What are the differences between chemical change and physical change?

Question

Accepted Answer

There are several notable differences between chemical change and physical change.

Basis of Differentiation
Physical Change
Chemical Change

Type of change 
A substance undergoes a change only in its physical properties such as size, shape, color or volume but its molecular composition remains the same. 
The molecular composition of the substance undergoes complete change resulting in the formation of a new substance having a different chemical composition.

Nature of the change
The change is temporary and reversible.  
The change is permanent and irreversible.

Molecular changes
There is no change in molecular composition.
The molecular composition is completely changed.

Recovery of original matter
The original matter can be easily recovered. 
The original matter cannot be recovered.

Impact
It impacts the physical properties like shape, size, color and more
chemical properties as well as the physical properties.

Energy absorption/ evolution 
The change occurs with very little to no absorption or evolution of energy.  
Absorption and evolution of energy occur during the change.

Energy generation
No energy is generated during the change. 
Energy is usually produced in the form of light, heat or sound.

Formation of new product
No new product is formed after the change despite the change in appearance. 
One or more new products are always formed after the change.

Example
Freezing water, cutting wood, mixing sand and water, melting ice cubes, shredding paper, and slicing onions are physical changes
Baking cookies and cakes, burning wood, rust formation, digesting food, and making caramel from sugar, cake are chemical changes

Basis of Differentiation	Physical Change	Chemical Change
Type of change	A substance undergoes a change only in its physical properties such as size, shape, color or volume but its molecular composition remains the same.	The molecular composition of the substance undergoes complete change resulting in the formation of a new substance having a different chemical composition.
Nature of the change	The change is temporary and reversible.	The change is permanent and irreversible.
Molecular changes	There is no change in molecular composition.	The molecular composition is completely changed.
Recovery of original matter	The original matter can be easily recovered.	The original matter cannot be recovered.
Impact	It impacts the physical properties like shape, size, color and more	chemical properties as well as the physical properties.
Energy absorption/ evolution	The change occurs with very little to no absorption or evolution of energy.	Absorption and evolution of energy occur during the change.
Energy generation	No energy is generated during the change.	Energy is usually produced in the form of light, heat or sound.
Formation of new product	No new product is formed after the change despite the change in appearance.	One or more new products are always formed after the change.
Example	Freezing water, cutting wood, mixing sand and water, melting ice cubes, shredding paper, and slicing onions are physical changes	Baking cookies and cakes, burning wood, rust formation, digesting food, and making caramel from sugar, cake are chemical changes

What are the differences between chemical change and physical change?

Posted April 25, 2022