Physical change is a change in matter that involves the substance going from one physical state to another. The reference to a physical state involves solids, liquids, and gases. When a substance undergoes a physical change it does not lose its original properties when changing from one phase to another.
Examples of Physical changes:
- Ice cream melting involves a change from a solid to a liquid and the substances maintain the properties of water because the molecules never change.
- Hot molten iron is a liquid and when left to cool will from solid steel and can take many forms.
Chemical change is a process where one or more substances are altered into one or more new and different substances. Thus, Chemical change is a chemical reaction involving the rearrangement of atoms. When a chemical change occurs, there is also a change in the energy of the system. A chemical change that gives off heat is called an exothermic reaction. One that absorbs heat is called an endothermic reaction.
Examples of Chemical Changes:
- Boiling an eggs.
- Burning a candle.
- The process of digesting food.
Difference Between Physical Change and Chemical Change
|Meaning||It refers to a change in which the molecules are rearranged but their internal composition remains same.||Chemical Change is a process in which the substance transforms into a new substance, having different chemical composition.|
|Reversibility||t is easily reversible i.e original substance can be recovered.||Chemical change is irreversible i.e. original substance cannot be recovered.|
|Formation of new substance||In rhis, no new substance is formed.||A chemical change is always accompanied by one or more new substance.|
|Involves||Change in physical properties of the substance, i.e. shape, size, color etc.||Change in chemical properties and composition of the substance.|
|Product Formation||No new product is formed.||New product is formed.|
|Energy||Absorption and evolution of energy do not take place.||Absorption and evolution of energy take place, during reaction.|