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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 changes involved in the following process as physical or chemical changes:
Photosynthesis
Tick the most appropriate answer.
4. Chemical changes involve
- change in shape.
- change in size.
- change in molecular composition.
- none of these
State whether the following is physical or chemical changes.
growing of a piglet into a pig —
Write true or false
Burning of sugar is a temporary change.
State what is meant by the term – interconversion of matter. Is interconversion of matter a physical change or a chemical change.
Compare the energy changes involved during a physical and a chemical change.
When a woolen yarn is knitted to get a sweater, the change can be classified as ____________.
Water is known as a universal solvent. Why?
Paheli’s mother made a concentrated sugar syrup by dissolving sugar in hot water. On cooling, crystals of sugar got separated. This indicates a –
Give an example to justify the statement that physical changes can be reversible as well as irreversible.
