Which of the following is NOT an example of a chemical change?

• A. Melting of ice
• B. Digestion of food
• C. Burning of wood
• D. Rusting of iron

Answer: (A)

Verified step by step guidance

1. Understand the difference between physical and chemical changes. A physical change affects the form of a substance but not its chemical composition, while a chemical change results in the formation of one or more new substances with different properties.
2. Analyze each option to determine if it involves a change in chemical composition:
3. Melting of ice: This is a phase change from solid to liquid water, which does not alter the chemical identity of H\_2O, so it is a physical change.
4. Digestion of food: This involves breaking down complex molecules into simpler ones through chemical reactions, indicating a chemical change.
5. Burning of wood: Combustion is a chemical reaction producing new substances like carbon dioxide and ash, so this is a chemical change.
6. Rusting of iron: This is an oxidation reaction where iron reacts with oxygen to form iron oxide, a new substance, so it is a chemical change.