Which of the following is an example that includes evidence of a chemical change?

• A. Salt dissolves in water.
• B. A piece of iron rusts when left outside in the rain.
• C. Water freezes to form ice cubes.
• D. A glass of water evaporates over time.

Answer: (B)

Verified step by step guidance

1. Understand the definition of a chemical change: it involves the formation of one or more new substances with different properties from the original substances, often accompanied by energy changes, color changes, gas production, or formation of a precipitate.
2. Analyze each option to determine if a new substance is formed:
3. - Salt dissolving in water is a physical change because the salt dissociates into ions but no new substance is created.
4. - Water freezing to form ice is a physical change because it is a change in state, not composition.
5. - A glass of water evaporating is a physical change because water changes from liquid to gas without altering its chemical identity.
6. - A piece of iron rusting involves iron reacting with oxygen and water to form iron oxide, a new substance, which is evidence of a chemical change.