Letter 17976

Cleansing pennies...INTERNET IS WRONG I AM RIGHT! [Florida] 

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Ok, so I did this science experiment on which liquid cleanses pennies most efficiently, and when I did my research, all of the places I went to said that acids cleanse the pennies better, but when I did the experiment, glass-cleaner with ammonia worked the best, and ammonia is a BASE!! So did my experiment go wrong, or am I right and everyone else is wrong? (I wish!)

Melissa
- Port Orange, FL

Copper, especially copper salts, react with ammonia solution to form a very deep blue cuprammonium salt complex. Hence I am not surprised you got a reaction; however, I am surprised it was faster than acids. I suppose you learn something every day and you have now seen the wonders of science and the importance of not believing everything you are told. Good luck and keep on experimenting.

Trevor Crichton R&D practical scientist - UK

I tried ammonia to see for myself, and I found it completely ineffective, Melissa. But part of the problem with this question is what do we mean by 'cleansing'? Most students mean 'removing tarnish', the brown color on pennies. But if you mean 'removing dirt, oil & grease, and fingerprints,, then you are right. Ammonia is a good cleanser, it's just not a good copper tarnish remover.

 
Ted Mooney, P.E.
finishing.com Inc. - Brick, NJ

I'm doing a project on cleaning pennies. I know for a fact that vinegar and solt can clean pennies.

Shewnsey
- Chicago, IL, United States

I recently conducted an experiment and found ammonia to clean pennies much more effective than vinegar. Can anyone explain the chemical reaction of copeer oxide and ammonia? (CuO + NH3, I think?) and why a weak base was more effective? I'm puzzled.

Beau O.
- Austin, TX, USA