Which term describes a modification of matter such as freezing or boiling that does not involve changing the chemical identity?

Which term describes a modification of matter such as freezing or boiling that does not involve changing the chemical identity?

• A. Physical Change
• B. Fire
• C. Chemical Reaction
• D. Exothermic Reaction

Answer: (A)

A physical change is a modification of matter where the chemical identity stays the same. When water freezes into ice or boils into steam, the molecules remain H2O; only their arrangement and energy state change. No new substances are formed, and these changes are often reversible by reversing the conditions (melting ice, condensing steam). In contrast, a fire, chemical reaction, or exothermic reaction involves making or breaking chemical bonds to form new substances, often with energy changes. That’s why those options describe chemical changes, not physical ones.

A physical change is a modification of matter where the chemical identity stays the same. When water freezes into ice or boils into steam, the molecules remain H2O; only their arrangement and energy state change. No new substances are formed, and these changes are often reversible by reversing the conditions (melting ice, condensing steam).

In contrast, a fire, chemical reaction, or exothermic reaction involves making or breaking chemical bonds to form new substances, often with energy changes. That’s why those options describe chemical changes, not physical ones.