Review of Physical Changes Physical changes are alterations in the form or structure of a substance without changing its chemical composition. These cha...
Review of Physical Changes
Physical changes are alterations in the form or structure of a substance without changing its chemical composition. These changes can be observed through physical properties, such as temperature, density, color, and texture.
Examples:
Melting: Solid to liquid phase (e.g., ice melting)
Freezing: Liquid to solid phase (e.g., water freezing)
Swelling: An object expanding when exposed to water
Crushing: An object becoming smaller when compressed
Dilation: An object expanding when heated
Chemical changes involve a change in the chemical composition of a substance, resulting in the formation of new chemical bonds. These changes can be detected through chemical properties, such as pH, solubility, and chemical reactions.
Examples:
Chemical reaction: Acids and bases reacting to form salt and water
Oxidation: Loss of electrons by a substance
Reduction: Gain of electrons by a substance
Key Differences Between Physical and Chemical Changes:
| Feature | Physical Change | Chemical Change |
|---|---|---|
| Chemical composition | Involves a change in the chemical formula | Does not involve a change in the chemical formula |
| Appearance | Can be observed through physical properties | Can be observed through chemical properties |
| Examples | Melting ice, freezing water, and changing color | Chemical reactions like burning, rusting, and corrosion |