GK
CHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Chemicals are used
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Molecules do not physically touch
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A new substance is formed and in physical change no new substance is formed
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The change can be seen but in physical change it cannot.
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Detailed explanation-1: -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.
Detailed explanation-2: -In a physical change the appearance or form of the matter changes but the kind of matter in the substance does not. However in a chemical change, the kind of matter changes and at least one new substance with new properties is formed.
Detailed explanation-3: -A change in which a substance undergoes a change in its physical properties is called a physical change. A physical change is generally reversible. In such a change no new substance is formed.
Detailed explanation-4: -Statement 2: New substances are formed during chemical changes. Q. Matter undergoes a change. The changes are of two types : Physical and chemical change.
Detailed explanation-5: -Therefore, a change in which no new substance is formed is known as physical change.