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

• A. Breaking a glass
• B. Dissolving sugar in water
• C. Rusting of iron (Fe forming Fe_2O_3)
• D. Melting of ice (H_2O(s) to H_2O(l))

Answer: (C)

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 chemical properties.
2. Analyze each option to determine if it involves a change in chemical composition:
3. Breaking a glass is a physical change because the glass is only broken into smaller pieces, but its chemical composition remains the same.
4. Dissolving sugar in water is generally a physical change because the sugar molecules disperse in water but do not chemically react or change their structure.
5. Rusting of iron involves iron reacting with oxygen to form iron oxide (Fe_2O_3), which is a new substance, indicating a chemical change.
6. Melting of ice is a physical change because water changes from solid to liquid state without altering its chemical formula (H_2O).