Question

List 3 points of difference between chemical and physical change

Answer 1

Following are the difference between a physical change and a chemical changes:-

Explanation:

• In physical change the molecules are rearranged and there is no change in the composition of the molecules. Whereas in chemical change the composition of the molecules changes.
• Physical changes are easily reversible hence are temporary changes. But chemical changes are irreversible because of the change in composition and hence are permanent changes.
• In physical changes only the molecules are rearranged and no new substances are formed. But in chemical changes the composition of molecules changes that's why new substances are formed.
• Examples of physical changes are melting of water, melting of wax, etc. While examples of chemical changes can be burning of coal, rusting, etc.

Answer 2

Difference between physical and chemical change

Explanation:

Physical Change:

1. The molecules are rearranged while their actual composition remains same.
2. Eg: Freezing of water, melting of wax.
3. No new substance is formed as a result.
4. No energy is produced.
5. Affects shape and size.

Chemical Change:

1. Molecule composition completely changes and a new substance is formed.
2. Eg: Digestion of food, burning of coal.
3. Results in one or more new substances.
4. Energy is produced.
5. Affects both physical and chemical properties of the substance.