Final answer:
The mixing of two clear liquids resulting in a white powder and a clear colorless liquid indicates a chemical reaction, specifically a precipitation reaction.
Step-by-step explanation:
When two clear liquids are mixed and result in a white powder suspended in a clear colorless liquid, this is an indication of a chemical reaction known as precipitation. The formation of the white powder, which is the precipitate, signifies that a new substance has been formed due to the reaction between the two liquids. Unlike a physical change, such as mixing a green and a colorless liquid to produce a pale green solution where no new substances are formed, the presence of a precipitate clearly indicates a chemical change has occurred.