You will need:
- Break chalk into small pieces.
- Fill half the glass container with vinegar.
- Add one piece of chalk to the container and observe the changes that take place.
- Record what you see happening.
- Add another piece of chalk to the container. Record what you see happening.
- Continue to add chalk until you do not see any more changes taking place.
Be careful no to rub your eyes when handling vinegar. Wash your hands immediately after finishing this experiment.
When the chalk is added to an acid like vinegar, a chemical reaction occurs. It’s called a neutralization. This occurs when an acid and a base are combined. During the reaction a gas and a neutral solution are formed. The gas produced in this activity is carbon dioxide and can be seen as bubbles in the vinegar. Crushing the chalk before adding it to the vinegar speeds up the reaction. Keep adding more chalk and eventually the bubbles stop forming. This shows that
all the acid in the vinegar has been used up. This reaction occurs in the environment when weak acids in rain react with limestone and other rocks. The result is erosion (the wearing away of rock). It occurs very gradually. Limestone and marble are made of the same material as chalk, and are used for constructing buildings and statues. Rain that is too acidic will “eat away” at these structures very quickly, the same way the vinegar ate away at the chalk.