Question

state the points which show that a physical change in different from a chemical change​

Answer 1

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

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Answer 2

Answer:

There are many differences between physical and chemical changes and it is important to understand them to be able to understand these concepts clearly. The comparisons and differences between physical and chemical changes are given below along with their examples. To understand physical and chemical properties and changes better, it is important to know what they are. Visit physical and chemical changes to know more about them in detail. In this article, the differences between physical changes and chemical changes are provided in a tabular format.

Explanation:

Differences Between Physical and Chemical Change:

Physical Change:

1. When a substance undergoes a physical change, its composition remains the same despite its molecules being rearranged.
2. Physical change is a temporary change.
3. A Physical change affects only physical properties i.e. shape, size, etc.
4. A physical change involves very little to no absorption of energy.
5. Some examples of physical change are freezing of water, melting of wax, boiling of water, etc.
6. Generally, physical changes do not involve the production of energy.
7. In a physical change, no new substance is formed.
8. Physical change is easily reversible i.e original substance can be recovered.

Chemical Change:

1. When a substance undergoes a chemical change, its molecular composition is changed entirely. Thus, chemical changes involve the formation of new substances.
2. A chemical change is a permanent change.
3. Chemical change both physical and chemical properties of the substance including its composition.
4. During a chemical reaction, absorption and evolution of energy take place.
5. A few examples of chemical change are digestion of food, burning of coal, rusting, etc.
6. Chemical changes usually involve the production of energy (which can be in the form of heat, light, sound, etc.)
7. A chemical change is always accompanied by one or more new substance(s).
8. Chemical changes are irreversible i.e. original substance cannot be recovered.

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