Question

difference between physical and chemical changes any 4 points​

Answer 1

Answer:

1

Explanation

In a physical change, the molecules are rearranged while their actual composition remains same.

In a chemical change, the molecular composition of a substance completely changes and a new substance is formed.

2

Example

Some example of physical change are freezing of water, melting of wax, boiling of water, etc.

A few examples of chemical change are digestion of food, burning of coal, rusting, etc.

3

Reversibility

Physical change is easily reversible i.e original substance can be recovered.

Chemical change is irreversible i.e. original substance cannot be recovered.

4

Formation of new substance

In physical change, no new substance is formed.

A chemical change is always accompanied by one or more new substance(s).

5

Type of Change

Physical change is a temporary change.

Chemical change is a permanent change.

6

Energy Production

In a physical change, no energy is produced.

In a chemical change, energy is produced (heat, light, sound, etc.)

7

Absorption of Energy

Physical change involves very little to no absorption of energy.

During chemical reaction, absorption and evolution of energy takes place.

8

Affects

Physical change affects only physical properties i.e. shape, size, etc.

Chemical change both physical and chemical properties of the substance including its composition.

Answer 2

Answer:

Physical changes:-

• This is a reversible change.
• This change is the change in the shape or size of a matter.
• The actual composition remains same.
• It is the change in the physical properties.

Chemical Changes:-

• This is an irreversible Change.
• This is the change in colour, odour , lusture or temperature.
• The actual composition doesn't remains constant.
• It is the change in chemical properties.