Which of the following is a reliable indicator that a chemical change has occurred?

• A. The temperature of the substance increases due to heating, but no new substance is produced.
• B. A new substance is formed with different properties from the original substances.
• C. The material is broken into smaller pieces but remains chemically the same.
• D. The substance changes from a solid to a liquid without altering its composition.

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 indicates a chemical change:
3. Option 1: Temperature increase due to heating without producing a new substance is a physical change, not chemical.
4. Option 2: Formation of a new substance with different properties clearly indicates a chemical change because the composition has changed.
5. Option 3 and 4: Breaking material into smaller pieces or changing state (solid to liquid) without altering composition are physical changes, not chemical.