When a copper coin changes color from copper to silver after a chemical reaction, is this an example of a physical change or a chemical change?

• A. Physical change
• B. Both physical and chemical change
• C. Chemical change
• D. Neither physical nor chemical change

Answer: (C)

Verified step by step guidance

1. Understand the difference between physical and chemical changes: A physical change affects the form or appearance of a substance without altering its chemical composition, while a chemical change results in the formation of one or more new substances with different chemical properties.
2. Consider the example of the copper coin changing color from copper (reddish-brown) to silver: This color change indicates that the surface of the coin has undergone a chemical reaction, likely forming a new compound or layer (such as copper oxide or another compound).
3. Recognize that a color change due to a chemical reaction is a common indicator of a chemical change because it reflects a change in the chemical composition of the material.
4. Conclude that since the copper coin's color change is due to a chemical reaction producing new substances, this is an example of a chemical change rather than a physical change.
5. Therefore, the correct classification for the copper coin changing color after a chemical reaction is a chemical change.