When drops of one liquid are added to another liquid, a purple powder forms where the liquids meet. Did the two liquids enter a chemical reaction?
A. No. Substances entering or leaving a solution are examples of physical changes, not chemical changes.
B. Yes. A change in state without heating or cooling is a common sign of a chemical reaction.
C. No. A chemical reaction usually forms gases, not solids.
D. Yes. The mixing of two liquids is a common sign of a chemical reaction.