Letter 29019

Corrode pennies [California]  

++++

I'm doing a Science Fair project on the question...In what liquid does a penny corrode faster in? And for my hypothesis I have been looking at the ingredients to all my liquids(Coke, Dr.Pepper, Cranberry Juice Water Orange Juice and chlorine water vinegarw/ water winegar)...but I dont no what half the stuff is!! And what would make the pwnny corrode!! Please help!!

Lizzy
student - Santee, California, U.S

Lizzy,

I hope you have done some homework on what you do not know by now. Vinegar is mainly a dilute acetic acid. Chlorine wate would normally be bleach is some water. In absolutes, chlorine water would be hydrochloric acid, which you do not want to mess around with! Orange juice will have mainly citric acid, but will have trace amounts of other organic acids. I do not know off the top of my head what Cranberry juice would have for a main acid, but would probably have some ascorbic acid which is vitamin C. Read the can for coke and DR Pepper. The main acid will be phosphoric, but will probably have one or two others in lesser amounts.

Copper dissolves in strong acids, but you do not have any strong acids, so you will get a slow conversion of the copper to copper ions which will react with some of the assorted anions to give you a nasty looking corrosion product. Note that new pennies have a zinc core. This is amphoteric, meaning it will dissolve in an acid or a base.Weak acids will do this, so look for the center of the copper sandwich to form white zinc corrosion products. Cut a penny in half to expose more of the zinc and compare the corrosion rates. You can do the rest of your homework with a dictionary and google. If all else fails, check out a chemistry book for the reactions.

James Watts
- FL

I want to answer or follow-up on this subject publicly (in non-commercial fashion).

 

My company is a supporting advertiser at finishing.com and we want the contact information to reach the inquirer privately.

 

I want to post a new question or inquiry of my own on a different subject.