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Question
A piece of iron is heated till it becomes red-hot. it then becomes soft and is beaten to a desired shape. What kind of changes are observed in this process-reversible or irreversible?
Solution
A piece of iron on heating can be beaten into desired shape. It is a reversible change because the object of desired shape can be again heated and beated to give the original shape.
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RELATED QUESTIONS
Very Short Answer Type Question:
Give two examples of irreversible changes.
Very Short Answer Type Question:
Some common changes are given in the below Table. Which of these changes do you think can be reversed?
Change | Can be reversed |
(i) Raw egg to boiled egg | Yes/No |
(ii) Batter to idli | |
(iii) Wet clothes to dirty clothes | |
(iv) Woollen yarn to knitted sweater | |
(v) Grain to its flour | |
(vi) Cold milk to hot milk | |
(vii) straight string to a cold string | |
(viii) Bud to flower | |
(ix) Milk to paneer | |
(x) Cow dung to biogas | |
(xi) stretched rubber band to its normal size | |
(xii) Melting of ice-cream |
Chemical reactions are example for
Differentiate reversible and irreversible changes.
Choose the odd one out. Give reason for your choice.
Changes which cannot be reversed are called ______.
Name the two types of changes.
Which of the following changes cannot be reversed?
- Blowing of a balloon
- Folding paper to make a toy aeroplane
- Rolling a ball of dough to make roti
- Baking cake in an oven
- Drying a wet cloth
- Making biogas from cow dung
- Burning of a candle
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.
Choose the odd one out. Give a reason for your choice.