Question

State the characteristics of physical change and chemical change.

Answer 1

Physical change: A physical change involves the formation of no new substance and there is no change in the chemical composition of the substance undergoing the change.

Characteristics of a physical change:

• It is a temporary change.
• It is a reversible change as most of the time, the substance can be brought back to its original state.
• Only physical properties like hardness, colour, etc. are changed during a physical change.
• Energy is neither consumed nor released as chemical bonds are not involved in the physical change.
• Examples: Conversion of Water $\left({\mathrm{H}}_2\mathrm{O}\right)$ from solid to liquid form, melting of the wax.

Chemical change: A chemical change involves the formation of one or more new substances and there is a change in the chemical composition of the substance undergoing the change.

Characteristics of chemical change:

• It is a permanent change.
• It is an irreversible change mostly as the substance undergoing change can not be brought back to its original state.
• Physical as well as chemical properties of the substance change during a chemical change.
• Energy is either consumed when bonds are broken or released when chemical bonds are formed.
• Examples: Rusting of Iron $\left(\mathrm{Fe}\right)$, Burning of wood.