Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: Shibbelina on 22/04/2006 19:12:27
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In science class we did an experiment where we put a penny in zinc dust and NaOH and it turned silver. After we washed off the zinc mixture, we put the penny in a flame and it turned gold. What caused the penny to change from copper to silver to gold [8D]
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The penny doesn't turn from copper to silver to gold. It simply obtains a layer of chemicals that are coloured so. In fact using the words silver and gold for colour description in science is usually avoided due to these misunderstandings.
The reason to the colour changes is that when the zinc is in the boiling sodium hydroxide solution, it becomes zincate ions ( [Zn(OH)4]-2 ). This is then reduced and forms a layer of zinc on the outside of the coin. Zinc has the pale grey colour that makes it look silvery. When heated, the zinc on the penny and the copper form brass, a yellow alloy. This causes the penny to look gold in colour.
I think that answers your question :)
"Knowledge has to be improved, challenged, and increased constantly, or it vanishes." Peter F. Drucker
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Thanks [:D] Too bad it's not real gold, that would be awesome!!
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Is that how chrome plating is done except with chromium??
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Yeah. it would be an alchemist's dream come true.
b.s
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The first US penny was minted in 1787; it was pure copper and was designed by Benjamin Franklin. The first Lincoln penny was issued in 1909, the 100th anniversary of Lincoln's birth. This was the first US coin to picture a President; it replaced the "Indian Head" penny. In 1943, the Lincoln penny was made of steel (with a zinc coating) because copper was needed for military use in World War II
"Lo" Loretta
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I forgot to add you can go to a website and see the composition and get a clearer understanding of it with the breakdown of the chemicals and find out why they used it or go to the us mint site and they will have even more about the history of it...I took my kids to one to see the process of how money is made and wow! I never saw so many pennies in my life and it was an interesting tour but my kids learned quite a bit...now if they will learn about the value of money??? Besides how valuable it is to spend it!
"Lo" Loretta
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wow
Science does not know its debt to imagination
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So true...forever am I indebted to it with mine...okay, it is a bit warped, I would like to blame it on something like Global Warming, but afraid the ozone layer of my brain is gone...too little sleep and not enough time.
"Lo" Loretta
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Hey Maz!
I have a question for you...Now don't hurt me to bad and explain in the simpliest terms possible as I am not the brightest star in the universe, you know? I was wondering if you know much about coins such as the series of the US quarters? How many of them have been issued out? How many of the series is left? How many per year is issued of the series? How long has this series been going on? I would like to know this as I heard something on TV in a documentary and thought you might have some valuable insight on it? Also, maybe you could tell me what a quarter is made out of and if a dime is made out of the same material? If you know any of this information...let us know...I don't know how to work my vcr or i could've recoreded it
"Lo" Loretta
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I'm far more interested in the alchemy again lol. Any ideas about how to manufacture or procure gold or platinum. There has to be some way around it, however much it would cost.
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Tanian,
I know there is a study being done under the ocean where seaweed maybe used to filter gold....and other things, but supposedly they can pull gold from underneath the ocean using something like this...hehe, okay maybe not enough gold to procure...
"Lo" Loretta
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tanian,
The only way to make gold is in a nuclear reactor. Otherwise you just have to be lucky and find a deposit of the metal somewhere.
"His mind is the ultimate weapon!"-MacGyver television series