Question

4. State four differences between a physical
change and chemical change.​

Answer 1

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

Answer:

PHYSICAL CHANGES

- The chemical composition of a substance does not change.

- Change is only in the state of matter and not in the chemical identity.

-Examples include- Vaporising of water and dissolution of sugar in water.

- Most changes are reversible.

- No new substances are formed. For example,

Ice → Water → Steam

 CHEMICAL CHANGES

- The chemical composition of a substance changes.

- Change is in chemical identity, but may or may not be in the state of matter.

- Examples include- Rusting of Iron, cooking of food etc.

- Most changes are irreversible.

- New substances are formed.For example,

methane → carbon dioxide and water