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प्रश्न
What do you observe when :
lighted match stick is brought near the mouth of the test tube containing hydrogen gas.
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उत्तर
We observe that hydrogen bums at the mouth of test tube with blue flame and pop sound is heard. It is chemical change.
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संबंधित प्रश्न
Classify the following as chemical or physical change:
Boiling of water to form steam.
Name a chemical change which takes place in presence of:
State whether the following is physical or chemical changes.
shaping a piece of glass —
Differentiate between a physical change and a chemical change with reference to – Energy change taking place during the respective change.
Name the following:
The final product of the physical change involved during the ‘melting of a piece of wax’.
Compare the energy changes involved during a physical and a 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
Breaking of glass
State which of the following 1 to 5 pertain to – A: Physical Change B: Chemical change :
- Sublimation.
- Fermentation.
- Liquefaction or condensation.
- Magnetization.
- Respiration.
Assertion: Burning of wood log to charcoal is a physical change.
Reason: The products formed of burning a piece of wood can be easily converted back to wood log.
