Which term describes a change in a substance that does not involve a change in the identity of the substance?

• A. Chemical change
• B. Energy change
• C. Physical change
• D. Nuclear change

Answer: (C)

Physical change means the substance changes form or state without changing its chemical identity. The molecules stay the same, so you still have the same substance at the end—just in a different form or amount. Examples include ice melting to water, water boiling to steam, or a metal being bent. Energy can be involved (heating or cooling), but no new substances are created. In contrast, a chemical change creates new substances with different properties (like rust forming from iron and oxygen). Nuclear changes alter the atomic nucleus. So the term that fits is physical change.