Which of the following is an indicator of a chemical change?

• A. Formation of a precipitate
• B. Dissolving sugar in water
• C. Change in state from solid to liquid
• D. Change in size or shape

Answer: (A)

Verified step by step guidance

1. Understand that a chemical change involves the formation of new substances with different properties, while a physical change affects only the form or appearance without creating new substances.
2. Review each option to determine if it represents a chemical or physical change:
3. Dissolving sugar in water is a physical change because the sugar molecules disperse but do not chemically react or form new substances.
4. Change in state from solid to liquid (melting) is a physical change since the substance's phase changes but its chemical identity remains the same.
5. Change in size or shape is a physical change because it alters only the form, not the chemical composition.
6. Formation of a precipitate indicates a chemical change because it involves the creation of a new solid substance from a solution, signaling a chemical reaction.