Re: pinhole Plating zinc onto a penny with sodium hydroxide

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From: Geoff Ruth (gruth@leadershiphigh.org)
Date: Tue Dec 14 2004 - 08:35:43 PST 

Message-Id: <p06110410bde4c6b406e2@[192.168.123.175]>
Date: Tue, 14 Dec 2004 08:35:43 -0800
From: Geoff Ruth <gruth@leadershiphigh.org>
Subject: Re: pinhole Plating zinc onto a penny with sodium hydroxide

Marc --

The attached files are all GIF's of the article.

- Geoff

>Geoff, I would love to see a copy of this article
>thanks
>marc
>
>On Dec 14, 2004, at 7:25 AM, Geoff Ruth wrote:
>
>>Some people at Saturday's Chemapolooza were curious about the
>>reactions when you heat up 6M sodium hydroxide + Zn to plate zinc
>>onto a penny.
>>
>>First, the "zincate" ion is created: [Zn(OH)4]-2
>>
>>This ion is then reduced to zinc metal at the surface of the penny.
>>The reducing agent is incorrectly reported on many web sites as
>>being copper or water, which doesn't make sense since pH is
>>constant throughout and since there is no color change (with Cu2+
>>being formed).
>>
>>According to the following interesting article in J Chemical
>>Education, the oxidation of zinc (at the Zn metal) itself provides
>>the e- needed to reduce the zinc back at the penny:
>>
>>Volume 72 Issue 5 / May 1995
>>Szczepankiewicz, Steven H.; Bieron, Joseph F.; Koz
>>The "Golden Penny" Demonstration: An Explanation of the Old
>>Experiment and the Rational Design of the New and Simpler
>>Demonstration, pp. 386-388
>>
>>
>>If anyone wants, I can e-mail or mail the actual JCE article.
>>
>>- Geoff Ruth

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