Classify the following as physical or chemical changes:
a. Water condenses on the surface of a cold glass.
b. Rust forms on the surface of an iron nail.
c. Black smoke rises when a candle is burned.
d. A drop of alcohol evaporates on a table.

• A. a. Physical change; b. Physical change; c. Chemical change; d. Chemical change
• B. a. Physical change; b. Chemical change; c. Chemical change; d. Physical change
• C. a. Chemical change; b. Chemical change; c. Physical change; d. Physical change
• D. a. Chemical change; b. Physical change; c. Physical change; d. Chemical change

Answer: (B)