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प्रश्न
What will you take into account while identifying the following?
A physical change in a substance.
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उत्तर
Physical changes are those changes in which only the forms of substances get modified; the chemical natures and compositions of the substances involved are not altered.
Characteristics:
- No new substance is formed during a physical change.
- Most physical changes can be reversed easily.
- The chemical composition of a substance undergoing physical change remains the same.
संबंधित प्रश्न
Tick the most appropriate answer.
3. Physical changes are
- permanent.
- periodic,
- temporary
- irreversible.
Fill in the blank.
A new substance is formed in a ............... change.
Write true or false
Earthquake is a desirable change.
Classify the following as a physical or a chemical change.
Boiling of water
Classify the following as a physical or a chemical change.
Burning of coal
Give three reasons why melting of wax, is considered a physical change while burning of a candle, a chemical change.
Ammonium chloride is also a sublimable solid. Give a reason why the sublimation of ammonium chloride involves a physical and a chemical change.
Match the examples of changes in List I with the correct.
| List I | List II |
| 1. Expansion of a steel rod on heating | A: Physical change |
| 2. Rotting of eggs | B: Chemical change |
| 3. Milk turning sour | |
| 4. Tarnishing of copper | |
| 5. Separation of naphthalene from a mixture of naphthalene and sodium chloride. |
Gas exists in three states as solid, liquid, and gas.
______ is the Universal Solvent.
