Question

what are the two types of changes . explain them​

Answer 1

There are two types of change in matter: physical change and chemical change. As the names suggest, physical changes never change the identity of the matter, only its size, shape or state.

Answer 2

★ Physical Change :

༺ A substance is said to undergo a physical change when only the physical properties such as the shape, size, colour, state or appearance of the substance change. Its chemical composition remains intact. Some characteristics of a physical change are:

• Temporary in nature.
• Does not affect the internal structure of a substance, only the molecules are rearranged.
• No new substance is formed.
• Most of the physical changes are reversible. We can obtain the substance back even after the change.

★ Chemical Change :

༺ A substance is said to undergo a chemical change when the chemical properties of a substance alter. As a result, there is either formation or breaking of atomic bonds at the molecular level. Some characteristics of a chemical change are:

• Permanent in nature.
• Since the original composition of the substance changes, one or more new substances are formed.
• Forms of energy, such as heat, light or electricity, may be emitted or absorbed.
• A chemical change is generally irreversible. At least, it cannot be reversed by simple physical means.

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