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प्रश्न
Given reason:
Freezing of water to ice and evaporation of water are physical changes.
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उत्तर
Freezing of water to ice and evaporation of water are physical change because water can be brought back to its original (liquid) form by
- We can heat the ice to bring it back to water.
- We can cool down the vapours to bring it back to water.
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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
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 |
State the various conditions that favour the process of evaporation.
Classify the following as a physical or a chemical change.
Drying of wet clothes
Give a reason why – Heating a platinum wire is a reversible change but, heating a magnesium wire is an irreversible change.
Stretching gold coin into a ring is a ______ change.
______ is the Universal Solvent.
Ice, water and water vapour look different and display different ______ properties but they are ______ the same.
Paheli’s mother made a concentrated sugar syrup by dissolving sugar in hot water. On cooling, crystals of sugar got separated. This indicates a –
The change of state of a substance from solid to liquid and liquid to gas is ______.
