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प्रश्न
What are reversible and irreversible changes ? Give one example for each.
Change is the law of nature and occur in our everyday life, at all times and in all places.
Differentiate between the following change with a suitable example.
Reversible and irreversible change.
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उत्तर
- Reversible change : When a change in a substance can be reversed by changing the conditions, it is said to be a reversible change.
Example : Melting of ghee or wax. - Irreversible change : When a substance can not be brought back to its original state after a change, it is said to be an irreversible change.
Example : Souring of milk.
संबंधित प्रश्न
What do you observe when :
lighted match stick is brought near the mouth of the test tube containing hydrogen gas.
Write true or false
Rusting of iron is a chemical change.
Change is the law of nature and occurs in our everyday life, at all times and in all places.
Differentiate between the following change with a suitable example.
Periodic and non-periodic change
Give a reason why
Change of seasons is a periodic change while the change of weather is a non-periodic 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 the reason why the following is considered as chemical changes.
A piece of magnesium strip is dropped into a beaker containing dilute hydrochloric acid.
______ is the Universal Solvent.
Two drops of dilute sulphuric acid were added to 1 g of copper sulphate powder and then small amount of hot water was added to dissolve it (step I). On cooling, beautiful blue coloured crystals got separated (step II). Step I and Step II are:
Keeping a stone in sunlight for few hours is ______.
Iron pipes coated with zinc do not get rusted easily.
