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Topic: Chemistry of Gramophone Records  (Read 4006 times)

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Chemistry of Gramophone Records
« on: January 04, 2005, 08:49:30 PM »
What i have researched is:

The process of elctroplating is used in the making of gramophone records. One surface of a plastic record on which the sound is recorded is coated with silver and then electroplated with nickel sulphate as the electrolyte. The resulting metal layer is then removed from the plastic record and used to make copies of the original record.
The silver is produced by allowing a solution of silver nitrate to react with another compound, methanal on the surface of the record.

My questions are:

What is the purpose of coating the plastic record with metal (silver) before the electroplating is done?

What is the equation that represents the conversion of silver ions into silver metal.

What name would be used to describe the property of methanal that caused the reaction to occur?

Considering the diagram used for electroplating what is at the anode and cathode and the reaction occuring at the anode?

And what effect would the electroplating have on the concentration of the electrolyte. What is the reasoning for the answer.

Offline Donaldson Tan

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Re:Chemistry of Gramophone Records
« Reply #1 on: January 05, 2005, 06:22:05 PM »
1. why coat metal?
plastic dont conduct electricity

the equation?
Ag+ + e => Ag

reaction with methanal? oxidation. (think: silver mirror test)
"Say you're in a [chemical] plant and there's a snake on the floor. What are you going to do? Call a consultant? Get a meeting together to talk about which color is the snake? Employees should do one thing: walk over there and you step on the friggin� snake." - Jean-Pierre Garnier, CEO of Glaxosmithkline, June 2006

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