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प्रश्न
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?
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उत्तर
Yes, rust is different from iron. It is a brown powder of iron oxide.
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संबंधित प्रश्न
Tick (√) the correct alternative from the choice given for the following statement.
The compound rust is a hydrated oxide of
Tick the most appropriate answer.
Physical changes are
Which of the following are physical changes and which are chemical changes?
Burning of candle wax, Melting of candle wax, Mixing of iron filings and sand, Burning of wood, Breaking a piece of chalk, Burning a piece of paper, Cutting a piece of paper.
Which of the following are chemical changes ?
- decaying of wood
- burning of wood
- sawing of wood
- hammering of nail into wood
Select the chemical changes from the following list of changes
The crystallisation of salt from its solution.
Filling up a balloon with hot air is a _______ change.
Water is known as a universal solvent. Why?
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 ______.
Mention some of the different conditions needed for chemical changes to occur.
