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प्रश्न
Write true or false
A natural change can also be a desirable change.
विकल्प
True
False
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उत्तर
True
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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
Fill in the blank.
When a candle burns, wax melts. Melting of wax is a ________ change.
Match the columns.
| Column A | Column B |
| 1. a change which cannot be easily reversed | a. man-made change |
| 2 a change that repeats itself at regular intervals | b. chemical chang |
| 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 formed | e. irreversible change |
| f . slow change |
Fill in the blank.
The reaction in which energy is evolved is called
State why addition of sodium chloride to water is considered a physical change, while addition of dilute sulphuric acid to zinc is considered a chemical change.
State whether the following statement is true or false. If false write the correct statement.
Melting of ice is an exothermic, irreversible chemical change.
Select the chemical changes from the following list of changes
The carbon cycle.
A change in which matter undergoes a change but the total mass of the substance is unaltered is a ______ change.
What type of energy changes is associated when ice melts?
Paheli’s mother made a concentrated sugar syrup by dissolving sugar in hot water. On cooling, crystals of sugar got separated. This indicates a –
