Which of the following is an example of a chemical change?

• A. Rusting of iron (Fe)
• B. Melting of ice (H2O)
• C. Breaking a glass
• 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. 1. Rusting of iron (Fe): This involves iron reacting with oxygen and water to form iron oxide, a new substance, indicating a chemical change.
4. 2. Melting of ice (H2O): This is a phase change from solid to liquid water, with no change in chemical composition, so it is a physical change.
5. 3. Breaking a glass: This changes the shape and size of the glass but does not alter its chemical composition, so it is a physical change.
6. 4. Dissolving sugar in water: The sugar molecules disperse in water but remain chemically unchanged, so this is a physical change.