Which of the following best describes the difference between a physical property and a chemical property?

• A. A physical property is unique to each element, while a chemical property is the same for all substances.
• B. A physical property always involves a change in composition, while a chemical property does not.
• C. A physical property is only observed during chemical reactions, while a chemical property is observed during phase changes.
• D. A physical property can be observed without changing the substance's chemical identity, while a chemical property describes the substance's ability to undergo a specific chemical change.

Answer: (D)

Verified step by step guidance

1. Understand that a physical property is a characteristic 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 phase (solid, liquid, gas).
2. Recognize that a chemical property describes a substance's ability to undergo a chemical change or reaction, which results in the formation of one or more new substances with different compositions and properties. Examples include flammability, reactivity with acids, and oxidation states.
3. Compare the options given by identifying which statement correctly distinguishes between physical and chemical properties based on whether the substance's chemical identity changes during observation.
4. Eliminate options that incorrectly describe physical properties as involving changes in composition or being unique to elements, or that confuse when these properties are observed (e.g., during phase changes or chemical reactions).
5. Conclude that the best description is: 'A physical property can be observed without changing the substance's chemical identity, while a chemical property describes the substance's ability to undergo a specific chemical change.'