Which of the following is an indicator that a chemical change has occurred during an experiment?

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

Answer: (B)

Verified step by step guidance

1. Understand the difference between physical and chemical changes. A physical change affects the form of a substance but not its chemical composition, while a chemical change results in the formation of one or more new substances with different properties.
2. Analyze each option to determine if it represents a physical or chemical change:
3. 1. Change in size or shape of the substance: This is a physical change because the substance's chemical identity remains the same.
4. 2. Formation of a precipitate: This indicates a chemical change because a new solid substance forms from a solution, showing a new chemical product.
5. 3. Change in the state of matter from solid to liquid: This is a physical change involving a phase change without altering chemical composition.
6. 4. Dissolving of a solid in water: This is generally a physical change where the solid disperses but does not chemically transform.