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प्रश्न
Write true or false
Cutting of paper into pieces is a chemical change.
विकल्प
True
False
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उत्तर
False
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संबंधित प्रश्न
Write short answer.
Name two reversible changes.
Write short answer.
Give an example of desirable change which can also be undesirable
Solve this crossword by using the clues that follow.
Across
1. Energy in the form of sunlight is absorbed by the green plants in this process.
4. The reddish-brown substance formed over iron in the presence of oxygen and moisture.
5. This change is permanent and irreversible.
6. The process in which a solid directly changes into gaseous state.
Down
1. It is the change that takes place in case of swinging pendulum of a clock.
2. Occurrence of this is a non-periodic change as well as a natural change.
3. It is a physical change
Photosynthesis cannot take place at night.
Fill in the blank.
The process of a liquid changing into a solid is called ________
Distinguish between the following.
Physical change and chemical 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.
Select the chemical changes from the following list of changes
Change of seasons
State which of the following 1 to 5 pertain to – A: Physical Change B: Chemical change :
- Sublimation.
- Fermentation.
- Liquefaction or condensation.
- Magnetization.
- Respiration.
Tearing of sheet of paper into pieces is ______ By the process of Heating of water, change.
