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

• A. A sample is crushed into a powder
• B. A solid melts into a liquid
• C. A new substance with different properties is formed
• D. A substance is dissolved in water

Answer: (C)

Verified step by step guidance

1. Understand the difference between physical and chemical changes: Physical changes affect the form of a substance but not its chemical composition, while chemical changes result in the formation of new substances with different properties.
2. Analyze each option to determine if it represents a physical or chemical change:
3. - Crushing a sample into a powder changes its shape and size but not its chemical identity, so it is a physical change.
4. - Melting a solid into a liquid changes its state of matter but not its chemical composition, so it is a physical change.
5. - Formation of a new substance with different properties indicates a chemical change because the original substances have undergone a chemical reaction to produce something new.