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प्रश्न
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. |
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उत्तर
| 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 | B: Chemical change |
| 4. Tarnishing of copper | B: Chemical change |
| 5. Separation of naphthalene from a mixture of naphthalene and sodium chloride. | A: Physical change |
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संबंधित प्रश्न
A burning candle shows both physical and chemical changes. Explain ?
Solve this crossword by using the clues that follow-
Across
1. Energy in the form of sunlight is absorbed by the green plants in this process.
4. The reddish-brown substance formed over iron in the presence of oxygen and moisture.
5. This change is permanent and irreversible.
6. The process in which a solid directly changes into gaseous state.
Down
1 . It is the change that takes place in case of swinging pendulum of a clock. –
2. Occurrence of this is a non-periodic change as well as a natural change.
3. It is a physical change.
Change is the law of nature and occurs in our everyday life, at all times and in all places.
Differentiate between the following change with a suitable example.
Periodic and non-periodic change
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Differentiate between the following change with a suitable example.
Slow and fast change.
Fill in the blank with the correct word of the statement given below:
Sublimation involves a __________ change.
Give a reason why – Heating a platinum wire is a reversible change but, heating a magnesium wire is an irreversible change.
Give the reason why the following is considered as chemical changes.
A piece of magnesium strip is dropped into a beaker containing dilute hydrochloric acid.
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 |
Name the following.
The salt obtained when a chemical change takes place on the addition of iron to dilute sulphuric acid.
Classify the following as physical or chemical properties
Metallic sodium is soft enough to be cut with a knife.
