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प्रश्न
Given reason:
Burning of paper is a chemical change.
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उत्तर
When a piece of paper is burnt a new substance ash is produced. Even when the burning is stopped, the ash cannot be changed back into paper. This shows that the formation of the ash from paper is a permanent and irreversible change.
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संबंधित प्रश्न
Fill in the blank.
Heat is .................... by a gas during the process of condensation.
Match the columns
| column A | coulmn B |
| 1. A change which cannot be easily reversed | a. man-made change |
| 2.A change that repeats itself at regular intervals | b. chemical change |
| 3. A change that is made by humans | c. physical change |
|
4. A change in which the original substance cannot be obtained |
d. periodic change |
| 5. A change where no new substance is formade | e. irreversible change |
| f. slow 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)
State whether the following is physical or chemical changes.
photosynthesis —
Write true or false
Earthquake is a desirable change.
Classify the following as physical or chemical change :
Formation of curd from milk
Name the following.
The salt obtained when a chemical change takes place on the addition of iron to dilute sulphuric acid.
The change of state of a substance from solid to liquid and liquid to gas is ______.
Adding sugar to milk is a physical change.
