Clean pennies with Vinegar and Salt

Uploaded by NurdRage on 09.09.2012

Greetings fellow nerds.
Once again time for some simple science.
In this video we’re going to do some kitchen chemistry of cleaning pennies.
Here are some pennies and some household vinegar.
As you can see these pennies are very tarnished and dull.
Now vinegar by itself doesn’t do very much to clean pennies.
Almost nothing.
So we add salt to the vinegar.
Add as much salt as you can with lots of mixing to make a saturated solution.
Once again we get a tarnished penny and dip it in.
And there we go.
The combination of acetic acid and sodium chloride has etched off the copper oxides and sulfides to give us the original copper underneath.
Be sure to wash your pennies with water after cleaning them
or the acid will continue to etch the copper and produce a green copper acetate and chloride coat.
Now a fun trick to do with younger kids is to clean pennies with your fingers.
First show the penny and dip your fingers into the solution.
Then start rubbing the penny with it and right before their eyes the penny will almost magically start shining.
Be sure to wash your hands of the acid after this since it can be somewhat irritating to the skin.
Anyway, there you have it. Simple kitchen chemistry of cleaning pennies.
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