Question

How do we know if it’s a physical or chemical change?

Answer 1

$\bf\large\underline\blue{Answer:-}$

A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity. Examples of chemical changes are burning, cooking, rusting, and rotting. Examples of physical changes are boiling, melting, freezing, and shredding.

Answer 2

In physical changes the change is

• temporary
• reversible
• no new substances are formed
• no change in properties and composition of substances
• no or little energy is evolved or absorbed

Tn chemical changes the change is

• permanent
• irreversible
• new substances with different compositions and properties are produced
• energy either evolved or absorbed.