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प्रश्न
Chemical changes are accompanied by changes in energy.
उत्तर
In a chemical change, molecules and atoms rearrange themselves to form new substances. This rearrangement involves some energy changes. It can either be absorption or evolution of energy.
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संबंधित प्रश्न
Fill in the blank
Burning of fuel is a _______ change.
State whether the following is physical or chemical changes.
burning of wood -
Tick (√) the correct alternative from the choice given for the following statement
When sugar is heated, its colour changes into
Distinguish between the following.
Periodic change and non-periodic change
Fill in the blanks with the appropriate words of the statement given below:
Chemical changes may involve exchange of energy in the form of __________ and _________.
How can a change occur in a substance?
Picture based question
Observe the picture and list down the changes that are accompanied in the picture.
- ______.
- ______.
- ______.
Some changes are listed in the following table. For each change, write in the blank column, whether the change can be reversed or not.
| S. No. | Change | Can be reversed (Yes/No) |
| 1. | The sawing of a piece of wood | |
| 2. | The melting of ice candy | |
| 3. | Dissolving sugar in water | |
| 4. | The cooking of food | |
| 5. | The ripening of a mango | |
| 6. | Souring of milk |
Paper, LPG, CNG petrol, etc, are ______ substances.
______ is the process in which something becomes different from what it was earlier.
