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

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

Answer: (D)

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 changing its chemical composition, while a chemical change results in the formation of one or more new substances with different chemical properties.
2. Analyze the observation: The copper coin changes color from copper (reddish-brown) to silver, indicating a change in its surface properties.
3. Consider what causes the color change: The color change is due to a chemical reaction between the copper metal and substances in the solution, forming new compounds such as copper salts or oxides on the coin's surface.
4. Recognize that the formation of new substances (compounds) on the coin's surface is evidence of a chemical change, not just a physical change like melting or bending.
5. Conclude that since the copper coin undergoes a chemical reaction resulting in new substances and a color change, this is an example of a chemical change.