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प्रश्न
Given reason:
Cutting of a cloth piece is a physical change, though it cannot be reversed.
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उत्तर
Because it does not change chemical composition of cloth and the change is only in the state, size, shape, colour, texture or the smell of some or all of the substances that undergo physical change.
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संबंधित प्रश्न
Write true or false for the statement
Decomposition of leaves is a fast change.
Write short answer.
Give an example of desirable change which can also be undesirable
Classify the following changes as physical or chemical:- melting of a solid (wax)
Which of the following are physical changes and which are chemical changes ?
Freezing of water
Is a change of state of matter – a physical or a chemical change. Give reasons.
Potassium chloride is added to water and stirred. A salt solution is obtained, which is then boiled, leaving behind a residue.
- Is the above change physical or chemical?
- Name the residue which remains behind after the salt solution is boiled.
- Is the change reversible or not reversible?
- Are the composition and properties of the original substance altered?
- Give a reason why the above experimentation would not be possible if calcium carbonate was taken in place of potassium chloride.
Select the chemical changes from the following list of changes
Rotting of eggs.
Give the reason why the following is considered as chemical changes.
An iron nail kept open in the atmosphere rusts.
Match the examples of changes in List I with the correct type of change in List II.
| List I | List II |
| 1. Burning of paper | A: Physical change |
| 2. The ringing of an electric bell | B: Chemical change |
| 3. Curdling of milk | |
| 4. Electric light is switched on | |
| 5. Melting of butter |
Mention a few physical properties of a substance.
