Examine the pennies, notice the grimy layer on them. Try to scrub this off with water… you won’t be able to get it shiny! Pour ½ cup of vinegar into the bowl and add 2 teaspoons of salt to it. Hold a penny halfway into the liquid for about 15 seconds and remove it.
Why is cleaning pennies important?
The chemical reaction that dissolves the copper oxide on your pennies is an ongoing process. Leaving your pennies in the cleaning solution longer gives the reaction more time to continue, and gives you shinier pennies!
Can you soak pennies in vinegar?
When you put your dirty pennies in the vinegar and salt, the copper oxide and some of the copper dissolve in the water. As you found out when you cleaned your pennies, your mixture of salt and vinegar is really good at dissolving metals and metal oxides.
How does vinegar and salt work to clean pennies?
It takes a chemical reaction! The acetic acid in the vinegar reacts with the copper oxide and dissolves it. We sprinkled salt over the pennies, and then used a dropper to coat them with vinegar.
What happens to pennies when you wash them?
After quite some time, or after exposure to an acid, pennies will form copper sulfate, carbonate, and chloride salts, which gives pennies a green color. Washing the pennies in a vinegar and salt solution removes the patina from the pennies, exposing the brighter copper underneath once more.
How do you get copper oxide out of pennies?
The acetic acid in the vinegar reacts with the copper oxide and dissolves it. We sprinkled salt over the pennies, and then used a dropper to coat them with vinegar. We rubbed the pennies a little with the salt, and they were shiny again! You can also dissolve the salt in the vinegar and then dip the pennies in the solution.
What kind of acid do you use to clean a penny?
The acids (usually vinegar – acetic acid) break the copper oxide free from the penny. As we have seen experimentally, acid alone does not clean as well as acid and salt.
