Question

write down three difference between physical and chemical change with example

Answer 1

The three differences between chemical and physical change are as follows:-

CHEMICAL CHANGE -
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1- In this change a new substance is formed with different molecules.

2- It's molecular structure changes.

3- It is a irreversible change.


PHYSICAL CHANGE -
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1- In this change a no new substance is formed without different molecules.

2- It's molecular structure doesn't changes.

3- It is a reversible change.

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Answer 2

Answer:

Physical Change Chemical Change

When a substance undergoes a physical change, its composition remains the same despite its molecules being rearranged. When a substance undergoes a chemical change, its molecular composition is changed entirely. Thus, chemical changes involve the formation of new substances.

Physical change is a temporary change. A chemical change is a permanent change.

A Physical change affects only physical properties i.e. shape, size, etc. Chemical change both physical and chemical properties of the substance including its composition

A physical change involves very little to no absorption of energy. During a chemical reaction, absorption and evolution of energy take place.

Some examples 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.

Generally, physical changes do not involve the production of energy. Chemical changes usually involve the production of energy (which can be in the form of heat, light, sound, etc.)

In a physical change, no new substance is formed. A chemical change is always accompanied by one or more new substance(s).

Physical change is easily reversible i.e original substance can be recovered. Chemical changes are irreversible i.e. original substance cannot be recovered.