Question

a physical change is when the chemical composition (such as h₂o) does not change, only the form. which of the following are physical changes? click all that apply! boiling water chopping wood breaking glass burning food

Explanation:

• Boiling water: Only changes from liquid to gas (steam), chemical composition ($H_2O$) remains same.
• Chopping wood: Changes physical form (size, shape) of wood, no new chemical substances formed.
• Breaking glass: Alters physical state (pieces instead of whole), chemical nature of glass (silica - based compound) unchanged.
• Burning food: Involves chemical reactions (e.g., combustion of organic compounds in food), new substances (like carbon dioxide, water vapor etc.) are formed.

Answer:

Boiling water, Chopping wood, Breaking glass.