Which of the following best explains the difference between physical properties and chemical properties?

• A. Physical properties are only observed during chemical reactions, while chemical properties are observed during physical changes.
• B. Physical properties always involve a change in composition, while chemical properties do not.
• C. Physical properties can be observed or measured without changing the substance's chemical identity, while chemical properties describe the substance's ability to undergo chemical changes.
• D. Physical properties are unique to each compound, while chemical properties are the same for all substances.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the definition of physical properties. Physical properties are characteristics of a substance that can be observed or measured without changing the substance's chemical identity. Examples include color, melting point, boiling point, density, and state of matter.
2. Step 2: Understand the definition of chemical properties. Chemical properties describe a substance's ability to undergo chemical changes or reactions that transform it into different substances. Examples include flammability, reactivity with acids, and oxidation states.
3. Step 3: Compare the two types of properties. Physical properties can be observed without altering the substance's composition, while chemical properties involve the potential for the substance to change into something new through a chemical reaction.
4. Step 4: Evaluate the given options based on these definitions. Identify which statement correctly distinguishes physical properties from chemical properties by focusing on whether the substance's chemical identity changes during observation or measurement.
5. Step 5: Conclude that the best explanation is: 'Physical properties can be observed or measured without changing the substance's chemical identity, while chemical properties describe the substance's ability to undergo chemical changes.' This accurately captures the fundamental difference between the two.