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

• A. A chemical change results in the formation of new substances with different chemical properties, while a physical change does not alter the chemical composition of a substance.
• B. A chemical change can be easily reversed, but a physical change cannot.
• C. A physical change always involves a change in color, while a chemical change does not.
• D. A physical change produces energy, whereas a chemical change does not.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the definitions of chemical and physical changes. A chemical change involves a transformation that produces one or more new substances with different chemical properties and compositions.
2. Step 2: Recognize that a physical change affects the form or appearance of a substance but does not change its chemical identity or composition.
3. Step 3: Analyze the options given by comparing them to these definitions. For example, consider whether the change results in new substances or just a change in state or shape.
4. Step 4: Evaluate the reversibility of changes. Physical changes are often reversible (like melting and freezing), while chemical changes usually are not easily reversed because new substances are formed.
5. Step 5: Conclude that the best description is the one stating that a chemical change results in new substances with different chemical properties, whereas a physical change does not alter the chemical composition.