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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.
APPEARS IN
संबंधित प्रश्न
Explain why burning of wood and cutting it into small piece are considered as two different types of changes.
Write short answer.
Give two examples of periodic changes
State whether the following is physical or chemical change.
Digestion of food —
What will you take into account while identifying the following?
A chemical change in a substance.
Give a reason why
Change of seasons is a periodic change while the change of weather is a non-periodic change.
Potassium chloride is added to water and stirred. A salt solution is obtained, which is then boiled, leaving behind a residue.
- Is the above change physical or chemical?
- Name the residue which remains behind after the salt solution is boiled.
- Is the change reversible or not reversible?
- Are the composition and properties of the original substance altered?
- Give a reason why the above experimentation would not be possible if calcium carbonate was taken in place of potassium chloride.
State which of the following 1 to 5 pertain to – A: Physical Change B: Chemical change :
- Sublimation.
- Fermentation.
- Liquefaction or condensation.
- Magnetization.
- Respiration.
Match the following
| Sr. No. | A | B | C |
| 1. | Melting | Change of state from liquid to solid | Ticking of clock |
| 2. | Condensation | Change of state from liquid to gas | Formation of ice cube |
| 3. | Evaporation | Change of state from solid to liquid | Collecting flowers |
| 4. | Freezing | Change of state from gas to liquid | Ice cube to water |
| 5. | Periodic change | Occurs at irregular time intervals | Water to steam |
| 6. | Non-periodic change | Occurs at regular time intervals | Steam to water drops |
______ is the substance that is dissolved in a solvent.
Give an example of a physical change in which the color of the substance changes.
