Which of the following lists includes five common signs that a chemical change has occurred?

• A. Melting, boiling, dissolving, freezing, and condensation
• B. Color change, formation of a precipitate, gas production, temperature change, and change in odor
• C. Evaporation, sublimation, magnetization, crystallization, and expansion
• D. Size change, shape change, phase change, mixing, and filtering

Answer: (B)

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. Identify common signs of chemical changes, which typically include: color change, formation of a precipitate (solid), gas production (bubbling or fizzing), temperature change (exothermic or endothermic reactions), and change in odor.
3. Review the given options and classify each listed process as either a physical or chemical change. For example, melting, boiling, freezing, and condensation are physical changes because they involve phase changes without altering chemical identity.
4. Recognize that processes like evaporation, sublimation, magnetization, crystallization, expansion, size change, shape change, mixing, and filtering are also physical changes, as they do not produce new substances.
5. Conclude that the list containing color change, formation of a precipitate, gas production, temperature change, and change in odor correctly represents common signs of a chemical change.