CHEMICAL REACTION

This is a fun and easy activity to do that involves
a chemical reaction. Your students will clean for
you, and they won't even complain!

MATERIALS

Tarnished pennies
Vinegar
Salt
Small bowl or jar

SAFETY PRECAUTION

Appropriate safety precautions to protect eyes while working with
vinegar should be used.

PROCEDURE

1. Place about ¼ cup (about 60 ml) vinegar into small bowl or jar.
2. Add about 2T (30ml) salt. Stir.
3. Add several tarnished pennies to the bowl. Leave one tarnished
penny aside to use for comparison.
4. Wait a few minutes. Ask, “What do you think will happen? Why?”
5. After a few minutes, remove the pennies.
6. Experiment with different amounts of vinegar and salt. Which
works best?

EXPLANATION

A chemical reaction occurred. Salt is sodium chloride. The chloride
from the salt combined with the hydrogen from the vinegar to form
hydrochloric acid, which cleaned the pennies.
You can use this formula to clean any copper or bronze object in your
home, or use especially formulated brass cleaner.