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प्रश्न
Give one example of change which occurs on heating but cannot be reversed.
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उत्तर
Baking chapati is an irreversible change.
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संबंधित प्रश्न
A stretched rubber band comes back to normal shape. It is an example for ________.
Burning of match stick is a reversible change.
Evaporation of water is a reversible change.
Analogy:
Irreversible change: Making idly front batter.
Reversible change: ______.
While lighting a candle, Paheli observed the following changes.
- Wax was melting
- Candle was burning
- Size of the candle was reducing
- Melted wax was getting solidified.
Of the above, the changes that can be reversed are
Rolling of chapati and baking of chapati are the changes that ______.
Paheli had bought a new bottle of pickle from the market. She tried to open the metal cap to taste it but could not do so. She then took a bowl of hot water and immersed the upper end of the bottle in it for five minutes. She could easily open the bottle now. Can you give the reason for this?
Boojho’s sister broke a white dove, a symbol of peace, made of Plaster of Paris (POP). Boojho tried to reconstruct the toy by making a powder of the broken pieces and then making a paste by mixing water. Will he be successful in his effort? Justify your answer.
Give one example of change which occurs on mixing two substances, but cannot be reversed.
Paheli mixed flour and water and
- made a dough,
- rolled the dough to make a chapati,
- baked the chapati on a pan,
- dried the chapati and ground it in a grinder to make powder.
Identify the changes (i) to (iv) as the changes that can be reversed or that cannot be reversed.
