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प्रश्न
Write true or false
Burning of paper and formation of curd are reversible changes.
विकल्प
True
False
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उत्तर
False.
Burning of paper and formation of curd are irreversible changes.
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संबंधित प्रश्न
Classify the following as chemical or physical change:
Passing of electric current through water, and water breaking down into hydrogen and oxygen gases.
Fill in the blank.
Heat is .................... by a gas during the process of condensation.
Write short answer.
Give an example of desirable change which can also be undesirable
True or false
Change of seasons is a non-periodic change.
Name the following:
The term involved in the change of state from – ‘water to ice’ – which is a physical change.
State which of the following pertain to – chemical changes.
- Substance retains its identity.
- The change is permanent.
- No new substance is formed.
- Is easily reversible.
- Produces one or more new substances by a change in its composition.
- The change is temporary.
- The composition and properties of the original substance are not altered.
Give a reason why – Heating a platinum wire is a reversible change but, heating a magnesium wire is an irreversible change.
You are given some candle wax. Can you make a candle doll from it? What kind of change is this?
Stretching gold coin into a ring is a ______ change.
If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.
Do you think rust is different from iron?
