Which statement best describes the difference between a physical change and a chemical change?

• A. A physical change alters the appearance or state of a substance without changing its chemical composition, while a chemical change results in the formation of new substances with different chemical properties.
• B. A physical change involves breaking chemical bonds, while a chemical change does not.
• C. A physical change always produces heat, while a chemical change does not.
• D. A physical change can only occur at high temperatures, while a chemical change can occur at any temperature.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the definitions of physical and chemical changes. A physical change affects the form or appearance of a substance but does not alter its chemical identity.
2. Step 2: Recognize that a chemical change involves making or breaking chemical bonds, resulting in new substances with different chemical properties.
3. Step 3: Compare the options given by checking if they correctly describe these fundamental differences between physical and chemical changes.
4. Step 4: Eliminate incorrect statements, such as those claiming physical changes always produce heat or only occur at high temperatures, since these are not universally true.
5. Step 5: Conclude that the best description is the one stating that a physical change alters appearance or state without changing chemical composition, while a chemical change forms new substances with different chemical properties.