Which of the following is one way a chemical property can be witnessed?

• A. Determining the color of copper metal
• B. Observing iron rusting when exposed to oxygen
• C. Recording the density of water
• D. Measuring the melting point of ice

Answer: (B)

Verified step by step guidance

1. Understand the difference between physical and chemical properties: Physical properties can be observed or measured without changing the substance's identity, while chemical properties describe a substance's ability to undergo changes that transform it into different substances.
2. Analyze each option to determine if it involves a chemical change or just a physical observation:
3. Determining the color of copper metal is a physical property because it does not involve changing copper into a new substance.
4. Observing iron rusting when exposed to oxygen is a chemical property because rusting involves iron reacting with oxygen to form a new compound (iron oxide), which is a chemical change.
5. Recording the density of water and measuring the melting point of ice are physical properties because they involve measuring characteristics without changing the chemical identity of water.