One example of a chemical change is when iron rusts. This happens when iron reacts with oxygen and moisture in the air to form iron oxide, which we see as rust. The original iron is no longer present, and a new substance has been created, showing that a chemical change occurred.
Another example is when vinegar is mixed with baking soda. This combination produces carbon dioxide gas, which creates bubbles and fizzing. The original substances, vinegar and baking soda, change into new substances, including water and sodium acetate, indicating a chemical change has taken place.