Which are clues a chemical change is happening?
1. Color change: A noticeable change in the color of a substance often indicates that a chemical reaction is taking place.
2. Formation of gas: The production of gas bubbles or a change in the volume of gas in a reaction can be a sign of a chemical change.
3. Temperature change: A noticeable change in temperature, such as heat being given off or absorbed, can indicate a chemical reaction is occurring.
4. Formation of a precipitate: The formation of a solid substance (precipitate) from two other liquids can be a clue that a chemical reaction is happening.
5. Odor change: A change in the smell of a substance can also be an indication that a chemical reaction is taking place.