Question

Composition of matter changes in a ____________ (physical/chemical) change.

Answer 1

Composition of matter changes in a Chemical(physical/chemical) change

Chemical Change:

• It is a permanent change and can not be reversed back.
• Change in the chemical composition of a substance takes place. A new substance is formed.

For example- Conversion of milk to curd, Rusting, etc.

$\underset{\mathrm{Iron}}{\mathrm{Fe}\left(\mathrm{s}\right)}+\underset{\mathrm{Water}}{{\mathrm{xH}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Hydrated}\mathrm{Iron}\mathrm{oxide}\left(\mathrm{Rust}\right)}{{\mathrm{Fe}}_2{\mathrm{O}}_3.{\mathrm{xH}}_2\mathrm{O}\left(\mathrm{s}\right)}$

Physical Change :

• These are temporary changes and can be reversed back.
• No change in the chemical composition of a substance takes place. No new substance is formed.
• For example, the Melting of ice into water.

Hence, the Composition of matter changes in a chemical (physical/chemical) change.