell.

The electrodes in an electrochemical cell are called the cathode and anode:

cathode: Cu2+ (aq) + 2 e– → Cu (s) reduction

anode: Zn (s) → Zn2+ (aq) + 2 e–

oxidation

cell reaction: Zn(s) + Cu2+ (aq) → Zn2+ (aq) + Cu (s)

Explanation:

Answer 2

Explanation:

The positively charged copper ions lose their positive charge on coming in contact with the negatively charged Ion key and from copper atoms.These copper atoms deposit on the iron key to form a thin layer of copper metal all over the surface of iron key.In this way, copper metal in the electrolyte comes out of the