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प्रश्न
Select the chemical changes from the following list of changes
The occurrence of lightning.
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उत्तर
Occurance of lightening is a CHEMICAL change, energy is produced, a new substance with new properties is produced.
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संबंधित प्रश्न
Tick the most appropriate answer.
4. Chemical changes involve
- change in shape.
- change in size.
- change in molecular composition.
- none of these
State the differences between a physical change and a chemical change.
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
Which of the following are chemical changes ?
- decaying of wood
- burning of wood
- sawing of wood
- hammering of nail into wood
Classify the Following as a Physical Or a Chemical Change.
Formation of Clouds
Fill in the blank.
There is no change in the _____________of the substance during a physical 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. |
Give the reason why the following is considered as chemical changes.
Copper carbonate on heat gives copper oxide and carbon dioxide.
Give the reason why the following is considered as chemical changes.
A bright light is seen evolved when a strip of magnesium is heated.
Wood to sawdust:______:: Wood to Ash: Chemical change
