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

• A. The substance is broken into smaller pieces
• B. A new substance with different properties is formed
• C. The temperature of the substance increases without any other change
• D. The substance changes from solid to liquid

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 or a physical change:
3. Option 1: 'The substance is broken into smaller pieces' describes a physical change because the substance's chemical identity remains the same despite the change in size.
4. Option 2: 'A new substance with different properties is formed' directly describes a chemical change, as new substances with new properties are created.
5. Option 3: 'The temperature of the substance increases without any other change' indicates a physical change (temperature change) without evidence of a new substance forming, and Option 4: 'The substance changes from solid to liquid' is a physical change (phase change) without altering chemical identity.