Which change is classified as a chemical change?

• A. Rusting of iron
• B. Boiling of water
• C. Melting of ice
• D. Dissolving sugar in water

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. Boiling of water involves changing water from liquid to gas, which is a physical change because the chemical formula H\_2O remains the same.
4. Melting of ice is the transition from solid to liquid water, also a physical change with no alteration in chemical composition.
5. Dissolving sugar in water is a physical change where sugar molecules disperse in water but do not chemically react or change their structure.
6. Rusting of iron is a chemical change because iron reacts with oxygen and moisture in the environment to form a new substance, iron oxide, which has different chemical properties from elemental iron.